Metal Coordination Stoichiometry Controlled Formation of Linear and Hyperbranched Supramolecular Polymers.

Controlling the topologies of polymers is a hot topic in polymer chemistry because the physical and/or chemical properties of polymers are determined (at least partially) by their topologies. This study exploits the host-guest interactions between dibenzo-24-crown-8 and secondary ammonium salts and metal coordination interactions between 2,6-bis(benzimidazolyl)-pyridine units with metal ions (ZnII and/or EuIII) as orthogonal non-covalent interactions to prepare supramolecular polymers. By changing the ratios of the metal ion additives (Zn(NO3)2 and Eu(NO3)3) linkers to join the host-guest dimeric complex, the linear supramolecular polymers (100 mol% Zn(NO3)2 per ligand) and hyperbranched supramolecular polymers (97 mol% Zn(NO3)2 and 3 mol% Eu(NO3)3 per ligand) are separately and successfully constructed. This approach not only expands topological control over polymeric systems, but also paves the way for the functionalization of smart and adaptive materials. [ABSTRACT FROM AUTHOR]