Three new Salamo-type homotrinuclear nickel(II) complexes possessing solvent effects: Syntheses, structures and fluorescence properties

Three new solvent-induced Ni(II) complexes with the chemical formulae [{Ni(L)(CH3OH))(2)(mu-OAc)(2)Ni] (1), [{Ni(L)(C3H2OH)(2)(mu-OAc)(2)Ni] (2) and [{NiL(H2O)}2(mu-OAc)(2)Ni] (3) were synthesized by the reaction of the Salamo-type ligand 4,4'-dinitro-2,2'-[1,2-ethylene-dioxybis(nitrilomethylidyne)]diphenol (H2L) with Ni(II) acetate tetrahydrate in different solvents and characterized by elemental analyses, FT-IR, UV-Vis spectra and X-ray crystallography. X-ray crystallographic analyses indicate that complexes 1, 2 and 3 have similar structures, consisting of three Ni(II) atoms, two completely deprotonated (L)(2-) units, two mu-acetate ions and two coordinated solvent (methanol, n-propanol and H2O) molecules, thereby forming slightly distorted octahedral geometries. Although the Ni(II) atoms are all hexa-coordinated in these complexes, there are obvious differences in their crystal and supramolecular structures due to solvent effects: Complex 1 forms an infinite 2D network structure, while complexes 2 and 3 form infinite 3D supramolecular structures by strong hydrogen bonding interactions. (C) 2017 Elsevier Ltd. All rights reserved.