Mononuclear Gold(I) bis-N-heterocyclic carbene: Synthesis and photophysical study

Publication date: Available online 26 January 2020Source: Journal of Organometallic ChemistryAuthor(s): Umie F.M. Haziz, Rosenani A. Haque, Shun-Ze Zhan, Mohd R. RazaliAbstractIn the current study, 1-butyl-3-propylbenzimidazolium bromide salt (1) was used as a carbene precursor to facilitate the formation of complex [NHC–Ag(I)–NHC]PF6 (2) (NHC = N-heterocyclic carbene) via in-situ deprotonation method with Ag2O. Furthermore, the formation of complex [NHC–Au(I)–NHC]PF6 (3) was achieved through a transmetalation approach of 2 with Au(SMe2)Cl. The formation of all compounds was proved by elemental analyses, FTIR, 1H- and 13C NMR. The successful complexation of NHC ligand with Ag(I) and Au(I) ions were suggested by the disappearance of H2′ carbene proton peak which previously present in the spectrum of 1 at 9.784 ppm. In addition, the shift of C2’ carbene carbon peak from 142 ppm in the spectrum of 1 to the area of 187–190 ppm in the spectra of 2 and 3 supports the formation of these metal-NHC complexes. Crystal analysis of 3 shows that the complex consists of one Au(I) ion in a linear geometry that coordinates to two NHC ligands with the presence of one PF6− cation in the lattice stabilizes the entire structure. In solid-state photophysical study of 3, upon excitation at 340 nm, complex 3 displays an intense photoluminescence with a strong emission maxima, λem = 500 nm at room temperature.Graphical abstract
Source: Journal of Organometallic Chemistry - Category: Chemistry Source Type: research