Schiff bases cadmium complexes

The PVC membrane electrode based on new Schiff base complexes of 2,2-[(l,3,dimethyl-l,3-propanediylidene)dini-trilojbis-benzenethiolato with Cd(II) [381] and cadmium-salen N, Ai -bis-salicyli-dene-l,2-ethylenediamine) complex [382] were used as the selective electrodes for tiocyanate ions. 

Schiff bases, especially multidentate ones, are powerful ligands for metal ions and zinc and cadmium complexes are well represented in this area. The findings of structural studies are interesting in that the ligand can control the stereochemistry of the complex and provide us with numerous examples of unusual geometry about the central metal ion, thus serving to illustrate the coordination flexibility of these ions. 

In fact, several reports have appeared on the spectroscopic features of complexes of zinc and cadmium with Schiff bases. The electronic absorption spectra of various salicylaldimine complexes of zinc have been determined335 to clarify assignments made previously for similar copper(II) complexes. A band at ca. 41000 cm-1 has been reassigned as an n-n transition of the oxygen lone pair, rather than the o-3d transition proposed earlier. 

Structural surprises are not confined to 2,6-DAP derivatives though zinc and cadmium complexes have been obtained with the quadridentate thioiminato Schiff base N,N -ethylenebis(monothioacetonimine) 347 uv and visible spectra indicate planar geometry, rather than the tetrahedral geometry observed for the salicylaldimine complexes. 

Several reports have appeared on complexes of zinc and cadmium with Schiff bases. The electronic absorption spectra of various salicylaldimine complexes of zinc have been determined54 to clarify assignments made previously for similar copper(n)... 

The complexes of zinc and cadmium with Schiff bases derived from salicylaldehyde and propan-2-olamine or 2-aminomethylpropanol have been reported,57 as well as their complexes with ethanolamine and propan-2-olamine.58,59 Zinc complexes of stoicheiometry ZnL2X2 have been obtained where L = benzoyl- and salicyl-hydra-zones of vanilline. furfural, and cinnamaldehyde. Zinc complexes of several substituted o-bydroxybutyrophenones and their oximes have been reported.60-62 Complexes of stoicheiometery ZnL2U have been reported where L = the a-nitroketonato-anion obtained from nitroacetone, 3,3-dimethyl-l-nitrobutan-2-one or 3-nitrocam-phor and L — bipyridyl or 1,10-phenanthroline.63... 

Majumder, A., Rosair, G. M., Mallick, A., Chattopadhyay, N., Mitra, S. (2006). Synthesis, structures and fluorescence of nickel, zinc and cadmium complexes with the N,N,0-tridentate Schiff base N-2-pyridylmethylidene-2-hydroxy-phenylamine. Polyhedron, 25, pp. 1753-1762, ISSN 0277-5387... 

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