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利用1HNMR技术研究了α 单取代环十二酮的α 边外取代 [3 3 3 3 ] 2 酮构象 (A)和α 角顺取代 [3 3 3 3 ] 2 酮构象 (B)相互转换的溶剂效应和温度效应 .结果显示 ,一般情况下随着溶剂极性的增加 ,构象B的含量增加 ,这可以解释为构象B较构象A有较大的偶极矩 .当分子中的取代基能与羰基形成分子内氢键时 ,情况则相反 ,随着溶剂极性的增加 ,构象B的含量降低 ,这可以解释为构象B的分子内氢键的减弱 .结果还显示 ,温度的升高有利于两个构象的相互转换而达到新的平衡
The 1HNMR technique was used to study the interconversion of the α-side [3 3 3 3] 2 ketone conformation (A) and the α-catenary [3 3 3 3] 2 ketone conformation (B) to α-monosubstituted cyclododecanone Effect and temperature effect.The results show that under normal conditions, the content of conformation B increases with the increase of solvent polarity, which can be explained as the larger dipole moment of conformation B compared with conformation A. When the substituent in the molecule can react with When the intramolecular hydrogen bond is formed by the carbonyl group, the converse is that the content of the conformation B decreases with the increase of the solvent polarity, which can be explained by the decrease of the intramolecular hydrogen bond of the conformation B. The results also show that the increase of the temperature is favorable The two conformations convert to each other to reach a new equilibrium