Chemical conversion and storage system for solar energy by use of catalytically active photogenerated hydride transients

金属有机配合物的光化学是目前研究的热点之一，人们对具有配位不饱和和高催化活性的光生短寿命金属有机碎片的性质进行了大量的研究。我们报道了四烷基（二乙基苯基膦酸盐）氢化钴(I) [Co-HL_4] （L=PPH (OEt)_2）在光照射下，随着一个配位膦酸盐配体L的解离，得到了一种瞬态氢化钴(I)“CoHL_3”。光生成的CoHL_3在许多均相反应中具有催化活性，包括烯烃的双键迁移和仲醇向酮的氢转移。本文研究了2-丙醇在液相中与氢化物（膦酸盐）钴(I)的光辅助脱氢反应。羟基钴(I)配合物CoHL_4在pyrex过滤光照射下催化液相2-丙醇脱氢反应，并释放丙酮。在82ºC条件下脱氢1h的翻转次数为4.6，在60ºC和82ºC条件下在366nm处的量子产率约为0.015。脱氢反应为光辅助型催化反应，光生成的氢化物瞬态CoHL_3是脱氢催化循环中起关键作用的中间体。

The photochemistry of organometallic complexes has been one of the currently active research-fields, and much effort has been focused on the properties of photogenerated short-lived organometallic fragments with coordinative unsaturation and high catalytic activities. We have reported that photoirtadiation of tetrakis (diethylphenylphosphonite) hydridocobalt (I) [Co-HL_4] (L=PPH (OEt)_2) gives a transient hydridocobalt (I) species "CoHL_3" with dissociation of one coordinated phosphonite ligand L.Catalytic activities of the photogenerated CoHL_3 species have been realized in many homogeneous reactions, involving double-bond migration of olefins and hydrogen transfer from secondary alcohols to ketones. The present study deals with photoassisted dehydrogenation of 2-propanol in the liquid phase with the hydrido (phosphonite) cobalt (I).The hydridocobalt (I) complex CoHL_4 under Pyrex-filtered photoirradiation catalyzed dehydrogenation reaction of 2-propanol in the liquid phase, with release of acetone. The turn-over number evaluated for the dehydrogenation for 1h at 82ﾟC was 4.6, and the quantum yields for the reaction at 366nm were determined to be about 0.015 at 60 and 82ﾟC.The dehydrogenation was characterized as a photoassisted-type catalytic reaction, and the photo generated hydrido transient CoHL_3 was attributed to a key-role-playing inter mediate in the catalytic cycle of the dehydrogenation.