14768-61-7Relevant academic research and scientific papers
Five-coordination in some complexes of nickel(II) with Schiff bases, formed from salicylaldehydes and N,N-substituted ethylenediamines. II
Sacconi,Nannelli,Nardi,Campigli
, p. 943 - 949 (1965)
Further studies on the complexes of nickel(II) with Schiff bases formed from ring-substituted salicylaldehydes and N,N-disubstituted ethylenediamines are presented. The compounds have a general formula [X-SALen-NR2]2Ni; when -NR2 is a dimethylamino group or pyrrolidino group the ligands are tridentate and all the complexes formed from them are paramagnetic and have distorted octahedral configuration. The complexes where -NR2 is a piperidino group are all diamagnetic and have the square-planar configuration. When -NR2 is a diethylamino group the configuration of the complex is square-planar or octahedral depending on the substituent X, except for X = 3-Cl, 5-Cl, and 3,4-benzo when the complexes are paramagnetic and five-coordinate with μeff ≈ 3.3 B.M. The configuration of the five-coordinate complex most resembles that of a distorted square pyramid ; the complexes are the first reported examples of high-spin five-coordinate complexes of nickel-(II).3 Most compounds of the present study exist in solution as mixtures of planar, five-coordinate, and octahedral forms.
Complexes of nickel (II) with Schiff bases formed from salicylaldehydes and N-substituted ethylenediamines. I
Sacconi,Nannelli,Campigli
, p. 818 - 822 (1965)
Schiff bases formed from ring-substituted salicyclaldehydes and N-substituted ethylenediamines form four types of complex with nickel(II) with a general formula [X-SALen-N(R)R′]2Ni. When R = H, R′ = n-alkyl, benzyl, the ligands are tridentate and their nickel complexes are six-coordinate, octahedral, and mononuclear both in the solid state and in noncoordinating solvents. They do not form adducts with pyridine. When R = H, R′ = ortho-substituted phenyl, the complexes are all square-planar and diamagnetic. When R′ = phenyl or para-substituted phenyl the complexes are either square-planar or octahedral depending on the ring substituent X. In inert solvents compounds with any substituted N-phenyl group exist as octahedral and square-planar forms in equilibrium, with a greater proportion of the square-planar form at higher temperatures. In pyridine the compounds are converted into octahedral pyridine adducts. When R = phenyl, R′ = methyl, phenyl, these Schiff bases function as bidentate ligands and form trans-planar complexes both in the solid state and in inert solvents, and the complexes form adducts with pyridine.
