Department of Chemistry, Faculty of Science, University of Qatar,P.O. Box 2713, Doha, State of Qatar 

New transition metal complexes of Co(II), Ni(II) and Cu(II) with
benzil-bis(4-ethyl thiosemicarbazone) and benzil-bis(4-butyl
thiosemicarbazone) have been synthesized. Attempts have been
made to ascertain their probable structures on the basis of elemental
analysis, spectra (lR, electronic), thermal studies and magnetic
measurements. The ligands can function as a binegative quadridentate
(NSSN) with the metal ions forming complexes in molar ratio
1: 1 having the empitical formulae ML and ML·2H₂O. The magnetic
moment measurements and the crystal field parameters calculated
for Co(II) and Ni(lI) complexes agree fairly well with that
reported for known octahedral complexes.