1
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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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2
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Moll J, Förster C, König A, Carrella LM, Wagner M, Panthöfer M, Möller A, Rentschler E, Heinze K. Panchromatic Absorption and Oxidation of an Iron(II) Spin Crossover Complex. Inorg Chem 2022; 61:1659-1671. [PMID: 35020386 DOI: 10.1021/acs.inorgchem.1c03511] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to expand and exploit the useful properties of d6-iron(II) and d5-iron(III) complexes in potential magnetic, photophysical, or magnetooptical applications, crucial ligand-controlled parameters are the ligand field strength in a given coordination mode and the availability of suitable metal and ligand frontier orbitals for charge-transfer processes. The push-pull ligand 2,6-diguanidylpyridine (dgpy) features low-energy π* orbitals at the pyridine site and strongly electron-donating guanidinyl donors combined with the ability to form six-membered chelate rings for optimal metal-ligand orbital overlap. The electronic ground states of the pseudo-octahedral d6- and d5-complexes mer-[Fe(dgpy)2]2+, cis-fac-[Fe(dgpy)2]2+, and mer-[Fe(dgpy)2]3+ as well as their charge-transfer (CT) and metal-centered (MC) excited states are probed by variable temperature UV/vis absorption, NMR, EPR, and Mössbauer spectroscopy, magnetic susceptibility measurements at variable temperature as well as quantum chemical calculations.
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Affiliation(s)
- Johannes Moll
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Christoph Förster
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Alexandra König
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Luca M Carrella
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Manfred Wagner
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Martin Panthöfer
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Angela Möller
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Eva Rentschler
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
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3
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Uritis S, Thummel RP, Lee HS, Hancock RD. A study of the complexes of Hg(II) with polypyridyl ligands by Fluorescence, absorbance Spectroscopy, and DFT calculations. The effect of ligand preorganization and relativistic effects on complex stability. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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4
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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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5
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Spin-Crossover in Iron(II) Complexes of N,N′-Disubstituted 2,6-Bis(Pyrazol-3-yl)Pyridines: An Effect of a Distal Substituent in the 2,6-Dibromophenyl Group. CRYSTALS 2021. [DOI: 10.3390/cryst11080922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A series of new bis(pyrazol-3-yl)pyridines (LR) N,N′-disubstituted by 4-functionalized 2,6-dibromophenyl groups have been synthesized to study the effect of a distal substituent on the spin-crossover (SCO) behaviour of the iron(II) complexes [Fe(LR)2](ClO4)2 by variable-temperature magnetometry, NMR spectroscopy, and X-ray diffraction. The SCO-assisting tendency of the substituents with different electronic and steric properties (i.e., the bromine atom and the methyl group) in the para-position of the 2,6-dibromophenyl group is discussed. Together with earlier reported SCO-active iron(II) complexes with N,N′-disubstituted bis(pyrazol-3-yl)pyridines, these new complexes open the way for this family of SCO compounds to emerge as an effective ‘tool’ in revealing structure–function relations, a prerequisite for successful molecular design of switchable materials for future breakthrough applications in sensing, switching, and memory devices.
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6
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Schönfeld S, Bauer W, Thallmair S, Hörner G, Weber B. Running in the Family: Molecular Factors controlling Spin Crossover of Iron(II) Complexes with Schiff‐base like Ligands. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000409] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Sophie Schönfeld
- Department of Chemistry University of Bayreuth Universitätsstraße 30 NWI 95440 Bayreuth Germany
| | - Wolfgang Bauer
- Department of Chemistry University of Bayreuth Universitätsstraße 30 NWI 95440 Bayreuth Germany
| | - Sebastian Thallmair
- Department of Chemistry University of Bayreuth Universitätsstraße 30 NWI 95440 Bayreuth Germany
- Present address: Frankfurt Institute for Advanced Studies Ruth-Moufang-Straße 1 60438 Frankfurt am Main Germany
| | - Gerald Hörner
- Department of Chemistry University of Bayreuth Universitätsstraße 30 NWI 95440 Bayreuth Germany
| | - Birgit Weber
- Department of Chemistry University of Bayreuth Universitätsstraße 30 NWI 95440 Bayreuth Germany
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7
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Kurz H, Hörner G, Weber B. An Iron(II) Spin Crossover Complex with a Maleonitrile Schiff base‐like Ligand and Scan Rate‐dependent Hysteresis above Room Temperature. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hannah Kurz
- Department of Chemistry University of Bayreuth Universitätsstraße 30, NWI 95447 Bayreuth Germany
| | - Gerald Hörner
- 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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8
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Capel Berdiell I, Kulmaczewski R, Warriner SL, Cespedes O, Halcrow MA. Iron and Silver Complexes of 4‐(Imidazol‐1‐yl)‐2,6‐di(pyrazol‐1‐yl)‐pyridine (
L
), Including a [Fe
3
(µ‐F)
2
F
6
L
8
]
+
Assembly. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | | | - Oscar Cespedes
- School of Physics and Astronomy University of Leeds EC Stoner Building LS2 9JT Leeds UK
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9
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Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy. CRYSTALS 2020. [DOI: 10.3390/cryst10090793] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.
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10
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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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11
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Pankratova Y, Aleshin D, Nikovskiy I, Novikov V, Nelyubina Y. In Situ NMR Search for Spin-Crossover in Heteroleptic Cobalt(II) Complexes. Inorg Chem 2020; 59:7700-7709. [PMID: 32383584 DOI: 10.1021/acs.inorgchem.0c00716] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Here we report the first successful attempt to identify spin-crossover compounds in solutions of metal complexes produced by mixing different ligands and an appropriate metal salt by variable-temperature nuclear magnetic resonance (NMR) spectroscopy. Screening the spin state of a cobalt(II) ion in a series of thus obtained homoleptic and heteroleptic compounds of terpyridines (terpy) and 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) by using this NMR-based approach, which only relies on the temperature behavior of chemical shifts, revealed the first cobalt(II) complexes with a 3-bpp ligand to undergo a thermally induced spin-crossover. A simple analysis of NMR spectra collected from mixtures of different compounds without their isolation or purification required by the current method of choice, the Evans technique, thus emerges as a powerful tool in a search for new spin-crossover compounds and their molecular design boosted by wide possibilities for chemical modifications in heteroleptic complexes.
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Affiliation(s)
- Yanina Pankratova
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Moscow State University, Leninskie gory, 1, 119991 Moscow, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047 Moscow, Russia
| | - Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
| | - Valentin 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, Dolgoprudny 141700, Moscow Region, Russia
| | - Yulia Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
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12
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Nikovskiy I, Polezhaev A, Novikov V, Aleshin D, Pavlov A, Saffiulina E, Aysin R, Dorovatovskii P, Nodaraki L, Tuna F, Nelyubina Y. Towards the Molecular Design of Spin-Crossover Complexes of 2,6-Bis(pyrazol-3-yl)pyridines. Chemistry 2020; 26:5629-5638. [PMID: 31967374 DOI: 10.1002/chem.202000047] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Indexed: 01/27/2023]
Abstract
The molecular design of spin-crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N'-disubstituted 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) are reported that, against the common wisdom, induce a spin-crossover in otherwise high-spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho-functionalized phenyl group. As N,N'-disubstituted 3-bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1-bpp or other families of popular bi-, tri- and higher denticity ligands, opens the way for their molecular design as spin-crossover compounds for future breakthrough applications.
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Affiliation(s)
- Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia
| | - Alexander 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
| | - Valentin 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, Dolgoprudny, 141700, Moscow Region, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Alexander Pavlov
- 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, Dolgoprudny, 141700, Moscow Region, Russia
| | - Elnara Saffiulina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Rinat Aysin
- 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, Dolgoprudny, 141700, Moscow Region, Russia
| | - Pavel Dorovatovskii
- National Research Centre "Kurchatov Institute", Akademika Kurchatova pl., 1, 123182, Moscow, Russia
| | - Lydia Nodaraki
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Floriana Tuna
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Yulia 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
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13
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Spin Crossover in 3D Metal Centers Binding Halide-Containing Ligands: Magnetism, Structure and Computational Studies. SUSTAINABILITY 2020. [DOI: 10.3390/su12062512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The capability of a given substance to change its spin state by the action of a stimulus, such as a change in temperature, is by itself a very challenging property. Its interest is increased by the potential applications and the need to find sustainable functional materials. 3D transition metal complexes, mainly with octahedral geometry, display this property when coordinated to particular sets of ligands. The prediction of this behavior has been attempted by many authors. It is, however, made very difficult because spin crossover (SCO), as it is called, occurs most often in the solid state, where besides complexes, counter ions, and solvents are also present in many cases. Intermolecular interactions definitely play a major role in SCO. In this review, we decided to analyze SCO in mono- and binuclear transition metal complexes containing halogens as ligands or as substituents of the ligands. The aim was to try and find trends in the properties which might be correlated to halogen substitution patterns. Besides a revision of the properties, we analyzed structures and other information. We also tried to build a simple model to run Density Functional Theory (DFT) calculations and calculate several parameters hoping to find correlations between calculated indices and SCO data. Although there are many experimental studies and single-crystal X-ray diffraction structures, there are only few examples with the F, Cl, Br and series. When their intermolecular interactions were not very different, T1/2 (temperature with 50% high spin and 50% low spin states) usually increased with the calculated ligand field parameter (Δoct) within a given family. A way to predict SCO remains elusive.
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14
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Photoinduced Mo−CN Bond Breakage in Octacyanomolybdate Leading to Spin Triplet Trapping. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Qi X, Pillet S, de Graaf C, Magott M, Bendeif EE, Guionneau P, Rouzières M, Marvaud V, Stefańczyk O, Pinkowicz D, Mathonière C. Photoinduced Mo-CN Bond Breakage in Octacyanomolybdate Leading to Spin Triplet Trapping. Angew Chem Int Ed Engl 2020; 59:3117-3121. [PMID: 31793123 DOI: 10.1002/anie.201914527] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Indexed: 01/30/2023]
Abstract
The photoinduced properties of the octacoordinated complex K4 MoIV (CN)8 ⋅2 H2 O were studied by theoretical calculations, crystallography, and optical and magnetic measurements. The crystal structure recorded at 10 K after blue light irradiation reveals an heptacoordinated Mo(CN)7 species originating from the light-induced cleavage of one Mo-CN bond, concomitant with the photoinduced formation of a paramagnetic signal. When this complex is heated to 70 K, it returns to its original diamagnetic ground state, demonstrating full reversibility. The photomagnetic properties show a partial conversion into a triplet state possessing significant magnetic anisotropy, which is in agreement with theoretical studies. Inspired by these results, we isolated the new compound [K(crypt-222)]3 [MoIV (CN)7 ]⋅3 CH3 CN using a photochemical pathway, confirming that photodissociation leads to a stable heptacyanomolybdate(IV) species in solution.
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Affiliation(s)
- Xinghui Qi
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, F-33600, Pessac, France
| | - Sébastien Pillet
- Université de Lorraine, CNRS, CRM2, Nancy, 54506, Vandoeuvre-les-Nancy, France
| | - Coen de Graaf
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Carrer Marcellí Domingo 1, Tarragona, Spain.,ICREA, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Michał Magott
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków, Poland
| | - El-Eulmi Bendeif
- Université de Lorraine, CNRS, CRM2, Nancy, 54506, Vandoeuvre-les-Nancy, France
| | - Philippe Guionneau
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, F-33600, Pessac, France
| | | | - Valérie Marvaud
- Sorbonne Université, IPCM-CNRS-UMR-8232, cc 229, 4 place Jussieu, 75252, Paris Cedex 05, France
| | - Olaf Stefańczyk
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, F-33600, Pessac, France.,Present address: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Dawid Pinkowicz
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków, Poland
| | - Corine Mathonière
- CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, F-33600, Pessac, France
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16
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Pavlov AA, Aleshin DY, Nikovskiy IA, Polezhaev AV, Efimov NN, Korlyukov AA, Novikov VV, Nelyubina YV. New Spin-Crossover Complexes of Substituted 2,6-Bis(pyrazol-3-yl)pyridines. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900432] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexander A. Pavlov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
- Moscow Institute of Physics and Technology; Institutskiy per., 9 141700 Dolgoprudny, Moscow Region Russia
| | - Dmitry Yu. Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
- Mendeleev University of Chemical Technology of Russia; Miusskaya pl., 9 125047 Moscow Russia
| | - Igor A. Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
| | - Alexander V. Polezhaev
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
- Bauman Moscow State Technical University; 2nd Baumanskaya Str., 5 105005 Moscow Russia
| | - Nikolay N. Efimov
- Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences; Leninsky pr., 31 119991 Moscow Russia
| | - Alexander A. Korlyukov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
| | - Valentin V. Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
- Moscow Institute of Physics and Technology; Institutskiy per., 9 141700 Dolgoprudny, Moscow Region Russia
| | - Yulia V. Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences; Vavilova Str., 28 119991 Moscow Russia
- Moscow Institute of Physics and Technology; Institutskiy per., 9 141700 Dolgoprudny, Moscow Region Russia
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17
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Schnaubelt L, Petzold H, Hörner G, Rüffer T, Klein N, Lang H. Tailoring of the Frontier Orbital Character in Co
2+/3+
Complexes with Triarylamine Substituted Terpyridine Ligands. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801433] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Linda Schnaubelt
- Technische Universität Chemnitz Faculty of Natural Sciences Institute of Chemistry Inorganic Chemistry 09107 Chemnitz Germany
| | - Holm Petzold
- Technische Universität Chemnitz Faculty of Natural Sciences Institute of Chemistry Inorganic Chemistry 09107 Chemnitz Germany
| | - Gerald Hörner
- Institute of Chemistry Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Tobias Rüffer
- Technische Universität Chemnitz Faculty of Natural Sciences Institute of Chemistry Inorganic Chemistry 09107 Chemnitz Germany
| | - Niels Klein
- Technische Universität Chemnitz Faculty of Natural Sciences Institute of Chemistry Inorganic Chemistry 09107 Chemnitz Germany
| | - Heinrich Lang
- Technische Universität Chemnitz Faculty of Natural Sciences Institute of Chemistry Inorganic Chemistry 09107 Chemnitz Germany
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18
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Petzold H, Hörner G, Schnaubelt L, Rüffer T. Slow spin crossover in bis-meridional Fe 2+ complexes through spin-state auto-adaptive N6/N8 coordination. Dalton Trans 2018; 47:17257-17265. [PMID: 30488935 DOI: 10.1039/c8dt03652g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Fe2+ spin crossover (SCO) complexes with long-lived excited high-spin (HS) states are promising molecular switches. An enhanced kinetic stability of spin-state isomers can be expected to foster applications beyond the limits of cooperative SCO. In this study, we describe a new approach to slow down the spin-state exchange by simple commutation of a phenyl substituent by a pyridyl substituent. To this end, N4 ligand 6-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)-2,2'-bipyridine (3b) is synthesized as an N4 homologue of the well-established meridional N3 ligands motif. Phenyl-substituted 6-(3-phenyl-1H-pyrazol-1-yl)-2,2'-bipyridine (3a) serves as an intrinsic N3 reference throughout. 3b offers variable coordination numbers, N3 versus N3(+1) and N4, reflecting the preferences of the metal center. As is shown herein through an extended solid-state structure-chemical and solution-state NMR study, which is augmented by density-functional theory modeling, both the coordination geometry and its structural dynamics are indeed highly sensitive towards the expansion of the nominal donor number. The additional donors in 3b introduced through the phenyl-pyridine commutation actually give rise to a rich and diverse stereochemistry of the derived Zn2+ and Fe2+ complexes. Notably, even within a single complex unit coordination of 3b ranges from strongly distorted N3 coordination with a long assisting additional contact (Zn2+ and Fe2+) to a more symmetric N2(+2) or N4 situation in Fe2+. DFT modeling unravels that the additional donors are hemi-labile and coordinate to the Fe2+ only in HS state, leaving the elusive low-spin (LS) state in a fairly undisturbed octahedral environment with 3b being N3 coordinate. That is, the coordination number of the complex autogeneously responds to the altered spin-state. Necessarily this switch in coordination number requires strong structural changes upon SCO. This leads to increased activation barriers for SCO as could be deduced from a temperature-dependent analysis of the dynamic 1H NMR-line broadening and corroborated by accompanying theoretical analysis of the SCO reaction coordinate. For [Fe(3b)2]2+ long spin-state lifetimes τ > 1 ms prevail below the characteristic temperature T (1 ms) = 235 K; this value should be compared with a lifetime of only 150 ns derived for the close analogue [Fe(3a)2]2+. The principle applied herein is general and allows transferring of LS Fe2+ complexes with suitably placed phenyl substituents into SCO complexes with spin-state adaptive coordination number and hence long-lived HS excited states.
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Affiliation(s)
- Holm Petzold
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Gerald Hörner
- TU Berlin, Institut für Chemie, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Linda Schnaubelt
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Tobias Rüffer
- TU Chemnitz, Institut für Chemie, Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany.
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19
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Intramolecular Spin State Locking in Iron(II) 2,6-Di(pyrazol-3-yl)pyridine Complexes by Phenyl Groups: An Experimental Study. MAGNETOCHEMISTRY 2018. [DOI: 10.3390/magnetochemistry4040046] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Here we report a series of 1-phenyl-5-substituted 2,6-di(pyrazol-3-yl)pyridine complexes with iron(II) ion found in a high spin state in solids (according to magnetochemistry) and in solution (according to NMR spectroscopy), providing experimental evidence for it being an intramolecular effect induced by the phenyl groups. According to X-ray diffraction, the high spin locking of the metal ion is a result of its highly distorted coordination environment (with a very low ‘twist’ angle atypical of 2,6-di(pyrazol-3-yl)pyridine complexes), which remains this way in complexes with different substituents and counterions, in a diamagnetic zinc(II) analogue and in their solutions. Three possible reasons behind it, including additional coordination with the phenyl group, energy penalty incurred by its rotation or intramolecular stacking interactions, are addressed experimentally.
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20
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Schnaubelt L, Petzold H, Dmitrieva E, Rosenkranz M, Lang H. A solvent- and temperature-dependent intramolecular equilibrium of diamagnetic and paramagnetic states in Co complexes bearing triaryl amines. Dalton Trans 2018; 47:13180-13189. [PMID: 30178800 DOI: 10.1039/c8dt02538j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Complexes [Co(L)2](ClO4)2 (L = o-substituted 2-(pyridine-2-yl)-1,10-phenanthrolines 1a-c) containing three redox active centres (a Co2+ ion and two triaryl amine (Tara) units) have been synthesised. The order of oxidation steps in [Co(L)2](ClO4)2 (L = 1a-c) was determined using cyclic voltammetry and EPR/UV-vis-NIR spectroelectrochemistry. In acetonitrile solutions, at room temperature, the first oxidation is Co-centred followed by the Tara oxidation at more anodic potentials. The order of oxidation is inverted in solutions of the less polar solvent dichloromethane. The Co3+/2+-centred redox event leads to a spin transition between the paramagnetic high-spin (HS) Co2+ and the diamagnetic low-spin (LS) Co3+ state, which was proven using 1H NMR and EPR spectroscopy. After one-electron oxidation of [Co(L)2](ClO4)2, an equilibrium between the diamagnetic [Co3+(L)]3+ and paramagnetic [Co2+(L)(L+)]3+ state in [Co(L)2]3+ (L = 1a-c) was found. Cyclic voltammetry showed enhanced intermolecular electron transfer between the [Co2+(L)2]2+ and [Co3+(L)2]3+ redox states mediated by [Co2+(L)(L+)]3+. Variable temperature vis-NIR spectroscopy of in situ generated [Co(L)2]3+ revealed a temperature-dependent redox equilibrium between the [Co3+(L)2]3+ and the [Co2+(L+)(L)]3+ states (L = 1a-c). Magnetic coupling between the HS-Co2+ ion and the Tara+ radical in [HS-Co2+(L+)(L)]3+ (L = 1a,c) was deduced from broad and undetectable lines observed in the corresponding EPR spectra. Complete oxidation to [LS-Co3+(L+)2]5+ (L = 1a,c) leads to characteristic EPR spectra of Tara biradicals with non-interacting spins.
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Affiliation(s)
- Linda Schnaubelt
- Technische Universität Chemnitz, Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, 09107 Chemnitz, Germany.
| | - Holm Petzold
- Technische Universität Chemnitz, Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, 09107 Chemnitz, Germany.
| | - Evgenia Dmitrieva
- Center of Spectroelectrochemistry, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany
| | - Marco Rosenkranz
- Center of Spectroelectrochemistry, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany
| | - Heinrich Lang
- Technische Universität Chemnitz, Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, 09107 Chemnitz, Germany.
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21
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Schnaubelt L, Petzold H, Speck JM, Rüffer T, Hörner G, Lang H. Spin Transition and Charge Transfer in Co2+
/Co3+
Complexes of Meridional Ligands Holding Nearby Redox-active Triarylamine. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Linda Schnaubelt
- Inorganic Chemistry, Institute of Chemistry; Faculty of Natural Sciences; Technische Universität Chemnitz; 09107 Chemnitz Germany
| | - Holm Petzold
- Inorganic Chemistry, Institute of Chemistry; Faculty of Natural Sciences; Technische Universität Chemnitz; 09107 Chemnitz Germany
| | - J. Matthäus Speck
- Inorganic Chemistry, Institute of Chemistry; Faculty of Natural Sciences; Technische Universität Chemnitz; 09107 Chemnitz Germany
| | - Tobias Rüffer
- Inorganic Chemistry, Institute of Chemistry; Faculty of Natural Sciences; Technische Universität Chemnitz; 09107 Chemnitz Germany
| | - Gerald Hörner
- Institute of Chemistry; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Heinrich Lang
- Inorganic Chemistry, Institute of Chemistry; Faculty of Natural Sciences; Technische Universität Chemnitz; 09107 Chemnitz Germany
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22
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Huang XC, Qi ZY, Ji CL, Guo YM, Yan SC, Zhang YQ, Shao D, Wang XY. High-coordinate CoII and FeII compounds constructed from an asymmetric tetradentate ligand show slow magnetic relaxation behavior. Dalton Trans 2018; 47:8940-8948. [DOI: 10.1039/c8dt01829d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A seven-coordinate CoII compound and an eight-coordinate FeII compound based on an asymmetric tetradentate ligand have been reported, and both of them exhibited slow magnetic relaxation behaviour.
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Affiliation(s)
- Xing-Cai Huang
- School of Chemistry and Environmental Engineering
- Yancheng Teachers University
- Yancheng
- China
| | - Zi-Yi Qi
- School of Chemistry and Environmental Engineering
- Yancheng Teachers University
- Yancheng
- China
| | - Cheng-Long Ji
- School of Chemistry and Environmental Engineering
- Yancheng Teachers University
- Yancheng
- China
| | - Yi-Ming Guo
- School of Chemistry and Environmental Engineering
- Yancheng Teachers University
- Yancheng
- China
| | - Shi-Chang Yan
- School of Chemistry and Environmental Engineering
- Yancheng Teachers University
- Yancheng
- China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS
- School of Physical Science and Technology
- Nanjing Normal University
- Nanjing 210023
- China
| | - Dong Shao
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Centre of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
| | - Xin-Yi Wang
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Centre of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
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