Tellurium coordination compounds

Ligands Other than Oxygen and Sulfur. See Sec. 3.1.7, Coordination Compounds, for acids containing ligands other than oxygen and sulfur (selenium and tellurium). 

Intramolecular chalcogen interactions may also stabilize reactive functional groups enabling the isolation of otherwise unstable species or their use as transient intermediates, especially in the case of selenium and tellurium. For example, tellurium(II) compounds of the type ArTeCl are unstable with respect to disproportionation in the absence of such interactions. The diazene derivative 15.23 is stabilized by a Te N interaction. Presumably, intramolecular coordination hinders the disproportionation process. Other derivatives of the type RTeX that are stabilized by a Te N interaction include 8-(dimethylamino)-l-(naphthyl)tellurium bromide, 2-(bromotelluro)-A-(p-tolyl)benzylamine, and 2-[(dimethylammo)methyl]phenyltellunum iodide. Intramolecular donation from a nitrogen donor can also be used to stabilize the Se-I functionality in related compounds." ... 

Complexes of both selenium(IV) and tellurium(IV) with sulfur-containing ligands are known although the structural properties appear to have been determined only for the tellurium(IV) species. However, due to the smaller size of selenium(IV) and its poorer acceptor properties, as compared with tellurium(IV), its maximum coordination number appears to be six whilst it has been found to be eight for tellurium.78 Furthermore, the greater tendency of tellurium to form secondary bonds may cause the structures of similar selenium(IV) and tellurium(IV) compounds to be different. 9 It is also pertinent to note that the reduction of tellurium(IV) to... 

Tellurium derivatives of inorganic nature, such as tellurium dihalides, that form coordination compounds with organic ligands, such as thiourea and ethylenethiourea, are not included in this section. 

The interest in coordination compounds containing transition metal-main group element bonds led to the preparation of tellurium derivatives, in which a bare tellurium atom is bonded to and bridges transition metal atoms such as Zr, Ilf, V, Cr, Mo, W, Mn, Re, Fe, Os, Co,... 

The P —Te and As —Te bonds were not attacked by water5,6 or methanol5. Trimethyl-stannane similarly cleaved the group V element-tellurium bonds in these compounds5 and in their coordination compounds with chromium and molybdenum carbonyls7. 

Coordination compounds of aryl tellurium thiocyanates with nitrogen, oxygen, or sulfur donors are described in the section on Tellurenic Acids. 

Halocarbonylmanganese4 and halocarbonylrhenium complexes5 reacted with diphenyl ditellurium. The resulting tellurium-containing coordination compounds had intact bridging diphenyl ditellurium moieties and no benzenetellurolate ligands. 

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). 

Tab. 14 Coordination Compounds with Diorgano Tellurium Compounds as Ligand... 

Diphenyl tellurium oxide and metal halides reacted in ethanol at 5° to produce coordination compounds with two or three diphenyl tellurium oxide ligands per metal atom. The complexes were recrystallized from ethanol5. 

Only after the publication of CCC (1987) were well-characterized coordination compounds of the. s-block elements containing bonds to Se or Te described. As a rule selenium or tellurium donor... 

Sulfur, selenium, and tellurium are all capable of forming six-coordinate compounds such as SEg. Give two reasons why oxygen cannot be the central atom in such six-coordinate molecules. 

Tellurium, tris(diethyldithiocarbamato)phenyl-stereochemistry, 82 Tellurium(II) complexes bis(dithiochelatc), 60 six-coordinate compounds structure, 53... 

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