The tetraurea-containing structure has been intensively studied in the field of host & guest chemistry due to the presence of secondary amine---which will interact with hydrogen bond acceptors (anions, water, etc.). Because of the potential hydrogen bond formation with guest molecules, most research of this complexation aimed to address the realistic problems such as water purification and extraction of toxic anions from industrial waste.
At present, the host & guest chemistry of most tetraurea structures showing selective uptakes are limited to molecular level by cooperating the complexes with lipid bilayer, yet it is lack of processibility as none of them can be directly used as the material with promising mechanical properties.
Therefore, we design a series of novel tetraurea contained polymers formed by the condensation of tetraurea macrocycle monomers. This polymerization is still being investigated, but Single Crystal X-ray Diffraction reveals that the precursors of tetraurea macrocycle monomers interact with guest molecules via hydrogen bond such as NH—O, NH—N, and the crystal configurations of host-guest complexes change as the guest molecules vary. These different responsive effects prove the potential of designed polymeric materials for uptaking various hydrogen bonding acceptors, as well as for differentiating guest molecules by triggering the change of crystal configuration.