Synthesis and characterisation of the reaction products from bis(thiosalicylohydrazidato)nickel(II) in base and acid solution

Abstract

Bis(thiosalicylohydrazidato)nickel(II), [Ni(HL)₂](1) transforms to [NiLL′] on reacting with nucleophiles (L′) in the presence of ethanolic K[OH], where H₂L = thiosalicylohydrazide, o-HOC₆H₄C(S)N^aHN^bH₂, and L′= H₂O, NEt₃, pyridine, 2-methylpyridine, 2,6-dimethylpyridine, 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen), propane-1,3-diamine, or NN′-diethylethylenediamine. But, in contrast, with ethylenediamine (en), complex (1) transforms to [Ni₂L₂(en)] where en bridges two metal ions through the terminal nitrogen atoms. In [NiLL′], thiosalicylohydrazide acts as a dibasic tridentate ligand and co-ordinates through (O,N^bS) sites. Complex (1) reacts with acetone to form bis(acetone thiosalicylhydrazonato)nickel(II) and also forms an adduct with dimethyl sulphoxide in acidic medium. In both these cases the bonding sites (N^a,O) observed in the parent species (1) change to (S,N^b) on reaction. In [Ni(H₂L)₂]Cl₂·5H₂O and [Ni(H₂L)₂][HSO₄]₂·2H₂O however, formed by treatment of (1) with mineral acid, no alteration of the bonding sites takes place. All the complexes, except [NiL(bipy)] and [NiL(phen)] which possess high-spin five-co-ordinate geometry, are square planar. All the reaction products are characterised by elemental analyses, magnetic moments, conductance, and spectral (¹H n.m.r., i.r., far-i.r., and electronic) data.