Sky-Blue Luminescent Au^I–Ag^I Alkynyl-Phosphine Clusters

Abstract

Treatment of the (AuC2R)n acetylides with phosphine ligand 1,4-bis(diphenylphosphino)butane (PbuP) and Ag(+) ions results in self-assembly of the heterobimetallic clusters of three structural types depending on the nature of the alkynyl group. The hexadecanuclear complex [Au12Ag4(C2R)12(PbuP)6](4+) (1) is formed for R = Ph, and the octanuclear species [Au6Ag2(C2R)6(PbuP)3](2+) adopting two structural arrangements in the solid state were found for the aliphatic alkynes (R = Bu(t) (2), 2-propanolyl (3), 1-cyclohexanolyl (4), diphenylmethanolyl (5), 2-borneolyl (6)). The structures of the compounds 1-4 and 6 were determined by single crystal X-ray diffraction analysis. The NMR spectroscopic studies revealed complicated dynamic behavior of 1-3 in solution. In particular, complexes 2 and 3 undergo reversible transformation, which involves slow interconversion of two isomeric forms. The luminescence behavior of the titled clusters has been studied. All the compounds exhibit efficient sky-blue room-temperature phosphorescence both in solution and in the solid state with maximum quantum yield of 76%. The theoretical DFT calculations of the electronic structures demonstrated the difference in photophysical properties of the compounds depending on their structural topology.

Low-Nuclearity Alkynyl d10 Clusters Supported by Chelating Multidentate Phosphines

“…Analysis of the structurally characterized d 10 polymetallic M x (M = Cu, Ag, Au; x ≥ 2) alkynyl phosphine compounds permits distinguishing three main synthetic strategies depending on the denticity and stereochemistry of the templating phosphine ligands (Chart ). In the type A clusters a homoleptic alkynyl core is supported by the external shell of di-/triphosphines with substantial spatial separation of the PR 2 R′ coordinating functions. , For the B species ligands with short spacers (bis­(diphenylphosphino)­methane and related bi- and tridentate phosphines with similar geometry) providing intermetallic distances in the range 2.8–3.4 Å are used on a periphery of metal–alkynyl frameworks. , …”

Triphosphine-supported bimetallic AuI–MI (M = Ag, Cu) alkynyl clusters

“…Following a general approach to the bimetallic alkynyl complexes Au I -M I (M = Ag, Cu) reported earlier, 20,23…”

“…The Ag-Au distances in 5 are also not exceptional and correlate well with the data observed for other structurally characterized Au-Ag compounds. 9,13,20 Formation of the dimeric cluster topology in 4 and 5 might be also favored by the presence of O⋯H-O hydrogen bonds, which operate between the dpep(AuC 2 R) 3 units. This is indicated by the short distances between the hydroxyl oxygen atoms; the O(1)-O( 4) and O(3)-O( 6) contacts in both 4 and 5 fall in the range 2.71-2.83 Å.…”

“…phosphines) to confine the otherwise uncontrolled growth of the metal framework. [9][10][11]13,[18][19][20] In this respect it is worth mentioning that the employment of tri-and higher-dentate phosphines in the cluster chemistry of coinage metals has been documented, 21,22 though there are only two types of mixed-metal alkynyl compounds reported in the literature. 19,23 Nevertheless, the data available clearly demonstrate that these ligands can serve as unique building blocks to stabilize unusual cluster structures with very interesting physical behavior.…”

Construction of Silver Clusters Capped by Zwitterionic Ethynide Ligands

“…Silver ethynide clusters have attracted great interest due to their fantastic structures and potential applications. − However, compared with their analogous thiolated silver clusters, the development of silver ethynide clusters has been lagging. − The easily available thiol ligands with different sizes, structures, and properties promote the booming advancement of thiolated silver clusters. − Among them, there is a class of zwitterionic thiol ligands for the extensive synthesis of hydrophilic metal clusters, , while similar zwitterionic ethynide ligands have not yet been explored. The zwitterionic molecule has both cationic and anionic groups − and possesses an electric dipole moment within the molecule, which has an important impact on the self-assembly process of the cluster .…”