Tellurium chemistry

Tellurium chemistry is often significantly different in comparison with selenium chemistry owing to the larger size and metallic character of tellurium (Section 1.1). As an illustration, the cyclocondensation of... 

The most employed redncing agents in the old tellurium chemistry were alkali sulphites or hydrogen snlphites, methylmagnesinm iodide and sodinm snlphide hydrate. The last reagent is still nsed, together with the more recently introdnced sodium borohydride, TUDO, hydrazine, samarinm diiodide and sodium ascorbate. ... 

This reagent, together with potassium hydrogen sulphite,has been used to reduce aryltellurium trichlorides since the early period of tellurium chemistry, and continues to find wide application. 

Reactions involving the attack of a nucleophilic carbon atom activated by an a-carbonyl group at the electrophilic tellurium atom of tellurium tetrachloride belong to the oldest methods of preparative organic tellurium chemistry. 

Aryltellurinic acids were described in the early period of tellurium chemistry as the products of the alkaline hydrolysis of the trichlorides. However, the structure of these compounds was later argued about, and the corresponding anhydrides are today accepted as the unequivocal products.The anhydrides are stable, colourless, solids with high melting points and have recently attained a relevant role as synthetic reagents. 

This method, which dates from the early German tellurium chemistry and is today widely employed, uses aqueous sodium hydroxide or ammonia as hydrolytic reagents. 

Tellurium is the fourth element of the VIA family of the periodic table, which starts with oxygen. Since tellurium exhibits an electronic configuration similar to that of selenium and sulphur, the chemical behaviour of these elements is obviously closely related. This similarity was a hindrance to the greater development of tellurium chemistry. During several decades, research was restricted to an extrapolation of well-established reactions for the preparation and use of organic sulphur compounds to selenium, and mainly from selenium to tellurium. 

This monograph is appropriate for chemists who, although not experts in tellurium chemistry, have had a basic grounding to graduate level in organic chemistry and with sufficient experience of typical experimental operations. 

Over a decade after the publication of the first edition of this book, it is unnecessary to emphasize once more the remarkable developments attained in organic tellurium chemistry. 

Undoubtedly tellurium chemistry can participate in several areas of organic chemistry, as well as in others, and ever-more research chemists introduce tellurium to solve a wide variety of problems. 

All this seems to us to be a good reason to write this new edition of the book. It does not differ in its general approach from the first one. Obviously it is not a compendium covering exhaustively all the aspects of organic tellurium chemistry. For this purpose the Irgolic E12b volume of Houben-Weyl is yet incomparable although 16 years old. 

We would be gratified if this new edition, with its broad level of information, can disclose basic knowledge to the beginner in tellurium chemistry as well as furnish salient features for opening new perspectives to advanced researchers. 

The analogous selenium and tellurium chemistry has not been explored. The [Tl2Te2]2-anion has been obtained by reacting KTITe with [2.2.2]cryptate in ethylenediamine to give [K([2.2.2]crypt)]2[Tl2Te2]2- en, in which the anion is butterfly-shaped with a 50° fold.328 The assignment of oxidation numbers is somewhat arbitrary in such systems (cf. Section 25.2.6.1.2), but it seems clear that thallium is in a low oxidation state. 

Since sulfur chemistry lies beyond the scope of this review and organo-tellurium chemistry so far has not been of any impact on organometallic chemistry in general, this section will be restricted to the discussion of redistribution equilibria on selenium. 

A. S. Pepito and D. C. Dittmer, Application of tellurium chemistry and sharpless asymmetric epoxidation to the synthesis of optically active boivinose, J. Org. Chem., 59 (1994) 4311 1312. 

This chapter is dedicated to describing the main routes to the most studied classes of organic compounds of tellurium and the useful synthetic transformations they can perform. As already mentioned, in the last two decades, a number of books and exhaustive review articles have been published on tellurium chemistry. Due to the enormous body of information available and to space limitations, we have selected the reactions which, in our point of view, present a greater synthetic potential and generality. In view of this fact, the text intends to be a comprehensive account rather than an exhaustive review. For a recent review with references to prior reviews and books, as well as recent advances in the tellurium chemistry not covered in this chapter, we recommend the reader to consult Ref 10. 

The discovery by Petragnani80 that organotellurium halides can be generated and captured in situ by nucleophiles opened a new chapter in organic tellurium chemistry, as exemplified by the reactions described in Section 9.13.6.1. 

Organo tellurium trihalides are the best known and most numerous compounds among the tellurinic acid derivatives. Most of the other derivatives are represented only by a few compounds, some of which have not been adequately characterized. Frequently, different products are claimed for similar reactions with identical starting materials. Much more work needs to be done with the various hydrolysis products of organo tellurium halides before this area of organic tellurium chemistry can be considered to be adequately explored. 

Devillanova, F. (Ed.). (2006). Handbook of Chalcogen Chemistry New Perspectives in Sulfur, Selenium and Tellurium. Cambridge RSC Publishing. A book devoted solely to the chemistry of the chalcogens. Greenwood, N. N., Eamshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford Butterworth-Heinemann. The monumental reference book in inorganic chemistry. Extensive coverage of sulfur, selenium, and tellurium chemistry in Chapters 15 and 16. 

There are relatively few of these, and it is obviously an area worthy of further investigation, as is that of osmium-tellurium chemistry. 

Although tellurium chemistry has been reasonably well studied, only relatively few mixed donor ligands have been described. A hard soft N,Te donor didentate is (47). An... 

Selenium and tellurium have a wide-range of oxidation states (-2 to -i-6) and form a variety of organic selenium and tellurium compounds. Several excellent books dealing with organoselenium and tellurium chemistry have been published and these provide a comprehensive overview of fhe preparation and reactivity of selenium and tellurium compounds [1]. 

The research volume in organic and organometallic tellurium chemistry has grown very rapidly in recent years. 

---