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

Silver compound [Ag(PPh3)2(NMP)]NO3 (1) (NMPZ2-(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 (lmaxZ522 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. q 2005 Elsevier B.V. All rights reserved.