Syntheses And Structures Of The Coordination Polymers Of N-containing Polycarboxylate Ligands

In this paper, seven novel polycarboxylate coordination complexes which have never been reported previously were synthesized. This article represents a systematical examination of their syntheses and structures. Two types of polycarboxylate ligands(see below): H₂L1 and H4L2 were chosen. In order to survey the influence of metal cations and the neutral ligands on the formation of polycarboxylate and the final structures of coordination complexes, the metal cations Zn^II,Cd^II,Co^II,Ni^II and two kinds of neutral ligands(see below): L3 and 1,10-phenanthroline(phen) were selected for study. Seven novel compounds have been synthesized: [Ni(H₂O)6]·L1·(C₂H₅OH)_0.5·H₂O (1), [Zn(H₂O)2(L1)]·H₂O (2), [Co(L1) (L3)]·CH₃OH (3), [Ni(L1)(L3)]·CH₃OH (4), [Zn(L1)(L3)]·CH₃OH (5), [Cd(L1) (L3)]·CH₃OH (6) and [Zn(L2)_0.5(phen)]·C₂H₅OH (7). The crystal structures have been determined by single-crystal X-ray diffraction. Compound 1 displays 0D structures, which are further linked through the hydrogen bonds to result in a left- or right-helical chain. The helical chains are further linked by hydrogen bonds to form a 2D layer. Compound 2 is a 42-membered ring with [Zn(L1)2Zn] unit. Compounds 3-6 display the same structure. The compounds possess 1D meso-chains linked by L1 ligands and metal atoms, and the 1D polymer chains extend towards different direction linked together through C—H…πinteraction to give rise to a 3D plywood network. But compound 4 is different from 3,5 and 6 in having the C—H…πinteraction between the chains of the same layer. Compound 7 possesses 2D layers which are further linked by hydrogen-bonding interaction to form a 3D supramolecular structure.