Seiders T J, Baldridge K K, Grube G H, Siegel J S
Contribution from the Department of Chemistry, University of California-San Diego, La Jolla, California 92093-0358, USA.
J Am Chem Soc. 2001 Jan 31;123(4):517-25. doi: 10.1021/ja0019981.
Synthesis of a series of corannulene derivatives with varying bowl depths has allowed for a study correlating the structure (bowl depth) and the energy of bowl inversion. Substituents placed in the peri positions are repulsive and flatten the bowl, thus causing a decrease in the bowl inversion barrier. Conversely, annelation across the peri positions causes a deepening of the bowl, thus an increase in the bowl inversion barrier. Barriers between 8.7 and 17.3 kcal/mol have been measured, and their structures have been calculated using a variety of ab initio methods. The energy profile of an individual corannulene derivative is assumed to fit a mixed quartic/quadratic function from which an empirical correlation of bowl depth and inversion barrier that follows a quartic function is derived. Structure/energy correlations of this type speak broadly of the nature of enzymatic and catalytic activation of substrates.
一系列具有不同碗状深度的碗烯衍生物的合成，使得人们能够开展一项研究，将结构（碗状深度）与碗状翻转能联系起来。处于迫位的取代基具有排斥作用，会使碗状结构变平，从而导致碗状翻转势垒降低。相反，跨越迫位的稠合作用会使碗状结构加深，进而使碗状翻转势垒增加。已测得势垒在8.7至17.3千卡/摩尔之间，并且使用多种从头算方法计算了它们的结构。假定单个碗烯衍生物的能量分布符合混合四次/二次函数，由此得出碗状深度与遵循四次函数的翻转势垒之间的经验相关性。这种类型的结构/能量相关性广泛地说明了底物的酶促和催化活化的本质。
