Highly Efficient β‐Functionalized Oxidomolybdenum(V) Corroles for Catalytic Oxidative Bromination of Phenols at Room Temperature

Abstract Two new β ‐functionalized oxidomolybdenum(V) corroles, oxido[3‐formyl‐5,10,15‐triphenylcorrolato]molybdenum(V) ( Mo‐1 ) and oxido[3‐dicyanovinyl‐5,10,15‐triphenylcorrolato]molybdenum(V) ( Mo‐2 ) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo‐2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron‐deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with d xy 1 configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo‐2 relative to Mo‐1 . Mo‐1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo‐2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo‐1 and Mo‐2 for the oxidative bromination of various phenols using H 2 O 2 ‐KBr‐HClO 4 mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β ‐functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h −1 ) for oxidative bromination of phenols relative to earlier reported meso ‐functionalized Mo(V) corroles (20781–61646 h −1 ). Hence, Mo‐1 and Mo‐2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities.