Alternative Energy Input for Transfer Hydrogenation using Iridium NHC Based Catalysts in Glycerol as Hydrogen Donor and Solvent
Alternative Energy Input for Transfer Hydrogenation using Iridium NHC Based Catalysts in Glycerol as Hydrogen Donor and Solvent
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DOI：
10.1021/om300109e
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发表时间：
2012-05-28
期刊：
影响因子：
2.8
通讯作者：
Colacino, Evelina
中科院分区：
文献类型：
--
作者：
Azua, Arturo;Mata, Jose A.;Colacino, Evelina
合成了4个含3，4，5-三甲氧基苄基N-取代基的Ir（I）和Ir（III）N-杂环卡宾配合物，并对其结构进行了表征。新的配合物已被用作催化剂，在减少醛和酮与甘油，和他们的活动已被比较，所示的其他Ir（III）NHC配合物以前报道。反应在油浴加热下进行，并使用微波（MW）和超声（US）活化进行了详细的比较研究。新的Ir（III）配合物被证明是最有效的还原酮，而Ir（I）配合物是更积极的还原醛。超声波的使用在缩短反应时间方面具有巨大的影响，并且在醛的还原中获得了良好的结果。在一些实验中，透射电子显微镜（TEM）和紫外-可见分析显示在MW或US活化后存在含铱纳米颗粒。
Four Ir(I) and Ir(III) N-heterocyclic carbene (NHC) based complexes with 3,4,5-trimethoxybenzyl N-substituents have been obtained and fully characterized. The new complexes have been used as catalysts in the reduction of aldehydes and ketones with glycerol, and their activities have been compared to those shown by other Ir(III) NHC-complexes previously reported. The reactions were carried out under oil bath heating, and a detailed comparative study has been carried out using microwave (MW) and ultrasound (US) activation. The new Ir(III) complexes proved to be most efficient in the reduction of ketones, while the Ir(I) complexes are more active in the reduction of aldehydes. The use of ultrasound has a tremendous impact in shortening reaction times, and good results have been obtained in the reduction of aldehydes. In some experiments transmision electron microscopy (TEM) and UV-vis analysis showed the presence of iridium-containing nanoparticles after MW or US activation.