The characterization of polysilanes by carbon-13, silicon-29, and proton NMR.

The (1)H, (13)C, and (29)Si NMR spectra of four polydialkylsilanes are reported in detail for the first time. The polymers, prepared by reaction of the dialkyldichlorosilane with sodium metal, are of high molecular weight (>10(6)) and relatively low polydispersity (1.5). They are: poly(methyl n-propylsilane), poly(methyl n-hexylsilane), poly(methyl n-dodecylsilane), and poly(di-n- hexylsilane). Except for the last, these polymers have pseudoasymmetric silicon atoms and exhibit the expected configurational sequencies. The silicon resonances and the carbon and proton resonances of groups directly bonded to silicon show the greatest sensitivity to tacticity, and their spectra show that the chains are random with a Bernoullian distribution of "odd-ad" sequences. The chlorine removal process thus shows no stereochemical preference.