Synthesis, X-ray crystallography, and photoluminescence studies of four coordinate gold(I) complexes with the weak Lewis base tri-2-furyl phosphine ligand

Abstract

The synthesis and structural characterization, and luminescence properties of two new four-coordinate gold(I) complexes containing the monodentate tri-2-furly phosphine is described. The gold(I) center easily accommodates up to four of the phosphine ligands forming a nearly tetrahedral geometry. Formation of four-coordinate gold(I) species is favored mainly due to electronic factors since the cone angle of the ligand is larger than several other alkyl phosphines hitherto unknown to form four coordination. In the complexes the gold center has a nearly regular tetrahedral geometry with an average P–Au–P angle of 109.37°. The crystal structure of [Au(TFP)4]Cl·CH3CN, 3, reveals four phosphine ligands bound to the gold(I) atom as well as free Cl− and CH3CN within the crystal lattice providing a nearly regular tetrahedral geometry with an average P–Au–P angle of 109.4°. The photo-luminescent properties of the complexes are compared with that of the ligand and show ligand centered emission perturbed by the metal coordination. DFT theoretical calculations were also conducted and support the assignment of the spectroscopic data.