Intensely Luminescent Homoleptic Alkynyl Decanuclear Gold(I) Clusters and Their Cationic Octanuclear Phosphine Derivatives

Abstract

Treatment of Au(SC(4)H(8))Cl with a stoichiometric amount of hydroxyaliphatic alkyne in the presence of NEt(3) results in high-yield self-assembly of homoleptic clusters (AuC(2)R)(10) (R = 9-fluorenol (1), diphenylmethanol (2), 2,6-dimethyl-4-heptanol (3), 3-methyl-2-butanol (4), 4-methyl-2-pentanol (4), 1-cyclohexanol (6), 2-borneol (7)). The molecular compounds contain an unprecedented catenane metal core with two interlocked 5-membered rings. Reactions of the decanuclear clusters 1-7 with gold-diphosphine complex [Au(2)(1,4-PPh(2)-C(6)H(4)-PPh(2))(2)](2+) lead to octanuclear cationic derivatives [Au(8)(C(2)R)(6)(PPh(2)-C(6)H(4)-PPh(2))(2)](2+) (8-14), which consist of planar tetranuclear units {Au(4)(C(2)R)(4)} coupled with two fragments [AuPPh(2)-C(6)H(4)-PPh(2)(AuC(2)R)](+). The titled complexes were characterized by NMR and ESI-MS spectroscopy, and the structures of 1, 13, and 14 were determined by single-crystal X-ray diffraction analysis. The luminescence behavior of both Au(I)(10) and Au(I)(8) families has been studied, revealing efficient room-temperature phosphorescence in solution and in the solid state, with the maximum quantum yield approaching 100% (2 in solution). DFT computational studies showed that in both Au(I)(10) and Au(I)(8) clusters metal-centered Au → Au charge transfer transitions mixed with some π-alkynyl MLCT character play a dominant role in the observed phosphorescence.

Gold(I)–Alkynyl Complexes with an N‐Donor Heterocyclic Ligand: Synthesis and Photophysical Properties

“…General Comments: 2‐Phenylpyrido[2,1‐ a ]pyrrolo[3,2‐ c ]isoquinoline (ppiq) was obtained according to a published procedure . The gold–alkynyl polymers [AuC 2 R] n [R = –C(C 6 H 5 ) 2 OH, –C 6 H 4 –C 6 H 5 , –C 6 H 4 –NN–C 6 H 5 , –pyrene] were synthesized according to a published procedure . Other reagents and solvents were used as received.…”

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

“…Alkynyl coinage metal complexes may exhibit intense photoluminescence with very high quantum yields , . In some cases, solvent molecules could significantly influence the luminescence.…”

Phosphine-Coordinated Pure-Gold Clusters: Diverse Geometrical Structures and Unique Optical Properties/Responses

“…Asides from conventional clusters, there is another line of studies on "Au(I)" clusters which do not contain formally zerovalent gold atoms [56,57]. Further, there are extensive studies on clusters whose skeletons are constituted primarily by gold but contain other metal elements [58,59] or encapsulated main group element (e.g., C, N) [60].…”