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

Abstract

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.

Alkynyl-functionalized gold NHC complexes and their coinage metal clusters

“…A combination of goldmetal bonds, enabled by the relativistic effects of gold, and alkynyl groups attached to a carbene complex, should facilitate the synthesis of oligomeric or supramolecular coinage metal assemblies. 29 Although terminal alkynes can act as bidentate ligands through end-on and side-on coordination, we initially focused on phenyl-protected alkyne substituents, which should allow for side-on coordination of different metals through π-bonding.…”

Highly Luminescent Octanuclear AuI–CuI Clusters Adopting Two Structural Motifs: The Effect of Aliphatic Alkynyl Ligands

“…[3,8,14] The non-bonding separations are 3.1932(7) and 3.2444(6) in 5 and 6, and exceed the sum of Cu and Au van der Waals radii (3.06 ), pointing to the absence of substantial metal-metal interaction. The nuclearity of the {Au 6 Cu 2 } cluster has been observed in some our previous works on Au I -Cu I alkynyl compounds, [17,21] but the structural arrangement of these novel clusters is unprecedented and has a dramatic influence on the photophysical properties (see the corresponding section below).…”

“…Interestingly, in the case of the alkynyl ligands with cyclohexanolyl and isopropanolyl substituents, the clusters [Au 6 Cu 2 A C H T U N G T R E N N U N G (C 2 R) 6 A C H T U N G T R E N N U N G (P^P) 3 ] 2 + (R = C 6 H 11 O (7), C 3 H 7 O (8)), which have the previously reported structural type, [17,20,21] were obtained nearly quantitatively when the higher amounts of the diphosphine were used (Scheme 4).…”

Synthesis, characterization and photophysical properties of gold(I)–copper(I) alkynyl clusters with 1,4-bis(diphenylphosphino)butane, effect of the diphosphine ligand on luminescence characteristics

“…On the other hand, it was shown that the contribution of the phosphine orbitals into emissive electronic states is essentially smaller. Nevertheless, these ligands undoubtedly affect the energy of the electronic transitions and dramatically influence the emission efficiency, varying the quantum yields from 96% to 8% for the structurally similar compounds with Ph 2 PeC 6 H 4 ePPh 2 and Ph 2 PeC^CeC^CePPh 2 diphosphines, respectively [24,25]. In the present work we report on the synthesis, structural characterization and spectroscopic studies of the "rods-in-belt" AueCu complexes based on the Ph 2 Pe (CH 2 ) 4 ePPh 2 ligand with non-rigid aliphatic spacer and comparison of their photophysical characteristics with those obtained for the related compounds containing aromatic spacers.…”

“…Additionally, accessible modification of these ligands provides an opportunity for fine tuning of the physicochemical properties of the resulting organometallic aggregates. Recently we have described a family of the polynuclear AueCu and AueAg complexes, which contain a central core composed of gold(bis-alkynyl) "rods" and copper or silver ions stabilized by the {Auediphosphine} 3 "belt" (diphosphines: Ph 2 Pe(C 6 H 4 ) n ePPh 2 , n ¼ 1e5, Ph 2 PeC^Ce(C 6 H 4 ) n eC^CePPh 2 , n ¼ 0e2) [17,24,25]. Particular attention was paid to the photophysical studies of these compounds, which demonstrate extremely high quantum yields of phosphorescence, negligible quenching of emission with molecular oxygen and intriguing non-linear properties.…”