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Banachowicz P, Das M, Kruczała K, Siczek M, Sojka Z, Kijewska M, Pawlicki M. Breaking Global Diatropic Current to Tame Diradicaloid Character: Thiele's Hydrocarbon Under Macrocyclic Constraints. Angew Chem Int Ed Engl 2024; 63:e202400780. [PMID: 38407458 DOI: 10.1002/anie.202400780] [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: 01/11/2024] [Revised: 02/18/2024] [Accepted: 02/23/2024] [Indexed: 02/27/2024]
Abstract
A diradical/biradical character of organic derivatives is one of the key aspects of contemporary research focusing on the fundamental studies followed by potential applicability relying on the unique optical, electronic, or magnetic properties assigned to unpaired electrons. A precise involvement of two p-phenylenes into a cyclophane-like conjugated, diatropic system creates a flexible molecule with the two different characters of both subunits (benzene and quinone) imprinting into the structure a Kekulé delocalized system. A dynamic of both carbocyclic subunits, and their mutual interaction generates a singlet open-shell state (J=-1.25 kcal/mol) as documented spectroscopically (NMR and EPR). The extended theoretical analysis has proved a correlation between dihedral angle and the diradicaloid character that shifts from a closed-shell singlet to an open-shell state, eventually showing the y0=0.86 for 78 degrees and ΔEST=-0.34 kcal/mol.
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Affiliation(s)
- Piotr Banachowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Mainak Das
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Krzysztof Kruczała
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Miłosz Siczek
- Department of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50383, Wrocław, Poland
| | - Zbigniew Sojka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Monika Kijewska
- Department of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50383, Wrocław, Poland
| | - Miłosz Pawlicki
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
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2
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Yan M, Hou L, Deng X, Shi X, Jiang F, Wang M. Anthraquinodimethane-Based Molecular Switches Tethered by Four-Arm Star-like Polymers. Chemistry 2023:e202303740. [PMID: 38149886 DOI: 10.1002/chem.202303740] [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: 11/09/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 12/28/2023]
Abstract
Molecular switches that reversibly change their structures and physical properties are important for applications such as sensing and information processing at molecular scales. In order to avoid the intermolecular aggregation that is often detrimental to the stimuli-responses of molecular switches, previous studies of molecular switches have been often conducted in dilute solutions which are difficult for applications in solid-state devices. Here we report molecular design and synthesis that integrates anthraquinodimethane as molecular switching units into polymers with amenable processibility in solid states. Optical and electron spin resonance characterizations indicate that the four-arm polymers of poly(ϵ-caprolactone) or poly(D,L-lactide) tethered from anthraquinodimethane slow down the dynamics of the conformational switching between the folded and the twisted conformations, enhance the photoluminescence in solid states and impart materials with a small energy gap from singlet ground state to thermally accessible triplet state.
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Affiliation(s)
- Mengwen Yan
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Liman Hou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Xianjun Deng
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Xinyuan Shi
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Feng Jiang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Mingfeng Wang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
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3
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Lien CY, Boyn JN, Anferov SW, Mazziotti DA, Anderson JS. Origin of Weak Magnetic Coupling in a Dimanganese(II) Complex Bridged by the Tetrathiafulvalene-Tetrathiolate Radical. Inorg Chem 2023; 62:19488-19497. [PMID: 37967380 DOI: 10.1021/acs.inorgchem.3c02534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Magnetic exchange coupling (J) between different spin centers plays a crucial role in molecule-based magnetic materials. Direct exchange coupling between an organic radical and a metal is frequently stronger than superexchange through diamagnetic ligands, and the strategy of using organic radicals to engender desirable magnetic properties has been an area of active investigation. Despite significant advances and exciting bulk properties, the magnitude of J for radical linkers bridging paramagnetic centers is still difficult to rationally predict. It is thus important to elucidate the features of organic radicals that govern this parameter. Here, we measure J for the tetrathiafulvalene-tetrathiolate radical (TTFtt3-•) in a dinuclear Mn(II) complex. Magnetometry studies show that the antiferromagnetic coupling in this complex is much weaker than that in related Mn(II)-radical compounds, in contrast to what might be expected for the S-based chelating donor atoms of TTFtt. Experimental and computational analyses suggest that this small J coupling may be attributed to poor overlap between Mn- and TTFtt-based magnetic orbitals coupled with insignificant spin density on the coordinating S-atoms. These factors override any expected increase in J from the comparatively strong S-donors. This work elucidates the magnetic coupling properties of the TTFtt3-• radical for the first time and also demonstrates how multiple competing factors must be considered in rationally designing organic radical ligands for molecular-based magnetic compounds.
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Affiliation(s)
- Chen-Yu Lien
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Jan-Niklas Boyn
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Sophie W Anferov
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - David A Mazziotti
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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4
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Jiang N, Boyn JN, Ramanathan A, La Pierre HS, Anderson JS. Tetrathiafulvalene-2,3,6,7-tetrathiolate linker redox-state elucidation via S K-edge X-ray absorption spectroscopy. Chem Commun (Camb) 2023; 59:9537-9540. [PMID: 37458323 PMCID: PMC10392963 DOI: 10.1039/d3cc02325g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/28/2023] [Indexed: 08/02/2023]
Abstract
Sulfur K-edge XAS data provide a unique tool to examine oxidation states and covalency in electronically complex S-based ligands. We present sulfur K-edge X-ray absorption spectroscopy on a discrete redox-series of Ni-based tetrathiafulvalene tetrathiolate (TTFtt) complexes as well as on a 1D coordination polymer (CP), NiTTFtt. Experiment and theory suggest that Ni-S covalency decreases with oxidation which has implications for charge transport pathways.
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Affiliation(s)
- Ningxin Jiang
- Department of Chemistry and The James Franck Institute, University of Chicago, Chicago, Illinois, 60637, USA.
| | - Jan-Niklas Boyn
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, 08544-5263, USA
| | - Arun Ramanathan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA.
| | - Henry S La Pierre
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA.
| | - John S Anderson
- Department of Chemistry and The James Franck Institute, University of Chicago, Chicago, Illinois, 60637, USA.
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5
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McNamara LE, Boyn JN, Melnychuk C, Anferov SW, Mazziotti DA, Schaller RD, Anderson JS. Bright, Modular, and Switchable Near-Infrared II Emission from Compact Tetrathiafulvalene-Based Diradicaloid Complexes. J Am Chem Soc 2022; 144:16447-16455. [PMID: 36037407 DOI: 10.1021/jacs.2c04976] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Near-infrared (NIR)-emitting molecules are promising candidates for biological sensing and imaging applications; however, many NIR dyes are large conjugated systems which frequently have issues with stability, solubility, and tunability. Here, we report a novel class of compact and tunable fluorescent diradicaloid complexes which are air-, water-, light-, and temperature-stable. These properties arise from a compressed π manifold which promotes an intense ligand-centered π-π transition in the NIR II (1000-1700 nm) region and which subsequently emits at ∼1200 nm. This emission is among the brightest known for monomolecular lumiphores with deep NIR II (>1100 nm) emission, nearly an order of magnitude brighter than the commercially available NIR II dye IR 26. Furthermore, this fluorescence is electrochemically sensitive, with efficient switching upon addition of redox agents. The brightness, stability, and modularity of this system distinguish it as a promising candidate for the development of new technologies built around NIR emission.
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Affiliation(s)
- Lauren E McNamara
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jan-Niklas Boyn
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Christopher Melnychuk
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Sophie W Anferov
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - David A Mazziotti
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - John S Anderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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6
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Huang Q, Chen J, Luan P, Ding C, Li C. Understanding the factors governing the water oxidation reaction pathway of mononuclear and binuclear cobalt phthalocyanine catalysts. Chem Sci 2022; 13:8797-8803. [PMID: 35975146 PMCID: PMC9350663 DOI: 10.1039/d2sc02213c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2022] Open
Abstract
The rational design of efficient catalysts for electrochemical water oxidation highly depends on the understanding of reaction pathways, which still remains a challenge. Herein, mononuclear and binuclear cobalt phthalocyanine (mono-CoPc and bi-CoPc) with a well-defined molecular structure are selected as model electrocatalysts to study the water oxidation mechanism. We found that bi-CoPc on a carbon support (bi-CoPc/carbon) shows an overpotential of 357 mV at 10 mA cm-2, much lower than that of mono-CoPc/carbon (>450 mV). Kinetic analysis reveals that the rate-determining step (RDS) of the oxygen evolution reaction (OER) over both electrocatalysts is a nucleophilic attack process involving a hydroxy anion (OH-). However, the substrate nucleophilically attacked by OH- for bi-CoPc is the phthalocyanine cation-radical species (CoII-Pc-Pc˙+-CoII-OH) that is formed from the oxidation of the phthalocyanine ring, while cobalt oxidized species (Pc-CoIII-OH) is involved in mono-CoPc as evidenced by the operando UV-vis spectroelectrochemistry technique. DFT calculations show that the reaction barrier for the nucleophilic attack of OH- on CoII-Pc-Pc˙+-CoII-OH is 1.67 eV, lower than that of mono-CoPc with Pc-CoIII-OH nucleophilically attacked by OH- (1.78 eV). The good agreement between the experimental and theoretical results suggests that bi-CoPc can effectively stabilize the accumulated oxidative charges in the phthalocyanine ring, and is thus bestowed with a higher OER performance.
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Affiliation(s)
- Qing'e Huang
- Department of Chemical Physics, University of Science and Technology of China Hefei 230026 China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
| | - Jun Chen
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Peng Luan
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
| | - Chunmei Ding
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
| | - Can Li
- Department of Chemical Physics, University of Science and Technology of China Hefei 230026 China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
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7
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Boyn JN, McNamara LE, Anderson JS, Mazziotti DA. Interplay of Electronic and Geometric Structure Tunes Organic Biradical Character in Bimetallic Tetrathiafulvalene Tetrathiolate Complexes. J Phys Chem A 2022; 126:3329-3337. [PMID: 35604797 DOI: 10.1021/acs.jpca.2c01773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis and design of organic biradicals with tunable singlet-triplet gaps have become the subject of significant research interest, owing to their possible photochemical applications and use in the development of molecular switches and conductors. Recently, tetrathiafulvalene tetrathiolate (TTFtt) has been demonstrated to exhibit such organic biradical character in doubly ionized bimetallic complexes. In this article we use high-level ab initio calculations to interrogate the electronic structure of a series of TTFtt-bridged metal complexes, resolving the factors governing their biradical character and singlet-triplet gaps. We show that the degree of biradical character correlates with a readily measured experimental predictor, the central TTFtt C-C bond length, and that it may be described by a one-parameter model, providing valuable insight for the future rational design of TTFtt based biradical compounds and materials.
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Affiliation(s)
- Jan-Niklas Boyn
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Lauren E McNamara
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - David A Mazziotti
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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8
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Sager LM, Schouten AO, Mazziotti DA. Beginnings of exciton condensation in coronene analog of graphene double layer. J Chem Phys 2022; 156:154702. [PMID: 35459326 DOI: 10.1063/5.0084564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exciton condensation, a Bose-Einstein condensation of excitons into a single quantum state, has recently been achieved in low-dimensional materials including twin layers of graphene and van der Waals heterostructures. Here, we computationally examine the beginnings of exciton condensation in a double layer composed of coronene, a seven-benzene-ring patch of graphene. As a function of interlayer separation, we compute the exciton population in a single coherent quantum state, showing that the population peaks around 1.8 at distances near 2 Å. Visualization reveals interlayer excitons at the separation distance of the condensate. We determine the exciton population as a function of the twist angle between two coronene layers to reveal the magic angles at which the condensation peaks. As with previous recent calculations showing some exciton condensation in hexacene double layers and benzene stacks, the present two-electron reduced-density-matrix calculations with coronene provide computational evidence for the ability to realize exciton condensation in molecular-scale analogs of extended systems such as the graphene double layer.
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Affiliation(s)
- LeeAnn M Sager
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Anna O Schouten
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - David A Mazziotti
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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9
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Chen X, Xie H, Lorenzo ER, Zeman CJ, Qi Y, Syed ZH, Stone AEBS, Wang Y, Goswami S, Li P, Islamoglu T, Weiss EA, Hupp JT, Schatz GC, Wasielewski MR, Farha OK. Direct Observation of Modulated Radical Spin States in Metal–Organic Frameworks by Controlled Flexibility. J Am Chem Soc 2022; 144:2685-2693. [DOI: 10.1021/jacs.1c11417] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Xiaofeng Chen
- School of Environmental and Geographical Sciences, Shanghai Normal University, Shanghai 200234, China
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Haomiao Xie
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Emmaline R. Lorenzo
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Charles J. Zeman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Yue Qi
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Zoha H. Syed
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Aaron E. B. S. Stone
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Yao Wang
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438, China
| | - Subhadip Goswami
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Peng Li
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438, China
| | - Timur Islamoglu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Emily A. Weiss
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joseph T. Hupp
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - George C. Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael R. Wasielewski
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Omar K. Farha
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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10
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Plaza-Lozano D, Ramírez-Palma D, Vela A, Olguín J. High spin iron( ii) complexes based on imidazolyl- and 1,2,3-triazolyl-thione ligands and NCE (E = S, Se or BH 3) co-ligands: effect of the S-functional group on the structural and magnetic properties. NEW J CHEM 2022. [DOI: 10.1039/d2nj01989b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Differing magnetic behaviour in complexes of the type [FeII(N2S2)(NCE)2]: thione-based complexes are stabilised in the HS-state, whilst a previously reported picolylbenzylthioether–iron(ii) complex shows a hysteretic spin crossover behaviour.
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Affiliation(s)
- Diego Plaza-Lozano
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN 2508, Col. San Pedro Zacatenco, Ciudad de México 07360, Mexico
| | - David Ramírez-Palma
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN 2508, Col. San Pedro Zacatenco, Ciudad de México 07360, Mexico
| | - Alberto Vela
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN 2508, Col. San Pedro Zacatenco, Ciudad de México 07360, Mexico
| | - Juan Olguín
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN 2508, Col. San Pedro Zacatenco, Ciudad de México 07360, Mexico
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11
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Li K, Feng Z, Ruan H, Sun Q, Zhao Y, Wang X. The catenation of a singlet diradical dication and modulation of diradical character by metal coordination. Chem Commun (Camb) 2022; 58:6457-6460. [DOI: 10.1039/d2cc01539k] [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
A singlet bis(triarylamine) diradical dication and its zigzag 1D magnetic chain catenated by silver cations were isolated and characterized by single-crystal X-ray crystallography, EPR spectroscopy, SQUID measurements, cyclic voltammetry and...
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12
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Normal & reversed spin mobility in a diradical by electron-vibration coupling. Nat Commun 2021; 12:6262. [PMID: 34716307 PMCID: PMC8556253 DOI: 10.1038/s41467-021-26368-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 09/29/2021] [Indexed: 11/26/2022] Open
Abstract
π−conjugated radicals have great promise for use in organic spintronics, however, the mechanisms of spin relaxation and mobility related to radical structural flexibility remain unexplored. Here, we describe a dumbbell shape azobenzene diradical and correlate its solid-state flexibility with spin relaxation and mobility. We employ a combination of X-ray diffraction and Raman spectroscopy to determine the molecular changes with temperature. Heating leads to: i) a modulation of the spin distribution; and ii) a “normal” quinoidal → aromatic transformation at low temperatures driven by the intramolecular rotational vibrations of the azobenzene core and a “reversed” aromatic → quinoidal change at high temperatures activated by an azobenzene bicycle pedal motion amplified by anisotropic intermolecular interactions. Thermal excitation of these vibrational states modulates the diradical electronic and spin structures featuring vibronic coupling mechanisms that might be relevant for future design of high spin organic molecules with tunable magnetic properties for solid state spintronics. In this manuscript, Negri, Zheng, Casado et al develop a stable and flexible diradical. Using a combination of experimental and theoretical techniques, they show how heating leads to change in the electronic and spin delocalizations ocurring between quinoidal and aromatic forms, and elucidate a unique spin-vibrational coupling.
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13
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Pyridyl-Thioethers as Capping Ligands for the Design of Heteroleptic Fe(II) Complexes with Spin-Crossover Behavior. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry7100134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mononuclear heteroleptic complexes [Fe(tpma)(bimz)](ClO4)2 (1a), [Fe(tpma)(bimz)](BF4)2 (1b), [Fe(bpte)(bimz)](ClO4)2 (2a), and [Fe(bpte)(bimz)](BF4)2 (2b) (tpma = tris(2-pyridylmethyl)amine, bpte = S,S′-bis(2-pyridylmethyl)-1,2-thioethane, bimz = 2,2′-biimidazoline) were prepared by reacting the corresponding Fe(II) salts with stoichiometric amounts of the ligands. All complexes exhibit temperature-induced spin crossover (SCO), but the SCO temperature is substantially lower for complexes 1a and 1b as compared to 2a and 2b, indicating the stronger ligand field afforded by the N2S2-coordinating bpte ligand relative to the N4-coordinating tpma. Our findings suggest that ligands with mixed N/S coordination can be employed to discover new SCO complexes and to tune the transition temperature of known SCO compounds by substituting for purely N-coordinating ligands.
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14
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Zhou ZY, Ge CY, Jiang M, Hou JL, Zhu QY, Dai J. Copper-bipyridine grid frameworks incorporating redox-active tetrathiafulvalene: structures and supercapacitance. Dalton Trans 2021; 50:11091-11098. [PMID: 34612245 DOI: 10.1039/d1dt01805a] [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
Redox active tetrathiafulvalene (TTF) and its derivatives when used as electrode additives have exhibited improved energy efficiency and sustainability in batteries. However, the structure-property relationship has not been investigated in detail until very recently. In this work, three redox-active TTF compounds were synthesized, and formulated as [Cu(HL)2(bpa)2]n (1), [Cu(bpe)2(H2O)2]n·2n(HL)·nMeOH·nH2O (2), and [Cu(bpp)2(H2O)2]n·2n(HL) (3) (L = dimethylthio-tetrathiafulvalene-bicarboxylate) for this work. The effects of conjugated state and spacer length of the linkers on structural assembly and band gap as well as the interactions of TTF-TTF/TTF-bpy are discussed. Compound 1 is a bpa and HL co-coordinated 1D Cu(ii) polymer. Compounds 2 and 3 are 2D Cu(ii)-bipyridine (4,4) MOFs incorporating HL (1-) as free anion columns. The photocurrent density of 2 is larger than those of 1 and 3 due to a strong charge transfer from TTF to bpe in compound 2. The supercapacitance performances of these compounds were evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. The results revealed that the 2D MOF structures of 2 and 3 are beneficial for good specific capacitance values (Csp). This work revealed the structure-property relationships of TTF derivatives for use as electrode active materials in energy transfer and storage.
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Affiliation(s)
- Zi-Yao Zhou
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
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15
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Üngör Ö, Choi ES, Shatruk M. Optimization of crystal packing in semiconducting spin-crossover materials with fractionally charged TCNQ δ- anions (0 < δ < 1). Chem Sci 2021; 12:10765-10779. [PMID: 34476058 PMCID: PMC8372557 DOI: 10.1039/d1sc02843j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/02/2021] [Indexed: 11/21/2022] Open
Abstract
Co-crystallization of the prominent Fe(ii) spin-crossover (SCO) cation, [Fe(3-bpp)2]2+ (3-bpp = 2,6-bis(pyrazol-3-yl)pyridine), with a fractionally charged TCNQ δ- radical anion has afforded a hybrid complex [Fe(3-bpp)2](TCNQ)3·5MeCN (1·5MeCN, where δ = -0.67). The partially desolvated material shows semiconducting behavior, with the room temperature conductivity σ RT = 3.1 × 10-3 S cm-1, and weak modulation of conducting properties in the region of the spin transition. The complete desolvation, however, results in the loss of hysteretic behavior and a very gradual SCO that spans the temperature range of 200 K. A related complex with integer-charged TCNQ- anions, [Fe(3-bpp)2](TCNQ)2·3MeCN (2·3MeCN), readily loses the interstitial solvent to afford desolvated complex 2 that undergoes an abrupt and hysteretic spin transition centered at 106 K, with an 11 K thermal hysteresis. Complex 2 also exhibits a temperature-induced excited spin-state trapping (TIESST) effect, upon which a metastable high-spin state is trapped by flash-cooling from room temperature to 10 K. Heating above 85 K restores the ground-state low-spin configuration. An approach to improve the structural stability of such complexes is demonstrated by using a related ligand 2,6-bis(benzimidazol-2'-yl)pyridine (bzimpy) to obtain [Fe(bzimpy)2](TCNQ)6·2Me2CO (4) and [Fe(bzimpy)2](TCNQ)5·5MeCN (5), both of which exist as LS complexes up to 400 K and exhibit semiconducting behavior, with σ RT = 9.1 × 10-2 S cm-1 and 1.8 × 10-3 S cm-1, respectively.
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Affiliation(s)
- Ökten Üngör
- Department of Chemistry and Biochemistry, Florida State University 95 Chieftan Way Tallahassee FL 32306 USA
| | - Eun Sang Choi
- National High Magnetic Field Laboratory 1800 E Paul Dirac Dr Tallahassee FL 32310 USA
| | - Michael Shatruk
- Department of Chemistry and Biochemistry, Florida State University 95 Chieftan Way Tallahassee FL 32306 USA
- National High Magnetic Field Laboratory 1800 E Paul Dirac Dr Tallahassee FL 32310 USA
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16
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Jesse KA, Chang MC, Filatov AS, Anderson JS. Iron(II) Complexes Featuring a Redox-Active Dihydrazonopyrrole Ligand. Z Anorg Allg Chem 2021; 647:1415-1420. [PMID: 36059917 PMCID: PMC9435867 DOI: 10.1002/zaac.202100097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Indexed: 09/04/2024]
Abstract
Nature uses control of the secondary coordination sphere to facilitate an astounding variety of transformations. Similarly, synthetic chemists have found metal-ligand cooperativity to be a powerful strategy for designing complexes that can mediate challenging reactivity. In particular, this strategy has been used to facilitate two electron reactions with first row transition metals that more typically engage in one electron redox processes. While NNN pincer ligands feature prominently in this area, examples which can potentially engage in both proton and electron transfer are less common. Dihydrazonopyrrole (DHP) ligands have been isolated in a variety of redox and protonation states when complexed to Ni. However, the redox-state of this ligand scaffold is less obvious when complexed to metal centers with more accessible redox couples. Here, we synthesize a new series of Fe-DHP complexes in two distinct oxidation states. Detailed characterization supports that the redox-chemistry in this set is still primarily ligand based. Finally, these complexes exist as 5-coordinate species with an open coordination site offering the possibility of enhanced reactivity.
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Affiliation(s)
- Kate A Jesse
- University of Chicago Department of Chemistry, 929 E 57 St. Chicago, IL, 60637
| | - Mu-Chieh Chang
- National Taiwan University Department of Chemistry, No. 1, Section 4, Roosevelt Rd, Da'an District, Taipei City, Taiwan 10
| | - Alexander S Filatov
- University of Chicago Department of Chemistry, 929 E 57 St. Chicago, IL, 60637
| | - John S Anderson
- University of Chicago Department of Chemistry, 929 E 57 St. Chicago, IL, 60637
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17
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Tiaouinine S, Flores Gonzalez J, Lefeuvre B, Guizouarn T, Cordier M, Dorcet V, Kaboub L, Cador O, Pointillart F. Spin Crossover and Field‐Induced Single‐Molecule Magnet Behaviour in Co(II) Complexes Based on Terpyridine with Tetrathiafulvalene Analogues. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Siham Tiaouinine
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
- Laboratory of Organic Materials and Heterochemistry University of Tebessa Rue de Constantine 12002 Tébessa Algeria
| | - Jessica Flores Gonzalez
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Bertrand Lefeuvre
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Thierry Guizouarn
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Marie Cordier
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Vincent Dorcet
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Lakehmici Kaboub
- Laboratory of Organic Materials and Heterochemistry University of Tebessa Rue de Constantine 12002 Tébessa Algeria
- Laboratory of Chemistry Molecular Engineering and Nanostructures University of Ferhat Abbas-Sétif 1 19000 Sétif Algeria
| | - Olivier Cador
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
| | - Fabrice Pointillart
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) – UMR 6226 35000 Rennes France
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18
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Hoffbauer MR, Iluc VM. [2+2] Cycloadditions with an Iron Carbene: A Critical Step in Enyne Metathesis. J Am Chem Soc 2021; 143:5592-5597. [DOI: 10.1021/jacs.0c12175] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Melissa R. Hoffbauer
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Vlad M. Iluc
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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19
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Boyn JN, Mazziotti DA. Accurate singlet-triplet gaps in biradicals via the spin averaged anti-Hermitian contracted Schrödinger equation. J Chem Phys 2021; 154:134103. [PMID: 33832273 DOI: 10.1063/5.0045007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The accurate description of biradical systems, and in particular the resolution of their singlet-triplet gaps, has long posed a major challenge to the development of electronic structure theories. Biradicaloid singlet ground states are often marked by strong correlation and, hence, may not be accurately treated by mainstream, single-reference methods such as density functional theory or coupled cluster theory. The anti-Hermitian contracted Schrödinger equation (ACSE), whose fundamental quantity is the two-electron reduced density matrix rather than the N-electron wave function, has previously been shown to account for both dynamic and strong correlations when seeded with a strongly correlated guess from a complete active space (CAS) calculation. Here, we develop a spin-averaged implementation of the ACSE, allowing it to treat higher multiplicity states from the CAS input without additional state preparation. We apply the spin-averaged ACSE to calculate the singlet-triplet gaps in a set of small main group biradicaloids, as well as the organic four-electron biradicals trimethylenemethane and cyclobutadiene, and naphthalene, benchmarking the results against other state-of-the-art methods reported in the literature.
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Affiliation(s)
- Jan-Niklas Boyn
- The Department of Chemistry, The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - David A Mazziotti
- The Department of Chemistry, The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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Deorukhkar N, Besnard C, Guénée L, Piguet C. Tuning spin-crossover transition temperatures in non-symmetrical homoleptic meridional/facial [Fe(didentate) 3] 2+ complexes: what for and who cares about it? Dalton Trans 2021; 50:1206-1223. [PMID: 33404561 DOI: 10.1039/d0dt03828h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The [FeN6] chromophores found in [Fe(didentate)3]2+ complexes, where didentate is a non-symmetrical 2-(6-membered-heterocyclic ring)-benzimidazole ligand (Lk), exist as mixtures of two geometrical mer (C1-symmetry) and fac (C3-symmetry) isomers. Specific alkyl-substituted six-membered heterocyclic rings connected to the benzimidazole unit (pyridines in ligands L1-L3, pyrazines in L4-L5 and pyrimidines in L6-L7) control the ligand field strength and the electron delocalization so that [FeII(Lk)3]2+ display tunable thermally-induced spin transitions in solution. Thermodynamic, spectroscopic (UV-Vis, NMR) and magnetic studies in solution demonstrate that [Fe(L6)3]2+ (L6 = 1-methyl-2-(pyrimidin-2-yl)-1H-benzo[d]imidazole) exhibits a close to room temperature spin transition (T1/2 = 273(3) K) combined with a high stability formation constant ( in acetonitrile), which makes this complex suitable for the potential modulation of lanthanide-based luminescence in polymetallic helicates. A novel method is proposed for assigning specific thermodynamic spin crossover parameters to fac-[Fe(L6)3]2+ and mer-[Fe(L6)3]2+ isomers in solution. The observed difference relies mainly on the entropic content ΔS-ΔS = 11(1) J mol-1 K-1, which favors the spin transition for the meridional isomer. Intermolecular interactions occurring in the crystalline state largely overcome minor thermodynamic trends operating in diluted solutions and a single configurational isomer is usually observed in the solid state. Among the thirteen solved crystal structures 1-13 containing the [M(Lk)3]2+ cations (M = Fe, Ni, Zn, Lk = L6-L7), pure meridional isomers are observed six times, pure facial isomers also six times and a mixture (44% mer and 56% fac) is detected only once. Solid-state magnetic data recorded for the FeII complexes show the operation of slightly cooperative spin transitions in 7 (fac-[Fe(L6)3]2+) and 12 (mer-[Fe(L7)3]2+). For the meridional isomer in 6, a two-step spin state transition curve, associated with two phase transitions, is detected.
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Affiliation(s)
- Neel Deorukhkar
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
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