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Morimoto Y, Kawai M, Nakanishi A, Sugimoto H, Itoh S. Controlling the Reactivity of Copper(II) Acylperoxide Complexes. Inorg Chem 2021; 60:8554-8565. [PMID: 33848148 DOI: 10.1021/acs.inorgchem.1c00475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The redox state of the metallomonooxygenases is finely tuned by imposing specific coordination environments on the metal center to reduce the activation energy for the generation of active-oxygen species and subsequent substrate oxygenation reactions. In this study, copper(II) complexes supported by a series of linear tetradentate ligands consisting of a rigid 6-, 7-, or 8-membered cyclic diamine with two pyridylmethyl (-CH2Py) side arms (L6Pym2, L7Pym2, and L8Pym2) are employed to examine the effects of the coordination environment on the reactivity of their acylperoxide adduct complexes. The UV-vis and electron paramagnetic resonance spectroscopic data indicate that the ligand-field splitting between the dx2-y2 and dz2 orbitals of the starting copper(II) complexes increase with an increase of the ring size of the diamine moiety (L6Pym2 → L7Pym2 → L8Pym2). In the reaction of these copper(II) complexes with m-chloroperbenzoic acid (m-CPBA), the L6Pym2 complex gives a stable m-CPBA adduct complex, whereas the L7Pym2 and L8Pym2 complexes are immediately converted to the corresponding m-chlorobenzoic acid (m-CBA) adducts, indicating that the reactivity of the copper(II) acylperoxide complexes largely depends on the coordination environment induced by the supporting ligands. Density functional theory (DFT) calculations on the m-CPBA adduct complexes show that the ligand-field-splitting energy increases with an increase of the ring size of the diamine moiety, as in the case of the starting copper(II) complexes, which enhances the reactivity of the m-CPBA adduct complexes. The reasons for such different reactivities of the m-CPBA adduct complexes are evaluated by using DFT calculations.
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Affiliation(s)
- Yuma Morimoto
- Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Makito Kawai
- Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Aya Nakanishi
- Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hideki Sugimoto
- Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shinobu Itoh
- Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Juliet sheela K, Krishnan SR, Shanmugam V, Subramanian P. Analysis of spin-Hamiltonian and molecular orbital coefficients of Cu 2+ doped C 8 H 11 KO 8 single crystal through EPR technique. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.12.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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