Tungsten xanthate structures

The three reported tungsten xanthate structures have as their common feature the presence of W—C bonds, and therefore are properly classed as... 

This section describes the structural chemistry of 14 molecular structures, 3 of chromium, 8 of molybdenum, and 3 of tungsten. The only binary xanthate structures are those of chromium, all other structures are at least ternary in nature. For the chromium and tungsten structures, conventional monodent-ate and bidentate coordination modes of the xanthate ligand are found. By contrast, a rich, diverse, and fascinating coordination range is observed for the... 

Although Mo (II) and W(II) exhibit the most extensive seven-coordinate chemistry yet known (consistent with the application of the effective atomic number rule to these systems), a survey of the substituted metal carbonyl complexes of molybdenum and tungsten reveals no structural data for compounds of the type M(00)3(6-6)2 where 6-6 is a bidentate monoanionic ligand. No tungsten tricarbonyls of this type have been reported to date, but McDonald and co-workers have synthesized and studied the closely related W(CO)2(PPh3) (6-6)2 compounds where 6-6 is a chelating dithiocarbamate (7), xanthate, or dithiophos-phate (8). For molybdenum, the compounds Mo(CO)3(dtc)2(dtc = R2NCS2") (9) are examples of the M(CO)3(6-6)2 type as is Mo(CO)3-[S2P(i-Pr)2]2 (10), which has been well characterized in solution. 

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