Tellurium compounds Subject

Many reviews have covered the chemistry of transition-metal, main-group compounds,5-12 and because the title subject is too vast to be covered fully in this review, emphasis will be given to complexes containing selenium and tellurium reference to compounds containing sulfur will be included for purposes of comparison. 

The subhalides of tellurium are an especially important class of solid state compounds, and they have been the subject of intensive studies, so that a rather complete picture of their chemistry and their properties has been obtained in recent years. Because of their high tellurium content they contain fragments of the homonuclear tellurium chains their modified tellurium structures are of great current interest with respect to possibly significant physical properties. Consequently, the results of various investigations on the synthesis of the compounds, on phase analysis by thermal methods, on crystal growth, on the structures, on spectroscopic, thermodynamic, optical, photoelectric, electrochemical properties have been reported in the last two decades. In a comprehensive review (237) all significant results are reported and discussed in detail so that the present chapter will be restricted to some selected and chemically important features. 

The 1,3-ditellurole derivative 149 was prepared from trimethylsilylacetylene according to Equation (60) <20020L2581>. Thus, lithium trimethylsilylacetylide was reacted with tellurium, whereupon the resulting tell-urolate was protonated to give 149. This compound suffered extensive decomposition during purification and could not be desilylated. Instead, it was subjected to Vilsmeier-Haack formylation giving a stable dialdehyde 150 (Equation 22). 

A similar pathway is observed with 2,2 -dilithiobinaphthyl < 91JHC433>. The application in the acyclic series has been explored by Brandsma <83TL2203>. When compound (22) is subjected first to metallation and then reacted with tellurium, a mixture of (23) and (24) is obtained. 

The tellurium subhalides represent a group of recently discovered compounds which have been investigated by the methods of solid-state and structural chemistry. Because of their high tellurium content and their crystal structures containing homonuclear tellurium connections they have attained significance as modified tellurium structures . As a consequence, tellurium subhalides have been the subject of various investigations in the fields of solid-state and chemical physics. 

Phospha- and arsasilenes undergo [2- -n] cycloadditions (n = 1-4), thermal decomposition, and reaction with P4, sulphur and tellurium. In order to avoid excessive redundancy the interested reader should consult the two reviews by Driess on this subject -. A number of theoretical treatments on unsaturated silicon phosphorous compounds, apart from those cited in the above-mentioned reviews, has been published " . ... 

Heterocyclic Chemistry is an annual publication which combines material previously reviewed in three separate SPR titles Saturated Heterocyclic Chemistry, Aromatic and Heteroaromatic Chemistry, and the heterocyclic sections of Organic Compounds of Sulphur, Selenium, and Tellurium. Heterocyclic Chemistry has now reached its fourth volume, which reviews the literature published on the subject during the period July 1981 to July 1982. 

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