Two novel copper(II) complexes constructed from dicarboxylate ligands with different spacer lengths and 2-phenylimidazo[4,5-f]1,10-phenanthroline (PIP): Synthesis, structures and properties

Two novel metal–organic coordination polymers [Cu(PIP)(bpea)(H₂O)]·H₂O (1) and [Cu(PIP)(1,4-bdc)] (2) have been obtained from hydrothermal reaction of copper(II) with the mixed ligands [biphenylethene-4,4′-dicarboxylic acid (bpea) for 1, benzene-1,4-dicarboxylic acid (1,4-H₂bdc) for 2, and 2-phenylimidazo[4,5-f]1,10-phenanthroline (PIP)]. Both complexes have been structurally characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. Structural analyses reveal that complex 1 possesses infinite one-dimensional zigzag chain, 2 exhibits a two-dimensional (4,4) network, both of which are extended into three-dimensional supramolecular network by weak interactions. The different structures of the title complexes illustrate the influence of the flexibility (the spacer length of carboxyl groups and the structural rigidity of the spacer) of organic dicarboxylate ligands on the formation of such coordination architectures. Moreover, the thermal properties and the voltammetric behavior of complexes 1 and 2 have been reported.