Formation of Ground State Triplet Diradicals from Annulated Rosarin Derivatives by Triprotonation
作者:Shunichi Fukuzumi、Kei Ohkubo、Masatoshi Ishida、Christian Preihs、Bo Chen、Weston Thatcher Borden、Dongho Kim、Jonathan L. Sessler
DOI:10.1021/jacs.5b05309
日期:2015.8.12
species. At low temperature, rosarins 2 and 3 are readily triprotonated in the presence of trifluoroacetic acid in dichloromethane to produce ground state triplet diradicals, as inferred from electron paramagnetic resonance (EPR) spectral studies. From an analysis of the fine structure in the EPR spectrum of triprotonated rosarin H₃3(3+), a distance of 3.6 Å between the two unpaired electrons was estimated
环化的 rosarins, β,β'-bridged hexaphyrin(1.0.1.0.1.0) 衍生物 1-3,是形式上的 24 π-电子抗芳香物质。从电子顺磁共振 (EPR) 光谱研究推断,在低温下,在三氟乙酸的存在下,罗沙林 2 和 3 很容易在二氯甲烷中三质子化以产生基态三线态双自由基。通过对三质子化罗沙林 H₃3(3+) 的 EPR 光谱中精细结构的分析,估计两个未配对电子之间的距离为 3.6 Å。单线态-三线态平衡的温度依赖性通过 EPR 滴定确定。对这些实验结果的支持来自在 (U)B3LYP/6-31G* 水平上进行的计算,该计算用于预测简化模型系统 1 的三质子化形式的非常低的三重态。