Bridging chalcogenides

The complexes [E Au2(/r-dppf) ] (E = S, Se) also serves as building blocks for preparing polynuclear triply bridging chalcogenide complexes such as (510).2893, 94 The crystal structure of [ S(Au2PPh3)2 2Au][SnMe3Cl] (511) has been reported.2902... 

Figure 1.41 Polynuclear gold(I) complexes with bridging chalcogenide ligands.

The bridging chalcogenides [(Me5C5)2Yb]2( X-E), in which E = S,Se,Te, can be obtained from the reaction of permethylated ytterbocene with R3PE (E = S,Se,Te), AS2S3, COS or directly with an excess of selenium or tellurium metal in hexane [14]. 

The oxide (p. 1209), chalcogenides (p. 1210) and halides (p. 1211) have already been described. Of them, the only ionic compound is HgF2 but other compounds in which there is appreciable charge separation are the hydrated salts of strong oxoacids, e.g. the nitrate, perchlorate, and sulfate. In aqueous solution such salts are extensively hydrolysed (HgO is only very weakly basic) and they require acidification to prevent the formation of polynuclear hydroxo-bridged species or the precipitation of basic salts such as Hg(OH)(N03) which contains infinite zigzag chains ... 

Mix bridging, 15 545 Mixed-alkali effect (MAE), 12 586-587 Mixed bauxites, 2 347 Mixed-bed columns, 14 405, 407 in ion exchange, 14 404 Mixed-bed resins, 14 412 Mixed chalcogenides, 12 359 Mixed formulation fertilizers, 11 123 Mixed-integer linear programming (MILP), 20 748 26 1023... 

Figure 2.30 Heterometallic complexes with chalcogenide bridging ligands.

In a similar vein, it was shown that molybdenum amido derivatives of the isolobal terminal phosphide and carbide, " and related chalcogenide atoms,could be obtained. Detailed mechanistic studies of the Mo N(R)Ar 3/N2 system involving X-ray, EXAFS, magnetic, Raman, and isotopicaUy labelled NMR spectroscopy showed that the reaction proceeded through an intermediate involving an end-on bound N2 bridging the molybdenum centres (Scheme... 

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