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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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2
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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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3
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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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4
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Denisov GL, Nikovskii IA, Aliev TM, Polezhaev AV, Nelyubina YV. Spin State of Cobalt(II) 2,6-Bis(pyrazol-3-yl)pyridine Complex with a Redox-Active Ferrocenyl Substituent. RUSS J COORD CHEM+ 2021. [DOI: 10.1134/s1070328421060014] [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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5
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Nikovskii IA, Polezhaev AV, Aleshin DY, Mel’nikova EK, Nelyubina YV. Synthesis and Spin State of the Iron(II) Complex with the N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine Ligand. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s107032842006007x] [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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6
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Nikovsky IA, Polezhaev AV, Melnikova EK, Nelyubina Y. New Iron(III) Oxo Complex with Substituted 2,6-Bis(Pyrazol-3-yl)Pyridine. RUSS J INORG CHEM+ 2020. [DOI: 10.1134/s0036023620060145] [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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7
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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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8
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Nikovskii IA, Polezhaev AV, Aleshin DY, Mel’nikova EK, Dorovatovskii PV, Nelyubina YV. Iron(II) and Cobalt(II) Complexes with 2,6-Bis(1,4-Diphenyl-5-Hydroxy-1H-Pyrazol-3-yl)pyridine: Synthesis, Structures, and Spin States. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s1070328420050048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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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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10
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Nikovskiy IA, Spiridonov KA, Zakharova DV, Platonova EO, Pavlov AA, Nelyubina YV, Polezhaev AV. Ortho-lithiation of N-aryl ferrocenylmethanimines. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.118976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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11
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Pavlov AA, Nikovskii IA, Polezhaev AV, Aleshin DY, Melnikova EK, Pankratova YA, Nelyubina YV. Spin State of the Iron(II) and Cobalt(II) 2,6-Di(5-Amino-1H-Pyrazol-3-yl)pyridine Complexes in Solution and in Crystal. RUSS J COORD CHEM+ 2019. [DOI: 10.1134/s1070328419060046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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12
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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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13
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Kiernicki JJ, Zeller M, Szymczak NK. Requirements for Lewis Acid-Mediated Capture and N-N Bond Cleavage of Hydrazine at Iron. Inorg Chem 2019; 58:1147-1154. [PMID: 30628782 PMCID: PMC6467759 DOI: 10.1021/acs.inorgchem.8b02433] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An iron complex bearing a pyridine(dicarbene) pincer was designed to probe the requirements of Lewis acid-enabled N2H4 capture and subsequent N-N bond cleavage. Appended boron Lewis acids were installed by two methods to circumvent the incompatibilities associated with Lewis acid/base quenching of free carbenes and boranes. N2H4 capture by borane Lewis acids is dependent on both the Lewis acidity and the steric profile about boron. A substitutionally inert primary coordination sphere at iron prevents an Fe-N2H4 interaction as well as N-N bond homolysis upon reduction.
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Affiliation(s)
- John J. Kiernicki
- Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, MI 48109
| | - Matthias Zeller
- H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, IN 47907
| | - Nathaniel K. Szymczak
- Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, MI 48109
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Alig L, Fritz M, Schneider S. First-Row Transition Metal (De)Hydrogenation Catalysis Based On Functional Pincer Ligands. Chem Rev 2018; 119:2681-2751. [PMID: 30596420 DOI: 10.1021/acs.chemrev.8b00555] [Citation(s) in RCA: 488] [Impact Index Per Article: 81.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The use of 3d metals in de/hydrogenation catalysis has emerged as a competitive field with respect to "traditional" precious metal catalyzed transformations. The introduction of functional pincer ligands that can store protons and/or electrons as expressed by metal-ligand cooperativity and ligand redox-activity strongly stimulated this development as a conceptual starting point for rational catalyst design. This review aims at providing a comprehensive picture of the utilization of functional pincer ligands in first-row transition metal hydrogenation and dehydrogenation catalysis and related synthetic concepts relying on these such as the hydrogen borrowing methodology. Particular emphasis is put on the implementation and relevance of cooperating and redox-active pincer ligands within the mechanistic scenarios.
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Affiliation(s)
- Lukas Alig
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
| | - Maximilian Fritz
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
| | - Sven Schneider
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
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15
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Cook BJ, Pink M, Chen C, Caulton KG. Electrophile Recruitment as a Structural Element in Bis‐Pyrazolate Pyridine Complex Aggregation. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Brian J. Cook
- Department of Chemistry Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
| | - Maren Pink
- Department of Chemistry Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
- Indiana University Molecular Structure Center Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
| | - Chun‐Hsing Chen
- Department of Chemistry Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
- Indiana University Molecular Structure Center Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
| | - Kenneth G. Caulton
- Department of Chemistry Indiana University‐Bloomington 800 E Kirkwood Avenue 47405 Bloomington IN USA
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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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17
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Pavlov AA, Belov AS, Savkina SA, Polezhaev AV, Aleshin DY, Novikov VV, Nelyubina YV. Synthesis and Spin State of the Cobalt(II) Complexes with Substituted 2,6-Bis(pyrazol-3-yl)pyridine Ligands. RUSS J COORD CHEM+ 2018. [DOI: 10.1134/s1070328418080067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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18
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Ahamad S, Patidar RK, Kumar A, Kant R, Mohanan K. Three-Component Synthesis of 3,4-Disubstituted Pyrazoles Using Diazosulfone as a Diazomethane Surrogate. ChemistrySelect 2017. [DOI: 10.1002/slct.201702384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shakir Ahamad
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
| | - Rajesh Kumar Patidar
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
| | - Anuj Kumar
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
| | - Ruchir Kant
- Molecular and Structural Biology; CSIR-Central Drug Research Institute; Lucknow 226031 India
| | - Kishor Mohanan
- Medicinal and Process Chemistry Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
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