Cluster core geometry

Complex Ag-AglA Ag-CIA 6=67 A Cluster-core geometry References... 

Cobalt offers many possibilities of cluster-core-geometry, but the chemistry of cobalt clusters is limited, again due to the weakness of first row metal-metal bonds and their susceptibihty to nucleophilic cleavage. Only in case of the methinyl tricobalt enneacarbonyls has a singular chemistry been developed, and therefore these compounds will be treated under a separate heading. 

Figure 13. The cluster core geometry of [H2RU8(/.6->/"-CO)(CO)i9( 7 -Ci6H,6)].

Figure 110. Cluster core geometries in [Mo3( 4 -E)(E2)3(S2CNR2)3] cations.

This disilaborane was an unexpected co-product in the synthesis of decaborane-alkylamine polymers. The Si2Bio cluster core consists of a distorted icosahedron in which the two silicon atoms occupy adjacent positions. The Si-Si interatomic distance is 2.308(2) A, which is slightly less than the Si-Si distance in organodisilanes (2.35 A) and the Si-B distances [2.017(3) to 2.116(3) A] are very close to the sum of the covalent radii of the two atoms (2.07 A). Further derivatives with disilaborane cluster geometry are known for the phenyl substituted compounds l,2-Ph2-doso-l,2-Si2B1oH1o and l-Me-2-Ph-doso-l,2-Si2BioHi0 [6, 7]. In addition to these disila-doso-dodecaborane clusters one example with two different group 14 elements as a part of the cluster core is known. In Scheme 3.3-2 the synthesis of this sila-stanna-doso-dodecaborate is shown. The structure of this heteroborate was determined in the solid state and the Si-Sn distance is 2.608(4) A (Scheme 3.3-2) [8]. 

To overcome this disorder, the same synthetic procedure was used with the substituted cyclopentadienyl compounds bis(terr-butylcyclopentadienyl)zinc and bis[(trimethylsilyl) cyclopentadienyljzinc. Indeed, the corresponding Zn4Ni2 clusters were formed, in which the geometry of the central cluster core and the bonding of the cyclopentadienyl groups... 

H2S04. This cluster has a trigonal-bipyramidal core geometry with the two bismuth atoms in apical positions in other work, Johnson and Lewis have described the synthesis and structure of the ruthenium analogue, 127, which... 

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