Excellent performance of aromatic polyguanamines induced by multiple hydrogen bondable tetraazacalix[2]arene[2]-triazine ring in their main chain

Polyguanamine Derivative-Based Supramolecular Assemblies with Multiple Hydrogen Bonding and Their Metal-Scavenging Abilities

Polyguanamine derivatives having cyclic moieties constituted by two phenyl and two triazine rings have been synthesized, and a supramolecular organization based on their multiple hydrogen-bonding ability was investigated. The obtained polyguanamine derivatives with cyclic moieties were transparent and amorphous in the bulk state and showed excellent mechanical strength emanating from multiple hydrogen bonds, owing to the abundant amino groups present in the structure. These polyguanamine derivatives formed stable monolayers at the air/water interface. The multilayers were transferred using the Langmuir-Blodgett method, and they formed highly periodic layered structures. To evaluate the metal scavenging ability of the cyclic moieties, the metal ions, Cd²⁺, Nd³⁺, and Pd²⁺, were introduced in the subphase. As a result, the cyclic moieties in the polyguanamine derivatives efficiently captured Cd²⁺, Nd³⁺, and Pd²⁺ metal ions. After the metal was captured, the layered structure of each organized film showed higher periodicity because of rearrangement. Moreover, the annular part had a cup-like structure, and the steric size effect of the ring influenced the metal scavenging.