Replacement of precious metal catalysts in the Guerbet upgrade of ethanol to n-butanol with first-row metal complex catalysts is highly appreciated due to their economic and environmental friendliness. The manganese pincer complexes of the type [(^RPNP)MnBr(CO)₂] (R = ⁱPr, Cy, ^tBu, Ph or Ad) are found to be excellent catalysts for upgrading ethanol to n-butanol. Under suitable reaction conditions and with an appropriate base, about 34% yield of n-butanol can be obtained in high selectivity. A detailed account on the effect of the temperature, solvent, nature, and proportion of base used and the stereoelectronic effects of the ligand substituents on the catalytic activity of the catalysts as well as the plausible deactivation pathways is presented.

中文翻译：

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锰介导的Guerbet反应催化乙醇降解为正丁醇

由于在经济和环境上的友好性，用第一行金属络合物催化剂将乙醇从Guerbet升级为正丁醇的Guerbet替代贵金属催化剂受到高度赞赏。发现[（^R PNP）MnBr（CO）₂ ]类型的锰钳夹配合物（R ＝ⁱ Pr，Cy，^t Bu，Ph或Ad）是将乙醇升级为正丁醇的优良催化剂。在适当的反应条件下和适当的碱下，n的收率约为34％可以以高选择性获得-丁醇。介绍了有关温度，溶剂，性质和所用碱的比例以及配体取代基对催化剂催化活性以及可能的失活途径的立体电子效应的影响的详细说明。