Rotational barriers of biphenyls having heavy heteroatoms as ortho-substituents: experimental and theoretical determination of steric effects
作者:Lodovico Lunazzi、Michele Mancinelli、Andrea Mazzanti、Susan Lepri、Renzo Ruzziconi、Manfred Schlosser
DOI:10.1039/c1ob06688a
日期:——
for the aryl–aryl rotation of 17 biphenyl derivatives, bearing a heavy heteroatom (S, Se, Te, P, Si, Sn) as ortho substituent, have been measured by variable temperature NMR. These numbers, so called B values, represent a meaningful measure of the steric hindrance exerted by the selected substituents. DFT computations match quite satisfactorily the experimental barriers and the ground state geometries
带有重杂原子的17个联苯衍生物的芳基-芳基旋转活化的自由能(S, 硒, 特,P, 硅, 锡作为邻位取代基,已通过可变温度NMR测定。这些数字,即所谓的B值,代表了所选取代基所施加的空间位阻的有意义的量度。DFT计算也非常令人满意地匹配了实验壁垒和基态几何形状(在两种情况下,由X射线衍射确定)。当前值扩展了B值的可用列表,因此仅基于实验确定结果即可为编制标准取代基的空间要求提供扩大的基础。