Design and Synthesis of Bimetallic Dioxidovanadium(v) Complex Derived from Dihydrazone Ligand. Crystal Structure, Catecholase, and Phenoxazinone Synthase Activities

A new bimetallic vanadium(V) complex of the composition [(Et 3 NH) 2 ][(VO 2 ) 2 L]; [L = N'1,N'4‐bis((E)‐5‐chloro‐2‐hydroxybenzylidene)succinohydrazide] is successfully synthesized and characterized by infrared spectroscopy (IR) and 1 H NMR spectroscopy. The structure of the complex is confirmed by single‐crystal X‐ray crystallography. The complex crystallizes in triclinic crystal system with space group P‐1 . The complex has two dioxovanadium centers coordinated at the two extremities of a molecule of the ONO chelating ligand. The synthesized vanadium(v) complex mimics the catalytic activity of the plant enzyme catechol oxidase by oxidizing 3,5‐di‐tert‐butylcatechol to its corresponding 3,5‐di‐tert‐butyl quinone and also shows phenoxazinone synthase activity. The kinetic parameters for catecholase activity in methanol are V max = 5.1 × 10 −5 Ms −1 , K M = 4.3 × 10 −4 m, and K cat = 2.1 × 10 3 h −1 . The kinetic parameters for phenoxazinone synthase activity in methanol are V max = 1.5 × 10 −4 Ms −1 , K M = 4.78 × 10 −3 m, and K cat = 1 × 10 5 h −1 , respectively.