Supersonic jet studies of ethoxybenzenes: geometry of their minimum energy conformations
作者:E. R. Bernstein、Hoong Sun Im、Mark A. Young、Henry V. Secor、Ronald L. Bassfield、Jeffrey I. Seeman
DOI:10.1021/jo00021a019
日期:1991.10
Supersonic jet mass resolved excitation spectroscopy and MOPAC 5/AM1 calculations are employed to demonstrate that the minimum energy conformation of ethoxybenzene and a number of its ortho-unsubstituted (i.e., sterically unhindered) derivatives is the planar form for which tau-1(C(ortho)-C(ipso)-O-C-beta) = 0-degrees and tau-2(C(ipso)-O-C-beta-C-gamma) = 180-degrees. For 1-ethoxy-3-methylbenzene, two spectroscopic origin transitions are observed, one each for the conformations in which the C-beta-H2-C-gamma-H3 fragment is syn and anti to the C(3)-methyl substituent. For 1-ethoxy-4-ethylbenzene, a single origin transition is observed, as demonstrated by examination of two deuteriated derivatives.