Structure of hexanuclear

C0gC(C0)i5 14), one case of a bicapped rhombus in Mo2Ni4(CO)i4 " 333), and one case of a bicapped tetrahedron in OSg(CO)jg [72] 284). The reasons for certain structures of hexanuclear clusters have been discussed in terms of several bonding approaches and will be treated in Chapter 2.3. 

The structure of the hexanuclear oxovanadium(IV) anion [(VO)6(CO)4(OH)9]5 (86) is highly reminiscent of the structure of the P4Mo6Eg anions with four C03 groups replacing the four phosphato groups. The connecting scheme is of type 5. The nine oxo bridges are protonated. 

Dithiocarbamates have been used as ligands for a long time. Recently the structure of [Ag(S2CNEt2)]6 has been reported and the compound is hexanuclear.1212 Complexes of the type... 

In compliance with the nuclearity principle, polynuclear clusters are subdivided into a number of other subgroups, e.g. hexanuclear, octanuclear, etc. The binuclear clusters of technetium may be classified according to the electronic structure of their Tc-Tc2 bonds. Then, the d4-d4 complexes with quadruple M-M bonds are the father of all binuclear complexes with Tc-Tc bonds. The addition or removal of electrons from Tc-Tc bonds [1,11] should result in a decrease in the formal multiplicity of M-M bonds. Thus, for instance, the formal multiplicity of Tc-Tc bonds of d3-d3 and d5-d5 binuclear complexes equals3 3, that of d4 d5 and d4-d3 complexes equals 3.5, etc. 

Figure 24 Structure of the cyclic hexanuclear species HC[C(But)NAr ]2Mg(C3H5) e (Ar = 2,6-diisoprophylphenyl) 48.

Figure 10.79 X-ray molecular structures of cyclic helicates (a) pentanuclear species formed from 10.124 and templated by Cl 87 (b) hexanuclear species formed from 10.126 and templated by C104 (reproduced by permission of The Royal Society of Chemistry).

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