1
|
Halcrow MA. Mix and match - controlling the functionality of spin-crossover materials through solid solutions and molecular alloys. Dalton Trans 2024; 53:13694-13708. [PMID: 39119634 DOI: 10.1039/d4dt01855a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
The influence of dopant molecules on the structure and functionality of spin-crossover (SCO) materials is surveyed. Two aspects of the topic are well established. Firstly, isomorphous inert metal ion dopants in SCO lattices are a useful probe of the energetics of SCO processes. Secondly, molecular alloys of iron(II)/triazole coordination polymers containing mixtures of ligands were used to tune their spin-transitions towards room temperature. More recent examples of these and related materials are discussed that reveal new insights into these questions. Complexes which are not isomorphous can also be co-crystallised, either as solid solutions of the precursor molecules or as a random distribution of homo- and hetero-leptic centres in a molecular alloy. This could be a powerful method to manipulate SCO functionality. Published molecular alloys show different SCO behaviours, which may or may not include allosteric switching of their chemically distinct metal sites.
Collapse
Affiliation(s)
- Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| |
Collapse
|
2
|
Kulmaczewski R, Halcrow MA. Iron(II) complexes of 2,6-bis(imidazo[1,2- a]pyridin-2-yl)pyridine and related ligands with annelated distal heterocyclic donors. Dalton Trans 2023; 52:14928-14940. [PMID: 37799008 DOI: 10.1039/d3dt02747c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Following a published synthesis of 2,6-bis(imidazo[1,2-a]pyridin-2-yl)pyridine (L1), treatment of α,α'-dibromo-2,6-diacetylpyridine with 2 equiv. 2-aminopyrimidine or 2-aminoquinoline in refluxing acetonitrile respectively gives 2,6-bis(imidazo[1,2-a]pyrimidin-2-yl)pyridine (L2) and 2,6-bis(imidazo[1,2-a]quinolin-2-yl)pyridine (L3). Solvated crystals of [Fe(L1)2][BF4]2 (1[BF4]2) and [Fe(L2)2][BF4]2 (2[BF4]2) are mostly high-spin, although one solvate of 1[BF4]2 undergoes thermal spin-crossover on cooling. The iron coordination geometry is consistently distorted in crystals of 2[BF4]2 which may reflect the influence of intramolecular, inter-ligand N⋯π interactions on the molecular conformation. Only 1 : 1 Fe : L3 complexes were observed in solution, or isolated in the solid state; a crystal structure of [FeBr(py)2L3]Br·0.5H2O (py = pyridine) is presented. A solvate crystal structure of high-spin [Fe(L4)2][BF4]2 (L4 = 2,6-di{quinolin-2-yl}pyridine; 4[BF4]2) is also described, which exhibits a highly distorted six-coordinate geometry with a helical ligand conformation. The iron(II) complexes are high-spin in solution at room temperature, but 1[BF4]2 and 2[BF4]2 undergo thermal spin-crossover equilibria on cooling. All the compounds exhibit a ligand-based emission in solution at room temperature. Gas phase DFT calculations mostly reproduce the spin state properties of the complexes, but show small anomalies attributed to intramolecular, inter-ligand dispersion interactions in the sterically crowded molecules.
Collapse
Affiliation(s)
- Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT.
| | - Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT.
| |
Collapse
|
3
|
Resines-Urien E, Fernandez-Bartolome E, Martinez-Martinez A, Gamonal A, Piñeiro-López L, Costa JS. Vapochromic effect in switchable molecular-based spin crossover compounds. Chem Soc Rev 2023; 52:705-727. [PMID: 36484276 DOI: 10.1039/d2cs00790h] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Coordination complexes based on transition metal ions displaying [Ar]3d4-3d7 electronic configurations can undergo the likely most spectacular switchable phenomena found in molecular coordination chemistry, the well-known Spin Crossover (SCO). SCO phenomena is a detectable, reproducible and reversible switch that occurs between the high spin (HS) and low spin (LS) electronic states of the transition metal actuated by different stimuli (i.e. light, temperature, pressure, the presence of an analyte). Moreover, the occurrence of SCO phenomena causes different outputs, one of them being a colour change. Altogether, an analyte in gas form could be detected by naked eye once it has triggered the corresponding HS ↔ LS transition. This vapochromic effect could be used to detect volatile molecules using a low-cost technology, including harmful chemical substances, gases and/or volatile organic compounds (VOCs) that are present in our environment, in our home or at our workplace. The present review condenses all reported iron coordination compounds where the colour change induced by a given molecule in its gas form is coupled to a HS ↔ LS spin transition. Special emphasis has been made on describing the nature of the post-synthetic modification (PSM) taking place in the material upon the analyte uptake. In this case, three types of PSM can be distinguished: based on supramolecular contacts and/or leading to a coordinative or covalent bond. In the latter, a colour change not only indicates the switch of the spin state in the material but also the formation of a new compound with different properties. It is important to indicate that some of the SCO coordination compounds discussed in the current report have been part of other spin crossover reviews, that have gathered thermally induced SCO compounds and the influence of guest molecules on the SCO behaviour. However, in the majority of examples in these reviews, the change of colour upon the uptake of analytes is not associated with a spin transition at room temperature. In addition, the observed colour variations have been mainly discussed in terms of host-guest interactions, when they can also be induced by a PSM taking place in different sites of the molecule, like the Fe(II) coordination sphere or by chemically altering its inorganic and/or organic linkers. Therefore, we present here for the first time an exhaustive compilation of all systems in which the interaction between the coordination compounds and the vapour analytes leads to a colour change due to a spin transition in the metal centre at room temperature.
Collapse
|
4
|
Qin CY, Zhou HW, Zhao SZ, Li YH, Wang S. Spin crossover mediated by hydrogen bonds in iodine-substituted manganese complexes. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
5
|
Kumar B, Paul A, Mondal DJ, Paliwal P, Konar S. Spin-State Modulation in Fe II -Based Hofmann-Type Coordination Polymers: From Molecules to Materials. CHEM REC 2022; 22:e202200135. [PMID: 35815939 DOI: 10.1002/tcr.202200135] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/21/2022] [Indexed: 11/05/2022]
Abstract
Spin crossover complexes that reversibly interconvert between two stable states imitate a binary state of 0 and 1, delivering a promising possibility to address the data processing concept in smart materials. Thus, a comprehensive understanding of the modulation of magnetic transition between high spin and low spin and the factors responsible for stabilizing the spin states is an essential theme in modern materials design. In this context, the present review attempts to provide a concise outline of the design strategy employed at the molecular level for fine-tuning the spin-state switching in FeII -based Hofmann-type coordination polymers and their effects on the optical and magnetic response. In addition, development towards the nanoscale architectures of HCPs, i. e., in terms of nanoparticles and thin films, are emphasized to bridge the gap between the laboratory and reality.
Collapse
Affiliation(s)
- Bhart Kumar
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Abhik Paul
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Dibya Jyoti Mondal
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Piyush Paliwal
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| | - Sanjit Konar
- Molecular Magnetism Lab, Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh, 462066, India
| |
Collapse
|
6
|
You M, Shao D, Deng YF, Yang J, Yao NT, Meng YS, Ungur L, Zhang YZ. [Au I(CN) 2]-Armed [Fe III2Fe II2] Square Complex Showing Unusual Spin-Crossover Behavior Due to a Symmetry-Breaking Phase Transition. Inorg Chem 2022; 61:5855-5860. [PMID: 35377631 DOI: 10.1021/acs.inorgchem.2c00192] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The incorporation of two different cyanide building blocks of [(TpR)FeIII(CN)3]- and [AuI(CN)2]- into one molecule afforded a novel hexanuclear [FeIII2FeII2AuI2] complex (1·2Et2O), in which the cyanide-bridged [FeIII2FeII2] square was further grafted by two [AuI(CN)2]- fragments as long arms in syn orientations. Complex 1·2Et2O undergoes a gradual spin crossover (SCO) ffrom low-spin (LS) to high-spin (HS) state for the Fe(II) centers upon desolvation. Remarkably, its desolvated phase (1) exhibits a reversible but atypical two-step (sharp-gradual) SCO behavior with considerable hysteresis (21 K). Variable-temperature single-crystal X-ray structural studies reveal that the hysteretic spin transition takes place synchronously with the concerted displacive motions of the molecules, representing another rare example including multistep and hysteretic spin transitions due to the synergetic SCO and structural phase transition.
Collapse
Affiliation(s)
- Maolin You
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China.,Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543
| | - Dong Shao
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Jiong Yang
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Nian-Tao Yao
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
| | - Yin-Shan Meng
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| |
Collapse
|
7
|
Kulmaczewski R, Kershaw Cook LJ, Pask CM, Cespedes O, Halcrow MA. Iron(II) Complexes of 4-(Alkyldisulfanyl)-2,6-di(pyrazolyl)pyridine Derivatives. Correlation of Spin-Crossover Cooperativity with Molecular Structure Following Single-Crystal-to-Single-Crystal Desolvation. CRYSTAL GROWTH & DESIGN 2022; 22:1960-1971. [PMID: 35431660 PMCID: PMC9007408 DOI: 10.1021/acs.cgd.2c00005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/24/2022] [Indexed: 06/14/2023]
Abstract
The complex salts [Fe(L 1)2]X2 (1X 2 ; L 1 = 4-(isopropyldisulfanyl)-2,6-bis(pyrazolyl)pyridine; X- = BF4 -, ClO4 -) form solvated crystals from common organic solvents. Crystals of 1X 2 ·Me2CO show abrupt spin transitions near 160 K, with up to 22 K thermal hysteresis. 1X 2 ·Me2CO cocrystallizes with other, less cooperative acetone solvates, which all transform into the same solvent-free materials 1X 2 ·sf upon exposure to air, or mild heating. Conversion of 1X 2 ·Me2CO to 1X 2 ·sf proceeds in a single-crystal to single-crystal fashion. 1X 2 ·sf are not isomorphous with the acetone solvates, and exhibit abrupt spin transitions at low temperature with hysteresis loops of 30-38 K (X- = BF4 -) and 10-20 K (X- = ClO4 -), depending on the measurement method. Interestingly, the desolvation has an opposite effect on the SCO temperature and hysteresis in the two salts. The hysteretic spin transitions in 1X 2 ·Me2CO and 1X 2 ·sf do not involve a crystallographic phase change but are accompanied by a significant rearrangement of the metal coordination sphere. Other solvates 1X 2 ·MeNO2, 1X 2 ·MeCN, and 1X 2 ·H2O are mostly isomorphous with each other and show more gradual spin-crossover equilibria near room temperature. All three of these lattice types have similar unit cell dimensions and contain cations associated into chains through pairwise, intermolecular S···π interactions. Polycrystalline [Fe(L 2)2][BF4]2·MeNO2 (2[BF 4 ] 2 ·MeNO2; L 2 = 4-(methyldisulfanyl)-2,6-bis(pyrazolyl)pyridine) shows an abrupt spin transition just above room temperature, with an unsymmetrical and structured hysteresis loop, whose main features are reversible upon repeated thermal scanning.
Collapse
Affiliation(s)
- Rafal Kulmaczewski
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | | | - Christopher M. Pask
- 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.
| |
Collapse
|
8
|
Xue S, Solre GFB, Wang X, Wang L, Guo Y. Vapor-triggered reversible crystal transformation of a nickel-based magnetic molecular switch. Chem Commun (Camb) 2022; 58:1954-1957. [PMID: 35043804 DOI: 10.1039/d1cc06076g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vapor-triggered crystal-to-crystal transformation between a discrete trinuclear complex [Ni3(sih)2(py)8] and a two-dimensional (2D) coordination polymer [Ni3(sih)2(py)2]n·2DMF·2H2O was demonstrated. It provides an example of a solid-state coordination-induced spin state switch behavior attributed to the structural phase transition triggered by solvent signal. The reversible nature can be detected by both optical (spectral) and magnetic responses in cycles.
Collapse
Affiliation(s)
- Shufang Xue
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Gideon F B Solre
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Xiaoqin Wang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Liang Wang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Yunnan Guo
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| |
Collapse
|
9
|
Zhao Y, Wang L, Xue S, Guo Y. Reversible coordination-induced spin state switching in a nickel( ii) complex via a crystal-to-crystal transformation. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01059c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An unprecedented CISSS behavior driven by a single-crystal-to-single-crystal (SCSC) process is found in a dinuclear nickel(ii) complex, which provides a new strategy for developing external-stimuli molecular magnetic materials.
Collapse
Affiliation(s)
- Yaqian Zhao
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Liang Wang
- 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
| | - Yunnan Guo
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| |
Collapse
|
10
|
Książek M, Weselski M, Kusz J, Bronisz R. Single crystal-to-single crystal transformation - from two distinct to three distinct spin crossover centers in 2D coordination polymer [Fe(bbtr) 3](CF 3SO 3) 2. Dalton Trans 2021; 51:958-968. [PMID: 34931210 DOI: 10.1039/d1dt03578a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,4-Di(1,2,3-triazol-1-yl)butane (bbtr) forms a two-dimensional (2D) coordination polymer (1) in a reaction with iron(II) triflate. In the crystal lattice there are two crystallographically unique iron(II) ions surrounded octahedrally by a 1,2,3-triazole ring coordinated through nitrogen atoms N3. Single crystal X-ray diffraction studies revealed that spin crossover for each crystallographically independent iron(II) ion proceeds at a different temperature (T1/2(Fe1) = 201 K; T1/2(Fe2) = 216 K), while the magnetic measurements showed that there is one step, complete thermally induced spin crossover (T1/2 = 205 K). Complex 1 undergoes, with time, single crystal-to-single crystal transformation (SCSC) to the converted system (1c) from the R3̄ to the P63 space group, accompanied by significant changes in the lattice parameter c (a shortening of approximately one-third) and consequently unit cell volume. Structural transformation is associated with rebuilding of the polymeric layer as well as the anion network, which is reflected in the results of Mössbauer studies. In the polymorphic system (1c) there are three crystallographically independent iron(II) ions. The temperature dependence results for magnetic susceptibility indicated complete, one-step spin crossover very similar to that of 1; however, single-crystal X-ray diffraction studies of 1c revealed that spin crossover for each crystallographically independent iron(II) ion occurs in a different manner, revealing three elementary stages (T1/2(Fe1) = 200 K; T1/2(Fe2) = 212 K, T1/2(Fe3) = 214 K).
Collapse
Affiliation(s)
- Maria Książek
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland.
| | - Marek Weselski
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Joachim Kusz
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland.
| | - Robert Bronisz
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| |
Collapse
|