Polychalcogenide anions

Only species Te 2- with short chains (n = 2-4) are present in polytelluride solutions [57]. Despite this fact many Zintl-type valence precise tellurium dianions of higher nuclearity have been isolated in the solid state in the presence of suitable counter cations. The three general synthetic routes to such polytelluride anions can be summarized with representative examples as follows  

More details on the preparation and structures of these valence precise dianions are given in a recent review article by Smith and Ibers [10]. 

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Evain M, Brec R (1992) A New Approach to Structural Description of Complex Polyhedra Containing Polychalcogenide Anions. 79 277-306... 

Several approaches have been used for the synthesis of metal carbonyl polychalcogenide anions.28-31... 

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... 

Hydro(solvo) thermal technique, synthesis of metal-carbonyl polychalcogenide anions, 250-252... 

A New Approach to Structural Description of Complex Polyhedra Containing Polychalcogenide Anions... 

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