1
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Izumiyama N, Fujii S, Kato K, Tokunaga R, Hayami S, Nakaya M. Spin-crossover cobalt(II) complexes exhibiting temperature- and concentration-dependent optical changes in solution. Dalton Trans 2024; 53:9547-9553. [PMID: 38768302 DOI: 10.1039/d4dt00433g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
This work investigated the spin states of the cobalt(II) complexes [Co(L1)2](X)2 (1·X; L1 = 4'-(4-N,N'-diphenylaminophenyl)-2,2':6',2''-terpyridine, X = PF6, BPh4) and [Co(L2)2](X)2 (2·X; L2 = 4'-(4-N,N'-dimethylaminophenyl)-2,2':6',2''-terpyridine, X = PF6, BPh4) in the solid state and in solution. In the solid state, 1·PF6 and 2·PF6, both containing smaller PF6- counter anions, showed gradual spin-crossover. In contrast, 1·BPh4 and 2·BPh4 remained in the high-spin state over the temperature range of 5-400 K due to a lower degree of molecular cooperativity. Each of the cobalt(II) complexes exhibited effects of temperature and concentration on their absorption spectra that were related to the spin states in various organic solvents. This work provides new insights into the spectroscopic properties resulting from the spin states of cobalt(II) complexes in solution.
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Affiliation(s)
- Naoki Izumiyama
- Department of Material Science, Graduate School of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
| | - Shun Fujii
- Department of Material Science, Graduate School of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
| | - Kiichi Kato
- Department of Chemistry, Faculty of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
| | - Ryuya Tokunaga
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Shinya Hayami
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
- Institute of Industrial Nanomaterials (IINa), Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Manabu Nakaya
- Department of Material Science, Graduate School of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
- Department of Chemistry, Faculty of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan
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2
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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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3
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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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4
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Change in the Electronic Structure of the Cobalt(II) Ion in a One-Dimensional Polymer with Flexible Linkers Induced by a Structural Phase Transition. Int J Mol Sci 2022; 24:ijms24010215. [PMID: 36613658 PMCID: PMC9820815 DOI: 10.3390/ijms24010215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022] Open
Abstract
A new 1D-coordination polymer [Co(Piv)2(NH2(CH2)6NH2)]n (1, Piv is Me3CCO2- anion) was obtained, the mononuclear fragments {Co(O2CR)2} within which are linked by μ-bridged molecules of hexamethylenediamine (NH2(CH2)6NH2). For this compound, two different monoclinic C2/c (α-1) and P2/n (β-1) phases were found at room temperature by single-crystal X-ray diffraction analysis, with a similar structure of chains and their packages in unit cells. The low-temperature phase (γ-1) of crystal 1 at 150 K corresponds to the triclinic space group P-1. As the temperature decreases, the structural phase transition (SPT) in the α-1 and β-1 crystals is accompanied by an increase in the crystal packing density caused by the rearrangements of both H-bonds and the nearest ligand environment of the cobalt atom ("octahedral CoN2O4 around the metal center at room temperature" → "pseudo-tetrahedral CoN2O2 at 150 K"). The SPT was confirmed by DSC in the temperature range 210-150 K; when heated above 220 K, anomalies in the behavior of the heat flow are observed, which may be associated with the reversibility of SPT; endo effects are observed up to 300 K. The SPT starts below 200 K. At 100 K, a mixture of phases was found in sample 1: 27% α-1 phase, 61% γ-1 phase. In addition, at 100 K, 12% of the new δ-1 phase was detected, which was identified from the diffraction pattern at 260 K upon subsequent heating: the a,b,c-parameters and unit cell volume are close to the structure parameters of γ-1, and the values of the α,β,γ-angles are significantly different. Further heating leads to a phase transition from δ-1 to α-1, which both coexist at room temperature. According to the DC magnetometry data, during cooling and heating, the χMT(T) curves for 1 form a hysteresis loop with ~110 K, in which the difference in the χMT values reaches 9%. Ab initio calculations of the electronic structure of cobalt(II) in α-1 and γ-1 have been performed. Based on the EPR data at 10 K and the ab initio calculations, the behavior of the χMT(T) curve for 1 was simulated in the temperature range of 2-150 K. It was found that 1 exhibits slow magnetic relaxation in a field of 1000 Oe.
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5
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Reza Ghiasi, Mrayam Rahimi. C-PCM Study of Solvent Polarity Effect on Spin Crossover in Complex cis-[Fe(phen)2(NCS)2]. RUSS J INORG CHEM+ 2022. [DOI: 10.1134/s0036023622600794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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6
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Khakina EA, Denisov GL, Nikovskii IA, Polezhaev AV, Nelyubina YV. Spin State of the Cobalt(II) Complex with N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422060021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Zapolotsky EN, Babailov SP, Chuykov IP, Kokovkin VV, Shakirova OG. SPIN CROSSOVER AND TEMPERATURE SENSITIVITY OF PARAMAGNETIC NMR CHEMICAL SHIFTS IN AN AQUEOUS SOLUTION OF THE IRON(II) NAPHTHALENESULFONATE COMPLEX WITH TRIS(PYRAZOL-1-YL)METHANE [Fe(HC(Pz)3)2](C10H7SO3)2. J STRUCT CHEM+ 2022. [DOI: 10.1134/s0022476622060099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Tao Y, Hu R, Xie Z, Lin P, Su W. Cobalt-Catalyzed Regioselective para-Amination of Azobenzenes via Nucleophilic Aromatic Substitution of Hydrogen. J Org Chem 2022; 87:4724-4731. [PMID: 35290054 DOI: 10.1021/acs.joc.2c00026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The metal-catalyzed nucleophilic aromatic substitution of hydrogen (SNArH) via coordination of the substituent on the aromatic ring to the metal catalyst, in terms of reactivity, substrate type, and reaction selectivity, complements the transition metal-catalyzed C-H functionalization that proceeds via C-H metalation but remains an elusive target. Described herein is the development of an unprecedented cobalt-catalyzed para-selective amination of azobenzenes, which is essentially a metal-promoted SNArH process as revealed by Hammett analysis, thus illustrating the concept that coordination of the substituent on the arene ring to the metal catalyst may result in electrophilic activation of the arene ring toward SNArH. This cobalt-catalyzed protocol allows the use of a variety of both aliphatic amines and anilines as aminating reagents, tolerates electronically diverse substituents of azobenzene, and furnishes the corresponding products in good yields with a regiospecific selectivity for para-amination.
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Affiliation(s)
- Yigao Tao
- State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Rong Hu
- State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Zeyu Xie
- School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ping Lin
- State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
| | - Weiping Su
- State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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9
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Transition Metal Complexes of Schiff Base Ligands Prepared from Reaction of Aminobenzothiazole with Benzaldehydes. INORGANICS 2022. [DOI: 10.3390/inorganics10040043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Schiff bases have played significant roles in the development of inorganic or coordination chemistry. Three Schiff base (NB, CB and HB) ligands, prepared for the reaction of 2-amino-6-methoxy-benzothiazole with 2-Nitrobenzaldehyde, 2-chlorobenzaldehyde and 2,4-Dihydroxybenzaldehyed, respectively, were investigated for their transition metal complexes, which were prepared by reacting the ligand (2:1 molar ratio) with Co(II), Ni(II), Cu(II), Cd(II), Cr(III) and Fe(III) chlorides. The nature of the interaction between the metal ions and ligands (L) was studied with the aid of magnetic susceptibility, elemental analysis, FTIR and 1H-NMR spectroscopy. Based on the magnetic superstability and elemental analysis results, octahedral structures of the complexes, such as [ML2Cl2] or [ML2Cl(OH)], were proposed for Cu(II), Cd(II), Co(II) and Ni(II) in which the ligand (L:NB, CB or HB) is bidentate through the azomethine and benzothiazole nitrogen. For Cr(III) and Fe(III) complexes, octahedral ML2Cl(OH)2 or ML2(OH)3 structures were proposed, where one ligand is monodentate and the other is bidentate. The azomethine ν(-HC=N-) and 1H-NMR peaks of NB and CB were shifted to a higher frequency and downfield, respectively, upon complexation with metal ions. The bonding of OH groups of HB to Co(II), Cu(II) and Ni(II) enables π-backdonation from these metals to the azomethine of Schiff bases and the consequent shift of ν(-HC=N-) to a lower frequency and changes in the intensity of the 1H-NMR peak of OH. On the other hand, this backdonation was not evidenced in the FTIR of HB complexes with high-charge Cr(III) and Fe(III) ions.
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10
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Aleshin DY, Diego R, Barrios LA, Nelyubina YV, Aromí G, Novikov VV. Unravelling of a [High Spin—Low Spin] ↔ [Low Spin—High Spin] Equilibrium in Spin‐Crossover Iron(II) Dinuclear Helicates Using Paramagnetic NMR Spectroscopy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202110310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dmitry Yu. Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
| | - Rosa Diego
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Leoní A. Barrios
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Yulia V. Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
- Moscow Institute of Physics and Technology Institutskiy per. 9 141700 Dolgoprudny Moscow region Russia
| | - Guillem Aromí
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Valentin V. Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
- Moscow Institute of Physics and Technology Institutskiy per. 9 141700 Dolgoprudny Moscow region Russia
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11
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Shahid N, Burrows KE, Pask CM, Cespedes O, Howard MJ, McGowan PC, Halcrow MA. Heteroleptic iron( ii) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate. Dalton Trans 2022; 51:4262-4274. [DOI: 10.1039/d2dt00393g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The spin-crossover properties of [Fe(LR)L][ClO4]2 (LR = a chiral PyBox {L1R} or ThioPyBox {L2R} derivative) show subtle differences depending on the tridentate ‘L’ co-ligand.
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Affiliation(s)
- Namrah Shahid
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Kay E. Burrows
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | | | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, WH Bragg Building, Leeds, UK LS2 9JT
| | - Mark J. Howard
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Patrick C. McGowan
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
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12
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KANETOMO T, Ni Z, Enomoto M. Hydrogen-Bonded Cobalt(II)-Organic Framework: Normal and Reverse Spin-Crossover Behaviours. Dalton Trans 2022; 51:5034-5040. [DOI: 10.1039/d2dt00453d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel hydrogen-bonded metal-organic framework (H-MOF) [Co(HL)2](DMF)1.2(H2O)2.4 (1·solv), in which L = 2,2’:6’,2”-terpyridine-5,5’-diyl biscarboxylate, was prepared. An intermolecular single H-bond between carboxy and carboxylate sites was present in this compound....
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13
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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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14
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Aleshin DY, Diego R, Barrios LA, Nelyubina YV, Aromí G, Novikov VV. Unravelling of a [High Spin-Low Spin] ↔ [Low Spin-High Spin] Equilibrium in Spin-Crossover Iron(II) Dinuclear Helicates Using Paramagnetic NMR Spectroscopy. Angew Chem Int Ed Engl 2021; 61:e202110310. [PMID: 34757659 DOI: 10.1002/anie.202110310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/10/2021] [Indexed: 12/11/2022]
Abstract
Spin-crossover between high-spin (HS) and low-spin (LS) states of selected transition metal ions in polynuclear and polymeric compounds is behind their use as multistep switchable materials in breakthrough electronic and spintronic devices. We report the first successful attempt to observe the dynamics of a rarely found broken-symmetry spin state in binuclear complexes, which mixes the states [HS-LS] and [LS-HS] on a millisecond timescale. The slow exchange between these two states, which was identified by paramagnetic NMR spectroscopy in solutions of two spin-crossover iron(II) binuclear helicates that are amenable to molecular design, opens a path to double quantum dot cellular automata for information storage and processing.
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Affiliation(s)
- Dmitry Yu Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia
| | - Rosa Diego
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Leoní A Barrios
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per. 9, 141700 Dolgoprudny, Moscow region, Russia
| | - Guillem Aromí
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Valentin V Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per. 9, 141700 Dolgoprudny, Moscow region, Russia
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15
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Novikov VV, Nelyubina YV. Modern physical methods for the molecular design of single-molecule magnets. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr5002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
Many paramagnetic metal complexes have emerged as unique magnetic materials (single-molecule magnets), which behave as conventional magnets at the single-molecule level, thereby making it possible to use them in modern devices for data storage and processing. The rational design of these complexes, however, requires a deep understanding of the physical laws behind a single-molecule magnet behaviour, the mechanisms of magnetic relaxation that determines the magnetic properties and the relationship of these properties with the structure of single-molecule magnets. This review focuses on the physical methods providing such understanding, including different versions and various combinations of magnetometry, electron paramagnetic and nuclear magnetic resonance spectroscopy, optical spectroscopy and X-ray diffraction. Many of these methods are traditionally used to determine the composition and structure of new chemical compounds. However, they are rarely applied to study molecular magnetism.
The bibliography includes 224 references.
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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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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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