Synthesis of Vanadyl Complexes of N-Confused Porphyrins and Their Bromoperoxidase -like Catalytic Activity.
Rajesh KumarVed PrakashMuniappan SankarPublished in: Inorganic chemistry (2024)
Two new vanadyl complexes of N-confused porphyrins (NCPs), [VONCTPP] ( V-1 ) and [VONCP(OMe) 8 ] ( V-2 ), have been synthesized for the first time and investigated as a catalyst for the oxidative bromination reaction of phenol and its derivatives. This article further delineates crystal structures, photophysical, and redox properties of both the vanadyl complexes. Complexes V-1 and V-2 exhibited a significant red shift in their absorption spectra compared with their respective free bases. The single-crystal structure of V-1 revealed that the complex is in the 2H tautomeric form, while EPR studies revealed the +4 oxidation state of vanadium metal having an axial compression with d xy 1 configuration. Catalytic potential for bromoperoxidases -like activity has been explored for both complexes V-1 and V-2 for the first time in NCP chemistry with excellent TOF values (4.7-6.3 s -1 for V-1 and 7.3-8.7 s -1 for V-2 ) using KBr as a source of bromine and H 2 O 2 as a green oxidant in aqueous acidic medium at 298 K. Notably, both catalysts show excellent recyclability over five cycles. The vanadyl-metalated NCPs exhibit excellent stability in the air.