Two Cu(II) Complexes with Schiff Base Ligands: Syntheses, Crystal Structures, Spectroscopic Properties, and Substituent Effect

Two new Cu(II) complexes [Cu(L-1)(2)](1) (HL1=1-(3-((2-hydroxybenzylidene)amino) phenyl) ethanone O-benzyl oxime) and [Cu(L-2)(2)] (2) (HL2=1-(3-((2-Hydroxy-naphthalen-1-ylmethylene)-amino)-phenyl)-ethanone oxime) have been synthesized and characterized by elemental analyses, IR spectra, UV-Vis spectra, fluorescence measurement and X-ray single crystal diffraction method. X-ray crystallographic analyses have indicated that complexes 1 and 2 have the similar structure, consisting of one Cu(II) ion, two ligand units. In the complexes, the Cu (II) ion lying on an inversion centre, is four-coordinated in a trans-CuN2O2 square-planar geometry by two hydroxy O and two imine N atoms from two symmetry-related N,O-bidentate Schiff base ligands. The supramolecular structures of the two complexes 1 and 2 are also similar two-dimensional supramolecular structure linking by different intermolecular interaction. Complex 1 forms an infinite two-dimensional supramolecular structure by two pi center dot center dot center dot pi interaction, while that of complex 2 by intermolecular O-H center dot center dot center dot N and C-H center dot center dot center dot pi hydrogen bond interactions. The fluorescence property of complex 1 and substituent effects of the two complexes are discussed. CCDC: 1003363, 1; 1043506, 2.