Synthesis and characterisation of a novel 2, 3-O-di acetyl-5, 6-O-benzylidene-l-ascorbic acid and its complexes of Cr (III)‎, Co (II)‎, Ni (II)‎, Cu (II)‎ and Zn (II)‎

Abstract EN

A new ligand type (O2) [2, 3-O-diacetyl-5, 6-O-benzylidene L- ascorbic acid] [L] and its complexes of general formula [M (L) 2 (X) (Y)]Cln (where : M = CrIII, X = Y=H2O, n = 3 ; CoII, X = Y = 0, n = 2; NiII and CuII, X = Cl, Y = H2O, n = 1 ; ZnII, X = Y = H2O, n = 2) are reported.

The ligand was prepared in two steps ; first step involved the synthesis of [5, 6-O-benzylidene-L-ascorbic acid] (A).

In second step derivative-A was then reacted with acetyl chloride and anhydrous pyridine as a base to give the titled ligand.

Metal complexes of the ligand with CrIII, CoII, NiII, CuII and ZnII were synthesised by direct reaction of the corresponding metal chloride with the ligand [L] in a 2L : 1M mole ratio.

The ligand and its complexes were characterised by spectroscopic methods 1H NMR, FTIR, (UV-Vis), atomic absorption, microanalyses, chloride content, melting point and conductance measurements.

These studies revealed that the geometry about CrIII, NiII, CuII and ZnII is octahedral while the complex of CoII adopts a tetrahedral geometry.