Molybdenum sulfur-bond cleavages

While all of the transformations detailed above take place at low-valent metal centers, a double sulfur-carbon bond cleavage process has also been postulated to occur at the molybdenum(VI) center (527, 528, 839). Thus, thermolysis of organic isocyanates with [Mo02(S2CNR2)2] affords imido-disulfide complexes, [Mo(NR )(S2)(S2CNR2)2] (Fig. 289), in moderate yields. The fate of the aminocarbyne fragment remains unknown and further, since monosulfido... 

Figure 295. Reversible carbon-sulfur bond formation and cleavage at a molybdenum center together with the irreversible formation of a thiocarboxamide complex.

The promotion effect of the CoMoS site appears to occur through increased hydrogen activation, which facilitates removal of sulfur atoms after cleavage of C-S bonds on exposed molybdenum ions/ Cobalt incorporated into the support may also act as a structural promoter by enhancing dispersion of the sulfided species. ... 

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