Metalation group 14 element organic halides

Metallo-organics are compounds in which the atom of an element is bound to one or more carbon atoms of an organic hydrocarbon group. Many of the elements used in MOCVD are the metals of groups Ila, Ilb, Illb, IVb, Vb, and VIb, which are non-transitional. The metallo-organics thus complement the halides and carbonyls, which are the precursors for the deposition of transition metals (Groups IVa, Va, and Via) and their compounds. 

The reaction of organic halides with metallic group 14 elements (eq (4))... 

Fig. 3.10. Types of (/i3-E)M3 units. E = main group element, M = transition metals, and R = halide or organic radical...

Figures 6 and 7 show that the main driving force for these reactions is, in general, the strongly exothermic formation of the metal halide. This is particularly striking for the Group IIB elements Zn, Cd and Hg, where the methyls are in each case endothermic compounds. Although Cd and Hg react directly with methyl iodide only in the presence of light, which initiates homolytic dissociation of the organic halide into -CHs and T, zinc as zinc/copper couple reacts readily to yield methylzinc iodide.

It is well known from extensive electron-spin resonance (ESR) studies [4-6] that organic halides in conjunction with an organometallic derivative of a transition element of groups VIA, VILA, and VIII, with the metal in a low... 

---