Synthesis, Characterization, and Singlet Oxygen Sensitization by Antimony (III/V) Corrole Complexes

Abstract The synthesis, structural, spectroscopic characterization, and DFT/TD‐DFT calculations of antimony corroles are reported herein. The studied complexes can be described as [(Corr)Sb III ] and [(Corr)(oxo)Sb V ] 2 , where Corr is the trianion of corrole. All these complexes are diamagnetic in nature as is evident from sharp peaks with normal chemical shifts in the 1 H NMR spectra. Single crystal XRD analysis reveals that the antimony(V) corrole complex is the bis‐ μ ‐oxo‐bridged dinuclear antimony(V). Both the tetra and hexa‐coordinated [(Corr)Sb III ] and [(Corr)(oxo)Sb V ] 2 antimony complexes adopt domed‐structure with weak d‐π electron coupling. The Sb−O bond distances in the co‐facial dimer of [(Corr)(oxo)Sb V ] 2 are 1.9802(16) Å (DFT: 2.0141 Å ) (for Sb1−O1), and 1.9639(17) Å (DFT: 1.9957 Å ) (for Sb2−O2) respectively. We observed that even though iodosobenzene is frequently used to oxidize [(Corr)Sb III ] species, the oxidation of [(Corr)Sb III ] is indeed very facile in nature and it even occurred in the air‐equilibrated CHCl 3 solution while storing for few days. Excitation of these antimony (III/V) corrole complexes in DCM/MeOH (1 : 1) at 77 K results in red emission with maxima at 640–720 nm. The singlet oxygen production of [(Corr)(oxo)Sb V ] 2 has a quantum yield of 69 % and is two times higher than the analogous [(Corr)Sb III ] derivatives.