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Falbo E, Fusè M, Lazzari F, Mancini G, Barone V. Integration of Quantum Chemistry, Statistical Mechanics, and Artificial Intelligence for Computational Spectroscopy: The UV-Vis Spectrum of TEMPO Radical in Different Solvents. J Chem Theory Comput 2022; 18:6203-6216. [PMID: 36166322 PMCID: PMC9558374 DOI: 10.1021/acs.jctc.2c00654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The ongoing integration of quantum chemistry, statistical
mechanics,
and artificial intelligence is paving the route toward more effective
and accurate strategies for the investigation of the spectroscopic
properties of medium-to-large size chromophores in condensed phases.
In this context we are developing a novel workflow aimed at improving
the generality, reliability, and ease of use of the available computational
tools. In this paper we report our latest developments with specific
reference to unsupervised atomistic simulations employing non periodic
boundary conditions (NPBC) followed by clustering of the trajectories
employing optimized feature spaces. Next accurate variational computations
are performed for a representative point of each cluster, whereas
intracluster fluctuations are taken into account by a cheap yet reliable
perturbative approach. A number of methodological improvements have
been introduced including, e.g., more realistic reaction field effects
at the outer boundary of the simulation sphere, automatic definition
of the feature space by continuous perception of solute–solvent
interactions, full account of polarization and charge transfer in
the first solvation shell, and inclusion of vibronic contributions.
After its validation, this new approach has been applied to the challenging
case of solvatochromic effects on the UV–vis spectra of a prototypical
nitroxide radical (TEMPO) in different solvents. The reliability,
effectiveness, and robustness of the new platform is demonstrated
by the remarkable agreement with experiment of the results obtained
through an unsupervised approach characterized by a strongly reduced
computational cost as compared to that of conventional quantum mechanics
and molecular mechanics models without any accuracy reduction.
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Affiliation(s)
- Emanuele Falbo
- Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Marco Fusè
- Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.,Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Federico Lazzari
- Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Giordano Mancini
- Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
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2
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Liu Y, Biczysko M, Moriarty NW. A radical approach to radicals. Acta Crystallogr D Struct Biol 2022; 78:43-51. [PMID: 34981760 DOI: 10.1107/s2059798321010809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/18/2021] [Indexed: 11/10/2022] Open
Abstract
Nitroxide radicals are characterized by a long-lived spin-unpaired electronic ground state and are strongly sensitive to their chemical surroundings. Combined with electron paramagnetic resonance spectroscopy, these electronic features have led to the widespread application of nitroxide derivatives as spin labels for use in studying protein structure and dynamics. Site-directed spin labelling requires the incorporation of nitroxides into the protein structure, leading to a new protein-ligand molecular model. However, in protein crystallographic refinement nitroxides are highly unusual molecules with an atypical chemical composition. Because macromolecular crystallography is almost entirely agnostic to chemical radicals, their structural information is generally less accurate or even erroneous. In this work, proteins that contain an example of a radical compound (Chemical Component Dictionary ID MTN) from the nitroxide family were re-refined by defining its ideal structural parameters based on quantum-chemical calculations. The refinement results show that this procedure improves the MTN ligand geometries, while at the same time retaining higher agreement with experimental data.
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Affiliation(s)
- Youjia Liu
- International Center for Quantum and Molecular Structures, Shanghai University, Shanghai 200444, People's Republic of China
| | - Malgorzata Biczysko
- International Center for Quantum and Molecular Structures, Shanghai University, Shanghai 200444, People's Republic of China
| | - Nigel W Moriarty
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235, USA
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3
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Massolle A, Dresselhaus T, Eusterwiemann S, Doerenkamp C, Eckert H, Studer A, Neugebauer J. Towards reliable references for electron paramagnetic resonance parameters based on quantum chemistry: the case of verdazyl radicals. Phys Chem Chem Phys 2018; 20:7661-7675. [PMID: 29497710 DOI: 10.1039/c7cp05657e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an efficient and accurate computational procedure to calculate properties measurable by EPR spectroscopy. We simulate a molecular dynamics (MD) trajectory by employing the quantum mechanically derived force field (QMDFF) [S. Grimme, J. Chem. Theory Comput., 2014, 10, 4497] and sample the trajectory at different time steps. For each snapshot EPR properties are calculated with a hybrid density functional theory (DFT) method. EPR spectra are simulated based on the averaged results. We applied the strategy to a number of previously published and novel verdazyl radicals, for which we recorded EPR spectra. The resulting simulated spectra are compatible with experiment already before employing an additional fitting step, in contrast to those from single point electronic-structure calculations. After the refinement, the experimental data are excellently reproduced, and the fitted EPR parameters do not deviate much from the calculated ones. This provides confidence in ascribing a direct physical meaning to the refined data in terms of experimental EPR parameters rather than merely considering them as mathematical fit parameters. We also find that couplings to hydrogen nuclei have a significant influence on the spectra of verdazyl radicals.
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Affiliation(s)
- Anja Massolle
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.
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Witwicki M, Jezierska J. Toward an Understanding of the Ambiguous Electron Paramagnetic Resonance Spectra of the Iminoxy Radical from o-Fluorobenzaldehyde Oxime: Density Functional Theory and ab Initio Studies. J Phys Chem A 2015; 119:9109-20. [PMID: 26258434 DOI: 10.1021/acs.jpca.5b06143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Iminoxy radicals (R1R2C═N—O•) possess an inherent ability to exist as E and Z isomers. Although isotropic hyperfine couplings for the species with R1 = H allow one to distinguish between E and Z, unequivocal assignment of the parameters observed in the EPR spectra of the radicals without the hydrogen atom at the azomethine carbon to the right isomer is not a simple task. The iminoxyl derived from o-fluoroacetophenone oxime (R1 = CH3 and R2 = o-FC6H5) appears to be a case in point. Moreover, for its two isomers the rotation of the o-FC6H5 group brings into existence the syn and anti conformers, depending on the mutual orientation of the F atom and C═N—O• group, making a description of hyperfine couplings to structure even more challenging. To accomplish this, a vast array of theoretical methods (DFT, OO-SCS-MP2, QCISD) was used to calculate the isotropic hyperfine couplings. The comparison between experimental and theoretical values revealed that the E isomer is the dominant radical form, for which a fast interconversion between anti and syn conformers is expected. In addition, the origin of the significant AF increase with solvent polarity was analyzed.
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Eaton SS, Eaton GR. Multifrequency Pulsed EPR and the Characterization of Molecular Dynamics. Methods Enzymol 2015; 563:37-58. [PMID: 26478481 PMCID: PMC5380387 DOI: 10.1016/bs.mie.2015.06.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
In fluid solution, motion-dependent processes dominate electron spin-lattice relaxation for nitroxides and semiquinones at frequencies between 250 MHz and 34 GHz. For triarylmethyl radicals, motion-dependent processes dominate spin-lattice relaxation at frequencies below about 3 GHz. The frequency dependence of relaxation provides invaluable information about dynamic processes occurring with characteristic times on the order of the electron Zeeman frequency. Relaxation mechanisms, methods of measuring spin-lattice relaxation, and motional processes for nitroxide, semiquinone, and triarylmethyl radicals are discussed.
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Affiliation(s)
- Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA.
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
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6
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Hermosilla L, Calle P, García de la Vega JM. Modeling EPR parameters of nitrogen containing conjugated radical cations. RSC Adv 2015. [DOI: 10.1039/c5ra08758a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DFT investigation on conjugated radical cations containing14N nucleus to obtain accurate isotropic hyperfine coupling constants.
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Affiliation(s)
- L. Hermosilla
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - P. Calle
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - J. M. García de la Vega
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
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7
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Biller JR, Elajaili H, Meyer V, Rosen GM, Eaton SS, Eaton GR. Electron spin-lattice relaxation mechanisms of rapidly-tumbling nitroxide radicals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 236:47-56. [PMID: 24056272 PMCID: PMC3952064 DOI: 10.1016/j.jmr.2013.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 05/12/2023]
Abstract
Electron spin relaxation times at 295 K were measured at frequencies between 250 MHz and 34 GHz for perdeuterated 2,2,6,6-tetramethyl-4-piperidone-1-oxyl (PDT) in five solvents with viscosities that result in tumbling correlation times, τR, between 4 and 50 ps and for three (14)N/(15)N pairs of nitroxides in water with τR between 9 and 19 ps. To test the impact of structure on relaxation three additional nitroxides with τR between 10 and 26 ps were studied. In this fast tumbling regime T2(-1)~T1(-1) at frequencies up to about 9 GHz. At 34 GHz T2(-1)>T1(-1) due to increased contributions to T2(-1) from incomplete motional averaging of g-anisotropy, and T2(-1)-T1(-1) is proportional to τR. The contribution to T1(-1) from spin rotation is independent of frequency and decreases as τR increases. Spin rotation dominates T1(-1) at 34 GHz for all τR studied, and at all frequencies studied for τR=4 ps. The contribution to T1(-1) from modulation of nitrogen hyperfine anisotropy increases as frequency decreases and as τR increases; it dominates at low frequencies for τR>~15 ps. The contribution from modulation of g anisotropy is significant only at 34 GHz. Inclusion of a thermally-activated process was required to account for the observation that for most of the radicals, T1(-1) was smaller at 250 MHz than at 1-2 GHz. The significant (15)N/(14)N isotope effect, the small H/D isotope effect, and the viscosity dependence of the magnitude of the contribution from the thermally-activated process suggest that it arises from intramolecular motions of the nitroxide ring that modulate the isotropic A values.
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Affiliation(s)
- Joshua R. Biller
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Virginia Meyer
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Gerald M. Rosen
- Department of Pharmaceutical Sciences, Center for EPR Imaging in Vivo Physiology, and Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
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8
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Hermosilla L, Prampolini G, Calle P, García de la Vega JM, Brancato G, Barone V. Extension of the AMBER Force Field for Nitroxide Radicals and Combined QM/MM/PCM Approach to the Accurate Determination of EPR Parameters of DMPO-H in Solution. J Chem Theory Comput 2013; 9:3626-36. [PMID: 26584116 PMCID: PMC4660035 DOI: 10.1021/ct4003256] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A computational strategy that combines both time-dependent and time-independent approaches is exploited to accurately model molecular dynamics and solvent effects on the isotropic hyperfine coupling constants of the DMPO-H nitroxide. Our recent general force field for nitroxides derived from AMBER ff99SB is further extended to systems involving hydrogen atoms in β-positions with respect to NO-moiety. The resulting force-field has been employed in a series of classical molecular dynamics simulations, comparing the computed EPR parameters from selected molecular configurations to the corresponding experimental data in different solvents. The effect of vibrational averaging on the spectroscopic parameters is also taken into account, by second-order vibrational perturbation theory involving semidiagonal third energy derivatives together first and second property derivatives.
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Affiliation(s)
- Laura Hermosilla
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain)
| | - Giacomo Prampolini
- Istituto per i Processi Chimico-Fisici, Consiglio Nazionale delle Ricerche, Area della Ricerca, via Moruzzi 1, I-56124, Pisa (Italy)
| | - Paloma Calle
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain)
| | | | - Giuseppe Brancato
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa (Italy)
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa (Italy)
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9
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Li X, Rinkevicius Z, Kongsted J, Murugan NA, Ågren H. Binding Mechanism and Magnetic Properties of a Multifunctional Spin Label for Targeted EPR Imaging of Amyloid Proteins: Insight from Atomistic Simulations and First-Principles Calculations. J Chem Theory Comput 2012; 8:4766-74. [DOI: 10.1021/ct300606q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Xin Li
- Department of Theoretical Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Zilvinas Rinkevicius
- Department of Theoretical Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
- Swedish e-Science Research Center
(SeRC), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics, Chemistry
and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - N. Arul Murugan
- Department of Theoretical Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Hans Ågren
- Department of Theoretical Chemistry
and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
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10
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Pacheco AB, Dietrick SM, Stevens PS, Iyengar SS. "Pump-probe" atom-centered density matrix propagation studies to gauge anharmonicity and energy repartitioning in atmospheric reactive adducts: case study of the OH + isoprene and OH + butadiene reaction intermediates. J Phys Chem A 2012; 116:4108-28. [PMID: 22401490 DOI: 10.1021/jp212330e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Time-resolved "pump-probe" ab initio molecular dynamics studies are constructed to probe the stability of reaction intermediates, the mechanism of energy transfer, and energy repartitioning, for moieties involved during the interaction of volatile organic compunds with hydroxyl radical. These systems are of prime importance in the atmosphere. Specifically, the stability of reaction intermediates of hydroxyl radical adducts to isoprene and butadiene molecules is used as a case study to develop novel computational techniques involving "pump-probe" ab initio molecular dynamics. Starting with the various possible hydroxyl radical adducts to isoprene and butadiene, select vibrational modes of each of the adducts are populated with excess energy to mimic the initial conditions of an experiment. The flow of energy into the remaining modes is then probed by subjecting the excited adducts to ab initio molecular dynamics simulations. It is found that the stability of the adducts arises directly due to the anhormonically driven coupling of the modes to facilitate repartitioning of the excess vibrational energy. This kind of vibrational repartitioning has a critical influence on the energy density.
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Affiliation(s)
- Alexander B Pacheco
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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11
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Caruso P, Causà M, Cimino P, Crescenzi O, D’Amore M, Improta R, Pavone M, Rega N. Effects of molecular dynamics and solvation on the electronic structure of molecular probes. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1211-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Meskaldji S, Zaiter A, Belkhiri L, Boucekkine A. A relativistic DFT study of magnetic exchange coupling in ketimide bimetallic uranium(IV) complexes. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1151-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Dietrick SM, Pacheco AB, Phatak P, Stevens PS, Iyengar SS. Influence of Water on Anharmonicity, Stability, and Vibrational Energy Distribution of Hydrogen-Bonded Adducts in Atmospheric Reactions: Case Study of the OH + Isoprene Reaction Intermediate Using Ab Initio Molecular Dynamics. J Phys Chem A 2011; 116:399-414. [DOI: 10.1021/jp204511v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Scott M. Dietrick
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Alexander B. Pacheco
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Prasad Phatak
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Philip S. Stevens
- Department of Chemistry and Center for Research in Environmental Science, School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
| | - Srinivasan S. Iyengar
- Departments of Chemistry and Physics, Indiana University, Bloomington, Indiana 47405, United States
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14
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Rinkevicius Z, Frecuş B, Murugan NA, Vahtras O, Kongsted J, Ågren H. Encapsulation Influence on EPR Parameters of Spin-Labels: 2,2,6,6-Tetramethyl-4-methoxypiperidine-1-oxyl in Cucurbit[8]uril. J Chem Theory Comput 2011; 8:257-63. [DOI: 10.1021/ct200816z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Zilvinas Rinkevicius
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Bogdan Frecuş
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - N. Arul Murugan
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Olav Vahtras
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Hans Ågren
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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15
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Panek P, Biczysko M, Latajka Z. Reinvestigation of spectroscopic properties for ammonia–hydrogen halide complexes from Car–Parrinello Molecular Dynamics. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.08.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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16
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Rinkevicius Z, Murugan NA, Kongsted J, Frecuş B, Steindal AH, Ågren H. Density Functional Restricted–Unrestricted/Molecular Mechanics Theory for Hyperfine Coupling Constants of Molecules in Solution. J Chem Theory Comput 2011; 7:3261-71. [DOI: 10.1021/ct2003572] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zilvinas Rinkevicius
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - N. Arul Murugan
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Bogdan Frecuş
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Arnfinn Hykkerud Steindal
- Centre of Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway
| | - Hans Ågren
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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17
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Chen X, Rinkevicius Z, Cao Z, Ruud K, Agren H. Zero-point vibrational corrections to isotropic hyperfine coupling constants in polyatomic molecules. Phys Chem Chem Phys 2010; 13:696-707. [PMID: 21063618 DOI: 10.1039/c0cp01443e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The present work addresses isotropic hyperfine coupling constants in polyatomic systems with a particular emphasis on a largely neglected, but a posteriori significant, effect, namely zero-point vibrational corrections. Using the density functional restricted-unrestricted approach, the zero-point vibrational corrections are evaluated for the allyl radical and four of its derivatives. In addition for establishing the numerical size of the zero-point vibrational corrections to the isotropic hyperfine coupling constants, we present simple guidelines useful for identifying hydrogens for which such corrections are significant. Based on our findings, we critically re-examine the computational procedures used for the determination of hyperfine coupling constants in general as well as the practice of using experimental hyperfine coupling constants as reference data when benchmarking and optimizing exchange-correlation functionals and basis sets for such calculations.
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Affiliation(s)
- Xing Chen
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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