Ultrathin Platinum Nanowire Catalysts for Direct CN Coupling of Carbonyls with Aromatic Nitro Compounds under 1 Bar of Hydrogen

Abstract

Traditionally important in the pharmaceutical, agrochemical, and synthetic dye industries, C-N coupling has proved useful for the preparation of a number of valuable organic compounds. Here, a new method for the direct one-pot reductive C-N coupling from carbonyl and aromatic nitro compounds is described. Employing ultrathin platinum nanowires as the catalyst and hydrogen as the reducing agent, N-alkylamines were achieved in high yields. Debenzylation products were not detected after prolonged reaction times. Time-dependent analysis, ReactIR spectroscopy and DFT calculations revealed that the C-N coupling proceeded through a different mechanism than traditional "reductive amination." N-Alkylamines were directly obtained by intermolecular dehydration over platinum nanowires under a hydrogen atmosphere, instead of intramolecular water elimination and imine hydrogenation.

Simulating periodic trends in the structure and catalytic activity of coinage metal nanoribbons

“…Doped nickel nanotubes have been proposed as selective oxidation catalysts . Platinum nanowires show catalytic activity to butane hydrogenolysis and CN coupling . Platinum nanowires also have shown a higher catalytic activity to the water–gas shift reaction than that of Pt nanoparticles .…”

Structural Dependence of Platinum Nanostructures on Catalytic Performance in Aromatic Azo Compound Reaction Investigated by X-ray Absorption Fine Structure Spectroscopy

“…25,26 Our previous work has demonstrated that ultra-thin Pt NWs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 with the average diameter of less than 2 nm showed excellent catalytic performance for the selective hydrogenation of nitrobenzene to the formation of Aazos compared to other Pt nanostructures such as NRs and NPs. 14,27 The representative TEM images of Pt NPs, Pt NRs and Pt NWs are shown in Figure 1 220) and (220). The higher intensity and sharper shape of peaks for Pt NPs are observed than those for Pt NWs and Pt NRs, indicating Pt NPs has the higher order crystalline structure than Pt NRs and NWs.…”

“…Then the RNOH could couple with RNO and consequently dehydrated into the Aazos as target product. 27 1Therefore, in the base, the reduction process of nitrobenzene is inclined to partial hydrogenation compared with preference full hydrogenation in acid under catalysis action of Pt NWs. Moreover, it is noticeable that the -OH radical in the form of Pt-OH is key component for the selectivity of Pt catalyst in the nitrobenzene reduction process.…”

Biomimetic Synthesis of an Ultrathin Platinum Nanowire Network with a High Twin Density for Enhanced Electrocatalytic Activity and Durability

“…[5,15,16] As a result, various methods including both top-down and bottom-up have been developed to synthesize Pt 1D nanostructures. [17][18][19][20][21][22][23][24][25] Most prior studies reported the production of single-crystalline Pt nanowires. [18,21,[23][24][25] Meanwhile, twinning of materials has been shown to greatly affect the physical and chemical material properties, including various surface adsorption, heterogeneous catalytic, and electrocatalytic processes.…”

“…[17][18][19][20][21][22][23][24][25] Most prior studies reported the production of single-crystalline Pt nanowires. [18,21,[23][24][25] Meanwhile, twinning of materials has been shown to greatly affect the physical and chemical material properties, including various surface adsorption, heterogeneous catalytic, and electrocatalytic processes. [26][27][28][29] While nanotwins have been widely employed to enhance mechanical properties, very limited effort has been devoted to engineering of twin defects in nanomaterials for improved catalysis and electrocatalysis.…”