Dimeric complexes of copper (II) arylcarboxylate with 4-cyanopyridine: synthesis, structural characterization and linear absorption properties

Abstract

Two new dimeric copper (II) complexes containing 2-chlorobenzoato/4-formylbenzoato and 4-cyanopyridine ligands, [Cu2(μ2-O2CC6H4-Cl)4(C5H4N-CN)2] (1) and [Cu2(μ2-O2CC6H4-CHO)4(C5H4N-CN)4] (2), were synthesized and characterized by elemental analysis, FT-IR and ESR spectroscopy and single-crystal X-ray diffraction methods. In the structure of 1, each copperII cation was surrounded by four oxygen atoms from four different carboxylate of four 2-chlorobenzoate molecules and one nitrogen atom of one 4-cyanopyridine ligand. In the crystal structure of 2, each copperII cation was coordinated by four oxygen atoms from one chelating and two bridging 4-formylbenzoate anions and two nitrogen atoms of two 4-cyanopyridine ligands. C–H···O and C–H···Cl hydrogen bonds (for 1) and C–H···O hydrogen bonds and weak C–H···π interactions (for 2) further stabilize the crystal structures. The linear optical absorption characterizations of the complexes were performed by using UV-Vis spectrophotometer. The results obtained from the linear absorption spectra of the complexes observed that these complexes can be used for optical filtration among nearly 600 and 950 nm wavelengths for concentrations which are higher than 4 g/L. Two new dimeric copper (II) complexes were synthesized. The complexes were characterized by elemental analysis, FT-IR and ESR spectroscopy and single-crystal X-ray diffraction methods. [Cu2(μ2-O2CC6H4-Cl)4(C5H4N-CN)2] (1) has a paddle-wheel structure unit. [Cu2(μ2-O2CC6H4-CHO)4(C5H4N-CN)4] (2) has an unusual and unique conformation. The linear optical absorption characterizations of the complexes were investigated. According to the results obtained from the linear absorption spectra of the complexes, these complexes can be used for optical filtration among nearly 600 and 950 nm wavelengths for concentrations which are higher than 4 g/L.