1
|
Kumar P, Devkota L, Casey MC, Fischer AA, Lindeman SV, Fiedler AT. Reversible Dioxygen Binding to Co(II) Complexes with Noninnocent Ligands. Inorg Chem 2022; 61:16664-16677. [PMID: 36206536 PMCID: PMC11218047 DOI: 10.1021/acs.inorgchem.2c02246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal-ligand cooperativity during the reversible binding of O2. The complexes have the general formula, [CoII(LS,N)(TpR2)] (R = Me, Ph), where LS,N is a bidentate o-aminothiophenolate and TpR2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O2 at room temperature results in one-electron oxidation and deprotonation of LS,N. The oxidized derivatives possess substantial "singlet diradical" character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ•-) ligand radical and a low-spin Co(II) ion. The [CoII(TpMe2)(X2ITSQ)] complexes, where X = H or tBu, coordinate O2 reversibly at reduced temperatures to provide Co/O2 adducts. The O2 binding reactions closely resemble those previously reported by our group (Kumar et al., J. Am. Chem. Soc. 2019,141, 10984-10987) for the related complexes [CoII(TpMe2)(tBu2SQ)] and [CoII(TpMe2)(tBu2ISQ)], where tBu2(I)SQ represents 4,6-di-tert-butyl-(2-imino)semiquinonate radicals. In each case, the oxygenation reaction proceeds via the addition of O2 to both the cobalt ion and the ligand radical, generating metallocyclic cobalt(III)-alkylperoxo structures. Thermodynamic measurements elucidate the relationship between O2 affinity and redox potentials of the (imino)(thio)semiquinonate radicals, as well as energetic differences between these reactions and conventional metal-based oxygenations. The results highlight the utility and versatility of noninnocent ligands in the design of O2-absorbing compounds.
Collapse
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Laxmi Devkota
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Maximilian C Casey
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Anne A Fischer
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Sergey V Lindeman
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| |
Collapse
|
2
|
Spielvogel KD, Coughlin EJ, Petras H, Luna JA, Benson A, Donahue CM, Kibasa A, Lee K, Salacinski R, Bart SC, Shaw SK, Shepherd JJ, Daly SR. The Influence of Redox-Innocent Donor Groups in Tetradentate Ligands Derived from o-Phenylenediamine: Electronic Structure Investigations with Nickel. Inorg Chem 2019; 58:12756-12774. [DOI: 10.1021/acs.inorgchem.9b01675] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Kyle D. Spielvogel
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Ezra J. Coughlin
- H.C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hayley Petras
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Javier A. Luna
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Austin Benson
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Courtney M. Donahue
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Amani Kibasa
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Kyounghoon Lee
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Ryan Salacinski
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Suzanne C. Bart
- H.C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Scott K. Shaw
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - James J. Shepherd
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| | - Scott R. Daly
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242-1294, United States
| |
Collapse
|