Two Trinuclear Cobalt(II) Salamo-Type Complexes: Syntheses, Crystal Structures, Solvent Effect and Fluorescent Properties

Two trinuclear Co(II) complexes, [Co3L(OAc)(2)(CH3CH2OH)2]center dot 2CH(3)CH(2)OH center dot 2CHCl(3) (1) and [Co3L(OAc)(2) (C3H7OH)(2)] (2) were synthesized by the reaction of a new Salamo-type bisoxime chelating ligand of 4,4'-dinitro-2,2'-(1,2-ethylenedioxybis (nitrilomethylidyne))diphenol (H2L) with cobalt (II) acetate tetrahydrate in different solvents. Complexes 1 and 2 were characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction methods. In complexes 1 and 2, there are two ligand L2- moieties (which provide N2O2 donors), two acetate ions, two coordinated ethanol or n-propanol molecules, respectively. Although the two complexes were synthesized in different solvents, it is worthwhile that the Co(II) ions in the structures of the two complexes adopt slightly distorted hexa-coordinated geometries. As a result, solvent effect was assumed to have played a crucial role in their coordination environment. In addition, when excited at 450 nm, the complexes 1 and 2 show an intense photoluminescence with maximum emission at ca. 568 and 566 nm, respectively.