Manganese-Catalyzed Sequential Hydrogenation of CO₂ to Methanol via Formamide

Abstract

Mn(I)-PNP pincer catalyzed sequential one-pot homogeneous CO 2 hydrogenation to CH 3 OH by molecular H 2 is demonstrated. The hydrogenation consists of two partsN-formylation of an amine utilizing CO 2 and H 2 , and subsequent formamide reduction to CH 3 OH, regenerating the amine in the process. A reported air-stable and welldefined Mn-PNP pincer complex was found active for the catalysis of both steps. CH 3 OH yields up to 84% and 71% (w.r.t amine) were obtained, when benzylamine and morpholine were used as amines, respectively; and a TON of up to 36 was observed. In our opinion, this study represents an important development in the nascent field of base-metal-catalyzed homogeneous CO 2 hydrogenation to CH 3 OH.

Manganese Catalyzed Hydrogenation of Organic Carbonates to Methanol and Alcohols

“…[9] Hydrogenation of CO 2 to formic acid/formate catalyzed by pincer complexes of earth-abundant metals has also been reported. [12] However, high pressure of CO 2 (> 30 bar) is required for the formation of formamide,w hereas organic carbonates can be formed at mild pressure of CO 2 and even at atmospheric pressure in some cases. [12] However, high pressure of CO 2 (> 30 bar) is required for the formation of formamide,w hereas organic carbonates can be formed at mild pressure of CO 2 and even at atmospheric pressure in some cases.…”

Manganese‐Catalyzed Dehydrogenative Alkylation or α‐Olefination of Alkyl‐Substituted N‐Heteroarenes with Alcohols

“…Noble metals are rare and used in av ariety of key technologies,s uch as catalysis.T he replacement of noble metals by earth-abundant transition metals,such as Mn, Fe,or Co,i sapossible strategy to reduce the use of noble metals, especially in homogeneous catalysis,where reusability of the active metal is challenging.The use of earth-abundant metals may also permit the discovery of new selectivity patterns in known reactions or the development of novel catalytic transformations.M anganese complexes have been used successfully in hydrogenation and dehydrogenation catalysis since early 2016. [1] Despite significant progress in the (transfer) hydrogenation of ketones, [2] esters, [3] amides, [4] and CO 2 , [5] as well as in dehydrogenative couplings, [6] dehydrogenative condensations, [7] and borrowing hydrogen/hydrogen autotransfer, [8] only few examples of novel catalytic transformations that have not yet been observed with other transition metals have been reported. [9] Olefins are highly important compounds as they are broadly used as starting materials for the synthesis of fine and bulk chemicals.…”

Mangan‐katalysierte dehydrierende Alkylierung oder α‐Olefinierung von Alkyl‐N‐heteroarenen durch Alkohole

“…[1] Tr otz erheblicher Fortschritte in der (Transfer)Hydrierung von Ketonen, [2] Estern, [3] Amiden [4] und CO 2 , [5] der dehydrierenden Kopplung, [6] der dehydrierenden Kondensation [7] und "Borrowing-Hydrogen/Hydrogen-Autotransfer"-Verfahren, [8] wurden nur wenige Beispiele fürneuartige katalytische Umwandlungen beschrieben, die noch nicht bei anderen Übergangsmetallen beobachtet wurden. B. in der Katalyse.D er Ersatz von Edelmetallen durch auf der Erde häufig vorkommende Übergangsmetalle,w ie Mn, Fe oder Co,i st eine mçgliche Strategie,u md en Einsatz von Edelmetallen zu reduzieren, insbesondere in der homogenen Katalyse,w od ie Wiederverwendbarkeit des aktiven Metalls eine Herausforderung darstellt.…”

“…Mangankomplexe werden seit Anfang 2016 erfolgreich in der Hydrierungs-und Dehydrierungskatalyse eingesetzt. [1] Tr otz erheblicher Fortschritte in der (Transfer)Hydrierung von Ketonen, [2] Estern, [3] Amiden [4] und CO 2 , [5] der dehydrierenden Kopplung, [6] der dehydrierenden Kondensation [7] und "Borrowing-Hydrogen/Hydrogen-Autotransfer"-Verfahren, [8] wurden nur wenige Beispiele fürneuartige katalytische Umwandlungen beschrieben, die noch nicht bei anderen Übergangsmetallen beobachtet wurden. [9] Olefine sind sehr wichtige Verbindungen, da sie eine breite Verwendung als Ausgangsmaterialien fürd ie Synthese von Fein-und Massenchemikalien erfahren.…”