<i>trans</i>-4-Acetylcyclohexanecarboxylic acid and (\pm)-<i>trans</i>-2-acetylcyclohexanecarboxylic acid: hydrogen-bonding patterns in two isomeric keto acids
作者:Jacob M. Newman、Hugh W. Thompson、Roger A. Lalancette
DOI:10.1107/s0108270102018553
日期:2002.12.15
Both title compounds, C(9)H(14)O(3), display carboxyl-dimer hydrogen-bonding patterns. The 4-acetyl isomer adopts a chiral conformation with negligible disordering of the methyl and carboxyl groups and forms centrosymmetric dimers across the b and c edges of the chosen cell [O.O = 2.667 (3) A and O-H.O = 175 degrees ]. Intermolecular C-H.O close contacts were found for both carbonyl groups. In the
两种标题化合物,C(9)H(14)O(3),都显示出羧基二聚体氢键合模式。4-乙酰基异构体采用手性构象,甲基和羧基的混乱程度可忽略不计,并在所选单元格的b和c边缘形成中心对称二聚体[OO = 2.667(3)A和OH.O = 175度]。发现两个羰基的分子间CH.O紧密接触。在2-乙酰基异构体中,羧基和乙酰基之间没有分子内相互作用,氢键涉及所选单元的ab和ac面上的中心对称羧基二聚化[OO = 2.668(2)A和OH.O = 173度]。羧基的无序性可以忽略不计,但是对于乙酰甲基发现了明显的旋转无序性。发现涉及酮基团的分子间CH.O紧密接触。