Three novel transition metal coordination polymers based on (2,3-f)-pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid sodium salt: Hydrothermal syntheses, structures, and properties

Three novel transition metal coordination polymers including [Cd-2(Na(2)PPDA)(2)Cl-4 (I), [Zn(Na(2)PPDA)(ClO4)(2)center dot 4H(2)O](n) (II) and [Ni(Na(2)PPDA)(ClO4)(2)center dot 4H(2)O](n) (III) were prepared under hydrothermal conditions based on (2,3-f)-pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid sodium salt (Na(2)PPDA) and characterized by elemental analysis, infrared spectrometry and single crystal X-ray diffraction. The outstanding structural feature oft is that four cadmium atoms are linked into a zigzag-shaped polymeric chain in the sequence of Cd-(Cl)(2)-Cd-(Cl)(2)-Cd-(Cl)(2)-Cd by three mu(2)-Cl bridges. Findings indicate that I displays a three-dimensional (3D) network constructed via hydrogen bonds and C-H ... pi interactions. Both coordination polymers of II and III present isomorphous and isostructural characters, in which the adjacent metal centers in the same chain connected up and down through hydrogen bonds (generated through mu(2)-ClO4- anions) to construct the left- and right-handed helical chains which are further interconnected by hydrogen bonds, thereby affording a two-dimensional (2D) layer. Moreover, thermogravimetric (TG) analyses, the magnetic and luminescent properties of as-synthesized coordination polymers were also investigated. (C) 2013 Elsevier Ltd. All rights reserved.