Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 96 Jinzhai Road, Hefei, China.
Chemistry. 2020 Oct 6;26(56):12743-12746. doi: 10.1002/chem.201905865. Epub 2020 Sep 16.
A new strategy was devised for estimating and screening pK values among different carbon acids under ambient conditions by using the UV/Vis absorption spectrum of persistent radical pairs (PRPs), which are generated from an N-substituted naphthalimide (NNI) derivative in the presence of various carbanions in organic solutions. The electron paramagnetic resonance (EPR) spectroscopy was used to examine the presence of radicals. Unexpectedly, it was discovered that the UV/Vis spectrum of PRPs reveals a distinct linear relationship between the PRP absorption and the pK value of a corresponding carbon acid, which is likely due to the energy difference among different RPRs. The finding may offer organic chemists an alternative reference to conduct carbanion-mediated reactions in various organic solutions.
一种新策略被设计用于通过使用持久自由基对（PRP）的紫外/可见吸收光谱来估计和筛选在环境条件下不同碳酸的 pk 值，PRP 是在有机溶液中存在各种碳负离子的情况下由 N-取代萘酰亚胺（NNI）衍生物产生的。电子顺磁共振（EPR）光谱用于检查自由基的存在。出乎意料的是，发现 PRP 的紫外/可见光谱显示 PRP 吸收与相应碳酸的 pk 值之间存在明显的线性关系，这可能是由于不同 RPR 之间的能量差异所致。这一发现可能为有机化学家提供一种替代的参考，以在各种有机溶液中进行碳负离子介导的反应。
