RAMAN-SPECTROSCOPIC STUDY OF THE MOLECULAR-CONFORMATION OF ALPHA-OCTYL-OMEGA-METHOXYOLIGO(OXYETHYLENE)S IN THE SOLID-STATE

The Raman spectra of alpha-octyl-omega-methoxyoligo(oxyethylene)s, CH3(CH2)7(OCH2CH2)mOCH3 (m = 1-4), were measured in the solid state. The molecular conformation of these compounds was determined by a spectral analysis based on the key conformational bands. The conformation of the inner oxyethylene segments changes from an extended structure to a helical structure as the number of oxyethylene units increases. The difference in the conformational behaviour between the present methoxy-ended compounds and the corresponding hydroxy-ended compounds is associated with the different layer structures of the crystals.