An EXAFS study of Mo(VI) and Mo(V) complexes with proline dithiocarbamate
An EXAFS study of Mo(VI) and Mo(V) complexes with proline dithiocarbamate
复制标题
Mo(VI) 和 Mo(V) 与脯氨酸二硫代氨基甲酸盐配合物的 EXAFS 研究
DOI：
10.1016/s0020-1693(99)00046-8
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发表时间：
1999
影响因子：
2.8
通讯作者：
M. Villa
中科院分区：
文献类型：
--
作者：
B. Macías;P. Malet;R. Paradinas;V. Rives;M. Villa
The reaction between proline and carbon disulfide in a basic medium yields the corresponding dithiocarbamate (hereafter dtc pro). Reaction of this compound with Na2MoO4· 2H2O leads to formation of a coordination compound with the formula MoO2(dtc Hpro)2, while reaction with MoCl5in an inert atmosphere leads to Mo2O4(dtc Hpro)4. Mo K XANES data are consistent with the presence of Mo(VI) in the former compound, while a lower oxidation state of molybdenum in the latter, Mo(V), shifts the absorption edge to lower energies. EXAFS data indicate that, in these complexes, molybdenum ions are in a different coordination environment. In the first it is in a distorted octahedral coordination, and oxygen atoms are in cis positions, with an Mo–O distance of 1.68 Å and an Mo–S distance of 2.48 Å. However, in the dimer the Mo atoms (Mo–Mo distance 2.55 Å) are bridged by two oxygen atoms (Mo–O distance 1.95 Å), and the Mo–S distance is 2.43 Å. The molybdenum atom in this case is pentacoordinated with a terminal oxygen atom distance Mo–O of 1.66 Å. The dithiocarbamate unit behaves in all cases as a bidentate ligand, both sulfur atoms being equivalent. Both complexes are diamagnetic, and FT-IR spectroscopy provides evidence that the carboxylic group is in the acidic form, not being coordinated to the Mo cations. Only charge transfer bands are detected in the UV–Vis spectra. EPR spectra produced evidence of the presence of a small amount of a paramagnetic Mo(V) species, probably Mo(dtc Hpro)3.
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
T.Nishigaki et al.;S.Itoh.et al.
通讯作者：
S.Itoh.et al.