The ruthenium-tris-bipyridyl dication as catalyst combined with the ascorbate dianion as bioavailable sacrificial donor provides the first regenerative source of hydrated electrons for chemical syntheses on millimolar scales. This electron generator is operated simply by illumination with a frequency-doubled Nd:YAG laser (532 nm) running at its normal repetition rate. Much more detailed information than by product studies alone was obtained by photokinetical characterization from submicroseconds (time-resolved laser flash photolysis) up to one hour (preparative photolysis). The experiments on short timescales established a reaction mechanism more complex than previously thought, and proved the catalytic action by unchanged concentration traces of the key transients over a number of flashes so large that the accumulated electron total surpassed the catalyst concentration many times. Preparative photolyses revealed that the sacrificial donor greatly enhances the catalyst stability through quenching the initial metal-to-ligand charge-transfer state before destructive dd states can be populated from it, such that the efficiency of this electron generator is no longer limited by catalyst decomposition but by electron scavenging by the accumulating oxidation products of the ascorbate. Applications covered dechlorinations of selected aliphatic and aromatic chlorides and the reduction of a model ketone. All these substrates are impervious to photoredox catalysts exhibiting lower reducing power than the hydrated electron, but the combination of an extremely negative standard potential and a long unquenched life allowed turnover numbers up to 1400 with our method.

中文翻译：

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使用单个绿色激光可持续产生的水合电子，实验室规模的光氧化还原催化

钌-三-联吡啶基指示剂与抗坏血酸二阴离子作为生物可利用的牺牲供体结合，为水合电子的第一个再生来源提供了以毫摩尔规模进行化学合成的水合电子。通过以正常重复频率运行的Nd：YAG倍频激光（532 nm）进行照明，可以简单地操作该电子发生器。通过光动力学表征，从亚微秒（时间分辨的激光闪光光解）到一小时（制备性光解），可以获得比单独的产品研究更多的详细信息。在短时间范围内进行的实验建立了比以前认为的更为复杂的反应机制，并通过多次瞬变中关键瞬态的浓度迹线未改变而证明了催化作用，以至于累积的电子总量多次超过催化剂浓度。制备型光解法显示，牺牲施主通过在破坏性的dd态可以填充之前，通过淬灭初始的金属-配体电荷转移态而极大地提高了催化剂的稳定性，因此该电子发生器的效率不再受催化剂分解的限制但通过积累抗坏血酸盐的氧化产物进行电子清除。应用包括选定的脂肪族和芳香族氯化物的脱氯以及模型酮的还原。所有这些底物都不能透过光氧化还原催化剂，其还原能力比水合电子低，