Tellurium complexes structure

Tellurium Selenides. Tellurium selenides or selenium tellurides are unknown. The molten elements are miscible in all proportions. The mixtures are not simple solid solutions but have a complex structure. Like the sulfides, the selenides exhibit semiconductor properties. 

In contrast to alkali metals or transition metals, complexation of [R2P(E)NP(E )PR 2] with main group elements is less well documented. Syntheses and structures of a number of tellurium complexes Te[R2P(E)N-P(E )PR 2]2 (E = S, Se) have been reported. It has been argued that electronic rather than steric effects control the geometry around the central tellurium atom. As examples four-coordination in (79) and two-coordination in (80). ... 

Tellurium, tetrakis(diethyldithiocarbamato)-stereochemistry, 94 Tellurium, tetrakis(thiourea)-dichloride structure, 60 Tellurium, tetraphenyl-benzene complex structure, 44... 

The structural chemistry of some metal dithiocarbamates, i.e. systematics, coordination modes, crystal packing, and supramolecular self-assembly patterns of nickel, zinc, cadmium, mercury, organotin, and tellurium, complexes has been thoroughly analyzed and discussed in detail. Supramolecular self-assembly frequently occurs in non-transition heavier soft metal dithiocarbamates. Thus, lead(II), bismuth(III) zinc, cadmium, and (organo)mercury dithiocarbamates are associated through M- S secondary bonds, to form either dimeric supermolecules or chain-like supramolecular arrays. The arsenic(III) and antimony(III) dithiocarbamates are... 

The only structurally characterized derivative of a trisimido organophos-phonate anion is the spirocyclic tellurium(IV) complex (19), which is obtained from the interesting redox reaction between PhPCl2 and [Li2Te(N Bu)3 ] 2 [27]. The phosphorus(V)-centered ligands are generated by imide transfer from tellurium to the phosphorus(III) atoms with concomitant reduction of one-half of the tellurium in the Te(IV) reagent to elemental tellurium [27]. 

A number of selenium and tellurium compounds of the presently discussed metals show a quite different behavior from the Fe-S system. Iron and selenium form two compounds FeSe with a broad stoichiometry range and FeSe2 with a much narrower composition field. Below 400 the non-stoichiometric Fei xSe exists by creation of iron vacancies and can have compositions lying between FeySes and Fe3Se4. At low temperatures there exist two phases an a (PbO type) and a f) (NiAs type) phase. The crystal sUiicture of the diselenide, FeSe2, is an orthorhombic, C18 (marcasite) type. In the Fe-Te system, the defect NiAs structure is found at a composition close to FeTei.s, as about one-third of the Fe atoms are missing. At compositions around FeTe the behavior is complex, and the f)-phase has the PbO structure (like FeSe) but with additional metal atoms (i.e., FeuTe). 

Multicomponent reactions (MCRs) have been known to produce highly complex and diverse structures [76]. There is a considerable interest in the application of new multicomponent reactions to access biologically relevant molecules [77,78] and natural products [79]. A recent report has disclosed multicomponent Passerini and Ugi reactions to produce, rapid and efficiently, a library of redox-active selenium and tellurium compounds [80]. The compounds showed promising cytotoxicity against several cancer cell lines. 

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