Nucleobases tagged to gold nanoclusters cause a mechanistic crossover in the oxidation of CO

Rai, Suresh; Ehara, Masahiro

doi:10.1039/c5cp04273a

Cited by 7 publications

(6 citation statements)

References 66 publications

(147 reference statements)

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“…The electronic charge on the NP increases with respect to an increase in the number of EP molecules adsorbed, which is limited by the maximum number of EP molecules that can directly interact with a given NP. It has been shown previously that adding an electron to metal clusters and tagging of small molecules such as DNA bases have a significant electronic effect on the physicochemical properties of metal nanoclusters. ,− This clearly suggests that model chemistries chosen for studying reactions catalyzed by NPs should also appropriately consider the environment of the system. Molecular dynamics simulations can effectively be used to generate initial model systems for further QM or DFT calculations.…”

Section: Resultsmentioning

confidence: 99%

Structure, Interaction, and Dynamics of Au/Pd Bimetallic Nanoalloys Dispersed in Aqueous Ethylpyrrolidone, a Monomeric Moiety of Polyvinylpyrrolidone

et al. 2016

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Bimetallic nanoparticles (NPs) have been shown to exhibit certain advantages over pure NPs in catalysis due to a synergistic effect. It is common to disperse NPs in a polymer matrix such as polyvinylpyrrolidone (PVP) to prevent flocculation, which imparts considerable electronic effects on the NPs. In the present study, the interactions between aqueous solutions of N-ethylpyrrolidone (EP, system chosen to model the monomeric form of PVP) and Au/Pd bimetallic NPs, which are relevant in catalysis, have been investigated using molecular dynamics simulations and density functional theory (DFT) method. The adequacy of the force fields used was assessed based on their ability to reproduce the structures and adsorption energies obtained using DFT calculations. The interactions of NPs with the environment were studied at various concentrations of aqueous solutions of EP to examine the strength of NP–EP and NP–water interactions. Free energy calculations and local mole fraction enhancement values show that that the EP adsorption on NPs is preferred over the adsorption of water. Extensive analysis of the interactions of the NPs with various concentrations of aqueous EP suggests the existence of isolated water molecules that may take part in reactions. Adsorption of unexpectedly large numbers of EP molecules was found to be possible leading to accumulation of the electron density on the Au/Pd NPs, which have previously been shown to enhance the catalytic activity of NPs. This study emphasizes the importance of including the electronic effects on the NPs due to the adsorption of stabilizing agents in modeling and demonstrates the utility of MD simulations to generate appropriate model chemistries for studying catalysis at higher level quantum chemical and density functional theory calculations.

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Section: Resultsmentioning

confidence: 99%

Structure, Interaction, and Dynamics of Au/Pd Bimetallic Nanoalloys Dispersed in Aqueous Ethylpyrrolidone, a Monomeric Moiety of Polyvinylpyrrolidone

et al. 2016

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“…It was vastly reported in earlier studies that the L–H mechanism is more promising for the CO oxidation reaction. , Therefore, we decided to proceed with the L–H mechanism which is divided into two half-reactions (1) CO + O 2 → CO 2 (involves the splitting of the side-on superoxo bond/breaking of the Ni–O bond) and (2) CO + O → CO 2 (the CO oxidation barrier depends on the breaking of the Ni–O bond) to perform CO oxidation over representative systems. Among the representative systems considered to perform CO oxidation, the flawless reaction profile is inspected for the Ni 12 Cu cluster with the lowest activation barrier 1.11 eV ( E a1 ) and 0.84 eV ( E a2 ) for the first and second half-reactions, respectively.…”

Section: Resultsmentioning

confidence: 99%

Dressing of Cu Atom over Nickel Cluster Stimulating the Poisoning-Free CO Oxidation: An Ab Initio Study

et al. 2021

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In this work using first-principles calculations based on spin-polarized density functional theory (DFT), the role of the Cu atom in degrading the poisoning of carbon monoxide (CO) over Ni n Cu clusters is unveiled. The search has been initiated with the examination of structural, magnetic, and electronic properties of Ni n+1 and Ni n Cu clusters (1 ≤ n ≤ 12). X-ray absorption near-edge structure (XANES) spectra of Ni K-edge are computed to extract the information on the oxidation states and coordination environment of metal sites of the clusters. This study is operated with the two forms of dispersion corrections, i.e., D2 and D3, with standard DFT (with LDA and GGA functionals) for the consideration of van der Waals interactions during CO adsorption. The PBE and PBE-D3 approaches are found to be capable of yielding the experimentally observed preferential site for CO adsorption. The effect of spin-polarization on the reactivity of transition metals (TMs) toward CO adsorption is crucially assessed by the electronic reactivity descriptors such as d-band center, d-band width, and fractional filling of d-band using a spin-polarized d-band center model. The effective charge transfer from Cu to Ni atoms makes Ni atoms more efficient of charge and is attributed to the degrading adsorption of CO over Ni n Cu clusters. The Ni12Cu cluster stands out with good CO oxidation activity for the Langmuir–Hinshelwood (L–H) reaction pathway.

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“…The M06 functional has been demonstrated to be a useful functional for applications in transition‐metal‐containing systems . In particular, we have recently shown that DFT calculations with the M06 functional is suitable for the study of chemical reactions on Au NCs . Benchmark calculations using the left‐eigenstate complete renormalized‐coupled cluster method with singles, doubles, and noniterative triples (CR‐CC(2,3)) for the reaction on Au NCs showed that M06 and B3LYP work well for the activation energy barrier, whereas B3LYP overestimates the reaction energy .…”

Section: Computational Detailsmentioning

confidence: 99%

Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

2017

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Density functional theory calculations have been used to investigate the mechanism of intramolecular hydroamination of unactivated alkenes by using primary amines on gold nanoclusters (NCs) under aerobic conditions. By examining the activation modes in the cyclization process, the olefin activation mechanism was calculated to be the most energetically feasible of the three possible pathways. The amine activation pathway suffered from a high activation barrier, which means that this pathway is unlikely to take place on gold NCs. The catalytic cycle comprises five elementary steps: (1) adsorption of O2 on Au NCs results in superoxo‐like species and provides Lewis acidic sites that allow the nucleophilic substrate, 2,2‐diphenyl‐4‐penten‐1‐amine, to be adsorbed effectively; (2) intramolecular cyclization (C−N bond formation) takes place on the Au NCs through anti‐addition of the amino group; (3) hydroperoxy moiety formation by hydrogen transfer from the cyclic intermediate to superoxo‐like species; (4) the formation of hydrogen peroxide and (5) product involves hydrogen transfer from a hydrated formic acid. Natural bond orbital analysis of the transition states that arise during C−N bond formation reveals that anti‐addition of the substrate is preferred over the syn‐addition mechanism. A possible side reaction, the formation of 2‐methylene‐4,4‐diphenylpyrrolidine through β‐hydrogen elimination, is also discussed.

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Nucleobases tagged to gold nanoclusters cause a mechanistic crossover in the oxidation of CO

Cited by 7 publications

References 66 publications

Structure, Interaction, and Dynamics of Au/Pd Bimetallic Nanoalloys Dispersed in Aqueous Ethylpyrrolidone, a Monomeric Moiety of Polyvinylpyrrolidone

Structure, Interaction, and Dynamics of Au/Pd Bimetallic Nanoalloys Dispersed in Aqueous Ethylpyrrolidone, a Monomeric Moiety of Polyvinylpyrrolidone

Dressing of Cu Atom over Nickel Cluster Stimulating the Poisoning-Free CO Oxidation: An Ab Initio Study

Intramolecular Hydroamination by a Primary Amine of an Unactivated Alkene on Gold Nanoclusters: A DFT Study

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