Clusters telluride

The semiconductor-like rhenium telluride phase Re2Tes has been characterized by X-ray crystallography and shown to possess the usual octahedral Re6 core (r(Re—Re) = 2.67-2.72 A) within the structure [Re5Te8]Te5 Te, in which the [Re6Te8] clusters are linked via butterfly-like [Te Te —Te—Te 2] units.202... 

On the other hand, polytellurides only seem to oxidize metals to the +1 or +11 state. Reaction of equimolar amounts of Te4 with M(CO)6 results in disubstitution of CO forming a cu-complex (CO)4MTe4 (M = Cr (45), W (47)47). If an excess of metal carbonyl is used in the presence of poly-telluride anion, multinuclear products can be isolated and metal-metal bonds can also form, leading to clusters. Careful manipulation of reaction conditions and choice of the polychalcogenide anion used makes possible partial oxidation of the metal centers and cluster formation. The reaction of iron carbonyls with polytelluride anions can lead to a wide array of cluster compounds, the identities of which are controlled by the stoichiometries and compositions of the starting telluride anions. For instance, reaction of [Fe(CO)5] with Te2 leads to the formation of [Fe3(CO)9(ju.3-Te)]2 (48),48 whereas its reaction with increasing amounts... 

The use of a more reduced telluride solution, namely, that of nominal composition Te2 with Cr(CO)6, yields an unusual cluster, [ Cr(CO)5 4Te2]2 (61) (Fig. 17), as the sole product, isolable as its (PPh4)+ salt. The tungsten and molybdenum analogs of this compound are not formed. The structure of the 61 dianion consists of a Te2 chain that is attached to four Cr(CO)5 groups, two on each tellurium atom. 

Unlike the copper telluride clusters, it has not yet proven possible to generate large silver telluride cluster complexes using a combination of R3P, Ag-X and Te(SiMe3)2. This suggests that the phosphine ligands are unable to kinetically... 

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