Syntheses, Structures and Phenoxazinone Synthase Activities of Two Cobalt(III) Complexes

Abstract

Abstract A mononuclear complex, [LCo(L′) 2 ]ClO 4 ⋅MeOH⋅H 2 O ( 1 ) ( L′ =4‐aminopyridine) and a binuclear heterometallic complex, [LCo(L′′) 2 Na(ClO 4 ) 2 ]⋅0.5H 2 O ( 2 ) ( L′′ =1‐methylimidazole) have been prepared from a Schiff‐base ligand ( H 2 L =N, N′‐bis(3‐methoxysalicylidehydene)cyclohexane‐1,2‐diamine). The formation of both complexes were confirmed by employing several analytical techniques including single crystal X‐ray diffraction. The molecular structure of 1 consists of a [LCo(L′) 2 ] + cation associated with a [ClO 4 ] − ion. Complex 2 contains a Co(III) ion and a Na(I) ion and thus it results a heterometallic Co(III)‐Na(I) compound. The Co(III) ion is in a distorted octahedral geometry in both complexes. Phenoxazinone synthase activity of 1 and 2 have been investigated. The oxidation of 2‐aminophenol (OAPH) to 2‐aminophenoxazine‐3‐one (APX) follows saturation rate kinetics with the formation of a catalyst‐substrate adduct. Mass analysis and electrochemical properties of both complexes have been investigated and they are in full support of the saturation rate kinetics.