THE COORDINATING BEHAVIOUR OF BENZOXAZOLE-2-THIONE TOWARDS SOME TRANSITION METAL HALIDES IN THE LIGHT OF SPECTROSCOPIC INVESTIGATIONS

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Abstract
Some benzoxazole-2-thione (bot) complexes of manganese(II), iron(III), iron(II), ruthenium(III) and osmium(III) have been prepared and their conductivities, electronic spectra, magnetic susceptibility data and i.r. spectra are reported and discussed. The metal–halogen stretching modes in the far i.r. region resulted particularly useful in distinguishing between the mer- and fac-isomers in the ruthenium and osmium compounds of the type ML3 X3. From the magnetic properties it was concluded that the above ligand forms low-spin complexes with ruthenium(III) and osmium(III) and high-spin complexes with manganese(II), iron(II) and iron(III). The wavelengths of the principal absorption peaks have been accounted for quantitatively in terms of the crystal field theory for manganese(II), tetrahedral iron(III), ruthenium(III) and osmium(III) derivatives. The values of B and C in the iron(III) derivatives are less than in the corresponding manganese(II) complexes. The charge-transfer observed in the ruthenium(III). osmium(III) and iron(III) derivatives is considerably lower than the corresponding one in the iron(II) iododerivative.