The effect of meta versus para substitution on the efficiency of chemiexcitation in the chemically triggered electron-transfer-initiated decomposition of spiroadamantyl dioxetanes
The effect of meta versus para substitution on the efficiency of chemiexcitation in the chemically triggered electron-transfer-initiated decomposition of spiroadamantyl dioxetanes
复制标题
DOI：
10.1021/jo000495a
复制
发表时间：
2000-10-06
影响因子：
3.6
通讯作者：
Trofimov, AV
中科院分区：
文献类型：
--
作者：
Adam, W;Trofimov, AV
已观察到对帕拉和间-取代的spiroadamantyl二氧杂环丁烷1的CIEEL效率的类似粘度依赖性，这意味着电子转移机制通过溶剂笼物种两个区域异构体操作。Meta位和对位取代的二氧杂环丁烷的化学激发产率的显着差异是合理的，在更大的（约。200倍）的速率常数，以提供激发的Meta CIEEL发光体。对帕拉与Meta区域异构体的激发态生成的粘度效应的深入动力学分析支持这一结论。
A similar viscosity dependence of the CIEEL efficiencies for the para- and meta-substituted spiroadamantyl dioxetanes 1 has been observed, which implies that an electron-transfer mechanism operates through solvent-caged species for both regioisomers. The pronounced difference in the chemiexcitation yields for the meta- and para-substituted dioxetanes is rationalized in terms of the much larger (ca. 200-fold) rate constant for the electron back-transfer (BET) step to afford the excited meta CIEEL emitter. An in-depth kinetic analysis of the viscosity effect on the excited-state generation for the para versus meta regioisomers supports this conclusion.