Isotope Effects on the Ring Inversion of Cyclooctatetraene

Citations Over TimeTop 11% of 1998 papers

Abstract

1H NMR studies (400 MHz) on isopropoxycyclooctatetraene (C8H7-O-C3H7) and its ring-d7 analogue (C8D7-O-C3H7) show that there is an inverse isotope effect on the rate of ring inversion of kH/kD = 0.68−0.57 in the temperature range from −10 to −50 °C. These experiments confirm the validity of previously published DFT calculations on cyclooctatetraene/cyclooctatetraene-d8, which predict an inverse isotope effect of about this size on the rate of ring inversion in this temperature range. The large inverse isotope effect upon ring inversion explains why the similarly large normal equilibrium isotope effect, found in the reduction of benzene to its corresponding anion radical, is not observed in the analogous reduction of cyclooctatetraene.

Related Papers

• → Isotope Effects on the Ring Inversion of Cyclooctatetraene(1998)28 cited
• → Electron Attachment and Detachment: Cyclooctatetraene(2002)23 cited
• → π‐Bond Configurations, Conformations, and Dynamic Behaviour of Benzo[c]octalene and Dibenzo[c,j]octalene(1980)6 cited
• → Dialkyl‐ und Diarylphosphinocyclooctatetraene: Eine neue Klasse von konformationsanalytisch und koordinationschemisch interessanten Verbindungen(1979)9 cited
• Determination of the Very High Barriers to Conformational Processes by the Neat Racemization Technique. Part 1: Barriers to Ring Inversion in Dibenzo [a,c] Dinaphtho [2,3-e; 2,3-g] Cyclooctatetraene and Hindered Rotation in 2,2'-Dimethyl Binaphthyl(1996)