Selenide clusters

An extensive range of transition metal selenide clusters result from (Me3Si)2Se and a range of transition metal salts. Cp TiC (Cp = MeCsH reacts with (Me3Si)2Se to give the cluster CpjTisSeg, which possesses a distorted trigonal bipyramidal structure with... 

Cadmium selenide clusters of different sizes appear to have different colors. 

ELECTROCHEMICAL DEPOSITION OF METAL SELENIDE CLUSTERS ON SELENIUM SURFACE... 

Mechanisms of electrochemical and photoelectrochemical deposition of metal selenide clusters (Me = Pb, Cd, Zn, Bi, In) onto the surface as well as into the selenium films have been studied. These clusters are formed as a result of underpotential and overpotential deposition of the metals onto Se. Photoinduced underpotential deposition of Bi onto Se was used to cover selenium colloidal particles with BiiSes clusters. The PbSe and Bi2Sc3 clusters modify the Se surface and form electronic surface states in the Se bandgap, thus promoting electron exchange processes between the valence band and redox species in solution and the rise of the subbandgap photocurrent. 

Apart from the upd, the process of overpotential deposition (opd) of metals might be used for metal selenide clusters formation. In contrast to the upd, bulk particles of metal (Mebuik) are formed in the latter case. The formation of metal selenide clusters occurs because of oxidation of the metal particles with Se can proceed at the places where MCbuik particles are in contact with the surface Se atoms, i.e. on Se Meb ik interface (Fig. 3a). The eleetrodeposition of Pb onto pol-Se electrode appears at E < -0.4 V (Fig. 3b) and results in Pbbuik particles formation on the surface. The reversible potential of Pb electrode in the same solution is -0.37 V,... 

Figures, a) Scheme demonstrating metal selenide clusters formation in the SejMebuit interface due to the chemical oxidation of metal with Se. b) Voltammogram of the Se electrode in...

A variety of sulfide and selenide clusters have been obtained from CpMCE and silylated or Li chalcogenides. The Cp TaS3 unit offers an example of a moiety with three terminal sulfides that might serve as a building block for more complex structures. The presence of the bridging pentasulfide g, ligand, derived from octasulfur, has... 

One of the stimuli for studying these complexes is their close relationship to the well-known Chevrel phases MMo Yg (Y = S, Se or Te). Accordingly, a noteworthy recent development is the discovery of octahedral rhenium-selenide clusters. The phase Re SegClj has been prepared by the high temperature reaction ( BOOK) of ReQj with mixtures of Re and Se. An X-ray crystal structure has shown the presence of the [RcgScg] core possessing Re—Re distances of 2.6 2.67 A. The presence of two terminal Re—Cl bonds tram to one another) inhibits interlayer linkages. ... 

The largest copper selenide clusters isolated to date possess 140 or 146 copper atoms with 70 or 73 selenium ligands, respectively. The molecular stmctures of 34, 36 [23], and 37 are shown in Figure 3.52. 

Scheme 3.6 Synthesis ofvarious copper selenide clusters in the presence of PEtjPh under different reaction conditions.

On examining Figure 3.61, it can be surmised that a normal cluster growth occurred in the presence of a tertiary phosphine - indeed under Se-C bond cleavage conditions - to result in the formation of a copper selenide cluster which is represented by the [Cu4oSe2o] central unit of 51. Only the sidewise attachment of... 

Figure 5.12 First dipole- and spin-allowed singlet or triplet excitations of selected naked copper selenide clusters [Cu2 Se ] (up to n = 15) calculated on the CIS level (CIS = configuration interaction with single excitations) for structures previously optimized...

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