The carbon-hydrogen stretching region of the Raman spectra of 1,6-hexanediamine: N-deuteration, ionisation and temperature effects

The Fermi resonance interaction between the methylene symmetric C-H stretching mode and appropriate binary combinations involving the methylene bending mode in the Raman spectra of polyamines, namely in 1,6-hexanediamine derivatives, under different conditions of deuteration and ionisation of the head amino groups and varying temperature has been analysed. The tentative assignment of the observed bands in the C-H stretching region of the registered Raman spectra is reported and the ratio of the Raman intensities of the symmetric stretching to the antisymmetric fundamentals is considered in its possible relation to the order/disorder of the skeletal hydrocarbon chains, from the all-trans prevailing geometry in the solid state at lower temperatures to the increasing amount of gauche arrangements on heating and melting. (C) 2002 Elsevier Science B.V. All rights reserved.