Three classes of manganese(I) complex cation, [(PNHN)Mn(CO)3]Br (Mn1), [(SNHN)Mn(CO)3]Br (Mn2) and [(NRNHN)Mn(CO)3]Br (Mn3 (NMe), Mn4 (NEt), Mn5 (NiPr)), all incorporating a chelating 5,6,7,8-tetrahydro-8-quinolinamine (NHN) but distinct in their third donor atom, have been assessed as catalysts for the dehydrogenative oxidation of primary alcohols to form their corresponding carboxylic acids. Using water as solvent and NaOH as base, PNHN-containing Mn1 proved the most effective allowing both aromatic and aliphatic alcohols to be converted at 160 °C with excellent functional group tolerance (25 examples disclosed). A possible mechanism for this process, that makes use of an acceptorless dehydrogenation pathway, has been proposed and supported by targeted experimentation. Overall, these catalysts show great promise for applications in atom-economic carboxylic acid synthesis as well as in the development of organic hydride-based hydrogen storage systems.

中文翻译：

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PNHN-羰基锰(I)配合物催化水中伯醇脱氢生成羧酸


三类锰 (I) 络合物阳离子：[(PNHN)Mn(CO)3]Br (Mn1)、[(SNHN)Mn(CO)3]Br (Mn2) 和 [(NRNHN)Mn(CO)3] Br（Mn3 (NMe)、Mn4 (NEt)、Mn5 (NiPr)）均包含螯合 5,6,7,8-四氢-8-喹啉胺 (NHN)，但其第三个供体原子不同，已被评估为用于伯醇脱氢氧化形成其相应的羧酸的催化剂。使用水作为溶剂和 NaOH 作为碱，含 PNHN 的 Mn1 被证明是最有效的，可以使芳香族和脂肪族醇在 160 °C 下转化，并具有优异的官能团耐受性（公开了 25 个例子）。已经提出了该过程的一种可能机制，即利用无受体脱氢途径，并得到了针对性实验的支持。总体而言，这些催化剂在原子经济的羧酸合成以及有机氢化物基储氢系统的开发中显示出巨大的应用前景。