EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE SPECTROSCOPIC STUDY OF ACETONE SOLUTIONS OF ZINC AND LEAD(II) ETHYLXANTHATE

EXAFS and vibrational spectra of acetone solutions of zinc and lead(II ) ethylxanthate have been recorded in order to correlate structural da ta with absorption bands in the mid-infrared region. Two ethylxanthate ions are monodentately coordinated to both zinc and lead(II) in aceto ne solution. Two acetone molecules are weakly coordinated to zinc to c omplete a tetrahedral configuration round zinc, while no acetone molec ules were found in the inner sphere of the lead(II) complex. A band co ntaining a large contribution from the C-S stretching, observed just a bove 1000 cm(-1) in solid zinc and lead(II) ethylxanthate, where the e thylxanthate ion is bridgingly and bidentately coordinated, respective ly, shifts upwards by 20 and 17 cm(-1) in the corresponding zinc and l ead(II) complexes, respectively, in acetone solution. An upward shift by about 8 cm(-1) is found in the nickel(II) and arsenic(III) complexe s, where the coordination of the ethylxanthate ion remains unchanged b ut acetone molecules solvate the central ion to complete an octahedral configuration. No shift was found in iron(III) ethylxanthate, where t he coordination remains unchanged and no acetone molecules solvate the iron(III) ion.