Clusters, metal main group

Dinuclear Pt complexes of the type [ Pt(PR3) 2(p-S)2] are also known to serve as the good precursors to the trinuclear clusters. A series of triangular cluster cores M Pt2(p3-S)2 has been constructed therefrom (M = transition metals, main-group metals).50... 

Between the simple metal-main group atom interactions discussed above and clusters discussed below one finds systems in which the main group fragment can be considered a polyhapto ligand. Although the... 

Boron Hydrides Boron Inorganic Chemistry Boron Organoboranes Boron Polyhedral Carboranes Cluster Compounds Inorganometalhc Compounds Containing Transition Metal Main Group Elements Electronic Structure of Main-group Compounds. 

Cluster Compounds Inorganometallic Compounds Containing Transition Metal Main Group Elements Polynuclear Organometallic Cluster Complexes. 

Mixed transition metal-main group element clusters are ultimately related to either homonuclear metal or main group element clusters. Although there are similarities between the bonding within these two limiting types of clusters, there are also significant differences, ft is these differences in the mixed... 

CLUSTER COMPOUNDS CONTAINING TRANSITION METAL MAIN GROUP ELEMENTS... 

Variation of the Transition Metal/Main Group Element Ratio in a Cluster Environment... 

For completeness, it is necessary to briefly mention a popular competing view of a transition metal-main group element cluster. This description will certainly be encountered if the topic is pursued in the literature and, indeed, has already been mentioned in Section 2.2.1. The main group element fragment can be viewed as a ligand, albeit often an exotic one, coordinated to the transition metal center or centers." ... 

In transition metal-main group element clusters, there is the possibility of ligand substitution at either type of element center. Displacement of an exo-cluster ligand on one of the metal centers (equation 10) is to be expected (see Mechanisms of Reaction of Organometallic Complexes) However, displacement at a main group cluster site has also been observed (equation 11 ). Indeed, phosphine substitution takes place exclusively at the boron atom, and the osmium-substituted BCO complex can only be prepared by synthesizing it from the phosphine-substituted osmium carbonyl starting material. 

It is interesting to note that the base displaced need not be a simple one, that is, dihydrogen is exclusively displaced from [HFe3(CO)9(/u-H)2BH] (equation 10). Indeed, a comparison of equations (10) and (11) demonstrates that cluster composition is important in determining the outcome of a Lewis base displacement reaction on a transition metal-main group element cluster. This implies that control of electronic structure via cluster element composition is a viable means of controlling reactivity. 

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