cis and trans Isomers of Dihalobis(2-acetylaminothiazole)nickel(II)

Abstract

The cis and trans isomers of Ni(aatz)₂,X₂ (X = Cl, Br, I and aatz = 2- acetylaminothiazole) have been prepared and characterized with the help of magnetic moment data and infrared and electronic spectra. The number of bands in the far infrared region (650-50 cm^-1) suggests a C_2h symmetry for the trans and C_2v symmetry for the cis isomers. Electronic spectral bands of cis isomers have higher molar extinction coefficients and show less splitting than the trans isomers. The ligand exerts a stronger ligand field in cis than in trans isomers. The spin orbit coupling constant values (λ?) and the Bohr magneton values increase from chloro to iodo in the case of cis complexes and decrease in trans complexes. The X-ray powder pattern data for both the isomers are identical. 2- Acetylaminothiazole acts as a bidentate ligand and the donor sites are carbonyl oxygen and ring sulphur.