Poly[bis(μ-5-iodoisophthalato)(methanol)dilead(II)] exhibiting a novel centrosymmetric rhombus-shaped I4 unit

The asymmetric unit of the title compound, [Pb2(C8H3IO4)2(CH4O)]n, contains two Pb(II) atoms, two 5-iodoisophthalate (5-IIP(2-)) ligands and one coordinated methanol molecule. One Pb atom is eight-coordinated, surrounded by seven carboxylate O atoms from five 5-IIP(2-) ligands and one O atom from the terminal methanol ligand. The other Pb atom is seven-coordinated in a hemidirected geometry, surrounded by seven carboxylate O atoms from five 5-IIP(2-) ligands. Both Pb atoms are connected by carboxylate groups to form a one-dimensional infinite rod along the a axis; neighbouring rods are further linked by the aromatic rings of 5-IIP(2-) to generate the final three-dimensional structure with channels in the a direction. An O-H···O hydrogen bond between the methanol ligand and one of the carboxylate groups of a 5-IIP(2-) ligand stablizes the three-dimensional framework. Interestingly, a centrosymmetric rhombus-shaped I4 unit is formed by four 5-IIP(2-) ligands, with I···I distances of 3.8841 (8) and 3.9204 (8) Å.