New photoluminescence coordination polymers constructed from different ligands, which are generated from maleic acid at hydrothermal conditions

A new coordination polymer, [Zn2(mal)(1,10-phen)Cl]n (1), (mal = malate, 1,10-phenanthroline), has been synthesized with malic acid and fumaric acid which are generated from maleic acid under hydrothermal reactions. At about the same condition, we get [Cd(fma)(2,2′-bpy)(H2O)]n (2) (fma = fumarate, 2,2′-bpy=2, 2′-bipyridine). The diverse products illustrate that the carbon–carbon doublebond of the maleic acid has two kinds of reaction trends under different conditions. Complex 1, which displays a two-dimensional (4, 8) lattice-type network, is formed from Zn and maleic through the addition reaction with water molecule. If the Zn is changed by Cd, at the same reaction condition with 1, a two-dimensional supramolecular network complex 2 is formed through the conformation transform reaction. To our knowledge, a lot of coordination polymers have been constructed from malic acid and fumaric acid directly; however, these kinds of complexes have seldom been synthesized from maleic acid under hydrothermal reaction. As is known, the rigid carbon–carbon double bond makes maleic acid lead to some unique structural features which the saturated aliphatic acid does not possess. To illustrate this clearly, a simple one dimensional complex 3, [Cd(glut)(1,10-phen)(H2O)]n (glut = glutarate), is synthesized. Furthermore, complex 1 and complex 3 exhibit intense photoluminescent property at room temperature.