Linear polymer of a copper(II) complex and its supramolecular selectivity

The supramolecular framework [Cu₂(TU)₄?·?(TAA)₄] _n (TU?=?thiourea; TAA?=?2-(2-imino-4-oxo-5-thiazolidinylidene)acetic anion) has been synthesized by reaction of CuCl₂?·?2H₂O with meso-2,3-dibromosuccinic acid and thiourea. The one-dimensional supramolecular structure of the title complex is constructed through bridge-linkage of the S atoms on the thioureas between adjacent Cu(II) atoms, forming an infinite chain with lots of positive charges. Around the infinite chain, there are four groups of negatively charged hydrogen-bond tubes constructed by four TAA anions. The hydrogen-bond and ionic interactions between adjacent metal-organic polymeric chains and hydrogen-bond tubes form the three-dimensional supramolecular structure of the complex. Supramolecular selectivity from isomers of 2-(2-imino-4-oxo-5-thiazolidinylidene)acetic anion (TAA) has been studied by quantum calculation.