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A potentially tridentate hemilabile ligand, PPh2-C6H4-PPh(O)-C6H4-PPh2 (P(3)O), has been used for the construction of a family of bimetallic complexes [MM'(P(3)O)2](2+) (M = M' = Cu (1), Ag (2), Au (3); M = Au, M' = Cu (4)) and their mononuclear halide congeners M(P(3)O)Hal (M = Cu (5-7), Ag (8-10)). Compounds 1-10 have been characterized in the solid state by single-crystal X-ray diffraction analysis to reveal a variable coordination mode of the phosphine-oxide group of the P(3)O ligand depending on the preferable number of coordination vacancies on the metal center. According to the theoretical studies, the interaction of the hard donor P[double bond, length as m-dash]O moiety with d(10) ions becomes less effective in the order CuAgAu. 1-10 exhibit room temperature luminescence in the solid state, and the intensity and energy of emission are mostly determined by the nature of metal atoms. The photophysical characteristics of the monometallic species were compared with those of the related compounds M(P(3))Hal (11-16) with the non-oxidized ligand P(3). It was found that in the case of the copper complexes 5-7 the P(3)O hybrid ligand introduces effective non-radiative pathways of the excited state relaxation leading to poor emission, while for the silver luminophores the P[double bond, length as m-dash]O group leads mainly to the modulation of luminescence wavelength.

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.

Reaction of the polymeric alkynyl complexes (AuC(2)C(6)H(4)R)(n) (R = 4-NH(2) and 3-NH(2)) with the diphosphine PPh(2)C(6)H(4)PPh(2) in the presence of Cu(+) ions gave two novel heterometallic aggregates [{Au(3)Cu(2)(C(2)C(6)H(4)R)(6)}Au(3)(PPh(2)C(6)H(4)PPh(2))(3)](PF(6))(2) (R = 4-NH(2) (2), 3-NH(2) (3)). The compounds obtained were characterized by NMR spectroscopy and ESI-MS measurements. The solid-state structure of their 4-NMe(2) congener 1 is reported. The complexes 1-3 reversibly react with strong (HSO(3)Me and HSO(3)CF(3)) acids to give the adducts [{Au(3)Cu(2)(C(2)C(6)H(4)-R)(6)*(R'SO(3)H)(6)}Au(3)(PPh(2)C(6)H(4)PPh(2))(3)](PF(6))(2) (R = 4-NMe(2) (4), 4-NH(2) (5), 3-NH(2) (6)) with six acid molecules bound to the amine groups of the alkynyl ligands. Composition and structure of the adducts were established using ESI-MS and multinuclear ((31)P, (1)H and (1)H-(1)H COSY) NMR spectroscopy. It was found that formation of these adducts results in crucial changes of luminescence characteristics of the complexes 1-3 to give substantial (ca. 100 nm) blue shift of the emission maxima and a sharp increase (about an order of magnitude) in luminescence quantum yield for 4-NR(2) substituted derivatives. In the case of 3-substituted complex 3 the effect of adduct formation is much less pronounced and leads to blue-shift of emission maximum for 30 nm accompanied with a small drop in emission quantum yield. Computational studies have been performed to provide additional insight into the structural, electronic and photophysical properties of the starting complexes and their acid adducts. Interpretation of the photophysical effects induced by the adduct formation was suggested.