Exploring a more flexible N2O2-donor ligand and its octahedral tri-nuclear Co(II) and Ni(II) complexes

Abstract

Two new tri-nuclear Co(II) and Ni(II) complexes, [{Co(L)(μ-OAc)(EtOH)}2Co]·2EtOH·2CH2Cl2 (1) and [{Ni(L)(μ-PhCOO)(MeOH)}2Ni]·2CH3OH·4H2O (2), were synthesized by complexing H2L (4-methylcoumarin-2,2′-[(propane-1,3-diyldioxy)bis(nitrilomethylidyne)]diphenol) with Co(OAc)2⋅4H2O and Ni(NO3)2·6H2O, respectively, and characterized by chemical-physical characterization. For 1, the crystallographic analysis revealed there are three Co(II) ions, two completely deprotonated ligands (L2–), two coordinated ethanol molecules and two bidentate bridging acetate groups (μ-OAc-). Complex 2 is composed of three Ni(II) ions, two completely deprotonated L2– ligands, two coordinated methanol molecules and two bidentate bridging benzoate groups (μ-PhCOO–). The fluorescence properties of 1 and 2 were studied. The supramolecular structures of 1 and 2 are formed by intermolecular hydrogen bonds or π-related interactions. The important intermolecular interactions of H2L and 1 and 2 were quantitatively determined by Hirshfeld surfaces analyses. In order to determine the kinetic stabilities of H2L, 1 and 2, DFT calculations were performed at B3LYP/SDD level of theory.