Heats of Formation of [2.2]Paracyclophane-1-ene and [2.2]Paracyclophane-1,9-diene - An Experimental Study

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• 作者：Armin de Meijere ; Sergei I. Kozhushkov ; Karsten Rauch ; Heiko Schill ; Sergey P. Verevkin ; Martin Kü ; mmerlin ; Hans-Dieter Beckhaus ; Christoph Rü ; chardt ; and Dmitrii S. Yufit
• 刊名：Journal of the American Chemical Society
• 出版年：2003
• 出版时间：December 10, 2003
• 年：2003
• 卷：125
• 期：49
• 页码：15110 - 15113
• 全文大小：98K
• 年卷期：v.125,no.49(December 10, 2003)
• ISSN：1520-5126

文摘

The enthalpies of formation [s/gifchars/Delta.gif" BORDER=0 >subscribe/journals/jacsat/125/i49/eqn/ja0374628e10001.gif">(g)] of tricyclo[8.2.2.2^4,7]hexadeca-1(13),2,4(16),5,7(15),10(14),11-heptaene (2, 1,2-dehydro[2.2]paracyclophane or [2.2]paracyclophane-1-ene) and tricyclo[8.2.2.2^4,7]hexadeca-1(13),2,4(16),5,7(15),8,10(14),11-octaene (3, 1,2,9,10-dehydro[2.2]paracyclophane or [2.2]paracyclophane-1,9-diene) have been determined by measuring their heats of combustion in a microcalorimeterand their heats of sublimation by the transpiration method. Values of the strain energies (SE) [SE(2) =34.7 kcal mol^-1, SE(3) = 42.0 kcal mol^-1] have been derived from the gas-phase heats of formation andare compared with those from MM3 and PM3 calculations and with the corresponding value SE(1) = 30.1kcal mol^-1 for the parent tricyclo[8.2.2.2^4,7]hexadeca-1(13),4(16),5,7(15),10(14),11-hexaene (1, [2.2]paracyclophane). The higher strain energies of 2 and 3 (by 4.6 and 11.9 kcal mol^-1) are in accord with thewell-known increased reactivities of their aromatic rings as a consequence of their increased bending. Asrevealed by an X-ray crystal structure analysis, the bending in the monoene 2 corresponds to that of 1 and3 at one of two bridging corners.