A trinuclear Pt(ii) compound with short Pt–Pt–Pt contacts. An analysis of the influence of π–π stacking interactions on the strength and length of the Pt–Pt bond

Abstract

In this work we report the first example of a trinuclear Pt(II) complex with Pt–Pt–Pt bonds that are not facilitated by direct intervention of bridging ligands but are partially held by the attractive π–π stacking interaction between the phenyl units of the 4,4′-dimethyl-2,2′-bipyridyl ligands. The effect of the π–π stacking interactions on the strength and length of the Pt–Pt bond has been discussed using reduced models of the interacting moieties in which the aromatic rings have been removed. The nature of the Pt–Pt bonds has been studied through energy decomposition and atoms-in-molecules analyses. The results indicate that the relatively strong (about 40 kcal mol⁻¹) Pt–Pt metallic bond has similar covalent and ionic contributions.