A DFT exploration of luminescent rhenium(I) tricarbonyl diimine complex with a triarylboron moiety and its F derivative

The geometry, electronic structure, and spectroscopic properties together with the fluoride binding nature of the luminescent rhenium(I) tricarbonyl diimine complex with a triarylboron moiety, [(arB)Re(CO)3(phen)] were investigated by density functional theory (DFT) approach, where, arB = (2,3,5,6-tetramethyl-4-ethynyl-benzene)3B, phen = 1,10-phenanthroline), The simulated UV–vis absorptions by M06 functional are in excellent agreement with the experimental results. All absorptions are attributed to intra-ligand charge-transfer (ILCT) within the triarylboron ligand but being disturbed by some contribution of metal-to-arylboron ligand charge-transfer (MLCT) characters. Moreover, the 676 nm phosphorescence computed by TPSSh functional originates from the 3LLCT/3LMCT transition. Binding the F− results in the re-configuration of the molecular geometry and the variation of the optical properties. The highest energy absorption band is intensified while the lower energy absorption bands are weakened and blue-shifted slightly. The emission maximum is red-shifted to 875 nm after binding the F−.