Supramolecular Polymer Networks Based on Calix[5]arene Tethered Poly(p-phenyleneethynylene)

A poly(p-phenyleneethynylene) polymer (PC[5]), featuring two π-rich cone-like calix[5]arene cavities (assembling cores) connected to a rigid p-phenyleneethynylene spacer was synthesized by a Pd-catalyzed cross-coupling reaction. NMR investigations provide support for the self-assembly dynamics of PC[5] (homopolytopic host molecule) and complementary 1,10-decanediyldiammonium (C10) guest in solution in the construction of supramolecular polymer networks. Upon variation of the host/guest molar ratio, two distinct types of assemblies were identified in solution: a 1:2 bis-endo-cavity assembly C10PC[5]C10 (PC[5]cap), and a polycapsular polymer network assembly PC[5]C10PC[5] (PC[5]net). The reversibility of the assembly/disassembly processes of PC[5]net and PC[5]cap upon successive additions of Et3N and TFA were also investigated. AFM analysis of PC[5]net revealed the formation of a homogeneous continuous network on surface.