Enthalpies of formation of cis- and trans-1,2-diethylcyclopropane and cis- and trans-bicyclo[6.1.0]nonane. Structural effects on energies of cyclopropane rings
作者:Kenneth B. Wiberg、Elmer C. Lupton、David J. Wasserman、Armin De Meijere、Steven R. Kass
DOI:10.1021/ja00318a032
日期:1984.3
enthalpies of formation of cis- and trans-1,2-diethylcyclopropane were determined by oxygen bomb calimetry. The cis-diethyl isomer was 1.1 kcal/mol less stable than the trans isomer. Alkyl groups were found to stabilize a cyclopropane ring by the same amount as for a carbon-carbon double bond. The enthalpies of formation cis- and trans-bicyclo(6.1,0)nonane formation, in contrast to cis- and trans-cyclooctene
顺式和反式 1,2-二乙基环丙烷的生成焓通过氧弹量热法测定。顺式二乙基异构体的稳定性比反式异构体低 1.1 kcal/mol。发现烷基以与碳-碳双键相同的量稳定环丙烷环。顺式和反式双环 (6.1,0) 壬烷的形成焓,与顺式和反式环辛烯形成对比。三角中心的引入使反式双环壬烷 3 kcal/mol 不如顺式异构体稳定。分子力学计算报告了一系列顺式和反式双环 (n.1,0) 烷烃。为了更好地估计反式双环(4.1.0)庚烷的应变能,通过从头算分子轨道理论计算了其与其顺式异构体之间的能量差。