Versatile Behavior of [Pt₂Ag₄(C⋮C-<i>t</i>-Bu)₈]: Synthesis, Structures, and Properties of [{Pt₂Ag₄(C⋮C-<i>t</i>-Bu)₈}{Ag(bipy)}]⁴⁺ and an Unprecedented Chain Polymeric Cocrystallization Adduct with a 2,2‘-bipy Ligand

Abstract

An unusual adduct, [{Pt2Ag4(C⋮C-t-Bu)8·(bipy)}]∞ (3), has been obtained from the reaction of the hexanuclear cluster [Pt2Ag4(C⋮C-t-Bu)8] (1) with 2,2‘-bipy independently of the molar ratio (1:1 or 1:excess) employed. The crystal structure of 3 shows the presence of an extended polymeric chain constructed by long-range, secondary misdirected Ag···N interactions between the cluster units and the 2,2‘-bipy ligand. 3 is highly emissive in the solid state and in frozen solution. A considerable enhancement of the luminescence and a notable red shift in the emission maximum of 3 (λmax 513 nm) relative to [Pt2Ag4(C⋮C-t-Bu)8] (1) (λmax 476 nm) is observed. In an attempt to obtain an analogous polymeric chain based on higher nuclearity building blocks, the reaction between [{Pt2Ag8(C⋮C-t-Bu)8}(OClO3)2(OCMe2)2](O2ClO2)2}∞ (2) and 2,2‘-bipy was also examined. Treatment of 2 with 2,2‘-bipy (molar ratio 1:4, Ag:bipy 1:0.5), however, produces [{Pt2Ag4(C⋮C-t-Bu)8}{Ag(bipy)}4](ClO4)4 (4), in which the cluster unit acts as an octadentate bridging ligand toward four Ag(bipy) fragments. The use of a higher proportion of 2,2‘-bipy (1:6 or 1:8 molar ratio) produces [Pt2Ag8(C⋮C-t-Bu)8(bipy)6](ClO4)4 (5).