Rhenium(VI) Benzylidyne Complexes, Re(⋮C-2,4,6-C₆H₂Me₃)(PPh₃)(H₂O)X₃ (X = Cl and Br):  Crystal Structure and Spectroscopic Properties

[ReV(⋮CAr‘)(PPh3)2(CO)(H2O)Cl]ClO4 (1) reacts with HCl in chloroform and is photooxidized in dibromomethane respectively to yield the rhenium(VI) benzylidyne complexes ReVI(⋮CAr‘)(PPh3)(H2O)X3 (X = Cl (2) and Br (3)). The crystal structure of 2 reveals a Re⋮C distance of 1.738(6) Å. Photoexcitation of 2 and 3 at λ > 300 nm in CH2Cl2 give red emission with lifetimes of 0.49 and 0.41 μs, respectively.