Dipole-moment measurements on metal chelate complexes. Part III. Dipole-moment and dielectric-relaxation measurements on some tetrahedral zinc(II) complexes of seven mercapto-β-diketones

Abstract

Dipole moments and relaxation times have been determined for tetrahedral zinc(II) complexes of the mercapto-β-diketones RC(SH):CH·C(O)R′[R = Me or Ph, R′= Ph; R = Me, C₄H₃S (2-thienyl), Ph, p-MeC₆H₄, or p-BrC₆H₄, R′= CF₃] from both static-polarization and dielectric-relaxation measurements. Group dipole moments for the R substituents have been derived and found to agree with the corresponding values for a series of square-planar complexes studied earlier. Group dipole moments for the metal–chelate rings have been calculated by comparison of results obtained for the square-planar and tetrahedral complexes. The magnitude and direction of these ring moments are dependent on the presence of a CF₃ group as R′ substituent.