Aggregation-Induced Phosphorescent Emission from ReI Complexes: Synthesis and Property Studies

Four Re-I complexes with aggregation-induced phosphorescent emission (AIPE) were synthesized with the formula Re(CO)(3)(Bath-n)Br (n = 1-4), where Bath-1 = 4,7-diphenyl-2-[4-(trimethylsilyl)-phenyl]-1,10-phenanthroline (1), Bath-2 = 4,7-diphenyl-2-[4-(dimethylphenylsilyl)phenyl]-1,10-phenanthroline (2), Bath-3 = 4,7-diphenyl-2-[4-(methyldiphenylsilyl)phenyl]-1,10-phenanthroline (3), and Bath-4 = 4,7-diphenyl-2-[4-(triphenylsilyl)phenyl]-1,10-phenanthroline (4), and fully characterized. The single crystals of 1 and 3 were obtained in the monoclinic crystal system by diffusion of diethyl ether into their dichloromethane solutions. Complexes 1-4 in pure THF (c approximate to 10(-5) molL(-1)) mainly present * emission at 370 nm and intraligand charge-transfer (ILCT) emission at 440 nm, whereas the powder samples of 1-4 solely give lower energy (MLCT)-M-3 (metal-to-ligand charge transfer) emission at approximately 560 nm. The lifetimes of the powder samples of 1-4 were measured at room temperature to be 0.335 mu s, 0.149 mu s, 0.289 mu s, and 1.301 mu s, respectively. Additionally, the emission spectra and the UV/Vis absorption spectra of 1-4 were analyzed in different THF/H2O mixtures to investigate their AIPE character. Furthermore, the ground states and the UV/Vis absorption spectra of 1-4 were also theoretically simulated at the B3LYP/(LANL2DZ+6-31G) level.