Synthesis and crystal structures of complexes based on the ligand meso-1,4-phenylenebis(hydroxyacetic acid)

The syntheses and crystal structures of compounds based on the ligand 1,4-phenylenebis (hydroxyacetic acid) (H2L) are reported for the first time. Three chain structures based on H2L and divalent metal cations were synthesized and characterized and their structures determined by single-crystal X-ray diffraction. The compounds PbL (1), CoL(H2O)2·2H2O (2), and ZnL(H2O)2·2H2O (3) have similar infinite chains of metal centers bridged by 1,4-phenylenebis(hydroxyacetic acid). The coordination spheres of the transition metal ions are completed by coordinating water molecules in the isostructural compounds 2 and 3. The non-covalent secondary bonding requirement of Pb2+ in 1 and interchain hydrogen bonds in 2 and 3 lead to different packing of the chains.