Effects of aryl and arylethynyl substituents at the 1-position on rotational barrier around C(sp)–C(sp3) bonds and bending deformation of acetylenic carbons in bis(9-triptycyl)ethynes
作者:Shinji Toyota、Takao Yamamori、Toshiaki Makino
DOI:10.1016/s0040-4020(01)00232-0
日期:2001.4
The barriers to rotation around C(sp)–C(sp3) single bonds in (1,4-dimethyl-9-triptycyl)(1-X-9-triptycyl)ethynes [X=phenyl, mesityl, phenylethynyl, or (1-naphthyl)ethynyl] were determined by the dynamic NMR method to examine the effect of nonspherically shaped aromatic substituents on the rotational barriers. The rotational barriers increase in the order of the pheny, arylethynyl and mesityl substituted
旋转围绕C(SP)-C(SP的障碍3)在(1,4-二甲基-9- triptycyl)单键(1-X-9-triptycyl)乙炔[X =苯基,三甲苯基,苯乙炔基,或( 1-萘基乙炔基]通过动态NMR方法测定,以检查非球形芳族取代基对旋转屏障的影响。旋转势垒按苯基,芳基乙炔基和异丁基取代的化合物的顺序从15.8 kcal / mol增加到18.8 kcal / mol。该结果表明,不仅取代基的体积大,而且取代基的形状和柔韧性也是确定旋转屏障的重要因素。通过MM2计算,在X射线结构和优化的结构中发现了炔碳的显着弯曲变形(约166°)。