Tungsten complexes hexanuclear clusters

A few cluster complexes with fused triangles of molybdenum or tungsten have been reported. They are tetranuclear and hexanuclear cluster complexes, which may be viewed also as having fused incomplete cu-banes of M3E4. 

The lower nuclearity clusters [Mo5Cl13]2 were isolated from MoCls in AlCl3/KCl/BiCl3/Bi melts that led to the hexanuclear species (17). This is the only intermediate isolated from reaction mixture that produces the Mo6C18 4+ core. Solution chemistry has yielded Mo2, Mo3, and Mo4 halide species from mononuclear molybdenum complexes, suggesting that a nucleation process similar to that proposed for the tungsten systems may take place during the formation of hexanuclear molybdenum clusters (18-22). 

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