Luminescent Chains Formed from Neutral, Triangular Gold Complexes Sandwiching Tl^I and Ag^I. Structures of {Ag([Au(μ-C²,N³-bzim)]₃)₂}BF₄·CH₂Cl₂, {Tl([Au(μ-C²,N³-bzim)]₃)₂}PF₆·0.5THF (bzim = 1-Benzylimidazolate), and {Tl([Au(μ-C(OEt)═NC₆H₄CH₃)]₃)₂}PF₆·THF, with MAu₆ (M = Ag⁺, Tl⁺) Cluster Cores

Abstract

It has been found that several trinuclear complexes of Au^I interact with silver and thallium salts to intercalate Ag⁺ and Tl⁺ cations, thereby forming chains. The resulting sandwich clusters center the cations between the planar trinuclear moieties producing structures in which six Au^I atoms interact with each cation in a distorted trigonal prismatic coordination. The resultant (B₃AB₃B₃AB₃)_∞ pattern of metal atoms also shows short (∼3.0 Å) aurophilic interactions between BAB molecular centers. These compounds display a strong visible luminescence, under UV excitation, which is sensitive to temperature and the metal ion interacting with the gold. X-ray crystal structures are reported for Ag([Au(μ-C²,N³-bzim)]₃)₂BF₄·CH₂Cl₂ (P [Formula: see text] , Z = 2, a = 14.4505(1)Å; b = 15.098(2)Å; c = 15.957(1)Å; α = 106.189(3)°; β = 103.551(5)°; γ = 101.310(5)°); Tl([Au(μ-C²,N³-bzim)]₃)₂PF₆·0.5C₄H₈O (P [Formula: see text] , Z = 2, a = 15.2093(1)Å; b =15.3931(4)Å; c = 16.1599(4)Å; α = 106.018(1)°; β = 101.585(2)°; γ=102.068(2)°); and Tl([Au(μ-C(OEt)═NC₆H₄CH₃)]₃)₂PF₆·C₄H₈O (P2(1)/n, Z = 4, a = 16.4136(3)Å; b = 27.6277(4)Å; c = 16.7182(1)Å; β = 105.644(1)°). Each compound shows that the intercalated cation, Ag⁺ or Tl⁺, coordinates to a distorted trigonal prism of six Au^I atoms. The counteranions reside well apart from the cations between the cluster chains.