1
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Sundaresan S, Eppelsheimer J, Gera E, Wiener L, Carrella LM, Vignesh KR, Rentschler E. A combined theoretical and experimental approach to determine the right choice of co-ligand to impart spin crossover in Fe(II) complexes based on 1,3,4-oxadiazole ligands. Dalton Trans 2024; 53:10303-10317. [PMID: 38832753 DOI: 10.1039/d4dt01141d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
We present the synthesis of two new novel tetradentate ligands based on 1,3,4-oxadiazole, 2-(2-pyridyl)-5-[N,N-bis(2-pyridylmethyl)aminomethyl]-1,3,4-oxadiazole (LTetraPy-ODA) and 2-(2-phenyl)-5-[N,N-bis(2-pyridylmethyl)aminomethyl]-1,3,4-oxadiazole (LTetraPh-ODA). The ligands were used to prepare six mononuclear complexes [FeII(LTetraPy-ODA)(NCE)] (C1-C3) and [FeII(LTetraPh-ODA)(NCE)] (C4-C6) where E = S, Se or BH3. In addition, the ligand LTetraPy-ODA was employed in the synthesis of a new di-nuclear complex [FeII2(LTetraPh)](ClO4)4·1 CH3NO2·1.5 H2O (C7). Characterization of all complexes was carried out using single-crystal X-ray crystallography, elemental analysis, and infrared spectroscopy. Magnetic susceptibility measurements, performed in the temperature range of 2-300 K using a SQUID magnetometer, revealed spin crossover behaviour exclusively in the mononuclear complexes C3 and C6, in which two monodentate NCBH3- co-ligands coordinate. The presence of the lattice solvent was found to be crucial to the spin transition property, with complex C3 exhibiting a switching temperature (T1/2) of approximately 165 K and C6 approximately 194 K. The other four mononuclear complexes C1, C2, C4, C5, as well as the dinuclear complex C7 are locked in the high spin state over the measured temperature range. Density Functional Theory (DFT) calculations were performed on complexes C1-C6 to rationalise the observed magnetic behaviour, demonstrating the significant effect of the NCS-, NCSe- and NCBH3- co-ligands ligands on the spin-crossover behaviour of the [FeII(L)(NCE)] complexes.
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Affiliation(s)
- Sriram Sundaresan
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Julian Eppelsheimer
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Esha Gera
- Department of Chemical Scienaces, Indian Institute of Science Education Research (IISER) Mohali, Sector-81, Knowledge City, S.A.S. Nagar, Mohali 140306, Punjab, India.
| | - Lukas Wiener
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Luca M Carrella
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Kuduva R Vignesh
- Department of Chemical Scienaces, Indian Institute of Science Education Research (IISER) Mohali, Sector-81, Knowledge City, S.A.S. Nagar, Mohali 140306, Punjab, India.
| | - Eva Rentschler
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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2
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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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3
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Capel Berdiell I, Michaels E, Munro OQ, Halcrow MA. A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes. Inorg Chem 2024; 63:2732-2744. [PMID: 38258555 PMCID: PMC10848207 DOI: 10.1021/acs.inorgchem.3c04138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
Reaction of 2,4,6-trifluoropyridine with sodium 3,4-dimethoxybenzenethiolate and 2 equiv of sodium pyrazolate in tetrahydrofuran at room temperature affords 4-(3,4-dimethoxyphenylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine (L), in 30% yield. The iron(II) complexes [FeL2][BF4]2 (1a) and [FeL2][ClO4]2 (1b) are high-spin with a highly distorted six-coordinate geometry. This structural deviation from ideal D2d symmetry is common in high-spin [Fe(bpp)2]2+ (bpp = di{pyrazol-1-yl}pyridine) derivatives, which are important in spin-crossover materials research. The magnitude of the distortion in 1a and 1b is the largest yet discovered for a mononuclear complex. Gas-phase DFT calculations at the ω-B97X-D/6-311G** level of theory identified four minimum or local minimum structural pathways across the distortion landscape, all of which are observed experimentally in different complexes. Small distortions from D2d symmetry are energetically favorable in complexes with electron-donating ligand substituents, including sulfanyl groups, which also have smaller energy penalties associated with the lowest energy distortion pathway. Natural population analysis showed that these differences reflect greater changes to the Fe-N{pyridyl} σ-bonding as the distortion proceeds, in the presence of more electron-rich pyridyl donors. The results imply that [Fe(bpp)2]2+ derivatives with electron-donating pyridyl substituents are more likely to undergo cooperative spin transitions in the solid state. The high-spin salt [Fe(bpp)2][CF3SO3]2, which also has a strong angular distortion, is also briefly described and included in the analysis.
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Affiliation(s)
| | - Evridiki Michaels
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Orde Q. Munro
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
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4
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Zeng FL, Jin XT, Zhao J, Zhang SX, Xue C, Luo YH. Construction and screening of spin-crossover-sponge materials based on iron(II)-triazole coordination polymers. Dalton Trans 2024; 53:2333-2340. [PMID: 38205731 DOI: 10.1039/d3dt03531j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Iron(II)-triazole coordination polymers have attracted considerable interest for their synthetic versatility, which allows tuning their spin-crossover (SCO) properties. Embedding SCO solid particles in sponge matrices is a simple, powerful, and generic approach to construct processable SCO materials. Here, we have studied a series of magnetic frameworks based on partial ligand substitution by using different chemical mixtures of two organic ligands, yielding four isostructural coordination polymers. The integration of the hygroscopic SCO material has endowed the composite sponge with the ability to capture moisture under ambient conditions. In particular, not only does a spin-crossover transition during absorption occur, but also a color variation has been achieved by varying humidity. The consequences of cooperativity and the exposed surface of the composite sponge on the spin transition were evaluated and the most promising materials among them were screened. This work provides guiding significance for the fabrication and practical application of spin-crossover-sponge materials.
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Affiliation(s)
- Feng-Lian Zeng
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
| | - Xue-Ting Jin
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
| | - Jie Zhao
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
| | - Shu-Xin Zhang
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
| | - Cheng Xue
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
| | - Yang-Hui Luo
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
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5
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Sundaresan S, Becker JG, Eppelsheimer J, Sedykh AE, Carrella LM, Müller-Buschbaum K, Rentschler E. Synergetic spin singlet-quintet switching and luminescence in mononuclear Fe(II) 1,3,4-oxadiazole tetradentate chelates with NCBH 3 co-ligand. Dalton Trans 2023; 52:13181-13189. [PMID: 37664901 DOI: 10.1039/d3dt02420b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
We report the multi-step synthesis of the tetradentate 2-(naphthalen-2-yl)-5-[N,N-bis(2-pyridylmethyl)aminomethyl]-1,3,4-oxadiazole ligand (LTetra-ODA) along with its corresponding [FeII(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) complex, which is the first mononuclear 1,3,4-oxadiazole based Fe(II) spin crossover (SCO) complex, and its zinc analogue [ZnII(LTetra-ODA)(NCBH3)2]·0.5H2O (C2). The spin transition is followed by variable temperature (VT-) X-ray crystallography of [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) at 120 and 220 K. The magnetic susceptibility measurements on the bulk sample recorded from 2 to 300 K show that the complex exhibits a complete abrupt reversible spin transition with a T1/2 of 207 K. The loss of the lattice solvent methanol shifts the T1/2 slightly to around 210 K. The spin transition in solution for [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) was followed using the VT-1H-NMR Evans method in CD3CN, with a T1/2 of 357 K. Solid state VT luminescence studies provide some preliminary evidence of interplay of luminescence and spin transition in the [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) complex.
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Affiliation(s)
- Sriram Sundaresan
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Jens-Georg Becker
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Julian Eppelsheimer
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Alexander E Sedykh
- Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Luca M Carrella
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Klaus Müller-Buschbaum
- Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Eva Rentschler
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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6
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Mihara N, Shimamura T, Takayama R, Shiga T, Nihei M. Structural Conversion of Supramolecular Assembly in Solution by Thermally Induced Intramolecular Electron Transfer of [Co 2 Fe 2 ] Complex. Chemistry 2023; 29:e202300954. [PMID: 37208296 DOI: 10.1002/chem.202300954] [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: 03/26/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/21/2023]
Abstract
Combining metal complexes with amphiphilic molecules leads to a wide variety of functional self-assembled nanostructures. Metal complexes exhibiting spin transitions can be good candidates as the trigger to cause structural conversion of such assembly because they respond to various external stimuli. In this work, we studied a structural conversion of a supramolecular assembly containing a [Co2 Fe2 ] complex through a thermally induced electron transfer-coupled spin transition (ETCST). With an amphiphilic anion, the [Co2 Fe2 ] complex formed reverse vesicles in solution and showed thermal ETCST. In contrast, thermal ETCST in the presence of a bridging hydrogen-bond donor caused structural conversion from the reverse vesicle structure to entangled one-dimensional chains through hydrogen bond formation.
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Affiliation(s)
- Nozomi Mihara
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Tomonari Shimamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Ryo Takayama
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Takuya Shiga
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Masayuki Nihei
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
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7
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Harris M, Kühne IA, Kelly CT, Jakobsen VB, Jordan R, O’Brien L, Müller-Bunz H, Felton S, Morgan GG. Compressed and Expanded Lattices - Barriers to Spin-State Switching in Mn 3+ Complexes. CRYSTAL GROWTH & DESIGN 2023; 23:3996-4012. [PMID: 37304401 PMCID: PMC10251414 DOI: 10.1021/acs.cgd.2c01284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 05/08/2023] [Indexed: 06/13/2023]
Abstract
We report the structural and magnetic properties of two new Mn3+ complex cations in the spin crossover (SCO) [Mn(R-sal2323)]+ series, in lattices with seven different counterions in each case. We investigate the effect on the Mn3+ spin state of appending electron-withdrawing and electron-donating groups on the phenolate donors of the ligand. This was achieved by substitution of the ortho and para positions on the phenolate donors with nitro and methoxy substituents in both possible geometric isomeric forms. Using this design paradigm, the [MnL1]+ (a) and [MnL2]+ (b) complex cations were prepared by complexation of Mn3+ to the hexadentate Schiff base ligands with 3-nitro-5-methoxy-phenolate or 3-methoxy-5-nitro-phenolate substituents, respectively. A clear trend emerges with adoption of the spin triplet form in complexes 1a-7a, with the 3-nitro-5-methoxy-phenolate donors, and spin triplet, spin quintet and thermal SCO in complexes 1b-7b with the 3-methoxy-5-nitro-phenolate ligand isomer. The outcomes are discussed in terms of geometric and steric factors in the 14 new compounds and by a wider analysis of electronic choices of Mn3+ with related ligands by comparison of bond length and angular distortion data of previously reported analogues in the [Mn(R-sal2323)]+ family. The structural and magnetic data published to date suggest a barrier to switching may exist for high spin forms of Mn3+ in those complexes with the longest bond lengths and highest distortion parameters. A barrier to switching from low spin to high spin is less clear but may operate in the seven [Mn(3-NO2-5-OMe-sal2323)]+ complexes 1a-7a reported here which were all low spin in the solid state at room temperature.
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Affiliation(s)
- Michelle
M. Harris
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
| | - Irina A. Kühne
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
- Department
of Functional Materials, FZU - Institute
of Physics - Czech Academy of Sciences, Na Slovance 1999/2, Prague
8, 182 21, Czech Republic
| | - Conor T. Kelly
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
| | - Vibe B. Jakobsen
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
| | - Ross Jordan
- Centre
for Quantum Materials and Technologies, School of Mathematics and
Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom
| | - Luke O’Brien
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
| | - Helge Müller-Bunz
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
| | - Solveig Felton
- Centre
for Quantum Materials and Technologies, School of Mathematics and
Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom
| | - Grace G. Morgan
- School
of Chemistry, University College Dublin, Belfield, Dublin, D04
V1W8, Ireland
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8
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Yazdani S, Phillips J, Ekanayaka TK, Cheng R, Dowben PA. The Influence of the Substrate on the Functionality of Spin Crossover Molecular Materials. Molecules 2023; 28:molecules28093735. [PMID: 37175145 PMCID: PMC10180229 DOI: 10.3390/molecules28093735] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Spin crossover complexes are a route toward designing molecular devices with a facile readout due to the change in conductance that accompanies the change in spin state. Because substrate effects are important for any molecular device, there are increased efforts to characterize the influence of the substrate on the spin state transition. Several classes of spin crossover molecules deposited on different types of surface, including metallic and non-metallic substrates, are comprehensively reviewed here. While some non-metallic substrates like graphite seem to be promising from experimental measurements, theoretical and experimental studies indicate that 2D semiconductor surfaces will have minimum interaction with spin crossover molecules. Most metallic substrates, such as Au and Cu, tend to suppress changes in spin state and affect the spin state switching process due to the interaction at the molecule-substrate interface that lock spin crossover molecules in a particular spin state or mixed spin state. Of course, the influence of the substrate on a spin crossover thin film depends on the molecular film thickness and perhaps the method used to deposit the molecular film.
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Affiliation(s)
- Saeed Yazdani
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Jared Phillips
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Thilini K Ekanayaka
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA
| | - Ruihua Cheng
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Peter A Dowben
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588-0299, USA
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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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10
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Qin CY, Zhao SZ, zhou HW, Li YH, Wang S. Effect of halogen substituents on the intermolecular interactions and magnetic properties of Mn(III) complexes. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.115896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Bondì L, Garden AL, Totti F, Jerabek P, Brooker S. Quantitative Assessment of Ligand Substituent Effects on σ‐ and π‐Contributions to Fe−N Bonds in Spin Crossover Fe
II
Complexes. Chemistry 2022; 28:e202104314. [PMID: 35224791 PMCID: PMC9310619 DOI: 10.1002/chem.202104314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Indexed: 11/24/2022]
Abstract
The effect of para‐substituent X on the electronic structure of sixteen tridentate 4‐X‐(2,6‐di(pyrazol‐1‐yl))‐pyridine (bppX) ligands and the corresponding solution spin crossover [FeII(bppX)2]2+ complexes is analysed further, to supply quantitative insights into the effect of X on the σ‐donor and π‐acceptor character of the Fe‐NA(pyridine) bonds. EDA‐NOCV on the sixteen LS complexes revealed that neither ΔEorb,σ+π (R2=0.48) nor ΔEorb,π (R2=0.31) correlated with the experimental solution T1/2 values (which are expected to reflect the ligand field imposed on the iron centre), but that ΔEorb,σ correlates well (R2=0.82) and implies that as X changes from EDG→EWG (Electron Donating to Withdrawing Group), the ligand becomes a better σ‐donor. This counter‐intuitive result was further probed by Mulliken analysis of the NA atomic orbitals: NA(px) involved in the Fe−N σ‐bond vs. the perpendicular NA(pz) employed in the ligand aromatic π‐system. As X changes EDG→EWG, the electron population on NA(pz) decreases, making it a better π‐acceptor, whilst that in NA(px) increases, making it a better σ‐bond donor; both increase ligand field, and T1/2 as observed. In 2016, Halcrow, Deeth and co‐workers proposed an intuitively reasonable explanation of the effect of the para‐X substituents on the T1/2 values in this family of complexes, consistent with the calculated MO energy levels, that M→L π‐backdonation dominates in these M−L bonds. Here the quantitative EDA‐NOCV analysis of the M−L bond contributions provides a more complete, coherent and detailed picture of the relative impact of M−L σ‐versus π‐bonding in determining the observed T1/2, refining the earlier interpretation and revealing the importance of the σ‐bonding. Furthermore, our results are in perfect agreement with the ΔE(HS‐LS) vs. σp+(X) correlation reported in their work.
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Affiliation(s)
- Luca Bondì
- Department of Chemistry MacDiarmid Institute of Advanced Materials and Nanotechnology University of Otago PO Box 56 Dunedin 9054 New Zealand
- Department of Chemistry ‘Ugo Schiff' and INSTM Research Unit University of Florence 50019 Sesto Fiorentino Italy
| | - Anna L. Garden
- Department of Chemistry MacDiarmid Institute of Advanced Materials and Nanotechnology University of Otago PO Box 56 Dunedin 9054 New Zealand
| | - Federico Totti
- Department of Chemistry ‘Ugo Schiff' and INSTM Research Unit University of Florence 50019 Sesto Fiorentino Italy
| | - Paul Jerabek
- Institute of Hydrogen Technology Helmholtz-Zentrum Hereon Max-Planck-Straße 1 21502 Geesthacht Germany
| | - Sally Brooker
- Department of Chemistry MacDiarmid Institute of Advanced Materials and Nanotechnology University of Otago PO Box 56 Dunedin 9054 New Zealand
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12
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Manipulating Selective Metal‐to‐Metal Electron Transfer to Achieve Multi‐Phase Transitions in an Asymmetric [Fe2Co]‐Assembled Mixed‐Valence Chain. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202115367] [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]
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13
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Meng YS, Yao NT, Zhao L, Yi C, Liu Q, Li YM, Oshio H, Liu T. Manipulating Selective Metal-to-Metal Electron Transfer to Achieve Multi-Phase Transitions in an Asymmetric [Fe2Co]-Assembled Mixed-Valence Chain. Angew Chem Int Ed Engl 2021; 61:e202115367. [PMID: 34971479 DOI: 10.1002/anie.202115367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Indexed: 11/08/2022]
Abstract
Manipulation of multi-functions in molecular materials is promising for future switching and memory devices, although is currently difficult. Herein, we assembled the asymmetric {Fe2Co} unit into a cyanide-bridged mixed-valence chain {[(Tp)Fe(CN)3]2Co(BIT)}·2CH3OH (1) (Tp = hydrotris(pyrazolyl)borate and BIT = 3,4-bis-(1H-imidazol-1-yl)thiophen), which showed reversible multi-phase transitions accompanied by the photo-switchable single-chain magnet property and dielectric anomalies. Variable temperature X-ray structural studies revealed thermo-and photo-induced selective electron transfer (ET) between the Co and one of the Fe ions. Alternating-current magnetic susceptibility studies revealed that 1 displayed on and off of the single-chain magnet behavior by alternating 946-nm and 532-nm light irradiations. A substantial anomaly in dielectric constant was discovered during the electron transfer process, which is uncommon in similar ET complexes. These findings illustrate that 1 provided a new platform for multi-phase transitions and multi-switches adjusted by selective metal-to-metal ET.
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Affiliation(s)
- Yin-Shan Meng
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, 2 Linggong Rd., Dalian, 116024, China., 116024, Dalian, CHINA
| | - Nian-Tao Yao
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Liang Zhao
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Cheng Yi
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Qiang Liu
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Ya-Ming Li
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Hiroki Oshio
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
| | - Tao Liu
- Dalian University of Technology, State Key Laboratory of Fine Chemicals, CHINA
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14
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Capel Berdiell I, Davies DJ, Woodworth J, Kulmaczewski R, Cespedes O, Halcrow MA. Structures and Spin States of Iron(II) Complexes of Isomeric 2,6-Di(1,2,3-triazolyl)pyridine Ligands. Inorg Chem 2021; 60:14988-15000. [PMID: 34547208 DOI: 10.1021/acs.inorgchem.1c02404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron(II) complex salts of 2,6-di(1,2,3-triazol-1-yl)pyridine (L1) are unexpectedly unstable in undried solvent. This is explained by the isolation of [Fe(L1)4(H2O)2][ClO4]2 and [Fe(NCS)2(L1)2(H2O)2]·L1, containing L1 bound as a monodentate ligand rather than in the expected tridentate fashion. These complexes associate into 44 grid structures through O-H···N hydrogen bonding; a solvate of a related 44 coordination framework, catena-[Cu(μ-L1)2(H2O)2][BF4]2, is also presented. The isomeric ligands 2,6-di(1,2,3-triazol-2-yl)pyridine (L2) and 2,6-di(1H-1,2,3-triazol-4-yl)pyridine (L3) bind to iron(II) in a more typical tridentate fashion. Solvates of [Fe(L3)2][ClO4]2 are low-spin and diamagnetic in the solid state and in solution, while [Fe(L2)2][ClO4]2 and [Co(L3)2][BF4]2 are fully high-spin. Treatment of L3 with methyl iodide affords 2,6-di(2-methyl-1,2,3-triazol-4-yl)pyridine (L4) and 2-(1-methyl-1,2,3-triazol-4-yl)-6-(2-methyl-1,2,3-triazol-4-yl)pyridine (L5). While salts of [Fe(L5)2]2+ are low-spin in the solid state, [Fe(L4)2][ClO4]2·H2O is high-spin, and [Fe(L4)2][ClO4]2·3MeNO2 exhibits a hysteretic spin transition to 50% completeness at T1/2 = 128 K (ΔT1/2 = 6 K). This transition proceeds via a symmetry-breaking phase transition to an unusual low-temperature phase containing three unique cation sites with high-spin, low-spin, and 1:1 mixed-spin populations. The unusual distribution of the spin states in the low-temperature phase reflects "spin-state frustration" of the mixed-spin cation site by an equal number of high-spin and low-spin nearest neighbors. Gas-phase density functional theory calculations reproduce the spin-state preferences of these and some related complexes. These highlight the interplay between the σ-basicity and π-acidity of the heterocyclic donors in this ligand type, which have opposing influences on the molecular ligand field. The Brønsted basicities of L1-L3 are very sensitive to the linkage isomerism of their triazolyl donors, which explains why their iron complex spin states show more variation than the better-known iron(II)/2,6-dipyrazolylpyridine system.
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Affiliation(s)
- Izar Capel Berdiell
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Daniel J Davies
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Jack Woodworth
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, E. C. Stoner Building, Leeds LS2 9JT, U.K
| | - Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
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15
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Galadzhun I, Kulmaczewski R, Cespedes O, Halcrow MA. Iron/2,6‐Di(pyrazol‐1‐yl)pyridine Complexes with a Discotic Pattern of Alkyl or Alkynyl Substituents. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Iurii Galadzhun
- School of Chemistry University of Leeds Woodhouse Lane Leeds LS2 9JT UK
| | | | - Oscar Cespedes
- School of Physics and Astronomy University of Leeds EC Stoner Building Leeds LS2 9JT UK
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16
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Guo Y, Rotaru A, Müller-Bunz H, Morgan GG, Zhang S, Xue S, Garcia Y. Auxiliary alkyl chain modulated spin crossover behaviour of [Fe(H 2Bpz 2) 2(C n-bipy)] complexes. Dalton Trans 2021; 50:12835-12842. [PMID: 34309614 DOI: 10.1039/d1dt01787j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three new alkyl chain substituted complexes [Fe(H2Bpz2)2(Cn-bipy)] (pz = pyrazolyl, Cn-bipy = bipyridine alkyl chain diester, n = 3 (3), 4 (4) and 5 (5)) show versatile spin state switching behaviour with different "tail" lengths as revealed by structural and magnetic analyses. The most striking phenomenon is observed for 5 which undergoes an abrupt spin transition accompanied by thermal hysteresis of ca. 10 K, which is attributed to crystal packing effects derived from the competition between ππ and C-HO interactions. Interestingly, each of the complexes exhibits similar gradual and complete spin crossover in methanol solution with a transition temperature around 249 K, as deduced from temperature-dependent UV-vis spectroscopy. This highlights the differences between the solid state (ligand field; crystal packing) and solution (ligand field; solvation) effects on spin crossover. This work demonstrates that the length of the complex's alkyl chain substituents on the complex can have a large impact on the transition temperature and profile of solid state spin crossover, offering a potential path to the fabrication of soft matter spin crossover materials.
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Affiliation(s)
- Yunnan Guo
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China. and Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, Louvain-la-Neuve 1348, Belgium.
| | - Aurelian Rotaru
- Department of Electrical Engineering and Computer Science & MANSiD Research Center, "Stefan cel Mare" University, University Street, 13, Suceava 720229, Romania
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Grace G Morgan
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Shishen Zhang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Shufang Xue
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China. and Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, Louvain-la-Neuve 1348, Belgium.
| | - Yann Garcia
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, Louvain-la-Neuve 1348, Belgium.
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17
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Turo-Cortés R, Valverde-Muñoz FJ, Meneses-Sánchez M, Muñoz MC, Bartual-Murgui C, Real JA. Bistable Hofmann-Type Fe II Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces. Inorg Chem 2021; 60:9040-9049. [PMID: 34047556 PMCID: PMC9129067 DOI: 10.1021/acs.inorgchem.1c01010] [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: 04/01/2021] [Indexed: 12/02/2022]
Abstract
Aiming at investigating the suitability of Hofmann-type two-dimensional (2D) coordination polymers {FeII(Lax)2[MII(CN)4]} to be processed as single monolayers and probed as spin crossover (SCO) junctions in spintronic devices, the synthesis and characterization of the MII derivatives (MII = Pd and Pt) with sulfur-rich axial ligands (Lax = 4-methyl- and 4-ethyl-disulfanylpyridine) have been conducted. The thermal dependence of the magnetic and calorimetric properties confirmed the occurrence of strong cooperative SCO behavior in the temperature interval of 100-225 K, featuring hysteresis loops 44 and 32.5 K/21 K wide for PtII-methyl and PtII/PdII-ethyl derivatives, while the PdII-methyl derivative undergoes a much less cooperative multistep SCO. Excluding PtII-methyl, the remaining compounds display light-induced excited spin-state trapping at 10 K with TLIESST temperatures in the range of 50-70 K. Single-crystal studies performed in the temperature interval 100-250 K confirmed the layered structure and the occurrence of complete transformation between the high- and low-spin states of the FeII center for the four compounds. Strong positional disorder seems to be the source of elastic frustration driving the multistep SCO observed for the PdII-methyl derivative. It is expected that the peripheral disulfanyl groups will favor anchoring and growing of the monolayer on gold substrates and optimal electron transport in the device.
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Affiliation(s)
- Rubén Turo-Cortés
- Instituto
de Ciencia Molecular/Departamento de Química Inorgánica, Universidad de Valencia, Catedrático Beltrán Martínez
2, 46980 Paterna, Valencia Spain
| | - Francisco Javier Valverde-Muñoz
- Instituto
de Ciencia Molecular/Departamento de Química Inorgánica, Universidad de Valencia, Catedrático Beltrán Martínez
2, 46980 Paterna, Valencia Spain
| | - Manuel Meneses-Sánchez
- Instituto
de Ciencia Molecular/Departamento de Química Inorgánica, Universidad de Valencia, Catedrático Beltrán Martínez
2, 46980 Paterna, Valencia Spain
| | - M. Carmen Muñoz
- Departamento
de Física Aplicada, Universitat Politècnica
de València, Camino
de Vera S/N 46022 Valencia, Spain
| | - Carlos Bartual-Murgui
- Instituto
de Ciencia Molecular/Departamento de Química Inorgánica, Universidad de Valencia, Catedrático Beltrán Martínez
2, 46980 Paterna, Valencia Spain
| | - José Antonio Real
- Instituto
de Ciencia Molecular/Departamento de Química Inorgánica, Universidad de Valencia, Catedrático Beltrán Martínez
2, 46980 Paterna, Valencia Spain
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18
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Schönfeld S, Hörner G, Heinemann FW, Hofmann A, Marschall R, Weber B. Spin States of 1D Iron(II) Coordination Polymers with Redox Active TTF(py)
2
as Bridging Ligand. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sophie Schönfeld
- Inorganic Chemistry IV University of Bayreuth Universitätsstraße 30 95448 Bayreuth Germany
| | - Gerald Hörner
- Inorganic Chemistry IV University of Bayreuth Universitätsstraße 30 95448 Bayreuth Germany
| | - Frank W. Heinemann
- Department Chemie und Pharmazie Friedrich‐Alexander‐Universität Erlangen‐Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Anja Hofmann
- Physical Chemistry III University of Bayreuth Universitätsstraße 30 95448 Bayreuth Germany
| | - Roland Marschall
- Physical Chemistry III University of Bayreuth Universitätsstraße 30 95448 Bayreuth Germany
| | - Birgit Weber
- Inorganic Chemistry IV University of Bayreuth Universitätsstraße 30 95448 Bayreuth Germany
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19
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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: 8] [Impact Index Per Article: 2.7] [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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20
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Rajendiran K, Yoganandham ST, Arumugam S, Arumugam D, Thananjeyan K. An overview of liquid crystalline mesophase transition and photophysical properties of “f block,” “d block,” and (SCO) spin-crossover metallomesogens in the optoelectronics. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Ouyang ZJ, Mo XY, Ye JQ, Yu XX, Huang SY, Liu XL, Chen WB, Gao S, Dong W. High temperature anionic Fe(III) spin crossover behavior in a mixed-valence Fe(II)/Fe(III) complex. Dalton Trans 2021; 50:5960-5967. [PMID: 33949504 DOI: 10.1039/d1dt00111f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two ion-pair Fe(iii) complexes (PPh4)[FeIII(HATD)2]·2H2O (1, H3ATD = azotetrazolyl-2,7-dihydroxynaphthalene) and [FeII(phen)3][FeIII(HATD)2]2·3DMA·3.5H2O (2, phen = 1,10-phenanthroline, DMA = N,N-dimethylformamide) were synthesized by employing the tridentate ligand H3ATD. Crystal structure analyses reveal that complexes 1 and 2 consist of FeIII ions in an octahedral environment where a FeIII ion is coordinated by two HATD2- ligands forming the [FeIII(HATD)2]- core. The shortest cationanion distance between the phosphorus ion of the (PPh4)+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 13.190 Å in complex 1, whereas that between the ferrous ion of the [FeII(Phen)3]2+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 7.821 Å in complex 2. C-HC and C-HO hydrogen interactions between the [FeII(phen)3]2+ cation and the [FeIII(HATD)2]- anion are observed in 2. Face-to-face π-π stacking interactions between naphthalene rings with the separated interplanar center to center distances of 3.421-3.680 Å were observed, which result in a one-dimensional supramolecular chain in complexes 1 and 2. Magnetic measurements show that complex 1 is in the low-spin (LS) state below 500 K, whereas 2 undergoes a high temperature spin crossover (SCO) between 360 and 500 K. Magneto-structural relationship studies reveal that π-stacking, hydrogen interactions and Coulomb interactions between the [FeIII(HATD)2]- anion and the [FeII(phen)3]2+ cation play a crucial role in the high temperature Fe(iii) SCO behaviour of complex 2.
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Affiliation(s)
- Zhi-Jian Ouyang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Ying Mo
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Jia-Qi Ye
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Xuan Yu
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Shu-Yuan Huang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Ling Liu
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Wen-Bin Chen
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Song Gao
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, P. R. China
| | - Wen Dong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
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22
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Galadzhun I, Kulmaczewski R, Shahid N, Cespedes O, Howard MJ, Halcrow MA. The flexibility of long chain substituents influences spin-crossover in isomorphous lipid bilayer crystals. Chem Commun (Camb) 2021; 57:4039-4042. [DOI: 10.1039/d1cc01073e] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
These two compounds are isomorphous but show different spin-state behaviour on cooling. This may be influenced by the packing of alkyl vs. alkynyl chains in the solid state.
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Affiliation(s)
| | | | - Namrah Shahid
- School of Chemistry
- University of Leeds
- Woodhouse Lane
- Leeds
- UK
| | - Oscar Cespedes
- School of Physics and Astronomy
- University of Leeds
- Leeds LS2 9JT
- UK
| | - Mark J. Howard
- School of Chemistry
- University of Leeds
- Woodhouse Lane
- Leeds
- UK
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23
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Qamar OA, Cong C, Ma H. Solid state mononuclear divalent nickel spin crossover complexes. Dalton Trans 2020; 49:17106-17114. [PMID: 33205805 DOI: 10.1039/d0dt03421e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin crossover complexes containing 3d4-3d7 transition metal ions with tunable electronic configurations in appropriate ligand field environments have been extensively investigated. In contrast, the development of 3d8 divalent nickel complexes displaying such a spin crossover behavior is far behind. The increasing number of X-ray single crystal structures along with magnetic evidence and thermodynamic equilibrium indicate that bistable divalent nickel complexes are gradually recognized to be a formal member of the "spin crossover family". Unfortunately, the rarity of nickel spin crossover complexes is occasionally mentioned. This Perspective article highlights examples of mononuclear 3d8 nickel spin crossover complexes in dynamic rearrangements with characterized solid state structures from the viewpoint of types of ligands utilized.
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Affiliation(s)
- Obaid Ali Qamar
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), Nanjing Tech University, 30 South Puzhu Road, Nanjing 21186, China.
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24
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Enriquez-Cabrera A, Rapakousiou A, Piedrahita Bello M, Molnár G, Salmon L, Bousseksou A. Spin crossover polymer composites, polymers and related soft materials. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213396] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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25
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Valverde-Muñoz FJ, Seredyuk M, Muñoz MC, Molnár G, Bibik YS, Real JA. Thermochromic Meltable Materials with Reverse Spin Transition Controlled by Chemical Design. Angew Chem Int Ed Engl 2020; 59:18632-18638. [PMID: 32666596 DOI: 10.1002/anie.202006453] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Indexed: 01/01/2023]
Abstract
We report a series of meltable FeII complexes, which, depending on the length of aliphatic chains, display abrupt forward low-spin to high-spin transition or unprecedented melting-triggered reverse high-spin to low-spin transition on temperature rise. The reverse spin transition is perfectly reproducible on thermal cycling and the obtained materials are easily processable in the form of thin film owing to their soft-matter nature. We found that the discovered approach represents a potentially generalizable new avenue to control both the location in temperature and the direction of the spin transition in meltable compounds.
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Affiliation(s)
| | - Maksym Seredyuk
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, 46980 Paterna, Valencia, Spain.,National Taras Shevchenko University, Department of Chemistry, Volodymyrska Str. 64, Kyiv, 01601, Ukraine
| | - M Carmen Muñoz
- Departamento de Física Aplicada, Universitat Politècnica de València, 46022, Valencia, Spain
| | - Gábor Molnár
- LCC, CNRS &, Université de Toulouse (UPS, INP), 205 route de Narbonne, 31077, Toulouse, France
| | - Yurii S Bibik
- National Taras Shevchenko University, Department of Chemistry, Volodymyrska Str. 64, Kyiv, 01601, Ukraine.,UkrSyntez Ltd., 67 Chervonotkatska Str., 02094, Kyiv, Ukraine
| | - José Antonio Real
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, 46980 Paterna, Valencia, Spain
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26
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Valverde‐Muñoz F, Seredyuk M, Muñoz MC, Molnár G, Bibik YS, Real JA. Thermochromic Meltable Materials with Reverse Spin Transition Controlled by Chemical Design. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006453] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Maksym Seredyuk
- Instituto de Ciencia Molecular (ICMol) Universidad de Valencia 46980 Paterna Valencia Spain
- National Taras Shevchenko University Department of Chemistry Volodymyrska Str. 64 Kyiv 01601 Ukraine
| | - M. Carmen Muñoz
- Departamento de Física Aplicada Universitat Politècnica de València 46022 Valencia Spain
| | - Gábor Molnár
- LCC, CNRS & Université de Toulouse (UPS, INP) 205 route de Narbonne 31077 Toulouse France
| | - Yurii S. Bibik
- National Taras Shevchenko University Department of Chemistry Volodymyrska Str. 64 Kyiv 01601 Ukraine
- UkrSyntez Ltd. 67 Chervonotkatska Str. 02094 Kyiv Ukraine
| | - José Antonio Real
- Instituto de Ciencia Molecular (ICMol) Universidad de Valencia 46980 Paterna Valencia Spain
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Kashiro A, Kohno W, Ishida T. Odd–Even Effect on the Spin-Crossover Temperature in Iron(II) Complex Series Involving an Alkylated or Acyloxylated Tripodal Ligand. Inorg Chem 2020; 59:10163-10171. [DOI: 10.1021/acs.inorgchem.0c01296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Atsushi Kashiro
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
| | - Wakana Kohno
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
| | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
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28
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Spin Crossover in Bipyridine Derivative Bridged One-Dimensional Iron(III) Coordination Polymer. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6030029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Herein, the syntheses, solid-state molecular structures, and characterization of two types of one-dimensional FeIII coordination polymers showing thermally induced spin crossover are reported. The reaction of [Fe(acen)Cl] (acen2− = N,N′-ethylenebis(acetylacetonylideneaminate) with 3,3′-bpy or 4,4′-bpy (bpy = bipyridine) produced zigzag and linear one-dimensional chain complexes, [Fe(acen)(3,3′-bpy)][BPh4] (1) or [NEt3H][Fe(acen)(4,4′-bpy)][BPh4]2·0.5(4,4′-bpy) (2), respectively, as confirmed by single crystal X-ray diffraction analysis. Variable-temperature single crystal X-ray diffraction measurements, continuous-wave X-band electron paramagnetic resonance (EPR) spectra, 57Fe Mössßauer spectra, and DC magnetic susceptibility data revealed that complex 1 exhibited a gradual and complete spin crossover at a transition temperature of 212 K, while complex 2 undergoes an incomplete spin crossover even at 400 K.
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29
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Schönfeld S, Dankhoff K, Baabe D, Zaretzke MK, Bröring M, Schötz K, Köhler A, Hörner G, Weber B. Iron(II) Spin Crossover Complexes Based on a Redox Active Equatorial Schiff-Base-Like Ligand. Inorg Chem 2020; 59:8320-8333. [PMID: 32496060 DOI: 10.1021/acs.inorgchem.0c00725] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sophie Schönfeld
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
| | - Katja Dankhoff
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
| | - Dirk Baabe
- Institute of Inorganic and Analytical Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Marc-Kevin Zaretzke
- Institute of Inorganic and Analytical Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Martin Bröring
- Institute of Inorganic and Analytical Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Konstantin Schötz
- Experimental Physics, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
| | - Anna Köhler
- Experimental Physics, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
| | - Gerald Hörner
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
| | - Birgit Weber
- Inorganic Chemistry IV, University of Bayreuth, Universitätsstraße 30, 95448 Bayreuth, Germany
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30
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Pan Y, Meng YS, Liu Q, Gao WQ, Liu CH, Liu T, Zhu YY. Construction of SCO-Active Fe(II) Mononuclear Complexes from the Thio-pybox Ligand. Inorg Chem 2020; 59:7398-7407. [PMID: 32401025 DOI: 10.1021/acs.inorgchem.9b03506] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of new spin-crossover complexes provides novel promising switching materials with significant potential at the molecular level. Ter-imine-type molecules represent one of the important classes of ligands in creating SCO-active complexes. Herein we report a family of mononuclear Fe(II) SCO-active compounds constructed from a new type of ter-imine ligand named the thio-pybox ligand (2,6-bis(4,4-dimethyl-4,5-dihydrothiazol-2-yl)pyridine, L1). Through the variation of counteranions, some cases display complete SCO and with T1/2 near ambient temperature. Among them, annealed [FeII(L1)2](ClO4)2 [1(ClO4)] shows T1/2↓ and T1/2↑ as 319 and 349 K, respectively. The wide thermal hysteresis of ΔT = 30 K originated from the weak interaction between complex cations and counteranions in the crystal lattice. Impressively, its high-spin population can be increased considerably by annealing at high temperature. The metastable high-spin phase is stable in the successive magnetic measurements and would gradually relax to its initial state with high population of low-spin configuration at ambient temperature. In acetonitrile-diluted solution, 1(ClO4) still maintains SCO with an estimated T1/2 at 240 K. Differential scanning calorimetry discloses the structural phase at around 355 K in the first heating process and the increase in the high-spin population concomitant with annealing was also corroborated by 57Fe Mössbauer measurements. Additionally, the influences on SCO by counteranion and ligand structure are investigated, which show that the fine tuning of complex structures can affect the behavior of the spin state significantly. Finally, magneto-structural correlation studies were performed on the structures of 1(ClO4) and its oxygen analogue at multiple temperatures. The analyses of some structural parameters, including terminal N···N donor separation, bite angle, patulous angle, and the root mean squared deviation indicate that the replacement of the oxygen atom with a sulfur atom can effectively improve the flexibility and release the steric strain and thus tune the SCO toward ambient temperature. Our research demonstrates the rational design of the ligand can lead to new SCO-active compounds with high performance.
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Affiliation(s)
- Yao Pan
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei 230009, China
| | - Yin-Shan Meng
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
| | - Qiang Liu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
| | - Wan-Qing Gao
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei 230009, China
| | - Chun-Hua Liu
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei 230009, China
| | - Tao Liu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
| | - Yuan-Yuan Zhu
- School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei 230009, China.,State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
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31
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Fleming C, Chung D, Ponce S, Brook DJR, DaRos J, Das R, Ozarowski A, Stoian SA. Valence tautomerism in a cobalt-verdazyl coordination compound. Chem Commun (Camb) 2020; 56:4400-4403. [PMID: 32242582 DOI: 10.1039/d0cc01770a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Coordination of 1-isopropyl-3,5-dipyridyl-6-oxoverdazyl to cobalt results in a dication best described in the solid state as a high spin cobalt(ii) ion coordinated to two radical ligands with an S = 3/2 ground state. On dissolution in acetonitrile, the cobalt(ii) form equilibrates with a cobalt(iii) valence tautomer with an S = 1/2 ground state.
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Affiliation(s)
- Connor Fleming
- Department of Chemistry, San Jose State University, One Washington Square, San Jose, CA 95126, USA.
| | - Dorothy Chung
- Department of Chemistry, San Jose State University, One Washington Square, San Jose, CA 95126, USA.
| | - Servando Ponce
- Department of Chemistry, San Jose State University, One Washington Square, San Jose, CA 95126, USA.
| | - David J R Brook
- Department of Chemistry, San Jose State University, One Washington Square, San Jose, CA 95126, USA.
| | - Jeffrey DaRos
- Department of Chemistry, San Jose State University, One Washington Square, San Jose, CA 95126, USA.
| | - Raja Das
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, 875 Perimeter Drive, Moscow, ID 83844, USA
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32
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The Tyranny of Arm-Wrestling Methyls on Iron(II) Spin State in Pseudo-Octahedral [Fe(didentate)3] Complexes. CHEMISTRY 2020. [DOI: 10.3390/chemistry2020015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The connection of a sterically constrained 3-methyl-pyrazine ring to a N-methyl-benzimidazole unit to give the unsymmetrical α,α’-diimine ligand L5 has been programmed for the design of pseudo-octahedral spin-crossover [Fe(L5)3]2+ units, the transition temperature (T1/2) of which occurs in between those reported for related facial tris-didentate iron chromophores fitted with 3-methyl-pyridine-benzimidazole in a LaFe helicate (T1/2 ~ 50 K) and with 5-methyl-pyrazine-benzimidazole L2 ligands (T1/2 ~350 K). A thorough crystallographic analysis of [Fe(L5)3](ClO4)2 (I), [Ni(L5)3](ClO4)2 (II), [Ni(L5)3](BF4)2∙H2O (III), [Zn(L5)3](ClO4)2 (IV), [Ni(L5)3](BF4)2∙1.75CH3CN (V), and [Zn(L5)3](BF4)2∙1.5CH3CN (VI) shows the selective formation of pure facial [M(L5)3]2+ cations in the solvated crystals of the tetrafluoroborate salts and alternative meridional isomers in the perchlorate salts. Except for a slightly larger intra-strand interannular twist between the aromatic heterocycles in L5, the metric parameters measured in [Zn(L5)3]2+ are comparable to those reported for [Zn(L2)3]2+, where L2 is the related unconstrained ligand. This similitude is reinforced by comparable ligand-field strengths (∆oct) and nephelauxetic effects (as measured by the Racah parameters B and C) extracted from the electronic absorption spectra recorded for [Ni(L5)3]2+ and [Ni(L2)3]2+. In this context, the strictly high-spin behavior observed for [Fe(L5)3]2+ within the 5–300 K range contrasts with the close to room-temperature spin-crossover behavior of [Fe(L2)3]2+ (T1/2 = 349(5) K in acetonitrile). This can be unambiguously assigned to an intraligand arm wrestling match operating in bound L5, which prevents the contraction of the coordination sphere required for accommodating low-spin FeII. Since the analogous 3-methyl-pyridine ring in [Fe(L3)3]2+ derivatives are sometimes compatible with spin-crossover properties, the consequences of repulsive intra-strand methyl–methyl interactions are found to be amplified in [Fe(L5)3]2+ because of the much lower basicity of the 3-methyl-pyrazine ring and the resulting weaker thermodynamic compensation. The decrease of the stability constants by five orders of magnitude observed in going from [M(L2)3]2+ to [M(L5)3]2+ (M = NiII and ZnII) is diagnostic for the operation of this effect, which had been not foreseen by the authors.
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33
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Göbel C, Hils C, Drechsler M, Baabe D, Greiner A, Schmalz H, Weber B. Confined Crystallization of Spin-Crossover Nanoparticles in Block-Copolymer Micelles. Angew Chem Int Ed Engl 2020; 59:5765-5770. [PMID: 31891660 PMCID: PMC7155125 DOI: 10.1002/anie.201914343] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Indexed: 12/31/2022]
Abstract
Nanoparticles of the spin-crossover coordination polymer [FeL(bipy)]n were synthesized by confined crystallization within the core of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer micelles. The 4VP units in the micellar core act as coordination sites for the Fe complex. In the bulk material, the spin-crossover nanoparticles in the core are well isolated from each other allowing thermal treatment without disintegration of their structure. During annealing above the glass transition temperature of the PS block, the transition temperature is shifted gradually to higher temperatures from the as-synthesized product (T1/2 ↓=163 K and T1/2 ↑=170 K) to the annealed product (T1/2 ↓=203 K and T1/2 ↑=217 K) along with an increase in hysteresis width from 6 K to 14 K. Thus, the spin-crossover properties can be shifted towards the properties of the related bulk material. The stability of the nanocomposite allows further processing, such as electrospinning from solution.
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Affiliation(s)
- Christoph Göbel
- Department of Chemistry, Inorganic Chemistry IV, Unversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Christian Hils
- Department of Chemistry, Macromolecular Chemistry IIUniversität BayreuthUniversitätsstr. 3095440BayreuthGermany
| | - Markus Drechsler
- Keylab Electron and Optical Microscopy, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Dirk Baabe
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Andreas Greiner
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Holger Schmalz
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer InstituteUniversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
| | - Birgit Weber
- Department of Chemistry, Inorganic Chemistry IV, Unversität BayreuthUniversitätsstrasse 3095440BayreuthGermany
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34
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Göbel C, Hils C, Drechsler M, Baabe D, Greiner A, Schmalz H, Weber B. Confined Crystallization of Spin‐Crossover Nanoparticles in Block‐Copolymer Micelles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Christoph Göbel
- Department of Chemistry, Inorganic Chemistry IV, Unversität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Christian Hils
- Department of Chemistry, Macromolecular Chemistry II Universität Bayreuth Universitätsstr. 30 95440 Bayreuth Germany
| | - Markus Drechsler
- Keylab Electron and Optical Microscopy, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Dirk Baabe
- Institut für Anorganische und Analytische Chemie Technische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Andreas Greiner
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Holger Schmalz
- Department of Chemistry, Macromolecular Chemistry II and Keylab Synthesis and Molecular Characterization, Bavarian Polymer Institute Universität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
| | - Birgit Weber
- Department of Chemistry, Inorganic Chemistry IV, Unversität Bayreuth Universitätsstrasse 30 95440 Bayreuth Germany
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35
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Kurz H, Sander J, Weber B. Influence of CF
3
Substituents on the Spin Crossover Behavior of Iron(II) Coordination Polymers with Schiff Base‐like Ligands. Z Anorg Allg Chem 2020. [DOI: 10.1002/zaac.201900354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hannah Kurz
- Department of Chemistry University of Bayreuth Universitätsstraße 30, NWI 95447 Bayreuth Germany
| | - Joan Sander
- Department of Chemistry University of Bayreuth Universitätsstraße 30, NWI 95447 Bayreuth Germany
| | - Birgit Weber
- Department of Chemistry University of Bayreuth Universitätsstraße 30, NWI 95447 Bayreuth Germany
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36
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Ouyang ZJ, Mo XY, Yang M, Zhong L, Chen WB, Gao S, Dong W. High temperature Fe(iii) spin crossover behaviours in three unprecedented FeIII–MII–FeIII (M = Fe, Cd) linear trinuclear complexes. Inorg Chem Front 2020. [DOI: 10.1039/c9qi01560d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An azo-based ligand of azotetrazolyl-2,7-dihydroxynaphthalene (H3ATD) was used to synthesize three FeIII–MII–FeIII (M = Fe, Cd) linear trinuclear complexes with different high temperature spin crossover (SCO) behaviours for the terminal FeIII ions.
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Affiliation(s)
- Zhi-Jian Ouyang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
| | - Xiao-Ying Mo
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
| | - Meng Yang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
| | - Li Zhong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
| | - Wen-Bin Chen
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
| | - Song Gao
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510641
- P. R. China
| | - Wen Dong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology
- School of Chemistry and Chemical Engineering
- Guangzhou University
- Guangzhou 510006
- P. R. China
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37
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Sundaresan S, Kitchen JA, Brooker S. Hydrophobic tail length in spin crossover active iron( ii) complexes predictably tunes T½ in solution and enables surface immobilisation. Inorg Chem Front 2020. [DOI: 10.1039/c9qi01478k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Linear correlation of the hydrophobic alkyl tail length R employed in [FeII(LH-OR)(NCBH3)2] with the spin crossover switching temperature is a very convenient method of predictably tuning the iron(ii) spin state.
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Affiliation(s)
- Sriram Sundaresan
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- University of Otago
- Dunedin 9054
- New Zealand
| | - Jonathan A. Kitchen
- School of Natural and Computational Sciences
- Massey University Auckland
- New Zealand
| | - Sally Brooker
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- University of Otago
- Dunedin 9054
- New Zealand
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38
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Berdiell IC, Hochdörffer T, Desplanches C, Kulmaczewski R, Shahid N, Wolny JA, Warriner SL, Cespedes O, Schünemann V, Chastanet G, Halcrow MA. Supramolecular Iron Metallocubanes Exhibiting Site-Selective Thermal and Light-Induced Spin-Crossover. J Am Chem Soc 2019; 141:18759-18770. [DOI: 10.1021/jacs.9b08862] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Izar Capel Berdiell
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Tim Hochdörffer
- Department of Physics, Technical University of Kaiserslautern, Erwin Schrödinger Straße 46, D-67663 Kaiserslautern, Germany
| | | | - Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Namrah Shahid
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Juliusz A. Wolny
- Department of Physics, Technical University of Kaiserslautern, Erwin Schrödinger Straße 46, D-67663 Kaiserslautern, Germany
| | - Stuart L. Warriner
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Oscar Cespedes
- School of Physics and Astronomy, EC Stoner Building, University of Leeds, Leeds LS2 9JT, U.K
| | - Volker Schünemann
- Department of Physics, Technical University of Kaiserslautern, Erwin Schrödinger Straße 46, D-67663 Kaiserslautern, Germany
| | | | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
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39
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Echeverría C, Rubio M, López D. Thermo-Reversible Hybrid Gels Formed from the Combination of Isotactic Polystyrene and [Fe(II) (4-Octadecyl-1,2,4-Triazole) 3(ClO 4) 2] n Metallo-Organic Polymer: Thermal and Viscoelastic Properties. Polymers (Basel) 2019; 11:polym11060957. [PMID: 31159458 PMCID: PMC6631267 DOI: 10.3390/polym11060957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 11/16/2022] Open
Abstract
Nano-sized one-dimensional metallo-organic polymers, characterized by the phenomenon of spin transition, are excellent candidates for advanced technological applications such as optical sensors, storage, and information processing devices. However, the main drawback of this type of polymers is their fragile mechanical properties, which hinders its processing and handling, and makes their practical use unfeasible. To overcome this problem, in this work, hybrid thermo-reversible gels are synthesized by combination of a metallo-organic polymer and isotactic polystyrene (iPS) in cis-decaline. A detailed investigation of the thermal and viscoelastic properties of the hybrid gels, in terms of iPS and metallo-organic polymer concentration is performed by means of differential scanning calorimetry and oscillatory rheology, respectively. From the analysis of the thermal properties, three transitions have been determined upon heating: Monotectic transition of the iPS gel, melting of the iPS gel, and melting of the metal-organic polymer gel, which suggest that the gels of the two polymers are formed independently in the hybrid gel, as long as the two polymers are in concentrations above the corresponding critical gelation concentrations. Results regarding viscoelastic properties and morphology confirmed that hybrid gels consisted of an interpenetrated network of polymer gels, formed by iPS and metallo-organic poymer gels growing independently.
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Affiliation(s)
- Coro Echeverría
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.
| | - Miguel Rubio
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.
| | - Daniel López
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.
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40
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Valverde-Muñoz FJ, Seredyuk M, Meneses-Sánchez M, Muñoz MC, Bartual-Murgui C, Real JA. Discrimination between two memory channels by molecular alloying in a doubly bistable spin crossover material. Chem Sci 2019; 10:3807-3816. [PMID: 31015922 PMCID: PMC6457193 DOI: 10.1039/c8sc05256e] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/20/2019] [Indexed: 11/21/2022] Open
Abstract
A multistable spin crossover (SCO) molecular alloy system [Fe1-x M x (nBu-im)3(tren)](P1-y As y F6)2 (M = ZnII, NiII; (nBu-im)3(tren) = tris(n-butyl-imidazol(2-ethylamino))amine) has been synthesized and characterized. By controlling the composition of this isomorphous series, two cooperative thermally induced SCO events featuring distinct critical temperatures (T c) and hysteresis widths (ΔT c, memory) can be selected at will. The pristine derivative 100As (x = 0, y = 1) displays a strong cooperative two-step SCO and two reversible structural phase transitions (PTs). The low temperature PTLT and the SCO occur synchronously involving conformational changes of the ligand's n-butyl arms and two different arrangements of the AsF6 - anions [T1c = 174 K (ΔT1c = 17 K), T2c = 191 K (ΔT2c = 23 K) (scan rate 2 K min-1)]. The high-temperature PTHT takes place in the high-spin state domain and essentially involves rearrangement of the AsF6 - anions [TPTc = 275 K (ΔTPTc = 16 K)]. This behavior strongly contrasts with that of the homologous 100P [x = 0, y = 0] derivative where two separate cooperative one-step SCO can be selected by controlling the kinetics of the coupled PTLT at ambient pressure: (i) one at low temperatures, T c = 122 K (ΔT c = 9 K), for temperature scan rates (>1 K min-1) (memory channel A) where the structural modifications associated with PTLS are inhibited; (ii) the other centered at T c = 155 K (ΔT c = 41 K) for slower temperature scan rates ≤0.1 K min-1 (memory channel B). These two SCO regimes of the 100P derivative transform reversibly into the two-step SCO of 100As upon application of hydrostatic pressure (ca. 0.1 GPa) denoting the subtle effect of internal chemical pressure on the SCO behavior. Precise control of AsF6 - ↔ PF6 - substitution, and hence of the PTLT kinetics, selectively selects the memory channel B of 100P when x = 0 and y ≈ 0.7. Meanwhile, substitution of FeII with ZnII or NiII [x ≈ 0.2, y = 0] favors the low temperature memory channel A at any scan rate. This intriguing interplay between PT, SCO and isomorphous substitution was monitored by single crystal and powder X-ray diffractometries, and magnetic and calorimetric measurements.
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Affiliation(s)
| | - Maksym Seredyuk
- Departament de Química Inorgànica , Institut de Ciència Molecular (ICMol) , Universitat de València , Valencia , Spain .
- On leave from Department of Chemistry , Taras Shevchenko National University of Kyiv , 64/13, Volodymyrska Street , 01601 , Kyiv , Ukraine . ;
| | - Manuel Meneses-Sánchez
- Departament de Química Inorgànica , Institut de Ciència Molecular (ICMol) , Universitat de València , Valencia , Spain .
| | - M Carmen Muñoz
- Departament de Física Aplicada , Universitat Politècnica de València , Camino de Vera s/n , E-46022 , Valencia , Spain
| | - Carlos Bartual-Murgui
- Departament de Química Inorgànica , Institut de Ciència Molecular (ICMol) , Universitat de València , Valencia , Spain .
| | - José A Real
- Departament de Química Inorgànica , Institut de Ciència Molecular (ICMol) , Universitat de València , Valencia , Spain .
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Five 2,6-Di(pyrazol-1-yl)pyridine-4-carboxylate Esters, and the Spin States of their Iron(II) Complexes. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two phenyl ester and three benzyl ester derivatives have been synthesized from 2,6-di(pyrazol-1-yl)pyridine-4-carboxylic acid and the appropriate phenyl or benzyl alcohol using N,N’-dicyclohexylcarbodiimide as the coupling reagent. Complexation of the ligands with Fe[BF4]2·6H2O in acetone yielded the corresponding [FeL2][BF4]2 complex salts. Four of the new ligands and four of the complexes have been crystallographically characterised. Particularly noteworthy are two polymorphs of [Fe(L3)2][BF4]2·2MeNO2 (L3 = 3,4-dimethoxyphenyl 2,6-di{pyrazol-1-yl}pyridine-4-carboxylate), one of which is crystallographically characterised as high-spin while the other exhibits the onset of spin-crossover above room temperature. The other complexes are similarly low-spin at low temperature but exhibit gradual spin-crossover on heating, except for an acetone solvate of [Fe(L5)2][BF4]2 (L5 = benzyl 2,6-di{pyrazol-1-yl}pyridine-4-carboxylate), which exhibits a more abrupt spin-transition at T½ = 273 K with 9 K thermal hysteresis.
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42
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Baldé C, Sylla MS, Desplanches C, Chastanet G. High-spin → low-spin relaxation kinetics and metal dilution effects in 1D spin-crossover chain compounds. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.11.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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43
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Weihermüller J, Schlamp S, Dittrich B, Weber B. Kinetic Trapping Effects in Amphiphilic Iron(II) Spin Crossover Compounds. Inorg Chem 2019; 58:1278-1289. [DOI: 10.1021/acs.inorgchem.8b02763] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
| | - Stephan Schlamp
- Department of Chemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Birger Dittrich
- Anorganische Chemie und Strukturchemie II, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Birgit Weber
- Department of Chemistry, University of Bayreuth, 95440 Bayreuth, Germany
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44
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Senthil Kumar K, Bayeh Y, Gebretsadik T, Elemo F, Gebrezgiabher M, Thomas M, Ruben M. Spin-crossover in iron(ii)-Schiff base complexes. Dalton Trans 2019; 48:15321-15337. [DOI: 10.1039/c9dt02085c] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A collective overview of iron(ii)-Schiff base complexes, showing abrupt and hysteretic SCO suitable for device applications, and the structure–property relationships governing the SCO of the complexes in the solid-state is presented.
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Affiliation(s)
- Kuppusamy Senthil Kumar
- Institut de Physique et de Chimie des Matériaux-Université de Strasbourg23
- F-67034 Strasbourg
- France
| | - Yosef Bayeh
- Department of Industrial Chemistry
- Addis Ababa Science and Technology University
- Addis Ababa
- Ethiopia
| | - Tesfay Gebretsadik
- Department of Industrial Chemistry
- Addis Ababa Science and Technology University
- Addis Ababa
- Ethiopia
| | - Fikre Elemo
- Department of Industrial Chemistry
- Addis Ababa Science and Technology University
- Addis Ababa
- Ethiopia
| | - Mamo Gebrezgiabher
- Department of Industrial Chemistry
- Addis Ababa Science and Technology University
- Addis Ababa
- Ethiopia
| | - Madhu Thomas
- Department of Industrial Chemistry
- Addis Ababa Science and Technology University
- Addis Ababa
- Ethiopia
| | - Mario Ruben
- Institut de Physique et de Chimie des Matériaux-Université de Strasbourg23
- F-67034 Strasbourg
- France
- Institute of Nanotechnology
- Karlsruhe Institute of Technology
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45
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Berdiell IC, Kulak AN, Warriner SL, Halcrow MA. Heterometallic Coordination Polymer Gels Supported by 2,4,6-Tris(pyrazol-1-yl)-1,3,5-triazine. ACS OMEGA 2018; 3:18466-18474. [PMID: 31458419 PMCID: PMC6644042 DOI: 10.1021/acsomega.8b02508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/13/2018] [Indexed: 05/04/2023]
Abstract
Complexes of type [M(tpt)2]X2 (M2+ = Fe2+, Co2+, Ni2+; tpt = 2,4,6-tri{pyrazol-1-yl}-1,3,5-triazine; X- = BF4 - or ClO4 -) crystallize in a cubic lattice, with the metal ion and ligand conformation showing unusual symmetry-imposed disorder. Addition of 1 equiv AgX to the corresponding preformed [M(tpt)2]X2 salt in concentrated MeNO2 solution affords thixotropic gels. Gelation was not observed in analogous reactions using [Mn(tpt)2][ClO4]2, or from reactions in other, more donating solvents. Scanning electron microscopy (SEM) images from dilute solutions of the reagents confirmed the fibrous microstructure of the gels and their homogeneous elemental composition. However, energy-dispersive X-ray data show a reduced Fe/Ag ratio compared to the Co/Ag and Ni/Ag gels, where a 1:1 ratio of metals is evident. More concentrated gels decomposed to silver nanoparticles during SEM sample preparation. Mass spectrometry and 1H NMR indicate that silver induces partial ligand displacement reactions in [Fe(tpt)2]2+ and [Co(tpt)2]2+, but not in [Ni(tpt)2]2+. Hence, the strength of the gels, which follows the order M = Mn (no gel) < Fe < Co < Ni, correlates with the stability of octahedral [M(tpt)2]2+ under gelation conditions. Iron(II) complexes of the related ligands 2,4,6-tri{pyrazol-1-yl}pyridine (tpp) and 2,4,6-tri{pyrazol-1-yl}pyrimidine (tpym) did not undergo gelation with silver salts under the above conditions. The unique properties of tpt as a gelator in this work may reflect the crystallographically observed ability of metal-coordinated tpt to chelate to exogenous silver ions, through its pendant pyrazolyl group and triazinyl N donors. In contrast, the pendant azolyl substituents in silver complexes of the nongelators tpp and tpym only bind exogenous silver in monodentate fashion.
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46
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47
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Galadzhun I, Kulmaczewski R, Cespedes O, Yamada M, Yoshinari N, Konno T, Halcrow MA. 2,6-Bis(pyrazol-1-yl)pyridine-4-carboxylate Esters with Alkyl Chain Substituents and Their Iron(II) Complexes. Inorg Chem 2018; 57:13761-13771. [DOI: 10.1021/acs.inorgchem.8b02289] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Iurii Galadzhun
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, E. C. Stoner Building, Leeds LS2 9JT, U.K
| | - Mihoko Yamada
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Nobuto Yoshinari
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takumi Konno
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K
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48
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Dankhoff K, Schneider S, Nowak R, Weber B. Iron(II) and Iron(III) Complexes of Tridentate NNO
Schiff Base-like Ligands - X-ray Structures and Magnetic Properties. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Katja Dankhoff
- Department Chemie; Universität Bayreuth; 95440 Bayreuth Germany
| | | | - René Nowak
- Department Chemie; Universität Bayreuth; 95440 Bayreuth Germany
| | - Birgit Weber
- Department Chemie; Universität Bayreuth; 95440 Bayreuth Germany
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49
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Bauer W, Ossiander T, Weber B. Synthesis of iron(II) complexes with asymmetric N2O2 coordinating Schiff base-like ligands and their spin crossover properties. Front Chem Sci Eng 2018. [DOI: 10.1007/s11705-018-1753-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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50
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Vela S, Paulsen H. Cooperativity in Spin Crossover Systems. An Atomistic Perspective on the Devil's Staircase. Inorg Chem 2018; 57:9478-9488. [PMID: 30040398 DOI: 10.1021/acs.inorgchem.8b01463] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cooperativity is key in defining the shape (i.e., gradual, abrupt, or hysteretic) of thermally driven spin transitions in magnetic switches. Despite its importance, there is very little information on its atomistic origin, which hinders the rational design of materials displaying a bistability region (i.e., hysteresis). In this paper, we investigate the spin transition of two solvatomorphs of [Fe(2-pic)3]Cl2, an Fe(II)-complex displaying thermal spin crossover (SCO) from a low-spin (LS) to a high-spin (HS) state with either gradual or abrupt two-step character. To do it, we apply a novel computational protocol to study the cooperativity of SCO compounds from DFT calculations, which does not rely on a priori assumptions on the studied system. The distinct shape of the spin transition is successfully captured, and the atomistic origin of cooperativity is traced back to geometrical distortions of the Fe-N6 core in case of the solvatomorph exhibiting an abrupt transition. According to our calculations, HS and LS molecules contribute differently to cooperativity, which results in a complex energetic evolution of the spin transition that cannot be described by the common Slichter-Drickamer model. The present work opens new avenues for the study of cooperativity of SCO systems having a chemically oriented perspective and demonstrates that quantum chemistry calculations can discriminate the shape of a spin transition, while providing insight into the atomistic underlying factors that contribute to its cooperative behavior.
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Affiliation(s)
- Sergi Vela
- Laboratoire de Chimie Quantique, UMR 7111 , CNRS-Université de Strasbourg , 4 rue Blaise Pascal , F-67000 Strasbourg , France
| | - Hauke Paulsen
- Institut für Physik , Universität zu Lübeck , Ratzeburger Allee 160 , D-23562 Lübeck , Germany
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