Synthesis and characterization of bis-chelated nickel(II) complexes of themethylpyruvate Schiff bases of S-alkyldithiocarbazates and the X-ray crystal structure of the [Ni(ONSMe)(2)] complex

New nickel(II) complexes of general empirical formula: [Ni(ONS)(2)] (ONS- i s the anionic form of tridentate ligands formed from methylpyruvate and S-m ethyl- and S-benzyldithiocarbazates) have been synthesized and characterize d by magnetic and spectroscopic techniques. The complexes are six-coordinat e and octahedral. The crystal and molecular structure of [Ni(ONSMe)(2)] (ON SMe- is the anionic form of the methylpyruvate Schiff base of S-methyldirhi ocarbazate) has been determined by X-ray diffraction which shows that the n ickel(II) complex has a distorted octahedral structure with the ligands coo rdinated to the nickel(II) ion as uninegatively charged tridentate chelatin g agents via the carbonyl oxygen, the azomethine nitrogen and the mercaptid e sulphur atoms. The distortion from regular octahedral geometry is attribu ted to the restricted bite angles of the planar ONS tridentate ligands. (C) 1998 Elsevier Science Ltd. All rights reserved.