Two Novel 3D Copper Phthalate Coordination Complexes Incorporating Isomeric Flexible Bis(pyridylformyl)piperazine Ligands

Abstract

AbstractTwo novel metal‐organic coordination complexes [Cu(3‐bpfp)(pht)(H2O)]·2H2O (1) and [Cu3(4‐bpfp)(pht)2(OH)2]·2H2O (2) were hydrothermally synthesized by self‐assembly of phthalic acid (H2pht), flexible bis(pyridylformyl)piperazine ligands [3‐bpfp = bis(3‐pyridylformyl)piperazine, 4‐bpfp = bis(4‐pyridylformyl)piperazine], and copper chloride. Single crystal X‐ray diffraction analysis revealed that the adjacent CuII ions are connected by pht showing different coordination modes [a bis(monodentate) coordination mode for 1 and a monodentate‐bidentate coordination mode for 2] to form 1D Cu‐pht‐Cu chains in 1 and 2D Cu‐pht layers in 2. In compound 1, a twofold interpenetrated CdSO4‐like topology is formed by connection of 3‐bpfp. Using the isomeric ligand 4‐bpfp instead of 3‐bpfp resulted in the formation of 2, which displays a novel 3, 4, 4, 4‐connected tetranodal 3D coordination polymeric framework. The ligand 3‐bpfp adopts a μ2‐bridging coordination mode in 1 (by ligation of the pyridyl nitrogen atoms), whereas the ligand 4‐bpfp adopts a μ4‐bridging coordination mode (by ligation of pyridyl nitrogen and carbonyl oxygen atoms) in 2. Moreover, the electrochemical properties of carbon paste electrodes bulk modified with the two copper complexes were studied.