Structures with different supramolecular interactions and spectral properties of monomeric, dimeric and polymeric benzoatocopper(II) complexes

Abstract

Three new monomeric benzoatocopper(II) complexes [Cu(3-MeObz)2(4-PM)2] (1), [Cu(3-Mebz)2(4-PM)2] (2) and [Cu(4-Mebz)2(4-PM)2] (3), two polymers [Cu2(2-Mebz)4(4-PM)]n (4) and [Cu2(3-Mebz)4(4-PM)]n (5), and the dimeric complex [Cu2(2-Fbz)4(4-PM)2] (6) (where 4-PM = 4-pyridylmethanol, 2-Fbz = 2-fluorobenzoate anion, 3-MeObz = 3-methoxy-benzoate anion and x-Mebz = 2-,3- or 4-methylbenzoate) have been synthesized and characterized by elemental analysis as well as by single-crystal diffraction. All the complexes have been studied by infrared, UV–vis and EPR spectroscopy. The neutral ligand 4-PM acts as a terminal ligand in 1–3 and 6, and as a bridging ligand in 4 and 5. The structural motives are evident in the EPR spectra, which have shown axial symmetric features for 1–3, whilst the polymers as well as the dimer (4–6) have exhibited an acetate-type feature. The monomeric complex molecules of 1–3 and the dimeric molecules of 6 are linked by terminal 4-PM H-bonds to create 2D supramolecular square-grid hydrogen-bonded networks. On the other hand, the 1D polymeric chains of 4 are linked into a 2D supramolecular network, while two coordination chains of 5 come together to generate a ladder type double chain.