Synthesis of Coordination Polymers Using Different Maleic Acid Ligands under Hydrothermal Conditions

A novel coordination polymer, [Ni(mal) (1,10′-phen) (H2O)]n (1) (mal = malate, 1,10′-phen = 1,10-phenanthroline) was synthesized using malic acid which was generated from maleic acid via hydrothermal reaction. Complex 1, which displays a two-dimensional supramolecular network, was formed by the addition reaction of Ni and maleic acid with water molecules. To our knowledge, several coordination polymers have been directly synthesized from malic acid, but these types of complexes have seldom been synthesized from maleic acid via hydrothermal reactions. When Ni (II) ion was changed to Zn(II) ion under the same condition, two-dimensional covalent complex 2 [Zn2(fma)2(1,10′-phen)2]n (fma = fumatic acid) was formed. Furthermore, complex 2 exhibits intense photoluminescent property at room temperature.