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Nikovskiy I, Aleshin DY, Novikov VV, Polezhaev AV, Khakina EA, Melnikova EK, Nelyubina YV. Selective Pathway toward Heteroleptic Spin-Crossover Iron(II) Complexes with Pyridine-Based N-Donor Ligands. Inorg Chem 2022; 61:20866-20877. [PMID: 36511893 DOI: 10.1021/acs.inorgchem.2c03270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A new synthetic pathway is devised to selectively produce previously elusive heteroleptic iron(II) complexes of terpyridine and N,N'-disubstituted bis(pyrazol-3-yl)pyridines that stabilize the opposite spin states of the metal ion. Such a combination of the ligands in a series of the heteroleptic complexes induces the spin-crossover (SCO) not experienced by the homoleptic complexes of these ligands or shifts it to lower/higher temperatures respective to the SCO-active homoleptic complex. The midpoint temperatures of the resulting SCO span from ca. 200 K to the ambient temperature and beyond the highest temperature accessible by NMR spectroscopy and SQUID magnetometry. The proposed "one-pot" approach is applicable to other N-donor ligands to selectively produce heteroleptic complexes─including those inaccessible by alternative synthetic pathways─with highly tunable SCO behaviors for practical applications in sensing, switching, and multifunctional devices.
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Affiliation(s)
- Igor Nikovskiy
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Dmitry Yu Aleshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Valentin V Novikov
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, 141700Dolgoprudny, Russia
| | - Alexander V Polezhaev
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Ekaterina A Khakina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,HSE University, Miasnitskaya Str., 20, 101000Moscow, Russia
| | - Elizaveta K Melnikova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Yulia V Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
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Mel’nikova EK, Nikovskii IA, Polezhaev AV, Nelyubina YV. Solvatomorphs of Iron(II) Complex with N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine with a Temperature-Induced Spin Transition in Solution. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422080048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract
The reaction of the tridentate ligand 4-(2,6-bis(5-tert-butyl-1-(2,6-dichlorophenyl)-1H-pyrazol-3-yl)pyridin-4-yl)benzonitrile (L) with iron(II) salt gave the complex [Fe(L)2](BF4)2, which was isolated in a pure state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction as two crystal polymorphs differing in the nature of the solvent molecule in the crystal (solvatomorphs I and II). According to the results of X-ray diffraction study (CCDC nos. 2104367 (I), 2104368 (II)), the iron(II) ion in these compounds occurs in different spin states and does not undergo a temperature-induced spin transition, which was previously observed for this complex in solution. The details of supramolecular organization of two solvatomorphs that prevent this transition were studied using the Hirshfeld surface analysis.
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Khakina EA, Denisov GL, Nikovskii IA, Polezhaev AV, Nelyubina YV. Spin State of the Cobalt(II) Complex with N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422060021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Aleshin D, Nikovskiy I, Novikov VV, Polezhaev AV, Melnikova EK, Nelyubina YV. Room-Temperature Spin Crossover in a Solution of Iron(II) Complexes with N, N'-Disubstituted Bis(pyrazol-3-yl)pyridines. ACS OMEGA 2021; 6:33111-33121. [PMID: 34901662 PMCID: PMC8655922 DOI: 10.1021/acsomega.1c05463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/09/2021] [Indexed: 05/15/2023]
Abstract
Here, we report a combined study of the effects of two chemical modifications to an N,N'-disubstituted bis(pyrazol-3-yl)pyridine (3-bpp) and of different solvents on the spin-crossover (SCO) behavior in otherwise high-spin iron(II) complexes by solution NMR spectroscopy. The observed stabilization of the low-spin state by electron-withdrawing substituents in the two positions of the ligand that induce opposite electronic effects in SCO-active iron(II) complexes of isomeric bis(pyrazol-1-yl)pyridines (1-bpp) was previously hidden by NH functionalities in 3-bpp precluding the molecular design of SCO compounds with this family of ligands. With the recent SCO-assisting substituent design, the uncovered trends converged toward the first iron(II) complex of N,N'-disubstituted 3-bpp to undergo an almost complete SCO centered at room temperature in a less polar solvent of a high hydrogen-bond acceptor ability.
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Affiliation(s)
- Dmitry
Yu Aleshin
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
| | - Igor Nikovskiy
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
| | - Valentin V. Novikov
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Moscow
Institute of Physics and Technology, Institutskiy per., 9, 141700 Dolgoprudny, Russia
| | - Alexander V. Polezhaev
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
| | - Elizaveta K. Melnikova
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Lomonosov
Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia
| | - Yulia V. Nelyubina
- A.N.
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str., 28, 119991 Moscow, Russia
- Bauman
Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005 Moscow, Russia
- Moscow
Institute of Physics and Technology, Institutskiy per., 9, 141700 Dolgoprudny, Russia
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