Trinuclear Cobalt(II) and Zinc(II) Salamo-type Complexes: Syntheses, Crystal Structures, and Fluorescent Properties

Two trinuclear Co-II and Zn-II complexes, [(CoL)(2)(OAc)(2)Co] and [(ZnL)(2)(OAc)(2)Zn], with an asymmetric Salentype bisoxime ligand [H2L = 4-(N,N-diethylamine)-2,2'-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol] were synthesized and characterized by elemental analyses, IR, UV/Vis, and fluorescent spectroscopy. The crystal structures of the CoII and ZnII complexes were determined by single-crystal X-ray diffraction methods. The CoII atom is pentacoodinated by N2O2 donor atoms from the (L)(2-) unit and one oxygen atom from the coordinated acetate ion, resulting in a trigonal bipyramid arrangement. With the help of intermolecular hydrogen bonding C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions, a self-assembled continual zigzag chain-like supramolecular structure is formed. The Zn-II atom is pentacoodinated by N2O2 donor atoms from the (L)(2-) unit and one oxygen atom from the coordinated acetate ion, resulting in an almost regular trigonal bipyramid arrangement. A self-assembled continual 1D supramolecular chain-like structure is formed by intermolecular hydrogen bonding C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions. Additionally, the photophysical properties of the Co-II and Zn-II complexes were discussed.