Abstract

Eight-coordinate tetrakis molybdenum(IV) complexes containing 5,7-dichloro-8-hydroxyquinolinol(Hdcq) and 2-mercaptopyrimidine(Hmpd) has been prepared. <TEX>$Mo(mpd)_4$</TEX>, <TEX>$Mo(dcq)(mpd)_3$</TEX>, <TEX>$Mo(dcq)_2(mpd)_2$</TEX>, <TEX>$Mo(dcq)_3(mpd)$</TEX> and <TEX>$Mo(dcq)_4$</TEX> complexes have been isolated by thin-layer chromatography on silicagel plates. These complexes have been charaterized by <TEX>$^1H-nmr$</TEX> spectrum and UV-Vis. spectrum. The chemical shift values of the protons <TEX>${\alpha}$</TEX> to the nitrogen in the ligands are shifted to down field. The relative intensities of the peaks which are positioned at the same proton of <TEX>$Mo(dcq)(mpd)_3$</TEX> and <TEX>$Mo(dcq)_3(mpd)$</TEX> are observed in 2:1 ratio, in case of <TEX>$Mo(dcq)_2(mpd)_2$</TEX> appears in approximately a 1:1 ratio. The stereochemistry of the complexes in discussed in terms of their nmr spectrum and Orgel's rule. By vertue of the intensities (<TEX>${\varepsilon}$</TEX>>10,000~25,000) the low energy(<TEX>$16,600{\sim}19,800cm^{-1}$</TEX>) bands are observed for the electronic spectra of the complexes are assigned as charge transfer bands.