Molecular structures of nickel(II) monochelates of a racemic tridentate ligand and co-ligand induced structural variations

Abstract

Using a racemic mixture of the tridentate ligand, (((2-pyridyl)ethylamine)methyl)phenolate ion ( L −) and N 3 - , NCS −, (NC) 2N −, OAc − as coligands, complexes having the formula [Ni( L)(N 3)] ( 1), [Ni( L)(NCS)] 2 ( 2), [Ni 2( L) 2(OAc)(N(CN) 2)] n ( 3) were prepared and structurally characterized. In 1, Ni(II) has a square planar geometry and phenolate oxygen is involved in dipolar O P δ - ⋯N δ+ interaction with electrophilic central nitrogen atom of coordinated azide ion. Complex 2 is dimeric in nature and nickel(II) is penta-coordinated. Compounds 1 and 2 exist as centrosymmetric dimers made up of a pair of R and S enantiomers of L. In 3, an acetate and phenoxo bridged dinickel complex is present which is further linked to a zig-zag coordination polymer by the dicyanamide ion. In a given chain of 3, both L have same enantiomeric form and either RR or SS dimers are repeated along the chain. The magnetic properties are described.