Synthesis, characterization, photophysics, and anion binding properties of gold(i) acetylide complexes with amide groups

Abstract

A series of mononuclear gold(I) acetylide complexes with amide groups, Ph₃PAuCCC₆H₄NHC(O)C₆H₄–R-4 (R = NO₂ (3a), CF₃ (3b), H (3c), and OMe (3d)), has been synthesized and characterized. The crystal structure of Ph₃PAuCCC₆H₄NHC(O)C₆H₄–NO₂-4 (3a) was determined by X-ray diffraction. The photophysical properties of gold(I) acetylide complexes 3b–3d were studied and the complexes show luminescence both in the solid state and in degassed THF solutions at 298 K. The anion-binding abilities of complexes 3a–3d in CDCl₃ were also studied through ¹H NMR titration experiments. They show similar anion selectivity trends and 3a exhibits the highest binding affinity towards anions due to the strongest electron-withdrawing ability of the NO₂ group. In DMSO, 3a shows a dramatic color change upon addition of F⁻, which provides access to naked eye detection of F⁻.