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Ferraz Lobato L, Ciattini S, Gallo A, Allão Cassaro RA, Sorace L, Poneti G. Thermodynamics of spin crossover in a bis(terpyridine) cobalt(II) complex featuring a thioether functionality. Dalton Trans 2024. [PMID: 38808660 DOI: 10.1039/d4dt00574k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
In this contribution, a terpyridine-based ligand bearing a thioether functionality is used to prepare a new cobalt(II) spin crossover complex: [Co(TerpyPhSMe)2](PF6)2 (1), where TerpyPhSMe is 4'-(4-methylthiophenyl)-2,2':6',2''-terpyridine. Its structure, determined by single crystal X-ray diffraction, reveals a mer coordination of the tridentate terpyridine ligands, leading to a tetragonally compressed octahedron. Intermolecular interactions in the crystal lattice freeze the complex in the high spin state in the solid state at all temperatures, as indicated by magnetometry and Electron Paramagnetic Resonance (EPR) spectra. When dissolved in acetonitrile, however, temperature dependent electronic, 1H-NMR and EPR spectra highlight an entropy-driven spin crossover transition, whose thermodynamics parameters have been determined. This is the first report of a cobalt(II) SCO complex featuring a thioether group, allowing its implementation in chemically grown bistable monolayers and may open important perspectives for the use of such systems in molecular spintronics.
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Affiliation(s)
- Lúcio Ferraz Lobato
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Samuele Ciattini
- Interdepartmental Center for Crystallography (CRIST), University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Angelo Gallo
- Department of Chemistry, University of Turin, Via Pietro Giuria 7, 10125 Torino, Italy
| | - Rafael A Allão Cassaro
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Lorenzo Sorace
- Department of Chemistry "U. Schiff" and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy.
| | - Giordano Poneti
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-909, Brazil
- Dipartimento di Scienze Ecologiche e Biologiche, Università degli Studi della Tuscia, Largo dell'Università, 01100, Viterbo, Italy.
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2
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Koucký F, Dobrovolná T, Kotek J, Císařová I, Havlíčková J, Liška A, Kubíček V, Hermann P. Transition metal complexes of the (2,2,2-trifluoroethyl)phosphinate NOTA analogue as potential contrast agents for 19F magnetic resonance imaging. Dalton Trans 2024. [PMID: 38596878 DOI: 10.1039/d4dt00507d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
A new hexadentate 1,4,7-triazacyclononane-based ligand bearing three coordinating methylene-(2,2,2-trifluoroethyl)phosphinate pendant arms was synthesized and its coordination behaviour towards selected divalent (Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) and trivalent (Cr3+, Fe3+, Co3+) transition metal ions was studied. The ligand forms stable complexes with late divalent transition metal ions (from Co2+ to Zn2+) and the complexes of these metal ions are formed above pH ∼3. A number of complexes with divalent metal ions were structurally characterized by means of single-crystal X-ray diffraction. The complex of the larger Mn2+ ion adopts a twisted trigonally antiprismatic geometry with a larger coordination cavity and smaller torsion of the pendant arms, whereas the smaller ions Ni2+, Cu2+ and Zn2+ form octahedral species with a smaller cavity and larger pendant arm torsion. In the case of the Co2+ complexes, both coordination arrangements were observed. The complexes with paramagnetic metal ions were studied from the point of view of potential utilization in 19F magnetic resonance imaging. A significant shortening of the 19F NMR longitudinal relaxation times was observed: a sub-millisecond range for complexes of Cr3+, Mn2+ and Fe3+ with symmetric electronic states (t2g3 and HS-d5), the millisecond range for the Ni2+ and Cu2+ complexes and tens of milliseconds for the Co2+ complex. Such short relaxation times are consistent with a short distance between the paramagnetic metal ion and the fluorine atoms (∼5.5-6.5 Å). Among the redox-active complexes (Mn3+/Mn2+, Fe3+/Fe2+, Co3+/Co2+, Cu2+/Cu+), the cobalt complexes show sufficient stability and a paramagnetic-diamagnetic changeover with the redox potential lying in a physiologically relevant range. Thus, the Co3+/Co2+ complex pair can be potentially used as a smart redox-responsive contrast agent for 19F MRI.
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Affiliation(s)
- Filip Koucký
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Tereza Dobrovolná
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Jan Kotek
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Jana Havlíčková
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Alan Liška
- Department of Molecular Electrochemistry and Catalysis, J. Heyrovský Institute of Physical Chemistry AS CR, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic
| | - Vojtěch Kubíček
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 42 Prague 2, Czech Republic.
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3
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Gou X, Wu Y, Wang M, Liu N, Lan W, Zhang YQ, Shi W, Cheng P. The influence of light on the field-induced magnetization dynamics of two Er(III) coordination polymers with different halogen substituents. Dalton Trans 2023; 53:148-152. [PMID: 38018387 DOI: 10.1039/d3dt02714g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Photocontrolled magnetic properties are fundamental for the applications of molecular magnets, which have the features of high time and space resolution; however, such magnetic properties are highly challenging to be achieved owing to the weak light-matter interactions. Herein, the influence of in situ light irradiation on the field-induced magnetization dynamics of two Er(III) coordination polymers 1 and 2 with the same coordination skeletons but different halogen substituents was studied. 1 and 2, and their in situ photoexcited products 1a and 2a, display field-induced magnetization dynamics based on Orbach and/or Raman processes. The magnetization dynamics are fine-modulated by the synergetic effect of light irradiation and a ligand substituent, due to the charge re-distribution of the excited states of the ligand.
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Affiliation(s)
- Xiaoshuang Gou
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Yuewei Wu
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Mengmeng Wang
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Ning Liu
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Wenlong Lan
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Yi-Quan Zhang
- School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Wei Shi
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
| | - Peng Cheng
- Department of Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
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4
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Bruns C, Ringleb R, Prediger I, Euchner F, Bernarding J, Plaumann M. Organic Fluorine Compounds and Their Uses as Molecular MR-Based Temperature Sensors. Chemphyschem 2023; 24:e202300512. [PMID: 37632422 DOI: 10.1002/cphc.202300512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/25/2023] [Accepted: 08/25/2023] [Indexed: 08/28/2023]
Abstract
The interest in fluorinated substances has increased significantly in recent decades due to their diverse properties and possible uses. An important analytical method in this context is NMR spectroscopy, which provides information on the structure as well as on intermolecular interactions or generally on changes in the environment of the nucleus under consideration. A physical quantity that is of great importance in most studies is temperature. However, this is not always easy, e. g. in shielded systems or within an organism. However, the application potential in chemical reactors or in medical diagnosis and therapy is very high and for this reason 13 fluorinated organic compound were chosen for a first 19 F NMR signal temperature sensitivity examination for determination of local temperatures in solution. Polyfluorinated molecules with separate 19 F MR signals are particularly suitable for temperature determination. Those can be serve as internal error-correcting thermometers without the need of a reference substance. Under these conditions, a 19 F MR signal shift of up to 0.03 ppm/K was detectable. Fluorine position and chemical environment were very important for the temperature sensitivity.
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Affiliation(s)
- Christian Bruns
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Rainer Ringleb
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Isabell Prediger
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Frederike Euchner
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Johannes Bernarding
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Markus Plaumann
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
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5
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Nakanishi K, Lugo-Fuentes LI, Manabe J, Guo R, Kikkawa S, Yamazoe S, Komaguchi K, Kume S, Szczepanik DW, Solà M, Jimenez-Halla JOC, Nishihara S, Kubo K, Nakamoto M, Yamamoto Y, Mizuta T, Shang R. Redox Activity of Ir III Complexes with Multidentate Ligands Based on Dipyrido-Annulated N-Heterocyclic Carbenes: Access to High Valent and High Spin State with Carbon Donors. Chemistry 2023; 29:e202302303. [PMID: 37553318 DOI: 10.1002/chem.202302303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/10/2023]
Abstract
Synthetic strategies to access high-valent iridium complexes usually require use of π donating ligands bearing electronegative atoms (e. g. amide or oxide) or σ donating electropositive atoms (e. g. boryl or hydride). Besides the η5 -(methyl)cyclopentadienyl derivatives, high-valent η1 carbon-ligated iridium complexes are challenging to synthesize. To meet this challenge, this work reports the oxidation behavior of an all-carbon-ligated anionic bis(CCC-pincer) IrIII complex. Being both σ and π donating, the diaryl dipyrido-annulated N-heterocyclic carbene (dpa-NHC) IrIII complex allowed a stepwise 4e- oxidation sequence. The first 2e- oxidation led to an oxidative coupling of two adjacent aryl groups, resulting in formation of a cationic chiral IrIII complex bearing a CCCC-tetradentate ligand. A further 2e- oxidation allowed isolation of a high-valent tricationic complex with a triplet ground state. These results close a synthetic gap for carbon-ligated iridium complexes and demonstrate the electronic tuning potential of organic π ligands for unusual electronic properties.
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Affiliation(s)
- Kazuki Nakanishi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Leonardo I Lugo-Fuentes
- Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, Campus Gto, Noria Alta s/n, 36050, Guanajuato, Mexico
| | - Jun Manabe
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Ronghao Guo
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Soichi Kikkawa
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan
| | - Seiji Yamazoe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan
| | - Kenji Komaguchi
- Department of Applied Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan
| | - Shoko Kume
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Dariusz W Szczepanik
- K. Guminski Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa, 2, 30-387, Kraków, Poland
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain
| | - J Oscar C Jimenez-Halla
- Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, Campus Gto, Noria Alta s/n, 36050, Guanajuato, Mexico
| | - Sadafumi Nishihara
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Kazuyuki Kubo
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Masaaki Nakamoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Yohsuke Yamamoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Tsutomu Mizuta
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Rong Shang
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
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6
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Mysegaes F, Spiteller P, Bernarding J, Plaumann M. 19 F VT NMR: Novel Tm 3+ and Ce 3+ Complexes Provide New Insight into Temperature Measurement Using Molecular Sensors. Chemphyschem 2023; 24:e202300057. [PMID: 37384817 DOI: 10.1002/cphc.202300057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
In the past few decades, magnetic resonance spectroscopy (MRS) and MR imaging (MRI) have developed into a powerful non-invasive tool for medical diagnostic and therapy. Especially 19 F MR shows promising potential because of the properties of the fluorine atom and the negligible background signals in the MR spectra. The detection of temperature in a living organism is quite difficult, and usually external thermometers or fibers are used. Temperature determination via MRS needs temperature-sensitive contrast agents. This article reports first results of solvent and structural influences on the temperature sensitivity of 19 F NMR signals of chosen molecules. By using this chemical shift sensitivity, a local temperature can be determined with a high precision. Based on this preliminary study, we synthesized five metal complexes and compared the results of all variable temperature measurements. It is shown that the highest 19 F MR signal temperature dependence is detectable for a fluorine nucleus in a Tm3+ -complex.
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Affiliation(s)
- Felix Mysegaes
- University Bremen, Instrumental Analytics, Leobener Str. 7, 28359, Bremen, Germany
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Peter Spiteller
- University Bremen, Instrumental Analytics, Leobener Str. 7, 28359, Bremen, Germany
| | - Johannes Bernarding
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Markus Plaumann
- Otto-von-Guericke University Magdeburg, Medical Faculty, Institute of Biometry and Medical Informatics, Leipziger Str. 44, 39120, Magdeburg, Germany
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7
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Kadakia RT, Ryan RT, Cooke DJ, Que EL. An Fe complex for 19F magnetic resonance-based reversible redox sensing and multicolor imaging. Chem Sci 2023; 14:5099-5105. [PMID: 37206407 PMCID: PMC10189869 DOI: 10.1039/d2sc05222a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 04/14/2023] [Indexed: 05/21/2023] Open
Abstract
We report a first-in-class responsive, pentafluorosulfanyl (-SF5)-tagged 19F MRI agent capable of reversibly detecting reducing environments via an FeII/III redox couple. In the FeIII form, the agent displays no 19F MR signal due to paramagnetic relaxation enhancement-induced signal broadening; however, upon rapid reduction to FeII with one equivalent of cysteine, the agent displays a robust 19F signal. Successive oxidation and reduction studies validate the reversibility of the agent. The -SF5 tag in this agent enables 'multicolor imaging' in conjunction with sensors containing alternative fluorinated tags and this was demonstrated via simultaneous monitoring of the 19F MR signal of this -SF5 agent and a hypoxia-responsive agent containing a -CF3 group.
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Affiliation(s)
- Rahul T Kadakia
- Department of Chemistry, University of Texas at Austin 105 E 24th St. Stop A5300 Austin TX 78712 USA
| | - Raphael T Ryan
- Department of Chemistry, University of Texas at Austin 105 E 24th St. Stop A5300 Austin TX 78712 USA
| | - Daniel J Cooke
- Department of Chemistry, University of Texas at Austin 105 E 24th St. Stop A5300 Austin TX 78712 USA
| | - Emily L Que
- Department of Chemistry, University of Texas at Austin 105 E 24th St. Stop A5300 Austin TX 78712 USA
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8
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Li J, Mundhenke TF, Smith TG, Arnold WA, Pomerantz WCK. Fluorous Liquids for Magnetic Resonance-Based Thermometry with Enhanced Responsiveness and Environmental Degradation. Anal Chem 2023; 95:6071-6079. [PMID: 37000984 DOI: 10.1021/acs.analchem.3c00172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Accurate temperature measurement via magnetic resonance is valuable for both in vitro and in vivo analysis of local tissue for evaluating disease pathology and medical interventions. 1H MRI-based thermometry is used clinically but is susceptible to error from magnetic field drift and low sensitivity in fatty tissue and requires a reference for absolute temperature determination. As an alternative, perfluorotributylamine (PFTBA), a perfluorocarbon liquid for 19F MRI thermometry, is based on chemical shift responsiveness and approaches the sensitivity of 1H MRI thermometry agents; however, environmental persistence, greenhouse gas concerns, and multiple resonances which can lead to MRI artifacts indicate a need for alternative sensors. Using a 19F NMR-based structure-property study of synthetic organofluorine molecules, this research develops new organofluorine liquids with improved temperature responsiveness, high signal, and reduced nonmagnetically equivalent fluorine resonances. Environmental degradation analysis using reverse-phase HPLC and quantitative 19F NMR demonstrates a rapid degradation profile mediated via the aryl fluorine core of temperature sensors. Our findings show that our lead liquid temperature sensor, DD-1, can be made in high yield in a single step and possesses an improved responsiveness over our prior work and an 83% increase in aqueous thermal responsiveness over PFTBA. Degradation studies indicate robust degradation with half-lives of less than two hours under photolysis conditions for the parent compound and formation of other fluorinated products. The improved performance of DD-1 and its susceptibility to environmental degradation highlight a new lead fluorous liquid for thermometry applications.
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9
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West CP, Morales AC, Ryan J, Misovich MV, Hettiyadura APS, Rivera-Adorno F, Tomlin JM, Darmody A, Linn BN, Lin P, Laskin A. Molecular investigation of the multi-phase photochemistry of Fe(III)-citrate in aqueous solution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:190-213. [PMID: 35634912 DOI: 10.1039/d1em00503k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Iron (Fe) is ubiquitous in nature and found as FeII or FeIII in minerals or as dissolved ions Fe2+ or Fe3+ in aqueous systems. The interactions of soluble Fe have important implications for fresh water and marine biogeochemical cycles, which have impacts on global terrestrial and atmospheric environments. Upon dissolution of FeIII into natural aquatic systems, organic carboxylic acids efficiently chelate FeIII to form [FeIII-carboxylate]2+ complexes that undergo a wide range of photochemistry-induced radical reactions. The chemical composition and photochemical transformations of these mixtures are largely unknown, making it challenging to estimate their environmental impact. To investigate the photochemical process of FeIII-carboxylates at the molecular level, we conduct a comprehensive experimental study employing UV-visible spectroscopy, liquid chromatography coupled to photodiode array and high-resolution mass spectrometry detection, and oil immersion flow microscopy. In this study, aqueous solutions of FeIII-citrate were photolyzed under 365 nm light in an experimental setup with an apparent quantum yield of (φ) ∼0.02, followed by chemical analyses of reacted mixtures withdrawn at increment time intervals of the experiment. The apparent photochemical reaction kinetics of Fe3+-citrates (aq) were expressed as two generalized consecutive reactions of with the experimental rate constants of j1 ∼ 0.12 min-1 and j2 ∼ 0.05 min-1, respectively. Molecular characterization results indicate that R and I consist of both water-soluble organic and Fe-organic species, while P compounds are a mixture of water-soluble and colloidal materials. The latter were identified as Fe-carbonaceous colloids formed at long photolysis times. The carbonaceous content of these colloids was identified as unsaturated organic species with low oxygen content and carbon with a reduced oxidation state, indicative of their plausible radical recombination mechanism under oxygen-deprived conditions typical for the extensively photolyzed mixtures. Based on the molecular characterization results, we discuss the comprehensive reaction mechanism of FeIII-citrate photochemistry and report on the formation of previously unexplored colloidal reaction products, which may contribute to atmospheric and terrestrial light-absorbing materials in aquatic environments.
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Affiliation(s)
- Christopher P West
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Ana C Morales
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Jackson Ryan
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Maria V Misovich
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | | | | | - Jay M Tomlin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Andrew Darmody
- Department of Aeronautics and Aerospace Engineering, Purdue University, West Lafayette, IN, USA
| | - Brittany N Linn
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Peng Lin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
- Department of Earth, Atmospheric & Planetary Sciences, Purdue University, West Lafayette, IN, USA
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10
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Resines-Urien E, Fernandez-Bartolome E, Martinez-Martinez A, Gamonal A, Piñeiro-López L, Costa JS. Vapochromic effect in switchable molecular-based spin crossover compounds. Chem Soc Rev 2023; 52:705-727. [PMID: 36484276 DOI: 10.1039/d2cs00790h] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Coordination complexes based on transition metal ions displaying [Ar]3d4-3d7 electronic configurations can undergo the likely most spectacular switchable phenomena found in molecular coordination chemistry, the well-known Spin Crossover (SCO). SCO phenomena is a detectable, reproducible and reversible switch that occurs between the high spin (HS) and low spin (LS) electronic states of the transition metal actuated by different stimuli (i.e. light, temperature, pressure, the presence of an analyte). Moreover, the occurrence of SCO phenomena causes different outputs, one of them being a colour change. Altogether, an analyte in gas form could be detected by naked eye once it has triggered the corresponding HS ↔ LS transition. This vapochromic effect could be used to detect volatile molecules using a low-cost technology, including harmful chemical substances, gases and/or volatile organic compounds (VOCs) that are present in our environment, in our home or at our workplace. The present review condenses all reported iron coordination compounds where the colour change induced by a given molecule in its gas form is coupled to a HS ↔ LS spin transition. Special emphasis has been made on describing the nature of the post-synthetic modification (PSM) taking place in the material upon the analyte uptake. In this case, three types of PSM can be distinguished: based on supramolecular contacts and/or leading to a coordinative or covalent bond. In the latter, a colour change not only indicates the switch of the spin state in the material but also the formation of a new compound with different properties. It is important to indicate that some of the SCO coordination compounds discussed in the current report have been part of other spin crossover reviews, that have gathered thermally induced SCO compounds and the influence of guest molecules on the SCO behaviour. However, in the majority of examples in these reviews, the change of colour upon the uptake of analytes is not associated with a spin transition at room temperature. In addition, the observed colour variations have been mainly discussed in terms of host-guest interactions, when they can also be induced by a PSM taking place in different sites of the molecule, like the Fe(II) coordination sphere or by chemically altering its inorganic and/or organic linkers. Therefore, we present here for the first time an exhaustive compilation of all systems in which the interaction between the coordination compounds and the vapour analytes leads to a colour change due to a spin transition in the metal centre at room temperature.
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11
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Nikovskiy I, Aleshin DY, Novikov VV, Polezhaev AV, Khakina EA, Melnikova EK, Nelyubina YV. Selective Pathway toward Heteroleptic Spin-Crossover Iron(II) Complexes with Pyridine-Based N-Donor Ligands. Inorg Chem 2022; 61:20866-20877. [PMID: 36511893 DOI: 10.1021/acs.inorgchem.2c03270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A new synthetic pathway is devised to selectively produce previously elusive heteroleptic iron(II) complexes of terpyridine and N,N'-disubstituted bis(pyrazol-3-yl)pyridines that stabilize the opposite spin states of the metal ion. Such a combination of the ligands in a series of the heteroleptic complexes induces the spin-crossover (SCO) not experienced by the homoleptic complexes of these ligands or shifts it to lower/higher temperatures respective to the SCO-active homoleptic complex. The midpoint temperatures of the resulting SCO span from ca. 200 K to the ambient temperature and beyond the highest temperature accessible by NMR spectroscopy and SQUID magnetometry. The proposed "one-pot" approach is applicable to other N-donor ligands to selectively produce heteroleptic complexes─including those inaccessible by alternative synthetic pathways─with highly tunable SCO behaviors for practical applications in sensing, switching, and multifunctional devices.
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Affiliation(s)
- Igor Nikovskiy
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Dmitry Yu Aleshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Valentin V Novikov
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, 141700Dolgoprudny, Russia
| | - Alexander V Polezhaev
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Ekaterina A Khakina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,HSE University, Miasnitskaya Str., 20, 101000Moscow, Russia
| | - Elizaveta K Melnikova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Yulia V Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
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12
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Zalewski M, Janasik D, Wierzbicka A, Krawczyk T. Design Principles of Responsive Relaxometric 19F Contrast Agents: Evaluation from the Point of View of Relaxation Theory and Experimental Data. Inorg Chem 2022; 61:19524-19542. [DOI: 10.1021/acs.inorgchem.2c03451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mariusz Zalewski
- Department of Chemical Organic Technology and Petrochemistry, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100Gliwice, Poland
| | - Dawid Janasik
- Department of Chemical Organic Technology and Petrochemistry, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100Gliwice, Poland
| | - Adrianna Wierzbicka
- Department of Chemical Organic Technology and Petrochemistry, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100Gliwice, Poland
| | - Tomasz Krawczyk
- Department of Chemical Organic Technology and Petrochemistry, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100Gliwice, Poland
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13
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Zapolotsky EN, Babailov SP. NMR thermosensor properties of lanthanide complexes with diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid [Ln(H2O)(DTPA)]2− (Ln = Pr, Dy, Ho, Yb). Russ Chem Bull 2022. [DOI: 10.1007/s11172-022-3642-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Morrow JR, Raymond JJ, Chowdhury MSI, Sahoo PR. Redox-Responsive MRI Probes Based on First-Row Transition-Metal Complexes. Inorg Chem 2022; 61:14487-14499. [PMID: 36067522 DOI: 10.1021/acs.inorgchem.2c02197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The presence of multiple oxidation and spin states of first-row transition-metal complexes facilitates the development of switchable MRI probes. Redox-responsive probes capitalize on a change in the magnetic properties of the different oxidation states of the paramagnetic metal ion center upon exposure to biological oxidants and reductants. Transition-metal complexes that are useful for MRI can be categorized according to whether they accelerate water proton relaxation (T1 or T2 agents), induce paramagnetic shifts of 1H or 19F resonances (paraSHIFT agents), or are chemical exchange saturation transfer (CEST) agents. The various oxidation state couples and their properties as MRI probes are summarized with a focus on Co(II)/Co(III) or Fe(II)/Fe(III) complexes as small molecules or as liposomal agents. Solution studies of these MRI probes are reviewed with an emphasis on redox changes upon treatment with oxidants or with enzymes that are physiologically important in inflammation and disease. Finally, we outline the challenges of developing these probes further for in vivo MRI applications.
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Affiliation(s)
- Janet R Morrow
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, New York 14260, United States
| | - Jaclyn J Raymond
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, New York 14260, United States
| | - Md Saiful I Chowdhury
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, New York 14260, United States
| | - Priya Ranjan Sahoo
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, New York 14260, United States
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15
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Mel’nikova EK, Nikovskii IA, Polezhaev AV, Nelyubina YV. Solvatomorphs of Iron(II) Complex with N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine with a Temperature-Induced Spin Transition in Solution. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422080048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract
The reaction of the tridentate ligand 4-(2,6-bis(5-tert-butyl-1-(2,6-dichlorophenyl)-1H-pyrazol-3-yl)pyridin-4-yl)benzonitrile (L) with iron(II) salt gave the complex [Fe(L)2](BF4)2, which was isolated in a pure state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction as two crystal polymorphs differing in the nature of the solvent molecule in the crystal (solvatomorphs I and II). According to the results of X-ray diffraction study (CCDC nos. 2104367 (I), 2104368 (II)), the iron(II) ion in these compounds occurs in different spin states and does not undergo a temperature-induced spin transition, which was previously observed for this complex in solution. The details of supramolecular organization of two solvatomorphs that prevent this transition were studied using the Hirshfeld surface analysis.
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16
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Üngör Ö, Ozvat TM, Ni Z, Zadrozny JM. Record Chemical-Shift Temperature Sensitivity in a Series of Trinuclear Cobalt Complexes. J Am Chem Soc 2022; 144:9132-9137. [PMID: 35549174 DOI: 10.1021/jacs.2c03115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Designing spins that exhibit long-lived coherence and strong temperature sensitivity is central to designing effective molecular thermometers and a fundamental challenge in the chemistry/quantum-information space. Herein, we provide a new pathway to both properties in the same molecule by designing a nuclear spin, which possesses a robust spin coherence, to mimic the strong temperature sensitivity of an electronic spin. This design strategy is demonstrated in the group of trinuclear Co(III) spin-crossover compounds [(CpCo(OP(OR)2)3)2Co](SbCl6) where Cp = cyclopentadienyl and R = Me (1), Et (2), i-Pr (3), and t-Bu (4). Nuclear magnetic resonance analyses of the 59Co nuclear spins reveal 59Co chemical-shift temperature sensitivity (Δδ/ΔT) values that span from 101(1) ppm/°C in 1 to 149(1) ppm/°C in 2 and 150(2) ppm/°C in 4, where the latter two are record temperature sensitivities for any nuclear spin. Additionally, complexes 2 and 4 have T2* values of 74 and 78 μs in solution at ambient temperatures surpassing those from electron-spin-based complexes, which typically display long coherence times only at extremely low temperatures. Our results suggest that spin-crossover phenomena can enable electron-spin-like temperature sensitivities in nuclear spins while retaining robust coherence times at room temperature.
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Affiliation(s)
- Ökten Üngör
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Tyler M Ozvat
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Zhen Ni
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Joseph M Zadrozny
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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17
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Babailov SP, Polovkova MA, Zapolotsky EN, Kirakosyan GA, Martynov AG, Gorbunova YG. Nuclear magnetic resonance thermosensing properties of holmium(III) and thulium(III) tris(tetra-15-crown-5-phthalocyaninato) complexes. J PORPHYR PHTHALOCYA 2022. [DOI: 10.1142/s1088424622500201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Temperature dependences of paramagnetic chemical shifts in NMR spectra of lanthanide tris-phthalocyaninates Ln2[(15C5)4Pc]3 (where [(15C5)4Pc][Formula: see text] is 2,3,9,10,16,17,24,25-tetrakis(15-crown-5)phthalocyaninate dianion, Ln = Ho(III), Tm(III)) have been studied in the physiological temperature range (from 303 to 323 K). The observed maximum temperature sensitivity [Formula: see text]/dTturns out to be 0.25 ppm/K for the signals of the thulium complex and 0.16 ppm/K for the holmium complex. By the example of Tm2[(15C5)4Pc]3, it has been shown that the use of temperature sensitivities normalized to signal half-widths ([Formula: see text]CT[Formula: see text]/[Formula: see text] is expedient to judge the applicability of the observed temperature dependences of LISs of analogous lanthanide complexes (Ln = Tb, Dy, Ho, Tm) for determining temperatures. The investigated kinetically and thermodynamically stable Ln2[(15C5)4Pc]3 complexes can be considered promising for the design of thermosensitive NMR probes for determination of the local temperature in nonpolar solutions.
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Affiliation(s)
- Sergey P. Babailov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Av. Lavrentyev 3, Novosibirsk, 630090, Russian Federation
| | - Marina A. Polovkova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31-4, Moscow, 119071, Russian Federation
| | - Evgeny N. Zapolotsky
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Av. Lavrentyev 3, Novosibirsk, 630090, Russian Federation
| | - Gayane A. Kirakosyan
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31-4, Moscow, 119071, Russian Federation
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119991, Russian Federation
| | - Alexander G. Martynov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31-4, Moscow, 119071, Russian Federation
| | - Yulia G. Gorbunova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31-4, Moscow, 119071, Russian Federation
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119991, Russian Federation
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18
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Babailov S, Zapolotsky E, Kokovkin V, Shakirova O, Mironov I, Chuikov I, Fomin E. Switching of shifting and relaxational NMR-thermosensor properties of iron (II) tris-(pyrazol-1-yl) methane complexes due to spin-crossover. Polyhedron 2022. [DOI: 10.1016/j.poly.2021.115611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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19
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Aleshin D, Nikovskiy I, Novikov VV, Polezhaev AV, Melnikova EK, Nelyubina YV. Room-Temperature Spin Crossover in a Solution of Iron(II) Complexes with N, N'-Disubstituted Bis(pyrazol-3-yl)pyridines. ACS OMEGA 2021; 6:33111-33121. [PMID: 34901662 PMCID: PMC8655922 DOI: 10.1021/acsomega.1c05463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/09/2021] [Indexed: 05/15/2023]
Abstract
Here, we report a combined study of the effects of two chemical modifications to an N,N'-disubstituted bis(pyrazol-3-yl)pyridine (3-bpp) and of different solvents on the spin-crossover (SCO) behavior in otherwise high-spin iron(II) complexes by solution NMR spectroscopy. The observed stabilization of the low-spin state by electron-withdrawing substituents in the two positions of the ligand that induce opposite electronic effects in SCO-active iron(II) complexes of isomeric bis(pyrazol-1-yl)pyridines (1-bpp) was previously hidden by NH functionalities in 3-bpp precluding the molecular design of SCO compounds with this family of ligands. With the recent SCO-assisting substituent design, the uncovered trends converged toward the first iron(II) complex of N,N'-disubstituted 3-bpp to undergo an almost complete SCO centered at room temperature in a less polar solvent of a high hydrogen-bond acceptor ability.
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Affiliation(s)
- Dmitry
Yu Aleshin
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
| | - Igor Nikovskiy
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
| | - Valentin V. Novikov
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Moscow
Institute of Physics and Technology, Institutskiy per., 9, 141700 Dolgoprudny, Russia
| | - Alexander V. Polezhaev
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
| | - Elizaveta K. Melnikova
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Lomonosov
Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia
| | - Yulia V. Nelyubina
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
- Moscow
Institute of Physics and Technology, Institutskiy per., 9, 141700 Dolgoprudny, Russia
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20
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Babailov SP, Zapolotsky EN. Dy-DOTA complex as promising shifting and relaxational NMR thermo-sensor probe. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120555] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Baranyai Z, Carniato F, Nucera A, Horváth D, Tei L, Platas-Iglesias C, Botta M. Defining the conditions for the development of the emerging class of Fe III-based MRI contrast agents. Chem Sci 2021; 12:11138-11145. [PMID: 34522311 PMCID: PMC8386674 DOI: 10.1039/d1sc02200h] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/07/2021] [Indexed: 02/05/2023] Open
Abstract
Fe(iii) complexes are attracting growing interest in chemists developing diagnostic probes for Magnetic Resonance Imaging because they leverage on an endogenous metal and show superior stability. However, in this case a detailed understanding of the relationship between the chemical structure of the complexes, their magnetic, thermodynamic, kinetic and redox properties and the molecular parameters governing the efficacy (relaxivity) is still far from being available. We have carried out an integrated 1H and 17O NMR relaxometric study as a function of temperature and magnetic field, on the aqua ion and three complexes chosen as reference models, together with theoretical calculations, to obtain accurate values of the parameters that control their relaxivity. Moreover, thermodynamic stability and dissociation kinetics of the Fe(iii) chelates, measured in association with the ascorbate reduction behaviour, highlight their role and mutual influence in achieving the stability required for use in vivo. An integrated 1H and 17O NMR relaxometric study on model systems allowed to highlight that the Fe(III) complexes might represent the best alternative to Gd-based MRI contrast agents at the magnetic fields of current and future clinical scanners.![]()
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Affiliation(s)
- Zsolt Baranyai
- Bracco Research Centre, Bracco Imaging S.p.A. Via Ribes 5 10010 Colleretto Giacosa Italy
| | - Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro" Viale T. Michel 11 15121 Alessandria Italy
| | - Alessandro Nucera
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro" Viale T. Michel 11 15121 Alessandria Italy
| | - Dávid Horváth
- Bracco Research Centre, Bracco Imaging S.p.A. Via Ribes 5 10010 Colleretto Giacosa Italy.,Department of Physical Chemistry, University of Debrecen Egyetem tér 1. H-4010 Debrecen Hungary
| | - Lorenzo Tei
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro" Viale T. Michel 11 15121 Alessandria Italy
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña 15071 A Coruña Galicia Spain
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro" Viale T. Michel 11 15121 Alessandria Italy
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22
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Spin-Crossover in Iron(II) Complexes of N,N′-Disubstituted 2,6-Bis(Pyrazol-3-yl)Pyridines: An Effect of a Distal Substituent in the 2,6-Dibromophenyl Group. CRYSTALS 2021. [DOI: 10.3390/cryst11080922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A series of new bis(pyrazol-3-yl)pyridines (LR) N,N′-disubstituted by 4-functionalized 2,6-dibromophenyl groups have been synthesized to study the effect of a distal substituent on the spin-crossover (SCO) behaviour of the iron(II) complexes [Fe(LR)2](ClO4)2 by variable-temperature magnetometry, NMR spectroscopy, and X-ray diffraction. The SCO-assisting tendency of the substituents with different electronic and steric properties (i.e., the bromine atom and the methyl group) in the para-position of the 2,6-dibromophenyl group is discussed. Together with earlier reported SCO-active iron(II) complexes with N,N′-disubstituted bis(pyrazol-3-yl)pyridines, these new complexes open the way for this family of SCO compounds to emerge as an effective ‘tool’ in revealing structure–function relations, a prerequisite for successful molecular design of switchable materials for future breakthrough applications in sensing, switching, and memory devices.
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23
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Sun L, Rotaru A, Robeyns K, Garcia Y. A Colorimetric Sensor for the Highly Selective, Ultra-sensitive, and Rapid Detection of Volatile Organic Compounds and Hazardous Gases. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c01389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Li Sun
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - Aurelian Rotaru
- Department of Electrical Engineering and Computer Science and MANSiD Research Center, “Stefan cel Mare” University, University Street, 13, Suceava 720229, Romania
| | - Koen Robeyns
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - Yann Garcia
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
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24
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Subasinghe SAAS, Romero J, Ward CL, Bailey MD, Zehner DR, Mehta PJ, Carniato F, Botta M, Yustein JT, Pautler RG, Allen MJ. Magnetic resonance thermometry using a Gd III-based contrast agent. Chem Commun (Camb) 2021; 57:1770-1773. [PMID: 33475101 PMCID: PMC7897303 DOI: 10.1039/d0cc06400a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The complexes described here serve as contrast agents for magnetic resonance imaging thermometry. The complexes differentially enhance contrast between 275 and 325 K. The basis of the temperature response of the fluorinated contrast complex is the modulation of water exchange caused by trifluoromethyl groups that can be chemically controlled.
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Affiliation(s)
- S A Amali S Subasinghe
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA.
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25
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Guionneau P, Marchivie M, Chastanet G. Multiscale Approach of Spin Crossover Materials: A Concept Mixing Russian Dolls and Domino Effects. Chemistry 2021; 27:1483-1486. [PMID: 32692437 DOI: 10.1002/chem.202002699] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Indexed: 12/22/2022]
Abstract
The spin crossover (SCO) phenomenon corresponds to a modification that originates at the atomic scale. However, the simple consideration of the transformations that occur following the SCO at this scale or in its close vicinity does not allow anyone to truly understand, anticipate and thus take advantage of what happens at the scale of the material, and even less at the device one. As the fruit of years of work and experience on this phenomenon, we formalize here the concept of the multiscale understanding of SCO. Clearly, the deflagration generated by the initial impressive atomic modification on all the physical scales of the solid must be understood in terms of structure-properties relationships that fit together, like Russian dolls, and propagate according to a kind of domino effect. Each scale can both give different and independent consequences from those of the other scales but at the same time can influence those of a larger or smaller scale, the whole being imperatively to take into account. The concept appears well illustrated by the volume modification, always the same at the atomic level but drastically different and adaptable, in amplitude and sense, at any other physical scale. This approach results in a much wider range of potential applications than the atomic level alone initially suggests, including one serious path to shape memory materials.
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Affiliation(s)
- Philippe Guionneau
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, 87 av. Dr A. Schweitzer, F-33600, Pessac, France
| | - Mathieu Marchivie
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, 87 av. Dr A. Schweitzer, F-33600, Pessac, France
| | - Guillaume Chastanet
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, 87 av. Dr A. Schweitzer, F-33600, Pessac, France
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26
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Du K, Zemerov SD, Hurtado Parra S, Kikkawa JM, Dmochowski IJ. Paramagnetic Organocobalt Capsule Revealing Xenon Host-Guest Chemistry. Inorg Chem 2020; 59:13831-13844. [PMID: 32207611 PMCID: PMC7672707 DOI: 10.1021/acs.inorgchem.9b03634] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We investigated Xe binding in a previously reported paramagnetic metal-organic tetrahedral capsule, [Co4L6]4-, where L2- = 4,4'-bis[(2-pyridinylmethylene)amino][1,1'-biphenyl]-2,2'-disulfonate. The Xe-inclusion complex, [XeCo4L6]4-, was confirmed by 1H NMR spectroscopy to be the dominant species in aqueous solution saturated with Xe gas. The measured Xe dissociation rate in [XeCo4L6]4-, koff = 4.45(5) × 102 s-1, was at least 40 times greater than that in the analogous [XeFe4L6]4- complex, highlighting the capability of metal-ligand interactions to tune the capsule size and guest permeability. The rapid exchange of 129Xe nuclei in [XeCo4L6]4- produced significant hyperpolarized 129Xe chemical exchange saturation transfer (hyper-CEST) NMR signal at 298 K, detected at a concentration of [XeCo4L6]4- as low as 100 pM, with presaturation at -89 ppm, which was referenced to solvated 129Xe in H2O. The saturation offset was highly temperature-dependent with a slope of -0.41(3) ppm/K, which is attributed to hyperfine interactions between the encapsulated 129Xe nucleus and electron spins on the four CoII centers. As such, [XeCo4L6]4- represents the first example of a paramagnetic hyper-CEST (paraHYPERCEST) sensor. Remarkably, the hyper-CEST 129Xe NMR resonance for [XeCo4L6]4- (δ = -89 ppm) was shifted 105 ppm upfield from the diamagnetic analogue [XeFe4L6]4- (δ = +16 ppm). The Xe inclusion complex was further characterized in the crystal structure of (C(NH2)3)4[Xe0.7Co4L6]·75 H2O (1). Hydrogen bonding between capsule-linker sulfonate groups and exogenous guanidinium cations, (C(NH2)3)+, stabilized capsule-capsule interactions in the solid state and also assisted in trapping a Xe atom (∼42 Å3) in the large (135 Å3) cavity of 1. Magnetic susceptibility measurements confirmed the presence of four noninteracting, magnetically anisotropic high-spin CoII centers in 1. Furthermore, [Co4L6]4- was found to be stable toward aggregation and oxidation, and the CEST performance of [XeCo4L6]4- was unaffected by biological macromolecules in H2O. These results recommend metal-organic capsules for fundamental investigations of Xe host-guest chemistry as well as applications with highly sensitive 129Xe-based sensors.
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27
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Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy. CRYSTALS 2020. [DOI: 10.3390/cryst10090793] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.
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Abozeid SM, Asik D, Sokolow GE, Lovell JF, Nazarenko AY, Morrow JR. Co II Complexes as Liposomal CEST Agents. Angew Chem Int Ed Engl 2020; 59:12093-12097. [PMID: 32330368 PMCID: PMC7502271 DOI: 10.1002/anie.202003479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Indexed: 12/23/2022]
Abstract
Three paramagnetic CoII macrocyclic complexes containing 2-hydroxypropyl pendant groups, 1,1',1'',1'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetrakis- (propan-2-ol) ([Co(L1)]2+ , 1,1'-(4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane-1,8-diyl)bis(propan-2-ol) ([Co(L2)]2+ ), and 1,1'-(4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane-1,8-diyl)bis(octadecan-2-ol) ([Co(L3)]2+ ) were synthesized to prepare transition metal liposomal chemical exchange saturation transfer (lipoCEST) agents. In solution, ([Co(L1)]2+ ) forms two isomers as shown by 1 H NMR spectroscopy. X-ray crystallographic studies show one isomer with 1,8-pendants in cis-configuration and a second isomer with 1,4-pendants in trans-configuration. The [Co(L2)]2+ complex has 1,8-pendants in a cis-configuration. Remarkably, the paramagnetic-induced shift of water 1 H NMR resonances in the presence of the [Co(L1)]2+ complex is as large as that observed for one of the most effective LnIII water proton shift agents. Incorporation of [Co(L1)]2+ into the liposome aqueous core, followed by dialysis against a solution of 300 mOsm L-1 produces a CEST peak at 3.5 ppm. Incorporation of the amphiphilic [Co(L3)]2+ complex into the liposome bilayer produces a more highly shifted CEST peak at -13 ppm. Taken together, these data demonstrate the feasibility of preparing CoII lipoCEST agents.
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Affiliation(s)
- Samira M. Abozeid
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, NY 14260, United States
| | - Didar Asik
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, NY 14260, United States
| | - Gregory E. Sokolow
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, NY 14260, United States
| | - Jonathan F. Lovell
- Department of Biomedical Engineering, University at Buffalo, the State University of New York, Amherst, NY 14260, United States
| | - Alexander Y. Nazarenko
- Chemistry Department, SUNY College at Buffalo, 1300 Elmwood Avenue, Buffalo, NY 14222, United States
| | - Janet R. Morrow
- Department of Chemistry, University at Buffalo, the State University of New York, Amherst, NY 14260, United States
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Blahut J, Benda L, Kotek J, Pintacuda G, Hermann P. Paramagnetic Cobalt(II) Complexes with Cyclam Derivatives: Toward 19F MRI Contrast Agents. Inorg Chem 2020; 59:10071-10082. [DOI: 10.1021/acs.inorgchem.0c01216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jan Blahut
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843 Prague 2, Czech Republic
- High-Field NMR Centre, CNRS FRE2034/UCB de Lyon 1/ENS de Lyon, 5 rue de la Doua, 69100 Lyon-Villeurbanne, France
| | - Ladislav Benda
- High-Field NMR Centre, CNRS FRE2034/UCB de Lyon 1/ENS de Lyon, 5 rue de la Doua, 69100 Lyon-Villeurbanne, France
| | - Jan Kotek
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843 Prague 2, Czech Republic
| | - Guido Pintacuda
- High-Field NMR Centre, CNRS FRE2034/UCB de Lyon 1/ENS de Lyon, 5 rue de la Doua, 69100 Lyon-Villeurbanne, France
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843 Prague 2, Czech Republic
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Avila Y, Crespo P, Plasencia Y, Mojica H, Rodríguez-Hernández J, Reguera E. Intercalation of 3X-pyridine with X = F, Cl, Br, I, in 2D ferrous nitroprusside. Thermal induced spin transition in Fe(3F-pyridine)2[Fe(CN)5NO]. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Pankratova Y, Aleshin D, Nikovskiy I, Novikov V, Nelyubina Y. In Situ NMR Search for Spin-Crossover in Heteroleptic Cobalt(II) Complexes. Inorg Chem 2020; 59:7700-7709. [PMID: 32383584 DOI: 10.1021/acs.inorgchem.0c00716] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Here we report the first successful attempt to identify spin-crossover compounds in solutions of metal complexes produced by mixing different ligands and an appropriate metal salt by variable-temperature nuclear magnetic resonance (NMR) spectroscopy. Screening the spin state of a cobalt(II) ion in a series of thus obtained homoleptic and heteroleptic compounds of terpyridines (terpy) and 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) by using this NMR-based approach, which only relies on the temperature behavior of chemical shifts, revealed the first cobalt(II) complexes with a 3-bpp ligand to undergo a thermally induced spin-crossover. A simple analysis of NMR spectra collected from mixtures of different compounds without their isolation or purification required by the current method of choice, the Evans technique, thus emerges as a powerful tool in a search for new spin-crossover compounds and their molecular design boosted by wide possibilities for chemical modifications in heteroleptic complexes.
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Affiliation(s)
- Yanina Pankratova
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Moscow State University, Leninskie gory, 1, 119991 Moscow, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047 Moscow, Russia
| | - Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
| | - Valentin Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny 141700, Moscow Region, Russia
| | - Yulia Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
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Abozeid SM, Asik D, Sokolow GE, Lovell JF, Nazarenko AY, Morrow JR. Co
II
Complexes as Liposomal CEST Agents. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003479] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Samira M. Abozeid
- Department of Chemistry University at Buffalo, The State University of New York Amherst NY 14260 USA
| | - Didar Asik
- Department of Chemistry University at Buffalo, The State University of New York Amherst NY 14260 USA
| | - Gregory E. Sokolow
- Department of Chemistry University at Buffalo, The State University of New York Amherst NY 14260 USA
| | - Jonathan F. Lovell
- Department of Biomedical Engineering University at Buffalo The State University of New York Amherst NY 14260 USA
| | | | - Janet R. Morrow
- Department of Chemistry University at Buffalo, The State University of New York Amherst NY 14260 USA
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Nikovskiy I, Polezhaev A, Novikov V, Aleshin D, Pavlov A, Saffiulina E, Aysin R, Dorovatovskii P, Nodaraki L, Tuna F, Nelyubina Y. Towards the Molecular Design of Spin-Crossover Complexes of 2,6-Bis(pyrazol-3-yl)pyridines. Chemistry 2020; 26:5629-5638. [PMID: 31967374 DOI: 10.1002/chem.202000047] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Indexed: 01/27/2023]
Abstract
The molecular design of spin-crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N'-disubstituted 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) are reported that, against the common wisdom, induce a spin-crossover in otherwise high-spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho-functionalized phenyl group. As N,N'-disubstituted 3-bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1-bpp or other families of popular bi-, tri- and higher denticity ligands, opens the way for their molecular design as spin-crossover compounds for future breakthrough applications.
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Affiliation(s)
- Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia
| | - Alexander Polezhaev
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str. 5, 105005, Moscow, Russia
| | - Valentin Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Alexander Pavlov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Elnara Saffiulina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Rinat Aysin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Pavel Dorovatovskii
- National Research Centre "Kurchatov Institute", Akademika Kurchatova pl., 1, 123182, Moscow, Russia
| | - Lydia Nodaraki
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Floriana Tuna
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Yulia Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str. 5, 105005, Moscow, Russia
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Spin Crossover in 3D Metal Centers Binding Halide-Containing Ligands: Magnetism, Structure and Computational Studies. SUSTAINABILITY 2020. [DOI: 10.3390/su12062512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The capability of a given substance to change its spin state by the action of a stimulus, such as a change in temperature, is by itself a very challenging property. Its interest is increased by the potential applications and the need to find sustainable functional materials. 3D transition metal complexes, mainly with octahedral geometry, display this property when coordinated to particular sets of ligands. The prediction of this behavior has been attempted by many authors. It is, however, made very difficult because spin crossover (SCO), as it is called, occurs most often in the solid state, where besides complexes, counter ions, and solvents are also present in many cases. Intermolecular interactions definitely play a major role in SCO. In this review, we decided to analyze SCO in mono- and binuclear transition metal complexes containing halogens as ligands or as substituents of the ligands. The aim was to try and find trends in the properties which might be correlated to halogen substitution patterns. Besides a revision of the properties, we analyzed structures and other information. We also tried to build a simple model to run Density Functional Theory (DFT) calculations and calculate several parameters hoping to find correlations between calculated indices and SCO data. Although there are many experimental studies and single-crystal X-ray diffraction structures, there are only few examples with the F, Cl, Br and series. When their intermolecular interactions were not very different, T1/2 (temperature with 50% high spin and 50% low spin states) usually increased with the calculated ligand field parameter (Δoct) within a given family. A way to predict SCO remains elusive.
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Shin JW, Jeong AR, Jeong JH, Zenno H, Hayami S, Min KS. Two-dimensional square-grid iron(ii) coordination polymers showing anion-dependent spin crossover behavior. RSC Adv 2020; 10:5040-5049. [PMID: 35498313 PMCID: PMC9049044 DOI: 10.1039/c9ra09782a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/24/2020] [Indexed: 11/21/2022] Open
Abstract
Two Fe(ii)-based coordination polymers [Fe(tpmd)2(NCS)2]·5.5H2O (1) and [Fe(tpmd)2(NCSe)2]·7H2O (2) with the framework of square-grid type have been assembled from FeSO4·7H2O, N,N,N′,N′-tetrakis(pyridin-4-yl)methanediamine (tpmd), and KNCS/KNCSe in methanol and characterized. By utilizing two pyridine groups of a tpmd ligand, 1 and 2 are formed in two-dimensional layered structures through coordination of octahedral iron(ii) ions with the tpmd to NCS−/NCSe− ligands in which they have a supramolecular isomorphous conformation. 1 shows a paramagnetic behavior between 2 and 300 K, while 2 exhibits two-step spin crossover (ca. 145 and 50 K) in the temperature range due to the coordination of NCSe− ligands. At 300 K 2 is fully high-spin state. However, at 100 K 2 becomes ca. 50% high spin and 50% low spin iron(ii) ions, which is verified by magnetic moments. In the structural analysis of 2 at 100 K, two different layers are observed with different bond distances around iron(ii) ions in which the layers are stacked alternately. Two-dimensional Fe-based coordination polymers with square-grid shapes were prepared by self-assembly and exhibited an interesting spin crossover behavior depending on the coordinated counter ions.![]()
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Affiliation(s)
- Jong Won Shin
- Department of Chemistry
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Ah Rim Jeong
- Department of Chemistry
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Jong Hwa Jeong
- Department of Chemistry
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Hikaru Zenno
- Department of Chemistry
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Shinya Hayami
- Department of Chemistry
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Kil Sik Min
- Department of Chemistry Education
- Kyungpook National University
- Daegu 41566
- Republic of Korea
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Gardinier JR, Meise KJ, Jahan F, Wang D, Lindeman SV. Selective Isomer Formation and Crystallization-Directed Magnetic Behavior in Nitrogen-Confused C-Scorpionate Complexes of Fe(O 3SCF 3) 2. Inorg Chem 2019; 58:8953-8968. [PMID: 31247826 DOI: 10.1021/acs.inorgchem.8b03454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex [Fe(HL*)2](OTf)2, 1, where HL* = bis(3,5-dimethylpyrazol-1-yl)(3-1H-pyrazole)methane, was prepared in order to compare its magnetic properties with those of the analogous parent complex, [Fe(HL)2](OTf)2, that lacks methyl groups on pyrazolyl rings and that undergoes spin crossover (SCO) from the low spin (LS) to the high spin (HS) form above room temperature. It was anticipated that this new semibulky derivative should favor the HS state and undergo SCO at a lower temperature range. During this study, six crystalline forms of 1 were prepared by controlling the crystallization conditions. Thus, when reagents are combined in CH3CN, an equilibrium mixture of cis and trans isomers is established that favors the latter below 311 K. The trans isomer can be isolated exclusively as a mixture of solvates, LS trans-1·2CH3CN and HS trans-1·4CH3CN, by cooling CH3CN solutions to -20 °C with the former being favored at high concentrations and short crystallization times. Subsequently, vapor diffusion of Et2O into CH3CN solutions of pure trans-1·2CH3CN gives solvate-free HS trans-1. Subjecting trans-1·2CH3CN to vacuum at room temperature gives microcrystalline trans-1·CH3CN, identified by elemental analysis and its distinct powder X-ray diffraction pattern. If an isomeric mixture of 1 is subject to room-temperature vapor diffusion, then a crystalline mixture of HS isomers cis-1 and trans-1 is obtained. Finally, slowly cooling hot acetonitrile solutions of isomeric mixtures of 1 to room temperature gives large prisms of HS co-1, a species with both cis and trans isomers in the unit cell. The complexes trans-1, trans-1·CH3CN, cis-1, and co-1 undergo SCO below 250 K while trans-1·xCH3CN (x = 2, 4) solvates do not undergo SCO before desolvation.
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Affiliation(s)
- James R Gardinier
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53201-1881 , United States
| | - Kristin J Meise
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53201-1881 , United States
| | - Fathiya Jahan
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53201-1881 , United States
| | - Denan Wang
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53201-1881 , United States
| | - Sergey V Lindeman
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53201-1881 , United States
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Chetty N, Ramkumar V, Murthy NN. Bis- and mono-tridentate chelated iron complexes with a new facially capping unsymmetrical nitrogen ligand: X-ray structural and spectroscopic studies. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Li W, Zhang Q, Joos JJ, Smet PF, Schmedt Auf der Günne J. Blind spheres of paramagnetic dopants in solid state NMR. Phys Chem Chem Phys 2019; 21:10185-10194. [PMID: 31063169 DOI: 10.1039/c9cp00953a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Solid-state NMR on paramagnetically doped crystal structures gives information about the spatial distribution of dopants in the host. Paramagnetic dopants may render NMR active nuclei virtually invisible by relaxation, paramagnetic broadening or shielding. In this contribution blind sphere radii r0 have been reported, which could be extracted through fitting the NMR signal visibility function f(x) = exp(-ar03x) to experimental data obtained on several model compound series: La1-xLnxPO4 (Ln = Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb), Sr1-xEuxGa2S4 and (Zn1-xMnx)3(PO4)2·4H2O. Radii were extracted for 1H, 31P and 71Ga, and dopants like Nd3+, Gd3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Mn2+. The observed radii determined differed in all cases and covered a range from 5.5 to 13.5 Å. While these radii were obtained from the amount of invisible NMR signal, we also show how to link the visibility function to lineshape parameters. We show under which conditions empirical correlations of linewidth and doping concentration can be used to extract blind sphere radii from second moment or linewidth parameter data. From the second moment analysis of La1-xSmxPO431P MAS NMR spectra for example, a blind sphere size of Sm3+ can be determined, even though the visibility function remains close to 100% over the entire doping range. Dependence of the blind sphere radius r0 on the NMR isotope and on the paramagnetic dopant could be suggested and verified: for different nuclei, r0 shows a -dependence, γ being the gyromagnetic ratio. The blind sphere radii r0 for different paramagnetic dopants in a lanthanide series could be predicted from the pseudo-contact term.
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Affiliation(s)
- Wenyu Li
- Inorganic Materials Chemistry, University of Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen, Germany.
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Thorarinsdottir AE, Harris TD. Dramatic enhancement in pH sensitivity and signal intensity through ligand modification of a dicobalt PARACEST probe. Chem Commun (Camb) 2019; 55:794-797. [DOI: 10.1039/c8cc09520e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A ratiometric dicobalt PARACEST pH probe that exhibits dramatic enhancements in sensitivity and signal intensity over analogous probes is reported.
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Sánchez-Viveros JM, Bucio-Ortega J, Ortiz-Pastrana N, Olguín J. Mononuclear complexes of Fe II, Co II and Co III containing imine-based ligands of 8-aminoquinoline and 7-aminoindazole: spin state tuning of Fe II complexes in solution. NEW J CHEM 2019. [DOI: 10.1039/c9nj01622h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Careful selection of the fused ring heterocycle and aldehyde synthons resulted in the spin state tuning of iron(ii) complexes in solution.
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Affiliation(s)
- José Manuel Sánchez-Viveros
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav)
- Ciudad de México 07360
- Mexico
| | - Job Bucio-Ortega
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav)
- Ciudad de México 07360
- Mexico
| | - Naytzé Ortiz-Pastrana
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav)
- Ciudad de México 07360
- Mexico
| | - Juan Olguín
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav)
- Ciudad de México 07360
- Mexico
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Wolny JA, Schünemann V, Németh Z, Vankó G. Spectroscopic techniques to characterize the spin state: Vibrational, optical, Mössbauer, NMR, and X-ray spectroscopy. CR CHIM 2018. [DOI: 10.1016/j.crci.2018.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Lee WT, Zeller M, Upp D, Politanska Y, Steinman D, Al-Assil T, Becker DP. Iron(II) complexes of dimethyltriazacyclophane. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2018; 74:1641-1649. [PMID: 30516148 DOI: 10.1107/s2053229618015255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/29/2018] [Indexed: 11/11/2022]
Abstract
Treatment of the ortho-triazacyclophane 1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-triene [(C6H5)3(NH)(NCH3)2, L1] with Fe[N(SiMe3)2]2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C20H18N3)4] or Fe2(L1)4 (9). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κN7)bis(tetrahydrofuran-κO)iron(II), [Fe(C20H18N3)2(C4H8O)2] or (L1)2Fe(THF)2 (10). The reaction is reversible and 10 reverts in vacuo to diiron complex 9. In the structures of both 9 and 10, the monoanionic triazacyclophane ligand L1- is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ3-coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1- ligands are bound in either a η2-chelating fashion through the amide and one amine donor (for one of the four ligands of 9), or solely through their amide N atoms in an even simpler monodentate η1-coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long Fe...Fe distance of 2.912 (1) Å observed in the solid state.
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Affiliation(s)
- Wei Tsung Lee
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
| | - Matthias Zeller
- Department of Chemistry, Purdue University, 560 Oval Dr., W. Lafayette, IN 47907-2084, USA
| | - David Upp
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
| | - Yuliya Politanska
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
| | - Doug Steinman
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
| | - Talal Al-Assil
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
| | - Daniel P Becker
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan Road, Chicago, Illinois 60660, USA
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Herynek V, Martinisková M, Bobrova Y, Gálisová A, Kotek J, Hermann P, Koucký F, Jirák D, Hájek M. Low-molecular-weight paramagnetic 19F contrast agents for fluorine magnetic resonance imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2018; 32:115-122. [PMID: 30498883 PMCID: PMC6514088 DOI: 10.1007/s10334-018-0721-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/24/2022]
Abstract
Objective 19F MRI requires biocompatible and non-toxic soluble contrast agents with high fluorine content and with suitable 19F relaxation times. Probes based on a DOTP chelate with 12 magnetically equivalent fluorine atoms (DOTP-tfe) and a lanthanide(III) ion shortening the relaxation times were prepared and tested. Methods Complexes of DOTP-tfe with trivalent paramagnetic Ce, Dy, Ho, Tm, and Yb ions were synthetized and characterized. 19F relaxation times were determined and compared to those of the La complex and of the empty ligand. In vitro and in vivo 19F MRI was performed at 4.7 T. Results 19F relaxation times strongly depended on the chelated lanthanide(III) ion. T1 ranged from 6.5 to 287 ms, T2 from 3.9 to 124.4 ms, and T2* from 1.1 to 3.1 ms. All complexes in combination with optimized sequences provided sufficient signal in vitro under conditions mimicking experiments in vivo (concentrations 1.25 mM, 15-min scanning time). As a proof of concept, two contrast agents were injected into the rat muscle; 19F MRI in vivo confirmed the in vivo applicability of the probe. Conclusion DOTP-based 19F probes showed suitable properties for in vitro and in vivo visualization and biological applications. The lanthanide(III) ions enabled us to shorten the relaxation times and to trim the probes according to the actual needs. Similar to the clinically approved Gd3+ chelates, this customized probe design ensures consistent biochemical properties and similar safety profiles.
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Affiliation(s)
- Vít Herynek
- Center for Advanced Preclinical Imaging, First Faculty of Medicine, Charles University, Salmovská 3, Prague, Czech Republic.
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, Prague, Czech Republic.
| | - Marie Martinisková
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843, Prague 2, Czech Republic
| | - Yulia Bobrova
- Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, Prague, Czech Republic
| | - Andrea Gálisová
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, Prague, Czech Republic
| | - Jan Kotek
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843, Prague 2, Czech Republic
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843, Prague 2, Czech Republic
| | - Filip Koucký
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 12843, Prague 2, Czech Republic
| | - Daniel Jirák
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, Prague, Czech Republic
| | - Milan Hájek
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, Prague, Czech Republic
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Petzold H, Hörner G, Schnaubelt L, Rüffer T. Slow spin crossover in bis-meridional Fe 2+ complexes through spin-state auto-adaptive N6/N8 coordination. Dalton Trans 2018; 47:17257-17265. [PMID: 30488935 DOI: 10.1039/c8dt03652g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Fe2+ spin crossover (SCO) complexes with long-lived excited high-spin (HS) states are promising molecular switches. An enhanced kinetic stability of spin-state isomers can be expected to foster applications beyond the limits of cooperative SCO. In this study, we describe a new approach to slow down the spin-state exchange by simple commutation of a phenyl substituent by a pyridyl substituent. To this end, N4 ligand 6-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)-2,2'-bipyridine (3b) is synthesized as an N4 homologue of the well-established meridional N3 ligands motif. Phenyl-substituted 6-(3-phenyl-1H-pyrazol-1-yl)-2,2'-bipyridine (3a) serves as an intrinsic N3 reference throughout. 3b offers variable coordination numbers, N3 versus N3(+1) and N4, reflecting the preferences of the metal center. As is shown herein through an extended solid-state structure-chemical and solution-state NMR study, which is augmented by density-functional theory modeling, both the coordination geometry and its structural dynamics are indeed highly sensitive towards the expansion of the nominal donor number. The additional donors in 3b introduced through the phenyl-pyridine commutation actually give rise to a rich and diverse stereochemistry of the derived Zn2+ and Fe2+ complexes. Notably, even within a single complex unit coordination of 3b ranges from strongly distorted N3 coordination with a long assisting additional contact (Zn2+ and Fe2+) to a more symmetric N2(+2) or N4 situation in Fe2+. DFT modeling unravels that the additional donors are hemi-labile and coordinate to the Fe2+ only in HS state, leaving the elusive low-spin (LS) state in a fairly undisturbed octahedral environment with 3b being N3 coordinate. That is, the coordination number of the complex autogeneously responds to the altered spin-state. Necessarily this switch in coordination number requires strong structural changes upon SCO. This leads to increased activation barriers for SCO as could be deduced from a temperature-dependent analysis of the dynamic 1H NMR-line broadening and corroborated by accompanying theoretical analysis of the SCO reaction coordinate. For [Fe(3b)2]2+ long spin-state lifetimes τ > 1 ms prevail below the characteristic temperature T (1 ms) = 235 K; this value should be compared with a lifetime of only 150 ns derived for the close analogue [Fe(3a)2]2+. The principle applied herein is general and allows transferring of LS Fe2+ complexes with suitably placed phenyl substituents into SCO complexes with spin-state adaptive coordination number and hence long-lived HS excited states.
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Affiliation(s)
- Holm Petzold
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Gerald Hörner
- TU Berlin, Institut für Chemie, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Linda Schnaubelt
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Tobias Rüffer
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
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Turcas R, Kripli B, Attia AAA, Lakk-Bogáth D, Speier G, Giorgi M, Silaghi-Dumitrescu R, Kaizer J. Catalytic and stoichiometric flavanone oxidation mediated by nonheme oxoiron(iv) complexes as flavone synthase mimics: kinetic, mechanistic and computational studies. Dalton Trans 2018; 47:14416-14420. [PMID: 30259930 DOI: 10.1039/c8dt03519a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The present study describes the first example of the stoichiometric and catalytic oxidation of flavanone by synthetic nonheme oxoiron(iv) complexes and their precursor iron(ii) complexes with m-CPBA as the terminal oxidant. These models, including detailed kinetic, mechanistic and computational studies, may serve as the biomimics of flavone synthase (FS) enzymes.
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Affiliation(s)
- Ramona Turcas
- Department of Chemistry, University of Pannonia, H-8201 Veszprém, Hungary.
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Tsitovich PB, Gendron F, Nazarenko AY, Livesay BN, Lopez AP, Shores MP, Autschbach J, Morrow JR. Low-Spin Fe(III) Macrocyclic Complexes of Imidazole-Appended 1,4,7-Triazacyclononane as Paramagnetic Probes. Inorg Chem 2018; 57:8364-8374. [DOI: 10.1021/acs.inorgchem.8b01022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Pavel B. Tsitovich
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York 14260, United States
| | - Frédéric Gendron
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York 14260, United States
| | - Alexander Y. Nazarenko
- Chemistry Department, State University of New York, College at Buffalo, 1300 Elmwood Avenue, Buffalo, New York 14222, United States
| | - Brooke N. Livesay
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Alejandra P. Lopez
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York 14260, United States
| | - Matthew P. Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York 14260, United States
| | - Janet R. Morrow
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York 14260, United States
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Peterson KL, Srivastava K, Pierre VC. Fluorinated Paramagnetic Complexes: Sensitive and Responsive Probes for Magnetic Resonance Spectroscopy and Imaging. Front Chem 2018; 6:160. [PMID: 29876342 PMCID: PMC5974164 DOI: 10.3389/fchem.2018.00160] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/20/2018] [Indexed: 12/11/2022] Open
Abstract
Fluorine magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) of chemical and physiological processes is becoming more widespread. The strength of this technique comes from the negligible background signal in in vivo19F MRI and the large chemical shift window of 19F that enables it to image concomitantly more than one marker. These same advantages have also been successfully exploited in the design of responsive 19F probes. Part of the recent growth of this technique can be attributed to novel designs of 19F probes with improved imaging parameters due to the incorporation of paramagnetic metal ions. In this review, we provide a description of the theories and strategies that have been employed successfully to improve the sensitivity of 19F probes with paramagnetic metal ions. The Bloch-Wangsness-Redfield theory accurately predicts how molecular parameters such as internuclear distance, geometry, rotational correlation times, as well as the nature, oxidation state, and spin state of the metal ion affect the sensitivity of the fluorine-based probes. The principles governing the design of responsive 19F probes are subsequently described in a "how to" guide format. Examples of such probes and their advantages and disadvantages are highlighted through a synopsis of the literature.
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Affiliation(s)
- Katie L Peterson
- Department of Chemistry, Bemidji State University, Bemidji, MN, United States
| | - Kriti Srivastava
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Valérie C Pierre
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
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A New Family of Heterometallic LnIII[12-MCFeIIIN(shi)-4] Complexes: Syntheses, Structures and Magnetic Properties. CRYSTALS 2018. [DOI: 10.3390/cryst8050229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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