Synthesis, electronic structure, and electron transfer dynamics of (aryl)ethynyl-bridged donor-acceptor systems

被引:96
作者
Redmore, NP [1 ]
Rubtsov, IV [1 ]
Therien, MJ [1 ]
机构
[1] Univ Penn, Dept Chem, Philadelphia, PA 19104 USA
关键词
D O I
10.1021/ja021278p
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The ET dynamics of a series of donor-spacer-acceptor (D-Sp-A) systems featuring (porphinato)zinc(II), (aryl)ethynyl bridge, and arene diimide units were investigated by pump-probe transient absorption spectroscopy. Analysis of these data within the context of the Marcus-Levich-Jortner equation suggests that the pi-conjugated (aryl)ethynyl bridge plays an active role in the charge recombination (CR) reactions of these species by augmenting the extent of (porphinato)zinc(II) cation radical electronic delocalization; this increase in cation radical size decreases the reorganization energy associated with the CR reaction and thereby attenuates the extent to which the magnitudes of the CR rate constants are solvent dependent. The symmetries of porphyrin-localized HOMO and HOMO-1, the energy gap between these two orbitals, and D-A distance appear to play key roles in determining whether the (aryl)ethynyl bridge simply mediates electronic superexchange or functions as an integral component of the D and A units.
引用
收藏
页码:8769 / 8778
页数:10
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