Tungsten 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. 

Jackson, J. A. Turro, C. Newsham, M. D. Nocera, D. G., Oxygen quenching of electronically excited hexanuclear molybdenum and tungsten halide clusters, J. Phys. Chem. 94 (1990) 4500-4507. 

Pd4(H)3( i-dppm)4] + was generated chemically and electrochemically from [Pd4(H)3( i-dppm)4] + and shown to be electrocatalytically active for both H2 evolution from carboxylic acids and decomposition/oxidation of formate. Hexanuclear clusters [M2Pd4( i3-S)2(p-S)4( i-dppm)2(S)2] (M = Mo, W) were prepared from [PdCl2(dppm)] and [MS4] Z-scan data revealed the tungsten cluster to have considerable self-defocusing properties. ... 

Inner-Transition Metal to Transition and Inner-Transition Metai Bond 83 9.2.9. Formation of Heavy Transition Metal Group VI Metal-Metal Bonds 9.2.9.8. Syntheses of Hexanuclear Molybdenum and Tungsten Clusters... 

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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