The direct selective halogenation of unactivated C(sp³)–H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450–500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.

中文翻译：

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在可见光和Ag @ AgX的共同催化下，未活化的C（sp ³）–H与NaX的高度选择性卤化

未活化C（sp ³的直接选择性卤化）–在室温下，在可见光或LED辐射下，在空气中存在NaX / HX水溶液作为卤化物源的情况下，使用纳米Ag / AgCl催化剂在室温下将H键转变为C-卤素键。烃的卤化为单卤化物取代的产物提供了95％的选择性，收率高于90％，甲苯的氯化率为81％，远高于使用二氯的40％转化率。机理研究表明，该反应是使用蓝光（450-500 nm）的自由基过程，可见光是最有效的光源。提出了辐照以引起AgCl键合电子被激发并且来自氯离子的电子转移引起氯自由基的形成，其驱动取代反应。