Molybdenum 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. 

Hexanuclear Clusters of six molybdenum, niobium, or tantalum atoms have been known for many... 

Hexanuclear Clusters Clusters of six molybdenum, niobium, or tantalum atoms have been known for many years, predating the work with rhenium. There two types In the first, an octahedron of six metal atoms is coordinated by eight chloride ligands, one on each face of the octahedron. This is found in molybdenum dichloride, Mo6C112, better formulated as [Mo6C18]C14. Each Mo (II) atom can use its four electrons to form four bonds with adjacent molybdenum atoms and can receive dative bonds from the four chloride ligands. 

The hexanuclear molybdenum halide clusters (Mo6Xs)X4, i.e. (Mo6X 8)CP2CF 4/2, are known to react with some transition metal halide compounds forming two different types of cluster polymeric clusters with bridging outer halide ligands (X ) and discrete clusters with terminal halide ligands (X ). 

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). 

High-Valence Metal Clusters. Structural properties of selected hexanuclear high-valence cluster complexes are described in Table 2.5. A series of molybdenum and tantalum derivatives of type [(M6Y8)X6] and [(M6Ys)L8] (M = Mo or W X = halide or alkoxide Y = halide or other monovalent anion and L = neutral Lewis-base) are known. The structures of these species are like that of the anion [(Mo6Cl8)Cl6] illustrated in Fig. 2.19 in which the molybdenum atoms are in the vertex of an octahedron. Metal-metal distances of about... 

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. 

Spin Sublevels of the Hexanuclear Molybdenum(ll) Chloride Cluster... 

As an example of the spin sublevels of metal cluster, we here discuss the hexanuclear molybdenum(II) chloride cluster in, [Mo5Cli4] As is shown in Fig. 15, the cluster is composed of six (Mo(II) ions and the point group is 0/,. Since the cluster has 48 d-electrons a theoretical treatment of the spin sublevels appears quite formidable. However, because of the high symmetry, the theoretical treatment can be simplified by the proper use of group theory. In the following, we briefly review the theory developed by Azumi and Saito [40] together with the experiments carried out by Saito et al. [41] and Miki et al. [42]. 

Fig. 16. Schematic representation of the spin sublevels associated with the lowest triplet state, T , of the hexanuclear molybdenum cluster ion, [MojCliJ ...

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