Diamine-templated crystal engineering of an anionic Co(II) bis(phthalate) based coordination polymer with promising antimicrobial activity

Abstract

A new amine-templated cobalt(II) bis(phthalate) coordination polymer, ({H3N(CH2)4NH3}[Co(OOC–C6H4–COO)2])ₙ (1), was synthesised by a conventional solution method using 1,4-diaminobutane as a structure-directing agent. Crystallographic studies reveal that the doubly deprotonated 1,2-benzenedicarboxylate (1,2-BDC2-) ligands bridge adjacent Co(II) centres through their carboxylate groups, generating repeated 14-membered cyclic units that extend into a one-dimensional anionic helical chain. 1,4-diammoniobutane occupies the interchain regions, where it serves as a charge-balancing species and a supramolecular template. Coulombic interactions, extensive N–H···O hydrogen bonding, and complementary weak intermolecular interactions act cooperatively to organise the crystal packing, assembling adjacent polymeric chains into a three-dimensional supramolecular network. Antimicrobial investigations demonstrated that the coordination polymer exhibits promising activity against selected microbial strains. The present study highlights the effectiveness of amine-templating strategies in constructing structurally intriguing cobalt(II)-based coordination polymers with potential biological applications.