Insights into the mechanism of nitrobenzene reduction to aniline over Pt catalyst and the significance of the adsorption of phenyl group on kinetics

Sheng, Tian; Qi, Yi-Jun; Lin, Xingyi; Hu, P.; Sun, Shi‐Gang; Lin, Wen‐Feng

doi:10.1016/j.cej.2016.02.066

Cited by 108 publications

(65 citation statements)

References 48 publications

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“…The category V adsorbates are aromatic compounds: nitrobenzene, benzonitrile, benzaldehyde, chlorobenzene, aniline, toluene, phenol, and benzene (from left to right in Figure ). For all these adsorbates, the aromatic rings lie flat on the Pt surface, which was earlier reported to be the most stable adsorption configuration . The negative adsorption solvation energies for all the adsorbates indicate a favorable effect of water on their adsorption.…”

Section: Resultsmentioning

confidence: 52%

Evaluating Solvent Effects at the Aqueous/Pt(111) Interface

Iyemperumal

Deskins

2017

ChemPhysChem

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Liquid-metal interfaces occur in a number of surface processes, and it is fundamentally important to accurately model them. Herein, it is systematically determined how the presence of water affects several processes by using density functional theory with implicit solvation models. Adsorption of 41 common adsorbates and four catalytic reactions in both vacuum and water over the Pt(111) surface were modeled. The results show that adsorption energies for some species can change significantly in the presence of water (by up to 0.44 eV). It is further shown that solvation effects can be explained and predicted by analyzing simple chemical descriptors such as dipole moment and adsorbate charge. Models from artificial neural networks involving several potential descriptors, including gas-phase solvation energy, adsorbate charge, dipole moment, and surface area, are also reported. When water is present, reaction energies change by up to 0.23 eV, although it appears that water solvent negligibly affects several elementary reaction steps. The results show that hydrogen bonding can be important for a number of reactions, but is largely absent in the implicit solvation models. Furthermore, other solvents besides water were also modeled, and if a solvent has a small dielectric constant, then small solvation effects occur. This work provides guidelines on when solvation effects may be important for surface chemistry, and also provides valuable insights into modeling such effects.

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Section: Resultsmentioning

confidence: 52%

Evaluating Solvent Effects at the Aqueous/Pt(111) Interface

Iyemperumal

Deskins

2017

ChemPhysChem

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“…For the reduction of nitrobenzene, we considered two possible mechanisms, direct deoxygenation and water-assisted deoxygenation (Figs 1 and 3 ). In the former case, two adsorption states of nitrobenzene ( E and F ) on the oxygen vacancy were identified, with the interactions with the surface via the nitro groups rather than phenyl group, in contrast to the chemistry that occurs on noble metal surfaces 14 , 34 , 35 . Estimates of the Bader charges show that the nitrobenzene moiety in species E is nearly neutral (−0.02 a.u.…”

Section: Resultsmentioning

confidence: 99%

Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation

et al. 2018

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Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydrogenation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn-TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various reducible groups. The high activity and selectivity of these catalysts result from the creation of oxygen vacancies on the TiO2 surface by single-site Sn, which leads to efficient, selective activation of the nitro group coupled with a reaction involving hydrogen atoms activated on metal nanoparticles.

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“…In the second step, with the transfer of another 2e − /2H + , IC 2 was converted to a hydroxylamine intermediate (IC 4 ). Finally, IC 4 received the last 2e − /2H + , followed by the production of aniline while eliminating a water molecule [45][46][47][48][49][50][51]. Generally, the reduction of nitrobenzene is mediated by nitroreductase, where reduced flavin mononucleotide (FMNH) is located at the active center as a coenzyme.…”

Section: Mechanism Of Single-electron Reduction Using Nitrobenzene Asmentioning

confidence: 99%

Reductive Activity and Mechanism of Hypoxia- Targeted AGT Inhibitors: An Experimental and Theoretical Investigation

Xiao

Sun

Fan

et al. 2019

IJMS

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O 6 -alkylguanine-DNA alkyltransferase (AGT) is the main cause of tumor cell resistance to DNA-alkylating agents, so it is valuable to design tumor-targeted AGT inhibitors with hypoxia activation. Based on the existing benchmark inhibitor O 6 -benzylguanine (O 6 -BG), four derivatives with hypoxia-reduced potential and their corresponding reduction products were synthesized. A reductase system consisting of glucose/glucose oxidase, xanthine/xanthine oxidase, and catalase were constructed, and the reduction products of the hypoxia-activated prodrugs under normoxic and hypoxic conditions were determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that the reduction products produced under hypoxic conditions were significantly higher than that under normoxic condition. The amount of the reduction product yielded from ANBP (2-nitro-6-(3-amino) benzyloxypurine) under hypoxic conditions was the highest, followed by AMNBP (2-nitro-6-(3-aminomethyl)benzyloxypurine), 2-NBP (2-nitro-6-benzyloxypurine), and 3-NBG (O6-(3-nitro)benzylguanine). It should be noted that although the levels of the reduction products of 2-NBP and 3-NBG were lower than those of ANBP and AMNBP, their maximal hypoxic/normoxic ratios were higher than those of the other two prodrugs. Meanwhile, we also investigated the single electron reduction mechanism of the hypoxia-activated prodrugs using density functional theory (DFT) calculations. As a result, the reduction of the nitro group to the nitroso was proven to be a rate-limiting step. Moreover, the 2-nitro group of purine ring was more ready to be reduced than the 3-nitro group of benzyl. The energy barriers of the rate-limiting steps were 34-37 kcal/mol. The interactions between these prodrugs and nitroreductase were explored via molecular docking study, and ANBP was observed to have the highest affinity to nitroreductase, followed by AMNBP, 2-NBP, and 3-NBG. Interestingly, the theoretical results were generally in a good agreement with the experimental results. Finally, molecular docking and molecular dynamics simulations were performed to predict the AGT-inhibitory activity of the four prodrugs and their reduction products. In summary, simultaneous consideration of reduction potential and hypoxic selectivity is necessary to ensure that such prodrugs have good hypoxic tumor targeting. This study provides insights into the hypoxia-activated mechanism of nitro-substituted prodrugs as AGT inhibitors, which may contribute to reasonable design and development of novel tumor-targeted AGT inhibitors. Figure 2. Typical selected reaction monitoring (SRM) ion chromatograms of ABG, AMBG, and O 6 -BG obtained from the four prodrugs (3-NBG, 2-NBP, ANBP, and AMNBP) and the internal standard D6-O 6 -BG. The prodrugs were reduced in normoxic or hypoxic condition. (A) Control sample without 3-NBG and ANBP. (B) Reduction of 3-NBG and ANBP under normoxic conditions. (C) Reduction of 3-NBG and ANBP under hypoxic conditions. (D) Control...

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Insights into the mechanism of nitrobenzene reduction to aniline over Pt catalyst and the significance of the adsorption of phenyl group on kinetics

Cited by 108 publications

References 48 publications

Evaluating Solvent Effects at the Aqueous/Pt(111) Interface

Evaluating Solvent Effects at the Aqueous/Pt(111) Interface

Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation

Reductive Activity and Mechanism of Hypoxia- Targeted AGT Inhibitors: An Experimental and Theoretical Investigation

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