Kumar R, Maji A, Biswas B, Draksharapu A. Amphoteric reactivity of a putative Cu(II)-
mCPBA intermediate.
Dalton Trans 2024;
53:5401-5406. [PMID:
38426906 DOI:
10.1039/d3dt03747a]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
In copper-based enzymes, Cu-hydroperoxo/alkylperoxo species are proposed as key intermediates for their biological activity. A vast amount of literature is available on the functional and structural mimics of enzymatic systems with heme and non-heme ligand frameworks to stabilize high valent metal intermediates, mostly at low temperatures. Herein, we report a reaction between [CuI(NCCH3)4]+ and meta-chloroperoxybenzoic acid (mCPBA) in CH3CN that produces a putative CuII(mCPBA) species (1). 1 was characterized by UV/Vis, resonance Raman, and EPR spectroscopies. 1 can catalyze both electrophilic and nucleophilic reactions, demonstrating its amphoteric behavior. Additionally, 1 can also conduct electron transfer reactions with a weak reducing agent such as diacetyl ferrocene, making it one of the reactive copper-based intermediates. One of the most important aspects of the current work is the easy synthesis of a CuII(mCPBA) adduct with no complicated ligands for stabilization. Over time, 1 decays to form a CuII paddle wheel complex (2) and is found to be unreactive towards substrate oxidation.
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