Supramolecular Porphyrin Copolymer Formed Via Competitive Host-Guest Interaction

Abstract

Polymer properties are directly associated with their primary structures. Control of monomer sequences in polymer sequences is a crucial topic in modern polymer chemistry. Therefore, reorganization of polymer sequences can regulate polymer properties. Sequence reorganization of supramolecular homopolymers to alternating polymers can be realized via competitive guest complexation. We have reported that self-assembly of tetrakisporphyrin 1 produced the supramolecular polymeric assemblies that was dissociated via competitive complexation of trinitrofluorenone (TNF). Employing bis(trinitrofluorenone) 2 instead of TNF as a guest resulted in sequence reorganization of homopolymers ( 1 )n to alternating copolymers ( 1 • 2 )n. The supramolecular polymerization of ( 1 • 2 )n was discussed using diffusion-ordered NMR technique, suggesting that large polymeric assemblies were formed with the alternating structures. Solution viscometry of ( 1 )n and ( 1 • 2 )n demonstrated quite contrastive behaviors. ( 1 • 2 )n formed entangled solution, whereas ( 1 )n behaved like a rigid rod in solution. Figure 1