Clusters copper selenide

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...

The crystals that are obtained from the cluster formation reactions are intensely colored. In fact, the intensity of the color increases when going from sulfur- to selenium- to tellurium-bridged compounds (see below), as might be expected for an increase in the covalent or (semi-) metallic binding properties. Small copper sulfide and selenide clusters form light red, orange, or purple crystals, but with increasing cluster size the color varies from dark red to reddish-black to (finally) black with a metallic sheen. The optical spectra of some copper selenide cluster compounds have been studied by means of solid-state UV-visible spectroscopy. 

This approach of using a combination of RSe-TMS and Se(TMS)2 for cluster synthesis should allow for the tailored functionalization of semiconductor nanoparticles. Recently, the ability to functionalize the surface of Cu2Se clusters has been demonstrated. The synthesis of l,l -bis(trimethyl-silyl)ferrocene, and its consequent reaction with CuOAc and excess phosphine has produced the polynuclear copper selenide cluster [Cug Fe(77 -C5H4Se)2 4(PPh2Et)4] (51) with surface redox-active ferrocene units that are intimately coupled to the cluster core (Figure 34). ... 

Scheme 3-26. Formation of high nuclearity copper selenide clusters from CuCl.

A final, really unexpected example of a zeolite-like material is the cluster compound Cui4gSe73(PPh3)3o which forms trigonal prismaticaUy shaped tri-phenylphosphonium coated copper selenide clusters of 4 nm length and a thickness of about 2nm [109]. This material crystallizes in a most amazing structure where the cluster molecules arrange in a way that they form uni-... 

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