Nickel(II) and copper(II) complexes of tetradentate unsymmetrical Schiff base ligands: First evidence of positional isomerism in such system

Synthesis and electrochemistry of M(II) N2O2 schiff base complexes: X-Ray structure of {Ni[Bis(3-chloroacetylacetone)ethylenediimine]}

“…Lack of any electronic transition at longer wavelengths indicated a large crystal-field spliting which was consistent with the square planar geometry of Ni(II) complexes. The apearance of the band about 550 nm in the absorption spectra was consistent with the square planar geometry of Cu(II) complexes [7,39,40].…”

Synthesis and characterization of nickel(II) and copper(II) complexes with tetradentate Schiff base ligands

“…The 1:1 condensation of 2,4-pentanedione and 1,2-diaminopropane under the condition of high dilution produces isomeric mixtures of mono-condensed terdentate Schiff bases 7-amino-4-methyl-5-aza-3-octene-2-one (HAMAO) or 7-amino-4,6-dimethyl-5-aza-3-heptene-2-one (HADAH) [26]. This mixture could be made to undergo condensation reaction with 2-acetylpyridine and pyridine-2-carboxaldehyde to form isomeric mixtures of tetradentate unsymmetrical Schiff bases which could be used to form complexes with transition metal ions.…”

Synthesis and characterization of Cu(II) complexes of tetradentate and tridentate symmetrical Schiff base ligands involving o-phenelenediamine, salicylaldehyde and diacetylmonoxime

“…The use of unsymmetrical ligands is more advantageous over their symmetrical analogues to explain the metal ion-binding site in metalloproteins and in efforts to mimic the enzymatic efficiency and selectivity of natural systems with synthetic materials [1][2][3][4][5][6]. The work in our laboratory with unsymmetrical ligands stems from the above observations [7][8][9][10][11]. Unsymmetrical ligands involving an oxime functionality exhibit an interesting chelating property in the area of complex chemistry [11][12][13][14].…”