博彩平台

Jiajun Liu^†, Xiaoguang Bao^*†（鲍晓光）, David A. Hrovat^‡, and Weston Thatcher Borden^*‡

^† College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China

^‡ Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States

J. Org. Chem., 2015, 80 (23), pp 11788–11793

B3LYP and CCSD(T) calculations, using an aug-cc-pVTZ basis set, have been carried out on the fragmentation of 1,2,3,4,5-cyclopentanepentone, (CO)₅, to five molecules of CO. Although this reaction is calculated to be highly exothermic and is allowed to be concerted by the Woodward–Hoffmann rules, our calculations find that the D_5h energy maximum is a multidimensional hilltop on the potential energy surface. This D_5h hilltop is 16–20 kcal/mol higher in energy than a C₂ transition structure for the endothermic cleavage of (CO)₅ to (CO)₄ + CO and 11–15 kcal/mol higher than a C_s transition structure for the loss of two CO molecules. The reasons for the very high energy of the D_5h hilltop are discussed, and the geometries of the two lower energy transition structures are rationalized on the basis of mixing of the e₂′ HOMO and the a₂″ LUMO of the hilltop.