A Structural Study of Ethylbenzene and a Conformational Study of N-Propylbenzene and n-Butylbenzene
B Mate, R D. Suenram, C Lugez
The rotational spectra of ethyl, n-propyl and n-butylbenzene have been observed and analyzed using a high-resolution Fourier transform microwave spectrometer. Only one stable conformation was found for ethylbenzene, in agreement with previous results from Caminati et al. [Molecular Physics 74(4), 885-895 (1991)]. The high sensitivity of the technique allows observation of the rotational spectra of the six 13C isotopes of ethylbenzene in natural abundance. The structural analysis indicates that the dihedral angle between the ethyl group and the ring plane is 88.7 0.9 . Two conformers have been found for the n-propylbenzene as predicted by ab initio calculations. Four conformers of the five theoretically predicted conformers [Dickinson et al., J. Chem. Soc. Faraday Trans. 93(8), 1467-1472 (1997)] have been found for n-butylbenzene.