Nunes Paulo M, Estacio Sílvia G, Lopes Gustavo T, Costa Cabral Benedito J, Borges dos Santos Rui M, Martinho Simões José A
Centro de Química e Bioquímica and Departamento de Química e Bioquímica Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal.
Org Lett. 2008 Apr 17;10(8):1613-6. doi: 10.1021/ol800333q. Epub 2008 Mar 19.
Gas-phase C-H bond dissociation enthalpies (BDEs) in norbornane were determined by quantum chemistry calculations and the C2-H BDE was experimentally obtained for the first time by time-resolved photoacoustic calorimetry. CBS-Q and CBS-QB3 methods were used to derive the values DH degrees (C1-H) = 449 kJ mol-1, DH degrees (C7-H) = 439 kJ mol-1, and DH degrees (C2-H) = 413 kJ mol-1. The experimental result DH degrees (C2-H) = 414.6 +/- 5.4 kJ mol-1 is in excellent agreement with the theoretical value. The trend DH degrees (C1-H) > DH degrees (C7-H) > DH degrees (C2-H) is discussed.
通过量子化学计算确定了降冰片烷中气相C-H键的离解焓（BDEs），并首次通过时间分辨光声量热法实验获得了C2-H的BDE。采用CBS-Q和CBS-QB3方法得出以下数值：ΔH°(C1-H) = 449 kJ mol-1，ΔH°(C7-H) = 439 kJ mol-1，以及ΔH°(C2-H) = 413 kJ mol-1。实验结果ΔH°(C2-H) = 414.6 ± 5.4 kJ mol-1与理论值高度吻合。文中讨论了ΔH°(C1-H) > ΔH°(C7-H) > ΔH°(C2-H)这一趋势。
