Molecular structures of nickel(II) monochelates of a racemic tridentate ligand and co-ligand induced structural variations
摘要:
Using a racemic mixture of the tridentate ligand, (((2-pyridyl)ethylamine)methyl)phenolate ion (L ) and N-3(-), NCS , (NC)(2)N , 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(delta-)center dot center dot center dot N delta+ 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. (C) 2010 Elsevier B. V. All rights reserved.