A tetranuclear Mn-diamond core complex as a functional mimic of catechol oxidase and phenoxazinone synthase enzymes. — ASN Events
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A tetranuclear Mn-diamond core complex as a functional mimic of catechol oxidase and phenoxazinone synthase enzymes. (#465)

Rakesh Kumar 1 2 , Rahul Keshri 2 , Koushik Prodhan 2 , Kanchan Shaikh 2 , Apparao Draksharapu 2
  1. Department of Chemistry, University of California Irvine, Irvine, California, United States
  2. Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India

Catechol oxidase and phenoxazinone synthase (PHS) enzymes play vital roles in oxidation processes in biological systems.1,2 Catechol oxidases, found in bacteria, fungi, and plants, catalyze the conversion of o-diphenols into o-quinones.3,4 While PHS catalyses the oxidative coupling of a variety of substituted o-aminophenols to the phenoxazinone chromophore.5,6 Many 3d metal-based model complexes have been designed for effective bio mimic.7 Herein, a tetranuclear Mn(II,III,III,II) diamond core, [Mn4(HPTP*)2(μ-O)2(H2O)4](ClO4)4 (1) complex, has been synthesised using a suitably designed septadentate ligand framework (HPTP*H = 1,3-bis(bis((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)amino)propan-2-ol) through dioxygen activation.8 1 was characterised using multiple spectroscopic techniques and X-ray crystallography. It exhibits excellent catalytic oxidation reactivity for the model substrates, namely, 3,5-di-tert-butylcatechol (3,5-DTBC) and 2-aminophenol, efficiently mimicking the enzymes catechol oxidase and PHS, respectively. Remarkably, we employed aerial oxygen to catalyze the oxidation of these model substrates 3,5-DTBC and 2-aminophenol, with turnover numbers of 835 and 14, respectively.6 A tetranuclear Mn-diamond core complex that mimics both catechol oxidase and PHS could pave the way for further research into their potential as multi-enzymatic functional mimics.

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  8. R. Kumar, R. Keshri, K. Prodhan, K. Shaikh and A. Draksharapu, Dalton Trans., 2023, 52, 15412-15419.
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