Synthesis, photophysical properties and cation-binding studies of bipyridine-functionalized gold(i) complexes

Abstract

Gold(I) has been used as an interlocking center to design five phenyl-bipyridine based complexes [LAu(L1)] and [RAu(L2)] where L1 = 5-(4-ethynylphenyl)-2,2′-bipyridine and L2 = 5-(4-(diphenylphosphino)phenyl)-2,2′-bipyridine (L = P(C₆H₁₁)₃, 1; C₆H₃(CH₃)₂NC, 2; R = Ph₂OHCC₂, 3; PhC₂, 4; C₆F₅, 5). The obtained compounds have been characterized by polynuclear NMR spectroscopy and X-ray crystallography. Investigation of their UV-Vis absorption and emission characteristics has been supported by density functional theory (DFT) calculations that rationalize the tunable electronic properties of these compounds. Complexation of the metal cations and the corresponding optical responses of [LAu(L1)], in particular for Cd(II) and Pb(II), indicate the important role of gold(I) ions in modulating the luminescence characteristics of these species upon binding the analyte cations.