Mesomorphic behavior induced by stacking interactions between poly(2-vinyl pyridine) and palladium pincer surfactants in the solid state

Abstract

Combining poly(2-vinyl pyridine) (P2VP) with organometallic surfactants based on a Pd-SCS pincer complex in the solid state leads to the formation of mesomorphic structures even with the lack of coordinative bonding between the pyridine groups and the surfactant molecules. Through a combination of spectroscopic methods and quantum chemical calculations we reveal that the interaction responsible for the formation of the supramolecular, comb polymer architectures leading to these mesomorphic structures is a dipolar stacking interaction between the Pd–C bond of the surfactant and the pyridine ring of the polymer. This conclusion is further supported by comparison to a system where coordinative binding between the surfactant and the polymer was induced. Additional DSC analysis shows that, unlike the system featuring coordinative binding, the weak binding to the polymer through dipolar stacking facilitates the crystallization of the alkyl residues. Such organized assemblies of metal precursors can serve for the creation of hybrid materials and organized nanocomposites.