Synthesis, Characterization, Photophysical, and Theoretical Studies of Supramolecular Gold(I)−Silver(I) Alkynyl-Phosphine Complexes

Abstract

The reactions of diphosphino-alkynyl gold complexes (PhC 2 Au)PPh 2 (C 6 H 4 ) n PPh 2 (AuC 2 Ph) (n ) 1, 2, 3) with Ag + lead to the formation of supramolecular heterometallic aggregates, which consist of the [Au x Ag y (C 2 Ph) 2x ] y-x clusters (x ) (n+1)(n+2)/2; y ) n(n+1)) "wrapped" in gold-diphosphine "belts". The composition of the "belts" depends on the size of the heterometallic cluster; for n ) 1 it is an open-loop tetrametallic diphosphine-alkynyl [Au(C 2 Ph)Au 2 Ag(PPh 2 (C 6 H 4 ) 2 PPh 2 ) 3 ] 3+ complex, and for n ) 2, 3 it is a symmetrical closed triangle [Au 3 {PPh 2 (C 6 H 4 ) n PPh 2 } 3 ] 3+ . The complex for n ) 1 was characterized crystallographically and spectrally; the larger ones (n ) 2, 3) were investigated in detail by NMR spectroscopy. Their luminescence behavior has been studied, and an intense room-temperature solution emission with maximum quantum yield of 0.35 (n ) 2) was detected. Computational studies have been performed to provide additional insight into the structural and electronic properties of these supramolecular complexes. Theoretical results obtained are in good agreement with the experimental data, supporting the proposed structural motif. These studies also suggest that the observed efficient long-wavelength luminescence is associated with transitions within the central Au(I)-Ag(I) heterometallic fragment.

Vapochromic Gold(I)–Silver(I) Cluster Protected by Alkynyl and Phosphine Ligands

“…Note that only one of the two nitrogen atoms of the pyrazinyl group were occupied, thus tridentate ligand mdppz only functions as bidentate ligand in 1 . The Au 5 Ag 6 motifs exhibit honeycomb‐like geometry, which is similar to structures previously reported by Koshevoy and Blanco et al In each motif, acetylides adopt the µ 3 bonding mode. Six PhC≡C – groups are connected to the central gold atoms via σ bonds, thus forming three linear PhC≡C–Au–C≡CPh substructures, which are further coordinated to six silver atoms through π bonding (Figure b).…”

“…In some cases, phosphine ligands are also introduced to act as peripheral protecting ligands and to enhance the stability of the structures. By using diphosphine ligands, Koshevoy and co‐workers synthesized a series of heterometallic coinage metal clusters, which have a general structure of an alkynyl–metal core wrapped by a [Au(PPh 2 (C 6 H 4 ) n PPh 2 )] 3 “belt” . Blanco et al reported a series of honeycomb‐like gold–silver aggregates, in which alkynyl ligand PhC≡C – , phosphine ligand PPh 3 , anion CF 3 SO 3 – , and solvent pyridine were found to co‐stabilize the clusters …”

Polypyridyl-functionalizated alkynyl gold(i) metallaligands supported by tri- and tetradentate phosphanes

“…These privileged features have made alkynyl gold(I) complexes ideal candidates as building blocks to assemble a great variety of organometallic supramolecular structures that frequently present aurophilic interactions and significant luminescence properties. 22,[27][28][29][30][31][32][33][34][35][36][37] In addition to the possibility of establishing aurophilic interactions, the functionalization of the alkynyl moiety with N-donor groups in gold(I) alkynyl compounds provides an alternative and/or complementary approach to obtain heterometallic and/or multicomponent complexes with a wide range † Electronic supplementary information (ESI) available: 1 H, 31 P and 13 C NMR spectra of the compounds, UV-VIS and emission spectra, crystallographic data and stability constants. CCDC 1559283 (6) and 1561541 (7).…”

Halide‐Directed Assembly of Multicomponent Systems: Highly Ordered AuI–AgI Molecular Aggregates

“…[11] The molecule consists of the heterometallic cluster [Au 9 Ag 12 (C 2 Ph) 18 I 3 ] surrounded by a cationic "belt" [Au 3 (P 3 P) 3 ] 3+ . Even though the general structural motif-a bimetallic cluster [Au x M y (C 2 Ph) z ] inside a [Au 3 (P n P) 3 ] 3+ triangle-has been described before, [12,13] the peculiarity of 3 resides in the central "axis" of three I À ions, which effectively directed the framework aggregation process and stabilized the resulting metal core. The IÀAg distances of 2.8330(14)-3.0173(13) suggest a significant contribution of a conventional bonding between the halide and metal ions.…”

“…The average Au-Ag distance (3.02 ) and the AuÀAu bonds between the central cluster and the external "belt" (2.8813 (6)-2.9055(6) ) are not exceptional and agree with the previously reported values. [9,10,13] Scheme 1. Assembly of the clusters [Au 12 Ag 12 (C 2 Ph) 18 X 3 (P 3 P) 3 ] 3+ (CH 2 Cl 2 /acetone, 12 h); X = Cl (1, 92 %), Br (2, 89 %), I (3, 88 %).…”