Knowledge Bank

The infrared spectra of 1,3-dideutero allene in the vapour phase and Raman spectra of the neat liquid were obtained. The fundamental frequencies were assigned and the force field for allene calculated using $allene-do,allene-1,1,-d2,allene-d4,allene-d1$, and $allene-1,3-d2$. For several substituted allenes we have measured the VCD in the C-H stretching, C$=C=C$ assymetric stretching and bending regions. For the simplest substituted, chiral, 1-methyl, 3-haloallenes wer have calculated the dipolar and rotational strengths using both an empirical transfered force field and a semi-empirical CNDO/2 force field, with the FPC and LMO models of VCD. The data indicates a qualitative agreement between theory and experiment for non overlapping bonds.