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Panda S, Dhara S, Singh A, Dey S, Kumar Lahiri G. Metal-coordinated azoaromatics: Strategies for sequential azo-reduction, isomerization and application potential. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Seikh L, Dey S, Dhara S, Singh A, Lahiri GK. Inner-Sphere Electron Transfer Induced Reversible Electron Reservoir Feature of Azoheteroarene Bridged Diruthenium Frameworks. Inorg Chem 2022; 61:15735-15746. [PMID: 36129962 DOI: 10.1021/acs.inorgchem.2c02921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article demonstrates the stabilization of ground- and redox-induced metal-to-ligand charge transfer excited states on coordination of azo-coupled bmpd(L4) [bmpd = (E)-1,2-bis(1-methyl-1H-pyrazol-3-yl)diazene; L4 = -N═N-] to the electron-rich {Ru(acac)2} (acac = acetylacetonate) unit in mononuclear RuII(acac)2(L4) (1) and diastereomeric dinuclear (acac)2Ru2.5(μ-L4•-)Ru2.5(acac)2 [rac, ΔΔ/ΛΛ (2a)/meso, ΔΛ (2b)] complexes, respectively. It also develops further one-step intramolecular electron transfer induced L4•- bridged isovalent higher analogue [(acac)2RuIII(μ-L4•-)RuIII(acac)2]ClO4 in diastereomeric forms, rac-[2a]ClO4/meso-[2b]ClO4. On the contrary, under identical reaction conditions electronically and sterically permuted bimpd [L5, (E)-1,2-bis(4-iodo-1-methyl-1H-pyrazol-3-yl)diazene)] delivered mononuclear RuII(acac)2(L5) (3) as an exclusive product. Further, the generation of unprecedented heterotrinuclear complex [(acac)2RuII(μ-L4)AgI(μ-L4)RuII(acac)2]ClO4 ([4]ClO4) involving unreduced L4 via the reaction of 1 and AgClO4 revealed the absence of any inner-sphere electron transfer (IET) as in precursor 1, which in turn reaffirmed an IET (at the interface of electron-rich Ru(acac)2 and acceptor L4) mediated stabilization of 2. Structural authentication of the complexes with special reference to the tunable azo distance (N═N, N-N•-, N-N2-) of L and their spectro-electrochemical events in accessible redox states including the reversible electron reservoir feature of 2 → 2+/2+ → 2 were evaluated in conjunction with density functional theory/time-dependent density functional theory calculations. The varying extent of IET as a function of heteroaromatics appended to the azo group of L (L1 = abpy = 2,2'-azobipyridine, L2 = abbt = 2,2'-azobis(benzothiazole), L3 = abim = azobis(1-methylbenzimidazole), L4 and L5, Schemes 1 & 2) in the Ru(acac)2-derived respective molecular setup has been addressed.
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Affiliation(s)
- Liton Seikh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Aditi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Lahiri GK, Panda S, Huang KW, Singh A, Dey S. Inner-sphere electron transfer at the ruthenium-azo interface. Dalton Trans 2022; 51:2547-2559. [DOI: 10.1039/d1dt03934b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal complexes exhibiting multiple reversible redox states have drawn continuing research interest due to their electron reservoir features. In this context, the present article described ruthenium-acac complexes (acac=acetylacetonate) incorporating redox-active...
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Xu S, Yang D, Wang B, Chen Y, Ye S, Qu J. Generation of a Sulfinamide Species from Facile N-O Bond Cleavage of Nitrosobenzene by a Thiolate-Bridged Diiron Complex. J Am Chem Soc 2021; 143:17374-17387. [PMID: 34617736 DOI: 10.1021/jacs.1c03542] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The activation of nitrosobenzene promoted by transition-metal complexes has gained considerable interest due to its significance for understanding biological processes and catalytic C-N bond formation processes. Despite intensive studies in the past decades, there are only limited cases where electron-rich metal centers were commonly employed to achieve the N-O or C-N bond cleavage of the coordinated nitrosobenzene. In this regard, it is significant and challenging to construct a suitable functional system for examining its unique reactivity toward reductive activation of nitrosoarene. Herein, we present a {Fe2S2} functional platform that can activate nitrosobenzene via an unprecedented iron-directed thiolate insertion into the N-O bond to selectively generate a well-defined diiron benzenesulfinamide complex. Furthermore, computational studies support a proposal that in this concerted four-electron reduction process of nitrosobenzene the iron center serves as an important electron shuttle. Notably, compared to the intact bridging nitrosoarene ligand, the benzenesulfinamide moiety has priority to convert into aniline in the presence of separate or combined protons and reductants, which may imply the formation of the sulfinamide species accelerates reduction process of nitrosoarene. The reaction pattern presented here represents a novel activation mode of nitrosobenzene realized by a thiolate-bridged diiron complex.
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Affiliation(s)
- Sunlin Xu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P.R. China
| | - Dawei Yang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P.R. China
| | - Baomin Wang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P.R. China
| | - Yifeng Chen
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China.,School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Jingping Qu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P.R. China.,State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China
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Singh H, MacKay A, Sheibany N, Chen F, Mosser M, Rouet PÉ, Rousseau F, Askari MS, Ottenwaelder X. Intramolecular H-bond stabilization of a primary hydroxylamine in salen-type metal complexes. Chem Commun (Camb) 2021; 57:10403-10406. [PMID: 34545379 DOI: 10.1039/d1cc03077a] [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
Primary hydroxylamines, RNHOH, decompose readily in the presence of transition metal ions. We show that this reactivity can be arrested by ligand design via an intramolecular hydrogen bond. Six metal complexes with an intact NHOH group were synthesized and crystallographically characterized. The Cu-hydroxylamine complexes can catalyze the aerobic oxidation of benzylic alcohols.
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Affiliation(s)
- Hardeep Singh
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Alyson MacKay
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Nooshin Sheibany
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Fei Chen
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Maëlle Mosser
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Pierre-Étienne Rouet
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Frédéric Rousseau
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Mohammad S Askari
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
| | - Xavier Ottenwaelder
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada.
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Zsombor-Pindera J, Effaty F, Escomel L, Patrick B, Kennepohl P, Ottenwaelder X. Five Nitrogen Oxidation States from Nitro to Amine: Stabilization and Reactivity of a Metastable Arylhydroxylamine Complex. J Am Chem Soc 2020; 142:19023-19028. [PMID: 33124796 DOI: 10.1021/jacs.0c09300] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Redox noninnocent ligands enhance the reactivity of the metal they complex, a strategy used by metalloenzymes and in catalysis. Herein, we report a series of copper complexes with the same ligand framework, but with a pendant nitrogen group that spans five different redox states between nitro and amine. Of particular interest is the synthesis of a unprecedented copper(I)-arylhydroxylamine complex. While hydroxylamines typically disproportionate or decompose in the presence of transition metal ions, the reactivity of this metastable species is arrested by the presence of an intramolecular hydrogen bond. Two-electron oxidation yields a copper(II)-(arylnitrosyl radical) complex that can dissociate to a copper(I) species with uncoordinated arylnitroso. This combination of ligand redox noninnocence and hemilability provides opportunities in catalysis for two-electron chemistry via a one-electron copper(I/II) shuttle, as exemplified with an aerobic alcohol oxidation.
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Affiliation(s)
- Joseph Zsombor-Pindera
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada.,Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Farshid Effaty
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Léon Escomel
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Brian Patrick
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Pierre Kennepohl
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Xavier Ottenwaelder
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
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