A new two-dimensional manganese(II) coordination polymer based on thiophene-3,4-dicarboxylic acid

Abstract

A novel manganese coordination polymer, poly[(μ5-thiophene-3,4-dicarboxylato)manganese(II)], [Mn(C6H2O4S)]n, was synthesized hydrothermally using 3,4-thiophenedicarboxylate (3,4-tdc2−) as the organic linker. The asymmetric unit of the complex contains an Mn2+cation and one half of a deprotonated 3,4-tdc2−anion, both residing on a twofold axis. Each Mn2+centre is six-coordinated by O atoms of bridging/chelating carboxylate groups from five 3,4-tdc2−anions, forming a slightly distorted octahedron. The Mn2+centres are bridged by 3,4-tdc2−anions to give an infinite two-dimensional layer which incorporates one-dimensional Mn–O gridlike chains, and in which the 3,4-tdc2−anion adopts a novel hexadentate chelating and μ5-bridging coordination mode. The fully deprotonated 3,4-tdc2−anion exhibits unexpected efficiency as a ligand towards the Mn2+centres, which it coordinates through all of its carboxylate O atoms to provide the novel coordination mode. The IR spectrum of the complex is also reported.