Assembly of the heterometallic Au(I)-M(I) (M = Cu, Ag) clusters containing the dialkyne-derived diphosphines: synthesis, luminescence and theoretical studies

The novel heterobimetallic Au(I)-M(I) (M= Cu, Ag) alkynyl-diphosphine clusters were effectively prepared using a family of dialkynyl-based diphosphines, PPh(2)-C(2)-(C(6)H(4))n-C(2)-PPh(2) (n = 0-2). These compounds consist of [Au(x)M(y)(C(2)C(6)H(4)R)(2x)](y-x) clusters (x = (n + 2)(n + 3)/2; y = (n + 1)(n + 2)) "wrapped" in gold-diphosphine "belts" (M = Cu, n = 0, R = H (4); n = 1, R = H (6), OMe (8), NMe(2) (9). M = Ag, n = 0, 1, 2, R = H (5, 7, 10). The solid-state structures of 5 and 6 have been determined by X-ray crystallographic studies, other complexes were characterized by NMR spectroscopy and ESI-MS measurements. The luminescence behavior of these compounds has been studied both in the solid state and solution, and intense room-temperature emission in fluid medium with maximum quantum yield of 0.5 (6) was detected. Computational studies have been carried out and the theoretical results obtained are in good agreement with the experimental data. The calculations provided additional information on the structural and electronic properties of the aggregates under investigation and allowed for the rationalization of the difference in their photophysical behavior.