Self-assembled construction of a sheet-type coordination polymer bearing cationic M2L4 cages: creation of channel-like space for removal of ClO4(-) and NO3(-) from aqueous solutions.

Treatment of CuCl2 with a bis-benzimidazole-type ligand, p-bbiteb, afforded a new 2D coordination polymer bearing cationic Cu2L4 cages on the sheet framework. The regular arrangement of the cages created channel-like space for anions. The compound removed ClO4(-) and NO3(-) from aqueous solutions by exchange with Cl(-) in the channels.