| Abstract: | Concentrated solutions of poly(n-octyl isocyanide) exhibit a mesomorphic structure, most probably nematic in nature. Poly(n-butyl isocyanide) and poly(benzyl isocyanide), of the molecular weights at our disposal, failed to show similar behavior. Upon acidification poly(n-butyl isocyanide) does not change, but the other two polymers turn essentially black. Infrared and proton NMR clearly demonstrate that upon acidification, poly(n-butyl isocyanide) and poly(benzyl isocyanide) are protonated on the nitrogen atom. This process is reversible. Carbon-13 NMR and x-ray patterns indicate that no chemical rearrangement or conformational changes take place upon acidification. This conclusion is supported by infrared studies and by inference from the poor electrical conductivity of the solid acidified polymers. |
