The ionic hydrogen bond. 1. Sterically hindered bonds. Solvation and clustering of protonated amines and pyridines
作者:Michael Meot-Ner、L. Wayne Sieck
DOI:10.1021/ja00348a005
日期:1983.5
2,6-dialkylpyridines, and tertiary amines were investigated in the gas phase in the absence of solvent effects. Steric hindrance causes major entropy effects unfavorable to dimerization or hydration. As long as a single confirmation exists in which the hydrogen bond can obtain optimal geometry, the bond strength is not weakened by steric crowding. However, steric crowding may result in major entropy
使用脉冲高压质谱仪,氢键二聚体离子 BH/sup +/.B 和 2-烷基吡啶、2,6-二烷基吡啶和叔胺的一水合物 BH/sup +/.H/sub 2/O在没有溶剂影响的气相中进行了研究。空间位阻导致不利于二聚化或水合的主要熵效应。只要存在氢键可以获得最佳几何形状的单一确认,键强度就不会因空间拥挤而减弱。然而,空间拥挤可能会由于二聚体和一水合物中内部转子的阻碍而导致主要的熵效应。8个数字,3个表格。