1
|
Máximo-Canadas M, Modesto-Costa L, Borges I. Ab initio electronic absorption spectra of para-nitroaniline in different solvents: Intramolecular charge transfer effects. J Comput Chem 2024. [PMID: 39212073 DOI: 10.1002/jcc.27493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 07/19/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024]
Abstract
Intramolecular charge transfer (ICT) effects of para-nitroaniline (pNA) in eight solvents (cyclohexane, toluene, acetic acid, dichloroethane, acetone, acetonitrile, dimethylsulfoxide, and water) are investigated extensively. The second-order algebraic diagrammatic construction, ADC(2), ab initio wave function is employed with the COSMO implicit and discrete multiscale solvation methods. We found a decreasing amine group torsion angle with increased solvent polarity and a linear correlation between the polarity and ADC(2) transition energies. The first absorption band involves π → π* transitions with ICT from the amine and the benzene ring to the nitro group, increased by 4%-11% for different solvation models of water compared to the vacuum. A second band of pNA is characterized for the first time. This band is primarily a local excitation on the nitro group, including some ICT from the amine group to the benzene ring that decreases with the solvent polarity. For cyclohexane, the COSMO implicit solvent model shows the best agreement with the experiment, while the explicit model has the best agreement for water.
Collapse
Affiliation(s)
- Matheus Máximo-Canadas
- Departamento de Química, Instituto Militar de Engenharia (IME), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lucas Modesto-Costa
- Department of Physics, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
| | - Itamar Borges
- Departamento de Química, Instituto Militar de Engenharia (IME), Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
2
|
Yu X, Cheng Y, Li Y, Polo-Garzon F, Liu J, Mamontov E, Li M, Lennon D, Parker SF, Ramirez-Cuesta AJ, Wu Z. Neutron Scattering Studies of Heterogeneous Catalysis. Chem Rev 2023. [PMID: 37315192 DOI: 10.1021/acs.chemrev.3c00101] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Understanding the structural dynamics/evolution of catalysts and the related surface chemistry is essential for establishing structure-catalysis relationships, where spectroscopic and scattering tools play a crucial role. Among many such tools, neutron scattering, though less-known, has a unique power for investigating catalytic phenomena. Since neutrons interact with the nuclei of matter, the neutron-nucleon interaction provides unique information on light elements (mainly hydrogen), neighboring elements, and isotopes, which are complementary to X-ray and photon-based techniques. Neutron vibrational spectroscopy has been the most utilized neutron scattering approach for heterogeneous catalysis research by providing chemical information on surface/bulk species (mostly H-containing) and reaction chemistry. Neutron diffraction and quasielastic neutron scattering can also supply important information on catalyst structures and dynamics of surface species. Other neutron approaches, such as small angle neutron scattering and neutron imaging, have been much less used but still give distinctive catalytic information. This review provides a comprehensive overview of recent advances in neutron scattering investigations of heterogeneous catalysis, focusing on surface adsorbates, reaction mechanisms, and catalyst structural changes revealed by neutron spectroscopy, diffraction, quasielastic neutron scattering, and other neutron techniques. Perspectives are also provided on the challenges and future opportunities in neutron scattering studies of heterogeneous catalysis.
Collapse
Affiliation(s)
- Xinbin Yu
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381, United States
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yuanyuan Li
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381, United States
| | - Felipe Polo-Garzon
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381, United States
| | - Jue Liu
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Meijun Li
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - David Lennon
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Stewart F Parker
- ISIS Pulsed Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
| | - Anibal J Ramirez-Cuesta
- Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Zili Wu
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381, United States
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| |
Collapse
|
3
|
Moorthi K, Maekawa S. Solvation Effects on Polarizability of Aromatic Fluids. J Phys Chem B 2023; 127:2237-2249. [PMID: 36877130 DOI: 10.1021/acs.jpcb.2c08520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Elucidating solvation effects on polarizability in condensed phases is important for the description of the optical and dielectric behavior of high-refractive-index molecular materials. We study these effects via the polarizability model combining electronic, solvation, and vibrational contributions. The method is applied to well-characterized highly polarizable liquid precursors: benzene, naphthalene, and phenanthrene. We find that the solvation and vibrational terms are of opposite signs and cancel almost exactly for benzene, but for naphthalene and phenanthrene, a 2.5 and 5.0% decrease relative to the equilibrium electronic polarizability of the respective monomer, α1e, is predicted, respectively. The increase in electronic polarizability affects interaction polarizability of all contacts, which is the main reason for the increasing importance of solvation contribution. The calculated refractive indices agree very well with experiment for all three systems.
Collapse
Affiliation(s)
- Krzysztof Moorthi
- R&D Center, Mitsui Chemicals, Inc., 580-32 Nagaura, Sodegaura 299-0265, Japan
| | - Shintaro Maekawa
- R&D Center, Mitsui Chemicals, Inc., 580-32 Nagaura, Sodegaura 299-0265, Japan
| |
Collapse
|
4
|
Belleflamme F, Hehn AS, Iannuzzi M, Hutter J. A variational formulation of the Harris functional as a correction to approximate Kohn-Sham density functional theory. J Chem Phys 2023; 158:054111. [PMID: 36754794 DOI: 10.1063/5.0122671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Accurate descriptions of intermolecular interactions are of great importance in simulations of molecular liquids. We present an electronic structure method that combines the accuracy of the Harris functional approach with the computational efficiency of approximately linear-scaling density functional theory (DFT). The non-variational nature of the Harris functional has been addressed by constructing a Lagrangian energy functional, which restores the variational condition by imposing stationarity with respect to the reference density. The associated linear response equations may be treated with linear-scaling efficiency in an atomic orbital based scheme. Key ingredients to describe the structural and dynamical properties of molecular systems are the forces acting on the atoms and the stress tensor. These first-order derivatives of the Harris Lagrangian have been derived and implemented in consistence with the energy correction. The proposed method allows for simulations with accuracies close to the Kohn-Sham DFT reference. Embedded in the CP2K program package, the method is designed to enable ab initio molecular dynamics simulations of molecular solutions for system sizes of several thousand atoms. Available subsystem DFT methods may be used to provide the reference density required for the energy correction at near linear-scaling efficiency. As an example of production applications, we applied the method to molecular dynamics simulations of the binary mixtures cyclohexane-methanol and toluene-methanol, performed within the isobaric-isothermal ensemble, to investigate the hydrogen bonding network in these non-ideal mixtures.
Collapse
Affiliation(s)
- Fabian Belleflamme
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Anna-Sophia Hehn
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Marcella Iannuzzi
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jürg Hutter
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| |
Collapse
|
5
|
McGrogan A, Byrne EL, Guiney R, Headen TF, Youngs TGA, Chrobok A, Holbrey JD, Swadźba-Kwaśny M. The structure of protic ionic liquids based on sulfuric acid, doped with excess of sulfuric acid or with water. Phys Chem Chem Phys 2023; 25:9785-9795. [PMID: 36647728 DOI: 10.1039/d2cp04292d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neutron scattering with isotopic substitution was used to study the structure of concentrated sulfuric acid, and two protic ionic liquids (PILs): a Brønsted-acidic PIL, synthesised using pyridine and excess of sulfuric acid, [Hpy][HSO4]·H2SO4, and a hydrated PIL, in which an equimolar mixture of sulfuric acid and pyridine has been doped with water, [Hpy][HSO4]·2H2O. Brønsted acidic PILs are excellent solvents/catalysts for esterifications, driving reaction to completion by phase-separating water and ester products. Water-doped PILs are efficient solvents/antisolvents in biomass fractionation. This study was carried out to provide an insight into the relationship between the performance of PILs in the two respective processes and their liquid structure. It was found that a persistent sulfate/sulfuric acid/water network structure was retained through the transition from sulfuric acid to PILs, even in the presence of 2 moles (∼17 wt%) of water. Hydrogen sulfate PILs have the propensity to incorporate water into hydrogen-bonded anionic chains, with strong and directional hydrogen bonds, which essentially form a new water-in-salt solvent system, with its own distinct structure and physico-chemical properties. It is the properties of this hydrated PIL that can be credited both for the good performance in esterification and beneficial solvent/antisolvent behaviour in biomass fractionation.
Collapse
Affiliation(s)
- Anne McGrogan
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK.
| | - Emily L Byrne
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK.
| | - Robert Guiney
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK.
| | - Thomas F Headen
- Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | | | - Anna Chrobok
- Department of Chemical Organic Technology and Petrochemistry, Silesian University of Technology, Krzywoustego 4, 44-100, Gilwice, Poland
| | - John D Holbrey
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK.
| | - Małgorzata Swadźba-Kwaśny
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK.
| |
Collapse
|
6
|
Liquid structure of a water-based, hydrophobic and natural deep eutectic solvent: the case of thymol-water. A Molecular Dynamics study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.121151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
7
|
Schewe HC, Brezina K, Kostal V, Mason PE, Buttersack T, Stemer DM, Seidel R, Quevedo W, Trinter F, Winter B, Jungwirth P. Photoelectron Spectroscopy of Benzene in the Liquid Phase and Dissolved in Liquid Ammonia. J Phys Chem B 2021; 126:229-238. [PMID: 34935378 DOI: 10.1021/acs.jpcb.1c08172] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report valence band photoelectron spectroscopy measurements of gas-phase and liquid-phase benzene as well as those of benzene dissolved in liquid ammonia, complemented by electronic structure calculations. The origins of the sizable gas-to-liquid-phase shifts in electron binding energies deduced from the benzene valence band spectral features are quantitatively characterized in terms of the Born-Haber solvation model. This model also allows to rationalize the observation of almost identical shifts in liquid ammonia and benzene despite the fact that the former solvent is polar while the latter is not. For neutral solutes like benzene, it is the electronic polarization response determined by the high frequency dielectric constant of the solvent, which is practically the same in the two liquids, that primarily determines the observed gas-to-liquid shifts.
Collapse
Affiliation(s)
- H Christian Schewe
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Krystof Brezina
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.,Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Vojtech Kostal
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Philip E Mason
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Tillmann Buttersack
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Dominik M Stemer
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Wilson Quevedo
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Florian Trinter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.,Institut für Kernphysik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main, Germany
| | - Bernd Winter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| |
Collapse
|
8
|
Bulk and Confined Benzene-Cyclohexane Mixtures Studied by an Integrated Total Neutron Scattering and NMR Method. Top Catal 2021. [DOI: 10.1007/s11244-021-01437-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AbstractHerein mixtures of cyclohexane and benzene have been investigated in both the bulk liquid phase and when confined in MCM-41 mesopores. The bulk mixtures have been studied using total neutron scattering (TNS), and the confined mixtures have been studied by a new flow-utilising, integrated TNS and NMR system (Flow NeuNMR), all systems have been analysed using empirical potential structure refinement (EPSR). The Flow NeuNMR setup provided precise time-resolved chemical sample composition through NMR, overcoming the difficulties of ensuring compositional consistency for computational simulation of data ordinarily found in TNS experiments of changing chemical composition—such as chemical reactions. Unique to the liquid mixtures, perpendicularly oriented benzene molecules have been found at short distances from the cyclohexane rings in the regions perpendicular to the carbon–carbon bonds. Upon confinement of the hydrocarbon mixtures, a stronger parallel orientational preference of unlike molecular dimers, at short distances, has been found. At longer first coordination shell distances, the like benzene molecular spatial organisation within the mixture has also found to be altered upon confinement.
Collapse
|
9
|
Onur Şahin E, Tüysüz H, Chan CK, Moon GH, Dai Y, Schmidt W, Lim J, Scheu C, Weidenthaler C. In situ total scattering experiments of nucleation and crystallisation of tantalum-based oxides: from highly dilute solutions via cluster formation to nanoparticles. NANOSCALE 2021; 13:150-162. [PMID: 33325940 DOI: 10.1039/d0nr07871a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The exact formation mechanism of tantalum oxides (and in general, metal/mixed metal oxides) from alkoxide precursors is still not fully understood, particularly when forming cluster-like or amorphous materials. The structural evolution of Ta-based oxides was studied in detail using X-ray total scattering experiments along with subsequent pair distribution function (PDF) analyses. Starting from a tantalum alkoxide precursor (Ta2(OEt)10), the formation of hydrolysed TaxOyHz clusters in highly diluted aqueous solution was analysed. From the PDF data, the connectivity and arrangement of TaxOy octahedra in the cluster could be deduced as well as the approximate size of the clusters (<1 nm). Construction of cluster models allowed for identification of common structural motifs in the TaxOyHz clusters, ruling out the formation of chain- or ring-like clusters. More likely, bulky clusters with a high number of corner-sharing octahedra are formed. After separation of the amorphous solid from the liquid, temperature-induced crystallisation processes were monitored via in situ total scattering experiments. Between room temperature and 600 °C, only small rearrangements of the amorphous structure are observed. At about 610 °C, amorphous TaxOyHz transforms directly into crystalline orthorhombic L-Ta2O5 without formation of any crystalline intermediate structures.
Collapse
Affiliation(s)
- Ezgi Onur Şahin
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Triolo A, Lo Celso F, Plechkova NV, Leonelli F, Gärtner S, Keeble DS, Russina O. Structure of anisole derivatives by total neutron and X-ray scattering: Evidences of weak C H⋯O and C H⋯π interactions in the liquid state. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
11
|
Huang HT, Zhu L, Ward MD, Wang T, Chen B, Chaloux BL, Wang Q, Biswas A, Gray JL, Kuei B, Cody GD, Epshteyn A, Crespi VH, Badding JV, Strobel TA. Nanoarchitecture through Strained Molecules: Cubane-Derived Scaffolds and the Smallest Carbon Nanothreads. J Am Chem Soc 2020; 142:17944-17955. [PMID: 31961671 DOI: 10.1021/jacs.9b12352] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Relative to the rich library of small-molecule organics, few examples of ordered extended (i.e., nonmolecular) hydrocarbon networks are known. In particular, sp3 bonded, diamond-like materials represent appealing targets because of their desirable mechanical, thermal, and optical properties. While many covalent organic frameworks (COFs)-extended, covalently bonded, and porous structures-have been realized through molecular architecture with exceptional control, the design and synthesis of dense, covalent extended solids has been a longstanding challenge. Here we report the preparation of a sp3-bonded, low-dimensional hydrocarbon synthesized via high-pressure, solid-state diradical polymerization of cubane (C8H8), which is a saturated, but immensely strained, cage-like molecule. Experimental measurements show that the obtained product is crystalline with three-dimensional order that appears to largely preserve the basic structural topology of the cubane molecular precursor and exhibits high hardness (comparable to fused quartz) and thermal stability up to 300 °C. Among the plausible theoretical candidate structures, one-dimensional carbon scaffolds comprising six- and four-membered rings that pack within a pseudosquare lattice provide the best agreement with experimental data. These diamond-like molecular rods with extraordinarily small thickness are among the smallest members in the carbon nanothread family, and calculations indicate one of the stiffest one-dimensional systems known. These results present opportunities for the synthesis of purely sp3-bonded extended solids formed through the strain release of saturated molecules, as opposed to only unsaturated precursors.
Collapse
Affiliation(s)
| | - Li Zhu
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road Northwest, Washington, DC 20015, United States
| | - Matthew D Ward
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road Northwest, Washington, DC 20015, United States
| | | | | | - Brian L Chaloux
- Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375, United States
| | - Qianqian Wang
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road Northwest, Washington, DC 20015, United States
| | | | | | | | - George D Cody
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road Northwest, Washington, DC 20015, United States
| | - Albert Epshteyn
- Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375, United States
| | | | | | - Timothy A Strobel
- Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road Northwest, Washington, DC 20015, United States
| |
Collapse
|
12
|
Dervin D, O'Malley AJ, Falkowska M, Chansai S, Silverwood IP, Hardacre C, Catlow CRA. Probing the dynamics and structure of confined benzene in MCM-41 based catalysts. Phys Chem Chem Phys 2020; 22:11485-11489. [DOI: 10.1039/d0cp01196g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Combined MD simulations and QENS experiments on benzene in MCM-41 provide insight into the dynamics and structure of benzene
Collapse
Affiliation(s)
- Daniel Dervin
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- Belfast
- UK
- UK Catalysis Hub
| | - A. J. O'Malley
- Centre for Sustainable Chemical Technologies
- Department of Chemistry
- University of Bath
- Claverton Down
- UK
| | - Marta Falkowska
- Department of Chemical Engineering and Analytical Science, School of Engineering
- The University of Manchester
- Manchester
- UK
| | - Sarayute Chansai
- Department of Chemical Engineering and Analytical Science, School of Engineering
- The University of Manchester
- Manchester
- UK
| | | | - Christopher Hardacre
- UK Catalysis Hub
- Research Complex at Harwell
- Rutherford Appleton Laboratory
- Harwell OX11 0FA
- UK
| | - C. R. A. Catlow
- UK Catalysis Hub
- Research Complex at Harwell
- Rutherford Appleton Laboratory
- Harwell OX11 0FA
- UK
| |
Collapse
|
13
|
Headen TF. Temperature dependent structural changes in liquid benzene studied using neutron diffraction. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1631496] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Thomas F. Headen
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, Oxon, UK
| |
Collapse
|
14
|
Basma NS, Headen TF, Shaffer MSP, Skipper NT, Howard CA. Local Structure and Polar Order in Liquid N-Methyl-2-pyrrolidone (NMP). J Phys Chem B 2018; 122:8963-8971. [DOI: 10.1021/acs.jpcb.8b08020] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Nadir S. Basma
- Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, U.K
- Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Thomas F. Headen
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, Oxfordshire, U.K
| | - Milo S. P. Shaffer
- Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, U.K
| | - Neal T. Skipper
- Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Christopher A. Howard
- Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| |
Collapse
|
15
|
Brown LC, Hogg JM, Gilmore M, Moura L, Imberti S, Gärtner S, Gunaratne HQN, O'Donnell RJ, Artioli N, Holbrey JD, Swadźba-Kwaśny M. Frustrated Lewis pairs in ionic liquids and molecular solvents - a neutron scattering and NMR study of encounter complexes. Chem Commun (Camb) 2018; 54:8689-8692. [PMID: 29938294 DOI: 10.1039/c8cc03794a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The presence of the weakly-associated encounter complex in the model frustrated Lewis pair solution (FLP): tris(tert-butyl)phosphine (P(tBu)3) and tris(pentafluorophenyl)borane (BCF) in benzene, was confirmed via PB correlation analysis from neutron scattering data. On average, ca. 5% of dissolved FLP components were in the associated state. NMR spectra of the FLP in benzene gave no evidence of such association, in agreement with earlier reports and the transient nature of the encounter complex. In contrast, the corresponding FLP solution in the ionic liquid, 1-decyl-3-methylimidazolium bistriflamide, [C10mim][NTf2], generated NMR signals that can be attributed to formation of encounter complexes involving over 20% of the dissolved species. The low diffusivity characteristics of ionic liquids is suggested to enhance high populations of encounter complex. The FLP in the ionic liquid solution retained its ability to split hydrogen.
Collapse
Affiliation(s)
- Lucy C Brown
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - James M Hogg
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Mark Gilmore
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Leila Moura
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Silvia Imberti
- ISIS, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Sabrina Gärtner
- ISIS, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - H Q Nimal Gunaratne
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Ruairi J O'Donnell
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Nancy Artioli
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - John D Holbrey
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| | - Małgorzata Swadźba-Kwaśny
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, UK.
| |
Collapse
|
16
|
Morrow BH, Maskey S, Gustafson MZ, Luning Prak DJ, Harrison JA. Impact of Molecular Structure on Properties of n-Hexadecane and Alkylbenzene Binary Mixtures. J Phys Chem B 2018; 122:6595-6603. [PMID: 29856636 DOI: 10.1021/acs.jpcb.8b03752] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Because of the complexity of petroleum-based fuels, researchers typically use simplified mixtures, known as surrogates, to study combustion behavior and to attempt to identify how physical properties are related to combustion. The process of determining the surrogate composition to yield a desired set of thermophysical properties can be a complicated and time-consuming task. As a result, the use of computer simulations to narrow the number of possible surrogate compositions is beginning to be explored. Herein, molecular dynamics (MD) simulations are used to model binary mixtures of n-hexadecane with either benzene, toluene, n-ethylbenzene, n-propylbenzene, or n-butylbenzene. Calculated densities are in quantitative agreement with experimental values. With the exception of the mixtures containing benzene, simulated excess molar volumes are also in very good agreement with measured values. Isentropic bulk moduli are in qualitative agreement with experiment, and reproduce interesting trends observed in the experimental data. Specifically, minima in the bulk moduli at intermediate compositions of several of the alkylbenzenes are correctly reproduced. In addition, the structures of the fluids are also examined. For mixtures of n-hexadecane with alkylbenzenes with longer chains, the orientation of the aromatic rings is not substantially impacted by composition. In contrast, increasing n-hexadecane content increases the ratio of parallel to perpendicular arrangements of benzene and toluene molecules. In those mixtures, this change in orientation of the aromatic rings could be responsible for the minima observed in the bulk moduli data. These results show that MD simulations can assist in development of fuel surrogates, both by predicting thermophysical properties and by providing insight into how molecular structure and composition affect those properties.
Collapse
Affiliation(s)
- Brian H Morrow
- Department of Chemistry , United States Naval Academy , Annapolis , Maryland 21402 , United States
| | - Sabina Maskey
- Department of Chemistry , United States Naval Academy , Annapolis , Maryland 21402 , United States
| | - Micah Z Gustafson
- Department of Chemistry , United States Naval Academy , Annapolis , Maryland 21402 , United States
| | - Dianne J Luning Prak
- Department of Chemistry , United States Naval Academy , Annapolis , Maryland 21402 , United States
| | - Judith A Harrison
- Department of Chemistry , United States Naval Academy , Annapolis , Maryland 21402 , United States
| |
Collapse
|
17
|
Falkowska M, Bowron DT, Manyar H, Youngs TGA, Hardacre C. Confinement Effects on the Benzene Orientational Structure. Angew Chem Int Ed Engl 2018; 57:4565-4570. [PMID: 29446870 PMCID: PMC6099463 DOI: 10.1002/anie.201713115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Indexed: 11/15/2022]
Abstract
Liquids under confinement exhibit different properties compared with their corresponding bulk phases, for example, miscibility, phase transitions, and diffusion. The underlying cause is the local ordering of molecules, which is usually only studied using pure simulation methods. Herein, we derive experimentally the structure of benzene confined in MCM-41 using total neutron scattering measurements. The study reveals a layering of molecules across a pore, and four concentric cylindrical shells can be distinguished for a pore with the radius of 18 Å. The nanoscale confinement of the liquid has a major effect on the spatial and orientational correlations observed between the molecules, when compared with the structure of the bulk liquid. These differences are most marked for molecules in parallel configurations, and this suggests differences in chemical reactivity between the confined and bulk liquids.
Collapse
Affiliation(s)
- Marta Falkowska
- School of Chemical Engineering and Analytical ScienceThe University of ManchesterUK
| | - Daniel T. Bowron
- ISIS Neutron and Muon SourceScience and Technology Facilities CouncilUK
| | - Haresh Manyar
- School of Chemistry and Chemical EngineeringQueen's University BelfastUK
| | | | - Christopher Hardacre
- School of Chemical Engineering and Analytical ScienceThe University of ManchesterUK
| |
Collapse
|
18
|
Falkowska M, Bowron DT, Manyar H, Youngs TGA, Hardacre C. Confinement Effects on the Benzene Orientational Structure. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201713115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Marta Falkowska
- School of Chemical Engineering and Analytical Science The University of Manchester UK
| | - Daniel T. Bowron
- ISIS Neutron and Muon Source Science and Technology Facilities Council UK
| | - Haresh Manyar
- School of Chemistry and Chemical Engineering Queen's University Belfast UK
| | | | - Christopher Hardacre
- School of Chemical Engineering and Analytical Science The University of Manchester UK
| |
Collapse
|
19
|
Macchiagodena M, Del Frate G, Brancato G, Chandramouli B, Mancini G, Barone V. Computational study of the DPAP molecular rotor in various environments: from force field development to molecular dynamics simulations and spectroscopic calculations. Phys Chem Chem Phys 2018; 19:30590-30602. [PMID: 29115317 DOI: 10.1039/c7cp04688j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Fluorescent molecular rotors (FMRs) belong to an important class of environment-sensitive dyes capable of acting as nanoprobes in the measurement of viscosity and polarity of their micro-environment. FMRs have found widespread applications in various research fields, ranging from analytical to biochemical sciences, for example in intracellular imaging studies or in volatile organic compound detection. Here, a computational investigation of a recently proposed FMR, namely 4-(diphenylamino)phthalonitrile (DPAP), in various chemical environments is presented. A purposely developed molecular mechanics force field is proposed and then applied to simulate the rotor in a high- and low-polar solvent (i.e., acetonitrile, tetrahydrofuran, o-xylene and cyclohexane), a polymer matrix and a lipid membrane. Subtle effects of the molecular interactions with the embedding medium, the structural fluctuations of the rotor and its rotational dynamics are analyzed in some detail. The results correlate with a previous work, thus supporting the reliability of the model, and provide further insights into the environment-specific properties of the dye. In particular, it is shown how molecular diffusion and rotational correlation times of the FMR are affected by the surrounding medium and how the molecular orientation of the dye becomes anisotropic once immersed in the lipid bilayer. Moreover, a qualitative correlation between the FMR rotational dynamics and the fluorescence lifetime is detected, a result in line with the observed viscosity dependence of its emission. Finally, optical absorption spectra are computed and successfully compared with their experimental counterparts.
Collapse
|
20
|
Ingram DJ, Headen TF, Skipper NT, Callear SK, Billing M, Sella A. Dihydrogen vs. hydrogen bonding in the solvation of ammonia borane by tetrahydrofuran and liquid ammonia. Phys Chem Chem Phys 2018; 20:12200-12209. [DOI: 10.1039/c7cp08220g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The solvation structures of two systems rich in hydrogen and dihydrogen bonding interactions have been studied in detail experimentally through neutron diffraction with hydrogen/deuterium isotopic substitution.
Collapse
Affiliation(s)
- David J. Ingram
- Department of Physics & Astronomy
- University College London
- London
- UK
- Department of Chemistry
| | | | - Neal T. Skipper
- Department of Physics & Astronomy
- University College London
- London
- UK
- London Centre for Nanotechnology
| | | | | | - Andrea Sella
- Department of Chemistry
- University College London
- London
- UK
| |
Collapse
|
21
|
Leutzsch M, Falkowska M, Hughes TL, Sederman AJ, Gladden LF, Mantle MD, Youngs TGA, Bowron D, Manyar H, Hardacre C. An integrated total neutron scattering – NMR approach for the study of heterogeneous catalysis. Chem Commun (Camb) 2018; 54:10191-10194. [DOI: 10.1039/c8cc04740e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By combining total neutron scattering with nuclear magnetic resonance (NeuNMR) in a single experimental apparatus, new insights into the kinetics and mechanisms of heterogeneous catalytic reactions occurring in situ, within the catalyst pore space, are possible.
Collapse
Affiliation(s)
- Markus Leutzsch
- Department of Chemical Engineering and Biotechnology
- Philippa Fawcett Drive
- University of Cambridge
- Cambridge
- UK
| | - Marta Falkowska
- School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester
- UK
| | - Terri-Louise Hughes
- School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester
- UK
| | - Andrew J. Sederman
- Department of Chemical Engineering and Biotechnology
- Philippa Fawcett Drive
- University of Cambridge
- Cambridge
- UK
| | - Lynn F. Gladden
- Department of Chemical Engineering and Biotechnology
- Philippa Fawcett Drive
- University of Cambridge
- Cambridge
- UK
| | - Michael D. Mantle
- Department of Chemical Engineering and Biotechnology
- Philippa Fawcett Drive
- University of Cambridge
- Cambridge
- UK
| | | | - Daniel Bowron
- STFC ISIS Facility
- Rutherford Appleton Laboratory Chilton
- Didcot
- UK
| | - Haresh Manyar
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- UK
| | - Christopher Hardacre
- School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester
- UK
| |
Collapse
|
22
|
Headen TF, Cullen PL, Patel R, Taylor A, Skipper NT. The structures of liquid pyridine and naphthalene: the effects of heteroatoms and core size on aromatic interactions. Phys Chem Chem Phys 2018; 20:2704-2715. [DOI: 10.1039/c7cp06689a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spatial and orientational structures of liquid naphthalene and pyridine revealed using neutron scattering combined with empirical potential structure refinement.
Collapse
Affiliation(s)
- T. F. Headen
- ISIS Neutron Facility, STFC Rutherford Appleton Laboratory, Harwell Campus
- Didcot
- UK
| | - P. L. Cullen
- University College London, Dept. Physics and Astronomy
- London
- UK
| | - R. Patel
- University College London, Dept. Physics and Astronomy
- London
- UK
| | - A. Taylor
- University College London, Dept. Physics and Astronomy
- London
- UK
| | - N. T. Skipper
- University College London, Dept. Physics and Astronomy
- London
- UK
| |
Collapse
|
23
|
Szala-Bilnik J, Falkowska M, Bowron DT, Hardacre C, Youngs TGA. The Structure of Ethylbenzene, Styrene and Phenylacetylene Determined by Total Neutron Scattering. Chemphyschem 2017; 18:2541-2548. [PMID: 28672104 PMCID: PMC5811833 DOI: 10.1002/cphc.201700393] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/30/2017] [Indexed: 11/10/2022]
Abstract
Organic solvents such as phenylacetylene, styrene and ethylbenzene are widely used in industrial processes, especially in the production of rubber or thermoplastics. Despite their important applications detailed knowledge about their structure is limited. In this paper the structures of these three aromatic solvents were investigated using neutron diffraction. The results show that many of their structural characteristics are similar, although the structure of phenylacetylene is more ordered and has a smaller solvation sphere than either ethylbenzene or styrene. Two regions within the first coordination sphere, in which the surrounding molecules show different preferable orientations with respect to the central molecule, were found for each liquid. Additionally, the localisation of the aliphatic chains reveals that they tend to favour closer interactions with each other than to the aromatic rings of the adjacent molecules.
Collapse
Affiliation(s)
- Joanna Szala-Bilnik
- School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK.,STFC ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| | - Marta Falkowska
- STFC ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK.,School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, UK
| | - Daniel T Bowron
- STFC ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| | - Christopher Hardacre
- School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK
| | - Tristan G A Youngs
- STFC ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| |
Collapse
|
24
|
Falkowska M, Bowron DT, Manyar HG, Hardacre C, Youngs TGA. Neutron Scattering of Aromatic and Aliphatic Liquids. Chemphyschem 2016; 17:2043-55. [PMID: 26990367 PMCID: PMC4999024 DOI: 10.1002/cphc.201600149] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 11/06/2022]
Abstract
Organic solvents, such as cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene, are widely used as both reagents and solvents in industrial processes. Despite the ubiquity of these liquids, the local structures that govern the chemical properties have not been studied extensively. Herein, we report neutron diffraction measurements on liquid cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene at 298 K to obtain a detailed description of the local structure in these compounds. The radial distribution functions of the centres of the molecules, as well as the partial distribution functions for the double bond for cyclohexene and methyl group for methylcyclohexane and toluene have been calculated. Additionally, probability density functions and angular radial distribution functions were extracted to provide a full description of the local structure within the chosen liquids. Structural motifs are discussed and compared for all liquids, referring specifically to the functional group and aromaticity present in the different liquids.
Collapse
Affiliation(s)
- Marta Falkowska
- STFC ISIS Facility, Rutherford Appleton Laboratory, Harwell, Oxford, Didcot, Oxon, OX11 0QX, UK.,CenTACat, School of Chemistry and Chemical Engineering, Queen's University, Belfast, Stranmillis Road, BT9 5AG, UK
| | - Daniel T Bowron
- STFC ISIS Facility, Rutherford Appleton Laboratory, Harwell, Oxford, Didcot, Oxon, OX11 0QX, UK
| | - Haresh G Manyar
- CenTACat, School of Chemistry and Chemical Engineering, Queen's University, Belfast, Stranmillis Road, BT9 5AG, UK
| | - Christopher Hardacre
- CenTACat, School of Chemistry and Chemical Engineering, Queen's University, Belfast, Stranmillis Road, BT9 5AG, UK.
| | - Tristan G A Youngs
- STFC ISIS Facility, Rutherford Appleton Laboratory, Harwell, Oxford, Didcot, Oxon, OX11 0QX, UK.
| |
Collapse
|
25
|
Falkowska M, Chansai S, Manyar HG, Gladden LF, Bowron DT, Youngs TGA, Hardacre C. Determination of toluene hydrogenation kinetics with neutron diffraction. Phys Chem Chem Phys 2016; 18:17237-43. [DOI: 10.1039/c6cp01494a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Total neutron scattering has been used to follow the hydrogenation of toluene-d8 to methylcyclohexane-d14 over 3 wt% platinum supported on highly ordered mesoporous silica (MCM-41) at 298 K and under 150–250 mbar D2 pressure.
Collapse
Affiliation(s)
- Marta Falkowska
- STFC ISIS Facility
- Rutherford Appleton Laboratory
- Harwell Campus
- Oxon
- UK
| | - Sarayute Chansai
- CenTACat
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- UK
| | - Haresh G. Manyar
- CenTACat
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- UK
| | - Lynn F. Gladden
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - Daniel T. Bowron
- STFC ISIS Facility
- Rutherford Appleton Laboratory
- Harwell Campus
- Oxon
- UK
| | | | - Christopher Hardacre
- CenTACat
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- UK
| |
Collapse
|