SYNTHESIS, MAGNETIC AND SPECTRAL PROPERTIES OF SOME METAL(II) COMPLEXES OF MERCAPTOACETIC AND 3-MERCAPTOPROPIONIC ACID-DERIVATIVES OF VITAMIN-B-1

(4'-Amino-2'-methyl-5'-pyrimidinylmethylthio) acetic acid, Hammpta, an d the propionic acid analogue, Hammptp, and their copper(II), cobalt(I I), zinc(II), palladium(II) and platinum(II) complexes have been synth esized. The pKa values of the acids (at 25 degrees C) are 2.76 (Hammpt a) and 2.74 (Hammptp). The complexes were characterized by microanalys es, IR and electronic spectra, conductivity and magnetic susceptibilit y measurements. While the zinc(II), palladium(II) and platinum(II) com plexes exhibit tetrahedral and square-planar geometries, the copper(II ) and cobalt(II) complexes exhibit a variety of geometries. One of the copper(II) complexes, [Cu(ammptp)ClH2O], and one of the cobalt(II) co mplexes, [Co(ammptp)Cl](2), are magnetically concentrated. [Co(Hammpta )(2)Cl-2] is presumed to be low-spin octahedral or square-planar (mu(e ) = 2.18 B.M.), whereas the cobalt(II) complexes of Hammptp/ammptp(-) are more prone to being tetrahedral.