Large Acceleration Effect of Photoinduced Electron Transfer in Porphyrin−Quinone Dyads with a Rigid Spacer Involving a Dihalosubstituted Three-Membered Ring
Large Acceleration Effect of Photoinduced Electron Transfer in Porphyrin−Quinone Dyads with a Rigid Spacer Involving a Dihalosubstituted Three-Membered Ring
复制标题
具有二卤代三元环刚性间隔基的卟啉-醌二价体中光致电子转移的大加速效应
DOI：
10.1021/ja9900454
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发表时间：
2000
影响因子：
15
通讯作者：
Y. Sakata
中科院分区：
文献类型：
--
作者：
H. Tsue;H. Imahori;T. Kaneda;Yoshinori Tanaka;T. Okada;and Koichi Tamaki;Y. Sakata
为了理解间隔结构对电子转移（ET）的贡献并调节氧化还原对之间的电子耦合，制备了卟啉-间隔基-苯醌分子，其中间隔基是反式萘烷和二卤代三环[4.4.1.0]十一烷，包括三元环。这些化合物被设计成在氧化还原对之间具有几乎相同的分离距离、相同数量的插入键以及与ET反应相关的几乎相等的自由能变化。基于荧光寿命评价电荷分离过程的ET速率。这些化合物的ET速率有很大的差异，含三元环的化合物的ET速率约为1.5%。比在THF中使用反式十氢化萘间隔基时大50至60倍。通过对电子转移速率随温度变化的分析，表明电子转移速率的加速是由电子耦合的增强和电子转移速率的降低共同引起的。
To understand the contribution of spacer structure toward electron transfer (ET) and to regulate electronic coupling between a redox pair, porphyrin−spacer−benzoquinone molecules were prepared where spacers are trans-decalin and dihalosubstituted tricyclo[4.4.1.0]undecane including a three-membered ring. These compounds were designed to have almost the same separation distance between a redox pair, the same number of intervening bonds, and the nearly equal free energy change associated with the ET reaction. The ET rates for the charge separation process were evaluated on the basis of the fluorescence lifetimes. A quite large difference in the ET rates was observed among these compounds, and the ET rates for the compounds having the three-membered rings were ca. 50 to 60 times larger than that with trans-decalin spacer in THF. From the analysis of temperature dependence of the ET rates, it was shown that the observed rate acceleration is caused by both an increase of the electronic coupling and a decrease ...