Chemical sulfur ligands

In most of the nonmetaHurgical uses of molybdenum compounds the metal is coordinated by oxygen or sulfur ligands. Molybdenum nitrides, carbides, and sihcides are, however, coming under increasing study for various appHcations. Roughly 75% of all molybdenum compounds are used as catalysts in the petroleum and chemicals industries. 

Another group of chemically related ligands comprises the compounds NMe(o-C6H4SH)2, PhPfa-CeKUSITh, and Pfo-CgPUSHb. They are prepared by methods similar to the preparation of S3—H2 (Section II.B). Lithiation of NMePh2, treatment with elemental sulfur, and acidification yielded NMe... 

The limited success with sodium citrate led to the trial and error testing of other chelating agents. Despite the fact that hard Lewis acids such as plutonium do not bind strongly to sulfur ligands, the success of 2,3-dimercapto-l-propanol, BAL, as an efficient chelator for arsenic79) led to testing its ability to remove actinides. As expected on a chemical basis, excretion of plutonium was not enhanced by treatment... 

CADMIUM-113 NMR SPECTROSCOPY IN BIOINORGANIC CHEMISTRY Table 6. Cadmium-113 Chemical Shifts—Sulfur Ligands... 

Chemical Properties. Although the chemical properties of the trivalent lanthanides are quite similar, some differences occur as a consequence of the lanthanide contraction (see Table 3). The chemical properties of yttrium are very similar too, on account of its external electronic stmcture and ionic radius. Yttrium and the lanthanides are typical hard acids, and bind preferably with hard bases such as oxygen-based ligands. Nevertheless they also bind with soft bases, typicaUy sulfur and nitrogen-based ligands in the absence of hard base ligands. 

The greater lability of 1-benzothiepin 1-oxides, compared to the parent compounds, may lead to differences in chemical behavior. Thus, treatment of the tricarbonyliron complex of 1-benzo-thiepin 1-oxide (8, X = SO) with ammonium cerium(IV) nitrate in acetone at — 30 °C leads, with the loss of sulfur monoxide, to naphthalene. In contrast, the iron ligand can be removed selectively from the corresponding 1-benzothiepin by ammonium cerium(IV) nitrate.23 92 For the synthesis of 1-benzothiepin 1-oxide, see Section 2.1.4.1,... 

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