Halides diorgano

These reductions were carried out in the presence of an alkyl halide that reacted with the sodium tellurolate. The expected unsymmetrical diorgano tellurium derivatives were isolated. 

These compounds are liquids or low melting solids with characteristic foul and persistent odors. They can be stored under an inert atmosphere in the refrigerator for long periods without decomposition. At 20° they decompose slowly to diorgano ditellurium derivatives while in air, tellurium is deposited. Protic agents such as water, hydrogen halides, and alcohols cleave the tellurium-group TV element bond. 

The complexes formed from diorgano ditellurium compounds and copper(I) halides in ethanol/acetonitrile are postulated to have intact Te-Te bonds1,3,4. 

Organo tellurium halides, also named organo tellurenyl halides, are in principle easily accessible through controlled halogenolysis of diorgano ditellurium compounds. However, 2-naphthyl tellurium iodide, prepared in 19592 from bis[2-naphthyl] ditellurium and iodine, remained the only compound of this type until 1971/72, when a series of ortho-carbonyl substituted phenyl tellurium halides were synthesized3-4. Aryl tellurium halides without substituents in the ortho-position to tellurium were isolated and characterized in 1975s. 

Elemental chlorine, bromine, and iodine, sulfuryl chloride and thionyl chloride convert diorgano ditellurium compounds to organo tellurium trihalides (p. 314). The reactions are carried out in inert organic solvents with stoichiometrically required amounts of reagents. Dialkyl ditellurium compounds may lose alkyl halides if the halogenolysis is not performed under mild conditions at low temperatures. When equimolar amounts of halogens and diaryl ditellurium derivatives are combined in appropriate solvents, aryl tellurium halides are formed (p. 239). The formation of aryl tellurium halides is facilitated by stabilizing substituents in the orf/to-position to the tellurium atom or by the presence of thioureas or selenoureas in the reaction mixture. 

Organo magnesium halides and organo lithium compounds are readily accessible alkylation and arylation reagents. However, they have little practical importance for the preparation of diorgano tellurium derivatives. Tellurium tetrachloride cannot be alkylated or arylated stepwise to give, for instance, diorgano tellurium dihalides, which could... 

Table 10 Unsymmetrical Diorgano Tellurium Compounds from Tellurolates and Alkyl Halides... 

Dialkyl cadmium was employed to convert ort/io-substituted phenyl tellurium halides to unsymmetrical diorgano tellurium products. These conversions were accomplished without affecting the carbonyl groups present in the molecules. 

This sequence of reactions transfers the alkyl group of a carboxylic acid to the tellurium atoms of a diaryl ditellurium. Because many carboxylic acids are commercially available at prices much lower than the corresponding alkyl halides, this reaction is a very useful alternative route to unsymmetrical diorgano tellurium compounds. 

Reaction of Diorgano Tellurium Dihalides with Sodium Sulfide General Procedure A 15-fold molar excess of sodium sulfide nonahydrate is mixed with the diorgano tellurium di halide and the mixture is heated at 90-95° on a boiling water bath. When the mixture has become liquid, it is stirred for an additional 10 min. and then cooled. Water is added to dissolve the sulfide and the mixture is filtered to collect the solid diorgano tellurium product. Liquid diorgano tellurium products are extracted into petroleum ether. Products are purified by recrystallization or distillation. 

Complexes of the following elements with dialkyl and/or diaryl telluriums have been prepared B, Ga, Sn, V, Ta, Cr, Mo, Mn, Re, Fe, Ru, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Cd, and Hg. Examples of coordination compounds with diorgano telluriums as ligands are given in Table 14 (p. 489). The adducts of mercury(II) halides with diorgano telluriums were used in ihe older literature to separate diorgano telluriums from reaction mixtures (Vol. IX, p. 1057). 

To Diorgano Tellurium Dihalides/Pseudo halides/ Carboxylates... 

Ethynyl phenyl telluriums, obtained from ethynyl lithiums and phenyl tellurium halide, are carboxylated in methanol in the presence of triethylamine and palladium(II) chloride to methyl ethynylcarboxylates5. 1,4-Diorgano-1,3-butadiynes are by-products in these reactions. 

Hydrazine, that generally reduces diorgano tellurium di halides in refluxing ethanol to diorgano telluriums (p. 430), does not react with the TeCl2 group of dibenzoyl tellurium dichlorides at 20°. 

Diorgano tellurium dihalides, when refluxed with silver fluoride in toluene, tetrahydro-furan, or acetone, precipitate silver halides. The diorgano tellurium difluorides crystallize upon cooling the filtrate of the reaction mixture or evaporating the filtrate under vacuum. 

Diorgano tellurium dihalides form complexes with iodine and interhalogen compounds organic compounds with N, P, O, S, and Se donor atoms boron, aluminum, and gallium trihalides antimony pentachloride and mercury(II) halides. 

The tendency to replace halide by hydroxide decreases in diorgano tellurium dihalides from chlorine to iodine. In cold or boiling water the dichlorides are converted to diorgano... 

The reactions of alkali metal, ammonium, phosphonium, or arsonium halides with diorgano tellurium dihalides produce diorganotrihalotellurates or diorgano tetra-halotellurates1,2 (page 668). 

The reaction of bis[trifluoromethyl] tellurium with chlorine fluoride at — 78° with fluorotrichloromethane as solvent first produced his[trifluoromethyl] tellurium chloride fluoride. When the reaction mixture was concentrated, the l9F-NMR signal of the chloride fluoride disappeared and was replaced by signals for bis[trifluoromethyl] tellurium difluoride and bis[trifluoromethyl] tellurium dichloride2. The diorgano tellurium dihalides reported in the literature as mixed dihalides might be mixtures of symmetrical dihalides. All mixed halide species were identified by 125Te- and 19F-NMR spectroscopy in dimethylformamide solutions prepared from equimolar amounts of two different tellurium dihalides3. 

Diorgano tellurium hydroxide halides with chloride1 4 bromide3,5"6, or iodide4,6> 7 as the halogen are known. 

Diorgano Tellurium Carboxylate Halides/Oximate Chlorides... 

Bisfdiorgano tellurium halide] oxides are the anhydrides of diorgano tellurium hydroxide halides. Aryl derivatives can be obtained by heating diaryl tellurium halide hydroxides to 150-180°3... 

Whether hydrolytic reactions of diorgano tellurium halides produce diorgano tellurium hydroxide halides or their anhydrides might be governed by the solubility of the anhydride, which is influenced by the halide. Treatment of the solutions obtained by boiling mixtures of diaryl tellurium dichlorides and water or treatment of aqueous solutions of diaryl tellurium hydroxide chlorides with potassium bromide1 or potassium iodide1 3 formed bis[diaryl tellurium halide] oxides. 

Diorgano tellurium dithiocarbamate halides are isolated in quantitative yield from reaction mixtures containing equimolar amounts of a diorgano tellurium dihalide and an ammonium or sodium dithiocarbamate1,2. 

As the bonding arrangement of cyanate and isocyanate groups to tellurium is not known (see p. 617), diorgano tellurium halide cyanates, isocyanates, thiocyanates, and isothiocyanates are treated together on the basis of formal tellurium-nitrogen bonding. 

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