COORDINATING ABILITY IN DMSO-WATER 80 20 WT/WT OF THE SCHIFF-BASE N,N'-3,4-TOLUENEBIS(SALICYLIDENEIMINE) WITH DIVALENT-CATIONS - CRYSTAL-STRUCTURE OF THE NICKEL(II) COMPLEX/

Potentiometric studies of the Schiff base ligand sal-3,4-toluen (N,N'- 3,4-toluenebis(salicylideneimine)) with Ni(II), Co(II), Zn(II), Cd(II) , Mg(II) and Ca(II) have been carried out in DMSO-water (80:20 wt./wt. ) at 25 degrees C and 0.5 mol dm(-3) in NaClO4. For all the studied sy stems the monomer species [ML] and [MHL](+) are found to be formed and their stability constants have been determined. This study in solutio n led us to establish the best conditions for the preparation of the s olid complex Ni(sal-3,4-toluen). 1.5CHCl(3). The molecular structure o f this complex has been determined by single-crystal X-ray analysis. T he compound crystallises in the triclinic system, space group <P(1)ove r bar>, with a=13.855(3), b=14.591(3), c=15.247(4) Angstrom, alpha=116 .24(2), beta=115.97(2), gamma=91.30(2)degrees and Z=4. Refinement of t he atomic parameters by least-squares gave a final R1 factor of 0.063 (wR2=0.1820) for 4017 unique reflections having I greater than or equa l to 2 sigma(I). The coordination geometry around the nickel atom is s quare planar with a cis-N2O2 donor set. Spectroscopical studies for th is complex were also carried out.