Three‐Component Cascade Reaction in a Tube: In Situ Synthesis of Pd Nanoparticles Supported on mpg‐C₃N₄, Dehydrogenation of Ammonia Borane and Hydrogenation of Nitroarenes

Abstract

We report herein a facile in situ synthesis of Pd nanoparticles (NPs) supported on mesoporous graphitic carbon nitride (mpg-C 3 N 4 /Pd) during the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of nitroarenes at room temperature. In the presented protocol, a three-component cascade reaction is realized in a pressure tube at room temperature, encompassing (i) in situ generation of Pd NPs supported on mpg-C 3 N 4 via reduction of mpg-C 3 N 4 /Pd(II) nanocomposites by AB, (ii) the mpg-C 3 N 4 /Pd catalyzed dehydrogenation of AB and (iii) the transfer hydrogenation of nitro groups through the mpg-C 3 N 4 /Pd catalyst. The scope of the mpg-C 3 N 4 /Pd catalyzed tandem dehydrogenation of AB and hydrogenation reactions were studied over a wide range of nitroarenes (10 examples), which are all selectively converted to the corresponding anilines within only 1-2 min with the yields up to 99 % under ambient conditions. It was also shown that the mpg-C 3 N 4 /Pd catalysts could be scaled up to large scale production of anilines and reused up to ten times without any significant loss in the yields. Additionally, the mpg-C 3 N 4 /Pd catalysts were isolated after the hydrogenation reactions and tested as catalysts in the hydrolysis of AB by studying the detailed reaction kinetics. The isolated mpg-C 3 N 4 /Pd nanocatalysts showed a very high performance in hydrogen generation from the hydrolysis of AB by providing an initial turnover frequency (TOF) of 66.3 min À1 .[a] Assist.

A facile and highly efficient transfer hydrogenation of ketones and aldehydes catalyzed by palladium nanoparticles supported on mesoporous graphitic carbon nitride

“…Based on our earlier attempts at hydrogenation and reductive amination, [20][21][22][23][24][25] we tried to optimize the hydrogenation conditions by experimenting with different parameters, such as solvent, temperature, time, the catalyst, and the amount of AB. 4′-Methoxyacetophenone was selected as the model reagent for the synthesis of the corresponding alcohol under optimized conditions.…”

“…22 In a recent study, we have also demonstrated that in situ synthesized Pd NPs supported on mesoporous graphitic carbon nitride (mpg-C 3 N 4 /Pd) are highly efficient catalysts in the A facile and highly efficient transfer hydrogenation of ketones and aldehydes catalyzed by palladium nanoparticles supported on mesoporous graphitic carbon nitride TH of nitroarenes to the corresponding aniline derivatives at room temperature. 23 In order to clarify the efficiency of the newly developed mpg-C 3 N 4 /Pd catalyst, we describe herein an efficient, selective, and fast reduction chemistry method for the synthesis of alcohols using AB as a hydrogen source with mpg-C 3 N 4 /Pd in a water/methanol mixture (v/v = 1/1). In addition, it should be noted that less AB was used for the hydrogenation reactions compared to our previous studies, [20][21][22][23] making our new methodology cost efficient and more practical.…”

“…23 In order to clarify the efficiency of the newly developed mpg-C 3 N 4 /Pd catalyst, we describe herein an efficient, selective, and fast reduction chemistry method for the synthesis of alcohols using AB as a hydrogen source with mpg-C 3 N 4 /Pd in a water/methanol mixture (v/v = 1/1). In addition, it should be noted that less AB was used for the hydrogenation reactions compared to our previous studies, [20][21][22][23] making our new methodology cost efficient and more practical.…”

Monodisperse CuPt alloy nanoparticles assembled on reduced graphene oxide as catalysts in the transfer hydrogenation of various functional organic groups

“…In this regard, upon the results of our research direction, addressed herein is the performance of binary Cu 7 Pt 3 alloy NPs assembled on reduced graphene oxide (Cu 7 Pt 3 ‐rGO) as catalyst for the TH using AB as a hydrogen donor molecule and water as sole solvent performed in a commercially available high‐pressure glass tube at room temperature. It should be noted that this study differs from our previous studies not only using CuPt‐rGO as the catalyst but also utilization of water as the sole solvent instead of aqueous methanol solution, which is considered to be important in terms of green chemistry …”

Palladium Nanoparticles Immobilized on a Resorcin[4]arene-Based Metal–Organic Framework for Hydrogenation of Nitroarenes

“…Palladium (Pd)-based catalysts have been previously demonstrated to be active materials for dehydrogenation of NH 3 BH 3 and selective hydrogenation of nitroarenes to anilines. − Although Pd nanoparticles (NPs) feature outstanding catalytic activity for the useful reactions, they are apt to aggregate, thus limiting their wide usages. To overcome this issue, the restriction of Pd NPs inside porous materials is known to be an effective method. − …”