Spectral characterization and X-ray structure of two dinuclear complexes constructed by di(2-pyridylcarbaldehyde)-6,6'-dicarboxylic acid hydrazone-2,2'-bipyridine) ligand

摘要

Two new bimetallic molecular squares constructed by di(2-pyridylcarbaldehyde)-6,6'-dicarboxylic acid hydrazone-2,2'-bipyridine (H2L), namely [Cu-2(HL)(2)](ClO4)(2)center dot 6H(2)O (1) and [Zn-2(HL)(2)](ClO4)(2)center dot 2H(2)O (2), have been synthesized and characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The architectures of the two bimetallic squares are mainly determined by the cooperation of the metal's coordination modes and the conformations of H2L. In 1, the ligand-adopted tridentate plus bidentate bridging modes to give a double helicate, in which two copper(II) ions exhibited two different coordination environments, hex-coordination and penta-coordinated, respectively. While in 2, the ligand-adopted bistridentate bridging modes also to form a double-helicate, in which two zinc(II) ions have the same distorted octahedral geometry. Very interestingly, the overall three-dimensional structures of 1 and 2 contain one-dimensional channels occupied by anions and solvents with H-bonds between square cations and anions. In addition, the solid-state photoluminescent properties of the ligand, complexes 1 and 2 were also studied. The variable-temperature magnetic measurement for the complex 1 shows very weak antiferromagnetic interaction between Cu(II) centers.