Biocatalytic Potential of Dinuclear Complexes Containing Imine and Oxime Groups: A Study on Catalase, Catecholase, and Phenoxazinone Synthase Enzymatic Activities

Authors : Baran Sevim, Bülent Dede

Pages : 103-112

Doi:10.56150/tjhsl.1715251

View : 67 | Download : 72

Publication Date : 2025-12-31

Article Type : Research Paper

Abstract :The development of biomimetic catalysts has emerged as a promising alternative to natural enzymes, which often suffer from instability under operational conditions. In this study, six dinuclear metal(II) complexes containing imine and oxime groups, three homodinuclear Cu(II)-Cu(II) and three heterodinuclear Cu(II)-Mn(II), were evaluated for their catalase-, catecholase-, and phenoxazinone synthase-like activities. Catalase-like activity was investigated through the volumetric measurement of O2 gas evolved from the catalytic disproportionation of hydrogen peroxide. Catecholase- and phenoxazinone synthase-like activities were assessed spectrophotometrically using 3,5-di-tert-butylcatechol and 2-aminophenol as model substrates, respectively. The catalytic reaction\\\'s rate constants (kobs) were calculated to quantify the enzymatic behavior. The results revealed that homodinuclear Cu(II)-Cu(II) complexes displayed significantly higher catalytic activities than their heterodinuclear counterparts in all three reactions. Complex 3 (p-acetylaniline-substituted) showed the highest catalase activity with 17 mL O2 evolution. In contrast, complex 2 (p-toluidine-substituted) demonstrated the highest catecholase- and phenoxazinone synthase-like activities with rate constants of 0.2385 min-1 and 0.2705 min-1, respectively. The enhanced activity was strongly correlated with the electronic nature of the substituents, where electron-donating groups promoted redox cycling, and electron-withdrawing groups modulated Lewis acidity at the metal center. This comprehensive study highlights the catalytic potential of diimine-dioxime-based dinuclear metal complexes. It emphasizes the impact of metal identity and ligand design on enzyme-mimicking functions, offering valuable insights for future applications in green chemistry, biotechnology, and medicine.
Keywords : Katalaz, katekolaz, metal kompleks, fenoksazinon sentaz

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