Nickel(II) Complexes of Some Quadridentate Schiff Base Ligands I
A series of nickel(II) complexes, NiL, of the Schiff bases formed by condensation of 5-chloro-2-hydroxybenzophenone with a series of alkanediamines, NH 2(CH 2) nNH 2 (n = 2-12), have been synthesized and their physicochemical properties investigated. Unlike their salicylaldimine analogs, the NiL complexes derived from long-chain alkanediamines are highly soluble in nondonor solvents. In nondonor solvents these complexes are low-spin planar monomers with the Schiff bases acting as quadridentate ligands, although there is a small degree of molecular association in some cases. In the solid state, some of the complexes (n = 5-12) contain both octahedral and square-planar Ni(II) usually in the ratio 1:2, and a trimeric structure has been proposed to account for this behavior. For n = 3-12, the complexes reversibly form bis-pyridine adducts: NiL + 2C 5H 5N ⇄ NiL·2C 5H 5N. The solid pyridine adducts were isolated from pyridine solution as paramagnetic solids and these complexes are assigned a trans-octahedral structure. A square-pyramidal complex, NiL·H 2O, has been isolated for n = 4.
G. M. Mockler et al., "Nickel(II) Complexes of Some Quadridentate Schiff Base Ligands I," Inorganic Chemistry, American Chemical Society (ACS), Jan 1972.
The definitive version is available at http://dx.doi.org/10.1021/ic50112a030
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© 1972 American Chemical Society (ACS), All rights reserved.