Computational and spectroscopic studies on luminescence of [Ag(PPh3)2(NMP)]NO3

Silver compound [Ag(PPh3)2(NMP)]NO3 (1) (NMP=2-(4-Dimethylaminophenyl)imidazo(4,5-f)(1,10)phenanthroline) has been synthesized and characterized by elemental analyses, IR and X-ray diffraction techniques. Two absorption bands (294 and 342 nm) have been observed in UV/vis absorption spectrum of 1. Compound 1 exhibits luminescence in solid state at room temperature and shows broad emission with maximum at 599 nm, which make red shift compared with free ligand NMP (λmax=522 nm). Short lifetime (2.2 ns) indicates that emission of 1 does not come form triplet excited state and the intense spin-orbital coupling of AgI has little effect on the lowest singlet excited state. Excited state of 1 was simulated by using the time-dependent density functional theory, which gave a sound explanation for absorption spectrum and indicated that emission of 1 originates form the metal-perturbed intraligand charge-transfer.