Conformational analysis of 1-chloro-4-iodobutane and 1-chloro-5-iodopentane

Infrared spectra were obtained for Cl(CH₂)₄I and Cl(CH₂)₅I in the liquid and solid states. Zero-order normal coordinate calculations were made for the five conformers of each compound that have all the carbon atoms coplanar. Comparison of the observed and calculated wavenumbers led to the conclusion that all five conformers of Cl(CH₂)₄I are present in the liquid and solid states. For Cl(CH₂)₅I, the TT, TG and GT conformers are present in the liquid state. No evidence was obtained that indicated either the presence or absence of the GG and GG' conformers. Only the TT conformer is present in the solid. Vibrational assignments were made for both compounds.