system. As in solution, the endo [4+2] adduct was the major product. When a La-exchanged Y zeolite containing TP+ was used, the degree of conversion was even lower. This suggests that CHD cyclodimerization must occur via electron transfer to singlet TP+. In the case of DT+ within ZSM-5, the selectivity was reversed with respect to TP+: the major product was the anti [2+2] dimer. This was attributed to
三苯基
吡啶鎓(TP +)和二苯并[a,d] tropylium(DT +)阳离子已掺入
沸石中,并已通过
1,3-环己二烯(CHD)的PET环二聚化测试了它们作为非均相光敏剂的潜力。反应。将含有TP +作为非均相光敏剂的
沸石的行为与使用可溶性TP +在均相溶液中获得的结果进行了比较。四
氟硼酸盐(
TPT)。用阳离子
沸石包裹的阳离子,反应进行得较慢,这可能是由于光散射和迁移率受限,与固体中的扩散困难有关。因此,在超大孔MC
M-41内部,反应效率提高了9倍,尽管它仍然低于均相体系。如在溶液中一样,内[4 + 2]加合物是主要产物。当使用含有TP +的La交换Y型
沸石时,转化度甚至更低。这表明CHD环二聚化必须通过电子转移到单线态TP +发生。对于ZSM-5内的DT +,相对于TP的选择性相反+:主要产物是抗[2 + 2]二聚体。这归因于在1 [CHD + ·/ DT·]阶段逆向电子转移的结果是生成了3个CHD