MAGNETIC-FIELD EFFECTS ON GEMINATE RADICAL-PAIR RECOMBINATION
MAGNETIC-FIELD EFFECTS ON GEMINATE RADICAL-PAIR RECOMBINATION
复制标题
DOI：
10.1039/dc9847800271
复制
发表时间：
1984-01-01
影响因子：
3.4
通讯作者：
TREICHEL, R
中科院分区：
文献类型：
--
作者：
WELLER, A;STAERK, H;TREICHEL, R
研究了在外加磁场作用下，纳秒激光在乙腈中产生的自由基离子对2A-+2D+。这些电子对是通过电子给体之间的光诱导电子转移在整体单重态中产生的（D，二甲基苯胺）和电子受体（A，芘）分子通过背电子转移复合形成芘的分子三重态。本文讨论了自由扩散体系和多亚甲基连接化合物的结果（A-[CH 2]n-D，n= 6-12）可以根据这样的假设来定量解释：初始自由基离子对中的自旋重排由每个自由基中未成对电子自旋与核自旋之间的超精细相互作用ΔEhfi和交换相互作用J（n）控制，的基本自旋。后者随链长n的减小而增加。本文讨论了短链（n ≤ 6）、中链（6 < n < 12）和长链（n <12）聚亚甲基链的化合物在孪晶三重态形成方面的行为差异。
Pairs of radical ions, 2A–+2D+, generated in acetonitrile by nanosecond laser flashes have been investigated in the presence of external magnetic fields. The pairs are produced in the overall singlet state via photoinduced electron transfer between electron-donor (D, dimethylaniline) and electron-acceptor (A, pyrene) molecules and they recombine geminately by back electron transfer to form the molecular triplet state of pyrene.The results obtained with both freely diffusing systems and polymethylene-linked compounds (A—[CH2]n—D, n= 6–12) can be interpreted quantitatively on the basis of the assumption that the spin realignment in the initial radical ion pair is governed by the hyperfine interaction, ΔEhfi, between the unpaired electron spin and the nuclear spins in each radical and by the exchange interaction, J(n), of the radical spins in the pair. The latter increases with decreasing chain length, n.The differences in behaviour with respect to geminate triplet formation of the linked compounds with short (n⩽ 6), medium (6 < n < 12) and long (n 12) polymethylene chains are discussed.