title: 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.
authors.affiliation: Department of Chemistry, University of Eastern Finland, Joensuu 80101, Finland. igor.koshevoy@uef.fi
authors.forename: Igor O
authors.initials: IO
authors.lastname: Koshevoy
authors.forename: Antti J
authors.initials: AJ
authors.lastname: Karttunen
authors.forename: Ilya S
authors.initials: IS
authors.lastname: Kritchenkou
authors.forename: Dmitrii V
authors.initials: DV
authors.lastname: Krupenya
authors.forename: Stanislav I
authors.initials: SI
authors.lastname: Selivanov
authors.forename: Alexei S
authors.initials: AS
authors.lastname: Melnikov
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Tunik
authors.forename: Matti
authors.initials: M
authors.lastname: Haukka
authors.forename: Tapani A
authors.initials: TA
authors.lastname: Pakkanen