Double bonds linked by C and Si, Ge or Sn atoms

Examples of such reactions are shown in Table 8.3. The fact that dimethyldivi-nylsilane will not undergo self-metathesis, while it can be cross-metathesized with deca-1,9-diene, indicates that the propagation reaction (7) is prohibited, but that 

Mainly dimer Finkel shtein 1981 28% cyclic Bespalova 1990 

Dimethyldiallylsilane is a good example of a reaction in which there is a very delicate balance between the intramolecular and intermolecular processes. The balance may be swung either way by adjusting the substrate concentration. Even more remarkable is the formation of all three cyclic dimers (cc, ct, and it) at an overall concentration which exceeds that of the residual cyclic monomeric species. 

The C NMR spectrum of one of these polymers, shown in Fig. 8.2, illustrates the very clean nature of the ADMET reaction. 

---