Conrotatory Photochemical Ring Opening of Alkylcyclobutenes in Solution. A Test of the Hot Ground-State Mechanism
作者:Bruce H. O. Cook、William J. Leigh、Robin Walsh
DOI:10.1021/ja003860o
日期:2001.6.1
and cis- and trans-tricyclo[6.4.0.0(2,7)]dodec-1(2)-ene (cis- and trans-9)-were selected so as to span a broad range in molecular weight and as broad a range as possible in Arrhenius parameters for thermal (ground-state) ring opening. RRKM calculations have been carried out to provide estimates of the rate constants for ground-state ring opening of each of the compounds over a range of thermal energies
已使用 228 nm 激发在己烷溶液中测量了六种烷基环丁烯的光化学开环的量子产率,该激发选择性地填充这些分子的最低 pi,R(3s) 激发单线态,并且先前已显示导致开环清洁旋转立体化学。本工作中研究的化合物 - 1,2-二甲基环丁烯 (1)、顺式和反式 1,2,3,4-四甲基环丁烯(顺式和反式 5)、六甲基环丁烯 (8) 以及顺式和反式选择三环[6.4.0.0(2,7)]dodec-1(2)-ene (cis-和trans-9)-以跨越宽范围的分子量和尽可能宽的Arrhenius参数范围用于热(基态)开环。已进行 RRKM 计算以提供每种化合物在 20 000 至 49 000 cm(-1) 热能范围内的基态开环速率常数的估计值。这些已被用于通过热基态机制估计开环量子产率的上限,假设 k(deact) = 10(11) s(-1) 的值用于碰撞失活的速率常数溶剂,从最低里德堡态到基态的内部