Spectroscopy, transition-metal sulfide

Through a co-assembling route, mesostructured lamellar molybdenum sulfides are formed hydrothermally at about 85 °C using cationic surfactant molecules as the templates. The reaction temperature and the pH value of the reaction system are important factors that affect the formation of the mesostructured compounds. The amount of the template and that of the S source are less critical in the synthesis of the compounds. For the three as-synthesized mesostructured materials, the interlayer distance increases linearly with the chain length of the surfactant. Infrared and X-ray photoelectron spectroscopy reveals that the individual inorganic layers for the three compounds are essentially the same both in composition and in structure. The formal oxidation state of the molybdenum in the materials is +4 whereas there exist S2 anions and a small amount of (S-S)2 ligands in the mesostructures. The successful synthesis of MoS-L materials indicates that mesostructured compounds can be extended to transition metal sulfides which may exhibit physico-chemical properties more diverse than non-transition metal sulfides because of the ease of the valence variation for a transition metal. 

Photoelectron spectroscopy has been used to determine the threshold of electron detachment in small cluster anions and in some cases electronic transitions may be observed. The group of Nakajima and co-workers (261-264) studied several metal sulfide cluster anions. Many other systems have been studied by photoelectron spectroscopy including the [LaCJ (265), [AuC6F6] (266), and mixed-metal cluster anions (267). 

The sulfide group forms a large number of complexes where it is in chelation with a different heteroatom. Among the common heteroatoms are N, P and As. These complexes are too numerous to list here, but individual complexes can be found from Table 9 or from refs. 1224 and 1667. It is also possible to synthesize compounds which will form bi-, tri- and tetra-dentate complexes to platinum(II), where sulfur, selenium and tellurium.are the only atoms which coordinate to the metal. A review of complexes formed from ligands of the type RS(CH2) SR has been recently published.1734 This article outlines the synthesis, reactions and spectroscopy of these complexes, and allows the complexes of platinum to be placed in context with those of other transition metals. 

Postcolumn derivatization spectroscopy Direct Indirect Transition metals, high sensitive Used for iodide, nitrate, sulfide Universal application, lacks sensitivity... 

---