Tellurolates

The first representatives of this group of compounds, 1,5-benzotelluroazepinones 57, have been prepared in 17% yield by the reaction between 2-iodopropyolanilides and NaHTe (98H631). The reaction proceeds, most probably, as nucleophilic substitution of the iodine, resulting in telluroles 58 and the subsequent nucleophilic addition of a hydrotelluride group to the triple bond. An alternative mechanism involving initial addition of NaTeH to the triple bond followed by the nucleophilic substitution of the iodine atom was mled out because the anilides PhNHCOC=CR do not react with NaTeH under the conditions at which the heterocycles 57 were obtained. Neither of the adducts PhNHCOCH=C(R)TeH or [PhNHCOCH=C(R)Te]2 was isolated. 

Like the three-coordinate aluminum and gallium alkoxides, the corresponding thiolates, selenolates, and tellurolates require very bulky substituents at the chalcogen atom to ensure a low metal coordination number. In addition, the steric requirements associated with the preservation of the low coordination number at the metal are increased by the longer M—S and M—Se bond lengths. The ten examples of low-coordinate,... 

Metal-Sulfur, -Selenium, and -Tellurium Bond Lengths, M—E—C Angles, and Torsion Angles for Three-Coordinate Aluminum, Gallium, and Indium Thiolates, Selenolates and Tellurolates", and Related Compounds... 

Far less abundant are selenolate or tellurolate silver(I) complexes. The reaction of AgN03 with (DME)LiSeC(TMS) yields the compound [Ag SeC(TMS)3 ]4 (142).1003 The tellurolate complex (Ph4P)2[Ag4[Pg.962]

Mixed silver telluride-tellurolate complexes have been prepared in a similar manner to those of selenium. The reactions of a silver salt with RTeTMS in the presence of phosphines as stabilizing agents are reported in Scheme 9 1043-1046... 

Zinc telluride and zinc selenide polymetallic species with phosphine ligands have been structurally characterized 301 further details are discussed in Section 6.8.7. The use of mono- and bidentate phosphine ligands of varying steric bulk contributes to the variation of structural types in the formation of zinc tellurolate polyzinc species with Zn10, Zn14, and Zn16 species structurally characterized by Fenske et al.30... 

The aim of this chapter is to review the chemistry of chalcogenolates in the last 10 years. The more recent reviews in this field included chalcogenolates of the s-block elements,13,14 early transition metal thiolates,15 metal complexes with selenolate and tellurolate ligands,16 copper(I), lithium and magnesium thiolates,17 functionalized thiolate complexes,18 19 pentafluorobenzenethiolate platinum group compounds,20 tellurium derivatives,21 luminescent gold compounds,22 and complexes with lanthanide or actinide.23... 

The starting material is always the chalcogenol and, consequently, is more used for thiols than selenols and tellurols. There are several types of reactions depending if the starting materials are metal hydrides (hydrogen elimination), complexes with M C (alkane elimination), M-N (transamination), or M-O (hydrolysis) bonds. 

The oxidative addition reaction of the type shown in Equation (9) were used to prepare some of the first selenolate and tellurolate complexes still used today. 

The chemistry of alkaline-earth chacogenolates have been developed from the nineties with the structural characterization of the first magnesium thiolate in 1990,69 magnesium and calcium tellurolates in 1992,70,71 and the first magnesium and strontium selenolates in 1994.72... 

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