1
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Sepali C, Gómez S, Grifoni E, Giovannini T, Cappelli C. Computational Spectroscopy of Aqueous Solutions: The Underlying Role of Conformational Sampling. J Phys Chem B 2024; 128:5083-5091. [PMID: 38733374 DOI: 10.1021/acs.jpcb.4c01443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Fully atomistic multiscale polarizable quantum mechanics (QM)/molecular mechanics (MM) approaches, combined with techniques to sample the solute-solvent phase space, constitute the most accurate method to compute spectral signals in aqueous solution. Conventional sampling strategies, such as classical molecular dynamics (MD), may encounter drawbacks when the conformational space is particularly complex, and transition barriers between conformers are high. This can lead to inaccurate sampling, which can potentially impact the accuracy of spectral calculations. For this reason, in this work, we compare classical MD with enhanced sampling techniques, i.e., replica exchange MD and metadynamics. In particular, we show how the different sampling techniques affect computed UV, electronic circular dichroism, nuclear magnetic resonance shielding, and optical rotatory dispersion of N-acetylproline-amide in aqueous solution. Such a system is a model peptide characterized by complex conformational variability. Calculated values suggest that spectral properties are influenced by solute conformers, relative population, and solvent effects; therefore, particular care needs to be paid for when choosing the sampling technique.
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Affiliation(s)
- Chiara Sepali
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Sara Gómez
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Emanuele Grifoni
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | | | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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2
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Gómez S, Cappelli C. When Tautomers Matter: UV-Vis Absorption Spectra of Hypoxanthine in Aqueous Solution from Fully Atomistic Simulations. Chemphyschem 2024:e202400107. [PMID: 38747323 DOI: 10.1002/cphc.202400107] [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: 01/31/2024] [Revised: 05/13/2024] [Indexed: 07/03/2024]
Abstract
The UV-Vis spectrum of the solvated purine derivative Hypoxanthine (HYX) is investigated using the Quantum Mechanics/Fluctuating Charges (QM/FQ) multiscale approach combined with a sampling of configurations through atomistic Molecular Dynamics (MD) simulations. Keto 1H7H and 1H9H tautomeric forms of HYX are the most stable in aqueous solution and form different stable complexes with the surrounding water molecules, ultimately affecting the electronic absorption spectra. The final simulated spectrum resulting from the combination of the individual spectra of tautomers agrees very well with most of the characteristics in the measured spectrum. The importance of considering the effect of the solute tautomers and, in parallel, the contribution of the different solvent arrangements around the solute when modeling spectral properties, is highlighted. In addition, the high quality of the computed spectra leads to suggesting an alternative way for acquiring tautomeric populations from combined computational/experimental spectra.
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Affiliation(s)
- Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
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3
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Gómez S, Ambrosetti M, Giovannini T, Cappelli C. Close-Up Look at Electronic Spectroscopic Signatures of Common Pharmaceuticals in Solution. J Phys Chem B 2024; 128:2432-2446. [PMID: 38416564 DOI: 10.1021/acs.jpcb.3c07795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Simulating electronic properties and spectral signals requires robust computational approaches that need tuning with the system's peculiarities. In this paper, we test implicit and fully atomistic solvation models for the calculation of UV-vis and electronic circular dichroism (ECD) spectra of two pharmaceutically relevant molecules, namely, (2S)-captopril and (S)-naproxen, dissolved in aqueous solution. Room temperature molecular dynamics simulations reveal that these two drugs establish strong contacts with the surrounding solvent molecules via hydrogen bonds. Such specific interactions, which play a major role in the spectral response and are neglected in implicit approaches, are further characterized and quantified with natural bond orbital methods. Our calculations show that simulated spectra, and especially ECD, are in good agreement with experiments solely when conformational and configurational dynamics, mutual polarization, and solute-solvent repulsion effects are considered.
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Affiliation(s)
- Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, Pisa 56126, Italy
| | - Matteo Ambrosetti
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, Pisa 56126, Italy
| | - Tommaso Giovannini
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, Pisa 56126, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, Pisa 56126, Italy
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4
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Sepali C, Lafiosca P, Gómez S, Giovannini T, Cappelli C. Effective fully polarizable QM/MM approaches to compute Raman and Raman Optical Activity spectra in aqueous solution. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 305:123485. [PMID: 37827000 DOI: 10.1016/j.saa.2023.123485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/22/2023] [Accepted: 10/01/2023] [Indexed: 10/14/2023]
Abstract
Raman and Raman Optical Activity (ROA) signals are amply affected by solvent effects, especially in the presence of strongly solute-solvent interactions such as Hydrogen Bonding (HB). In this work, we extend the fully atomistic polarizable Quantum Mechanics/Molecular Mechanics approach, based on the Fluctuating Charges and Fluctuating Dipoles force field to the calculation of Raman and ROA spectra. Such an approach is able to accurately describe specific HB interactions, by also accounting for anisotropic contributions due to the inclusion of fluctuating dipoles. To highlight the potentiality of the novel approach, Raman and ROA spectra of L-Serine and L-Cysteine dissolved in aqueous solution are computed and compared both with alternative theoretical approaches and experimental measurements.
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Affiliation(s)
- Chiara Sepali
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, Pisa, 56126, Italy
| | - Piero Lafiosca
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, Pisa, 56126, Italy
| | - Sara Gómez
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, Pisa, 56126, Italy
| | | | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, Pisa, 56126, Italy.
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5
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Wormell P, Michal P, Scott A, Venkatesan K, Mylvaganam K, von Arx T, Kitamura J, Koshoubu J, Rodger A. New Approaches to Stretched Film Sample Alignment and Data Collection for Vibrational Linear Dichroism. ACS OMEGA 2023; 8:37490-37500. [PMID: 37841173 PMCID: PMC10568702 DOI: 10.1021/acsomega.3c05774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023]
Abstract
Rapid measurements of vibrational linear dichroism (VLD) infrared spectra are shown to be possible by using stretched polymer films and an extension of existing instrumentation designed for vibrational circular dichroism spectroscopy. Earlier techniques can be extended using additional inexpensive polymer substrates to record good-quality VLD spectra of a significantly wider range of compounds with comparatively short sample-preparation times. The polymer substrates used, polyethylene and polytetrafluoroethylene, are commonly available and inexpensive, and samples are more easily prepared than that for many earlier stretched-film and crystal studies. Data are presented for neutral hydrophobic organic molecules on hydrophobic films including acridine, anthracene, fluorene, and recently synthesized S-(4-((4-cyanophenyl)ethynyl)phenyl)ethanethioate. We extend the approach to polar or ionic species, including 2,2'-bipyridine, 1,10-phenanthroline, and sodium dodecyl sulfate, by oxidizing polyethylene films to change their wetting properties. The combination of new instrumentation and modified sample preparation methods is useful in basic spectroscopy for untangling and assigning complicated infrared spectra. Nevertheless, it is not a panacea as surface-adsorbed molecules are often not monodispersed, and higher analyte concentrations can lead to aggregation and resonance phenomena that have previously been observed for infrared spectra on surfaces. These effects can be assessed by varying the sample concentration. The focus of this paper is experimental, and detailed analysis of most of the spectra lies outside its scope, including some well-studied compounds such as acridine and anthracene that allow comparisons with earlier research.
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Affiliation(s)
- Paul Wormell
- School
of Science, Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751, Australia
| | - Pavel Michal
- Department
of Optics, Palacký University Olomouc, 17. Listopadu 12, Olomouc 77146, Czech Republic
| | - Adam Scott
- School
of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Koushik Venkatesan
- School
of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Kausala Mylvaganam
- School
of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Tobias von Arx
- School
of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Junya Kitamura
- JASCO
International Co., Ltd, Hachioji, Tokyo 192-0046, Japan
| | - Jun Koshoubu
- JASCO
Corporation, Hachioji, Tokyo 192-8537, Japan
| | - Alison Rodger
- School
of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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6
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Lemler PM, Craft CL, Pollok CH, Regan TP, Vaccaro PH. Isolated and solvated chiroptical behavior in conformationally flexible butanamines. Chirality 2023; 35:586-618. [PMID: 37550220 DOI: 10.1002/chir.23570] [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: 03/15/2023] [Revised: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 08/09/2023]
Abstract
The nonresonant optical activity of two highly flexible aliphatic amines, (2R)-3-methyl-2-butanamine (R-MBA) and (2R)-(3,3)-dimethyl-2-butanamine (R-DMBA), has been probed under isolated and solvated conditions to examine the roles of conformational isomerism and to explore the influence of extrinsic perturbations. The optical rotatory dispersion (ORD) measured in six solvents presented uniformly negative rotatory powers over the 320-590 nm region, with the long-wavelength magnitude of chiroptical response growing nearly monotonically as the dielectric constant of the surroundings diminished. The intrinsic specific optical rotation,α λ T (in deg dm-1 [g/mL]-1 ), extracted for ambient vapor-phase samples of R-MBA [-11.031(98) and -2.29 (11)] and R-DMBA [-9.434 (72) and -1.350 (48)] at 355 and 633 nm were best reproduced by counterintuitive solvents of high polarity (yet low polarizability) like acetonitrile and methanol. Attempts to interpret observed spectral signatures quantitatively relied on the linear-response frameworks of density-functional theory (B3LYP, cam-B3LYP, and dispersion-corrected analogs) and coupled-cluster theory (CCSD), with variants of the polarizable continuum model (PCM) deployed to account for the effects of implicit solvation. Building on the identification of several low-lying equilibrium geometries (nine for R-MBA and three for R-DMBA), ensemble-averaged ORD profiles were calculated at T = 300 K by means of the independent-conformer ansatz, which enabled response properties predicted for the optimized structure of each isomer to be combined through Boltzmann-weighted population fractions derived from corresponding relative internal-energy or free-energy values, the latter of which stemmed from composite CBS-APNO and G4 analyses. Although reasonable accord between theory and experiment was realized for the isolated (vapor-phase) species, the solution-phase results were less satisfactory and tended to degrade progressively as the solvent polarity increased. These trends were attributed to solvent-mediated changes in structural parameters and energy metrics for the transition states that separate and putatively isolate the equilibrium conformations supported by the ground electronic potential-energy surface, with the resulting displacement of barrier locations and/or decrease of barrier heights compromising the underlying premise of the independent-conformer ansatz.
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Affiliation(s)
- Paul M Lemler
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Intel Corporation, Hillsboro, Oregon, USA
| | - Clayton L Craft
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- United States Air Force Research Laboratory, Rome, New York, USA
| | - Corina H Pollok
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Organische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Thomas P Regan
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Patrick H Vaccaro
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
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7
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Aschi M, Palombi L, Amadei A. Theoretical-Computational Modeling of CD Spectra of Aqueous Monosaccharides by Means of Molecular Dynamics Simulations and Perturbed Matrix Method. Molecules 2023; 28:molecules28083591. [PMID: 37110825 PMCID: PMC10144652 DOI: 10.3390/molecules28083591] [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: 03/25/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The electronic circular dichroism (ECD) spectra of aqueous d-glucose and d-galactose were modeled using a theoretical-computational approach combining molecular dynamics (MD) simulations and perturbed matrix method (PMM) calculations, hereafter termed MD-PMM. The experimental spectra were reproduced with a satisfactory accuracy, confirming the good performances of MD-PMM in modeling different spectral features in complex atomic-molecular systems, as already reported in previous studies. The underlying strategy of the method was to perform a preliminary long timescale MD simulation of the chromophore followed by the extraction of the relevant conformations through essential dynamics analysis. On this (limited) number of relevant conformations, the ECD spectrum was calculated via the PMM approach. This study showed that MD-PMM was able to reproduce the essential features of the ECD spectrum (i.e., the position, the intensity, and the shape of the bands) of d-glucose and d-galactose while avoiding the rather computationally expensive aspects, which were demonstrated to be important for the final outcome, such as (i) the use of a large number of chromophore conformations; (ii) the inclusion of quantum vibronic coupling; and (iii) the inclusion of explicit solvent molecules interacting with the chromophore atoms within the chromophore itself (e.g., via hydrogen bonds).
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Affiliation(s)
- Massimiliano Aschi
- Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila via Vetoio (Coppito 2), 67010 l'Aquila, Italy
| | - Laura Palombi
- Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila via Vetoio (Coppito 2), 67010 l'Aquila, Italy
| | - Andrea Amadei
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Roma, Italy
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8
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Rojas-Valencia N, Gómez S, Giovannini T, Cappelli C, Restrepo A, Núñez Zarur F. Water Maintains the UV-Vis Spectral Features During the Insertion of Anionic Naproxen and Ibuprofen into Model Cell Membranes. J Phys Chem B 2023; 127:2146-2155. [PMID: 36877579 DOI: 10.1021/acs.jpcb.2c08332] [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
UV-vis spectra of anionic ibuprofen and naproxen in a model lipid bilayer of the cell membrane are investigated using computational techniques in combination with a comparative analysis of drug spectra in purely aqueous environments. The simulations aim at elucidating the intricacies behind the negligible changes in the maximum absorption wavelength in the experimental spectra. A set of configurations of the systems constituted by lipid, water, and drugs or just water and drugs are obtained from classical Molecular Dynamics simulations. UV-vis spectra are computed in the framework of atomistic Quantum Mechanical/Molecular Mechanics (QM/MM) approaches together with Time-Dependent Density Functional Theory (TD-DFT). Our results suggest that the molecular orbitals involved in the electronic transitions are the same, regardless of the chemical environment. A thorough analysis of the contacts between the drug and water molecules reveals that no significant changes in UV-vis spectra are a consequence of ibuprofen and naproxen molecules being permanently microsolvated by water molecules, despite the presence of lipid molecules. Water molecules microsolvate the charged carboxylate group as expected but also microsolvate the aromatic regions of the drugs.
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Affiliation(s)
- Natalia Rojas-Valencia
- Facultad de Ciencias Básicas, Universidad de Medellín, Carrera 87 No. 30-65, 050026, Medellín, Colombia
| | - Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Tommaso Giovannini
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia, UdeA, Calle 70 No. 52-21 050010, Medellín, Colombia
| | - Francisco Núñez Zarur
- Facultad de Ciencias Básicas, Universidad de Medellín, Carrera 87 No. 30-65, 050026, Medellín, Colombia
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9
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Giovannini T, Marrazzini G, Scavino M, Koch H, Cappelli C. Integrated Multiscale Multilevel Approach to Open Shell Molecular Systems. J Chem Theory Comput 2023; 19:1446-1456. [PMID: 36780359 PMCID: PMC10018740 DOI: 10.1021/acs.jctc.2c00805] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We present a novel multiscale approach to study the electronic structure of open shell molecular systems embedded in an external environment. The method is based on the coupling of multilevel Hartree-Fock (MLHF) and Density Functional Theory (MLDFT), suitably extended to the unrestricted formalism, to Molecular Mechanics (MM) force fields (FF). Within the ML region, the system is divided into active and inactive parts, thus describing the most relevant interactions (electrostatic, polarization, and Pauli repulsion) at the quantum level. The surrounding MM part, which is formulated in terms of nonpolarizable or polarizable FFs, permits a physically consistent treatment of long-range electrostatics and polarization effects. The approach is extended to the calculation of hyperfine coupling constants and applied to selected nitroxyl radicals in an aqueous solution.
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Affiliation(s)
| | - Gioia Marrazzini
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Marco Scavino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Henrik Koch
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.,Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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10
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Gómez S, Lafiosca P, Egidi F, Giovannini T, Cappelli C. UV-Resonance Raman Spectra of Systems in Complex Environments: A Multiscale Modeling Applied to Doxorubicin Intercalated into DNA. J Chem Inf Model 2023; 63:1208-1217. [PMID: 36745496 PMCID: PMC9976284 DOI: 10.1021/acs.jcim.2c01495] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
UV-Resonance Raman (RR) spectroscopy is a valuable tool to study the binding of drugs to biomolecular receptors. The extraction of information at the molecular level from experimental RR spectra is made much easier and more complete thanks to the use of computational approaches, specifically tuned to deal with the complexity of the supramolecular system. In this paper, we propose a protocol to simulate RR spectra of complex systems at different levels of sophistication, by exploiting a quantum mechanics/molecular mechanics (QM/MM) approach. The approach is challenged to investigate RR spectra of a widely used chemotherapy drug, doxorubicin (DOX) intercalated into a DNA double strand. The computed results show good agreement with experimental data, thus confirming the reliability of the computational protocol.
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Affiliation(s)
- Sara Gómez
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy,E-mail:
| | - Piero Lafiosca
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Franco Egidi
- Software
for Chemistry and Materials BV, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Tommaso Giovannini
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Chiara Cappelli
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy,E-mail:
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11
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Nicoli L, Giovannini T, Cappelli C. Assessing the quality of QM/MM approaches to describe vacuo-to-water solvatochromic shifts. J Chem Phys 2022; 157:214101. [PMID: 36511555 DOI: 10.1063/5.0118664] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The performance of different quantum mechanics/molecular mechanics embedding models to compute vacuo-to-water solvatochromic shifts is investigated. In particular, both nonpolarizable and polarizable approaches are analyzed and computed results are compared to reference experimental data. We show that none of the approaches outperform the others and that errors strongly depend on the nature of the molecular transition to be described. Thus, we prove that the best choice of embedding model highly depends on the molecular system and that the use of a specific approach as a black box can lead to significant errors and, sometimes, totally wrong predictions.
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Affiliation(s)
- Luca Nicoli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | | | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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12
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Gómez S, Giovannini T, Cappelli C. Multiple Facets of Modeling Electronic Absorption Spectra of Systems in Solution. ACS PHYSICAL CHEMISTRY AU 2022; 3:1-16. [PMID: 36718266 PMCID: PMC9881242 DOI: 10.1021/acsphyschemau.2c00050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/24/2022]
Abstract
In this Perspective, we outline the essential physicochemical aspects that need to be considered when building a reliable approach to describe absorption properties of solvated systems. In particular, we focus on how to properly model the complexity of the solvation phenomenon, arising from dynamical aspects and specific, strong solute-solvent interactions. To this end, conformational and configurational sampling techniques, such as Molecular Dynamics, have to be coupled to accurate fully atomistic Quantum Mechanical/Molecular Mechanics (QM/MM) methodologies. By exploiting different illustrative applications, we show that an effective reproduction of experimental spectral signals can be achieved by delicately balancing exhaustive sampling, hydrogen bonding, mutual polarization, and nonelectrostatic effects.
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13
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Monti M, Stener M, Aschi M. A computational approach for modeling electronic circular dichroism of solvated chromophores. J Comput Chem 2022; 43:2023-2036. [PMID: 36134712 PMCID: PMC9825941 DOI: 10.1002/jcc.27001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 07/29/2022] [Accepted: 08/25/2022] [Indexed: 01/11/2023]
Abstract
The present study consists in a novel computational protocol to model the UV-circular dichroism spectra of solvated species. It makes use of quantum-chemical calculations on a series of conformations of a flexible chromophore or on a series of chromophore/solvent clusters extracted from molecular dynamic simulations. The protocol is described and applied to the aqueous cationic tripeptide GAG+ and to the aqueous neutral decapeptide (GVGVP)2 . The protocol has proven able to: (i) properly consider the conformational motion of solute in the given environment; (ii) give the actual statistical weight of each conformational state; (iii) provide a reliable quantum mechanical method able to reproduce the spectral features. Temperature effects on conformations and spectral properties are properly taken into account. The role of explicit solvent on the conformational analysis and the spectra calculation is discussed. The comparison of the calculated circular dichroism spectra with experimental ones recorded at different temperatures represents a strict validation test of the method.
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Affiliation(s)
- Marta Monti
- Dipartimento di Scienze Chimiche e FarmaceuticheUniversità di TriesteTriesteItaly
| | - Mauro Stener
- Dipartimento di Scienze Chimiche e FarmaceuticheUniversità di TriesteTriesteItaly
| | - Massimiliano Aschi
- Dipartimento di Scienze Fisiche e ChimicheUniversità dell'AquilaL'AquilaItaly
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14
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Computational hints for the simultaneous spectroscopic detection of common contaminants in water. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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15
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Lafiosca P, Gómez S, Giovannini T, Cappelli C. Absorption Properties of Large Complex Molecular Systems: The DFTB/Fluctuating Charge Approach. J Chem Theory Comput 2022; 18:1765-1779. [PMID: 35184553 PMCID: PMC8908768 DOI: 10.1021/acs.jctc.1c01066] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
We report on the
first formulation of a novel polarizable QM/MM
approach, where the density functional tight binding (DFTB) is coupled
to the fluctuating charge (FQ) force field. The resulting method (DFTB/FQ)
is then extended to the linear response within the TD-DFTB framework
and challenged to study absorption spectra of large condensed-phase
systems.
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Affiliation(s)
- Piero Lafiosca
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Tommaso Giovannini
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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16
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17
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Ambrosetti M, Skoko S, Giovannini T, Cappelli C. Quantum Mechanics/Fluctuating Charge Protocol to Compute Solvatochromic Shifts. J Chem Theory Comput 2021; 17:7146-7156. [PMID: 34619965 PMCID: PMC8582258 DOI: 10.1021/acs.jctc.1c00763] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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Despite the potentialities
of the quantum mechanics (QM)/fluctuating
charge (FQ) approach to model the spectral properties of solvated
systems, its extensive use has been hampered by the lack of reliable
parametrizations of solvents other than water. In this paper, we substantially
extend the applicability of QM/FQ to solvating environments of different
polarities and hydrogen-bonding capabilities. The reliability and
robustness of the approach are demonstrated by challenging the model
to simulate solvatochromic shifts of four organic chromophores, which
display large shifts when dissolved in apolar, aprotic or polar, protic
solvents.
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Affiliation(s)
| | - Sulejman Skoko
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | | | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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18
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Lafiosca P, Giovannini T, Benzi M, Cappelli C. Going Beyond the Limits of Classical Atomistic Modeling of Plasmonic Nanostructures. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:23848-23863. [PMID: 34765073 PMCID: PMC8573767 DOI: 10.1021/acs.jpcc.1c04716] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/08/2021] [Indexed: 05/27/2023]
Abstract
Theoretical modeling of plasmonic phenomena is of fundamental importance for rationalizing experimental measurements. Despite the great success of classical continuum modeling, recent technological advances allowing for the fabrication of structures defined at the atomic level require to be modeled through atomistic approaches. From a computational point of view, the latter approaches are generally associated with high computational costs, which have substantially hampered their extensive use. In this work, we report on a computationally fast formulation of a classical, fully atomistic approach, able to accurately describe both metal nanoparticles and graphene-like nanostructures composed of roughly 1 million atoms and characterized by structural defects.
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19
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Guo YT, Xiao YH, Zhang JG, Bian SD, Zhou JZ, Wu DY, Tian ZQ. Inspecting the structural characteristics of chiral drug penicillamine under different pH conditions using Raman optical activity spectroscopy and DFT calculations. Phys Chem Chem Phys 2021; 23:22119-22132. [PMID: 34580687 DOI: 10.1039/d1cp02219a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The investigation of the structural characteristics of chiral drugs in physiological environments is a challenging research topic, which may lead to a better understanding of how the drugs work. Raman optical activity (ROA) spectroscopy in combination with density functional theory (DFT) calculations was exploited to inspect the structural changes in penicillamine under different acid-base states in aqueous solutions. The B3LYP/aug-cc-PVDZ method was employed and the implicit solvation model density (SMD) was considered for describing the solvation effect in H2O. The conformations of penicillamine varied with pH, but penicillamine was liable to stabilize in the form of the PC conformation (the sulfur atom is in a trans orientation with respect to carboxylate) in most cases for both D- and L-isomers. The relationship between the conformations of penicillamine and the ROA peaks, as well as peak assignments, were comprehensively studied and elucidated. In the fingerprint region, two ROA couplets and one ROA triplet with different patterns were recognized. The intensity, sign and frequency of the corresponding peaks also changed with varying pH. Deuteration was carried out to identify the vibrational modes, and the ROA peaks of the deuterated amino group in particular are sensitive to change in the ambient environment. The results are expected not only to serve as a reference for the interpretation of the ROA spectra of penicillamine and other chiral drugs with analogous structures but also to evaluate the structural changes of chiral molecules in physiological environments, which will form the basis of further exploration of the effects of structural characteristics on the pharmacological and toxicological properties of chiral drugs.
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Affiliation(s)
- Yu-Ting Guo
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - Yuan-Hui Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - Ji-Guang Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - Si-Da Bian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - Jian-Zhang Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - De-Yin Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
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20
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Uribe L, Gómez S, Giovannini T, Egidi F, Restrepo A. An efficient and robust procedure to calculate absorption spectra of aqueous charged species applied to NO 2. Phys Chem Chem Phys 2021; 23:14857-14872. [PMID: 34223573 DOI: 10.1039/d1cp00652e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Accurate calculation of absorption spectra of aqueous NO2- requires rigorously sampling the quantum potential energy surfaces for microsolvation of NO2- with at least five explicit water molecules and embedding the resulting clusters in a continuum solvent accounting for the statistical weighted contributions of individual isomers. This method, which we address as ASCEC + PCM, introduces several desired features when compared against MD simulations derived QM/MM spectra: comparatively fewer explicit solvent molecules to be treated with expensive QM methods, the identification of equilibrium structures in the quantum PES to be used in further vibrational spectroscopy, and the unequivocal identification of cluster orbitals undergoing electronic transitions and charge transfer that originate the spectral bands.
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Affiliation(s)
- Lina Uribe
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Tommaso Giovannini
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Franco Egidi
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy.
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
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21
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Paolino M, Giovannini T, Manathunga M, Latterini L, Zampini G, Pierron R, Léonard J, Fusi S, Giorgi G, Giuliani G, Cappelli A, Cappelli C, Olivucci M. On the Transition from a Biomimetic Molecular Switch to a Rotary Molecular Motor. J Phys Chem Lett 2021; 12:3875-3884. [PMID: 33856801 DOI: 10.1021/acs.jpclett.1c00526] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The experimental investigation of the unidirectional motion characterizing the photoisomerization of single-molecule rotary motors requires accessible lab prototypes featuring an electronic circular dichroism (ECD) signal that is sensitive to the geometrical and electronic changes occurring during an ultrafast reactive process. Here we report a combined experimental/computational study of a candidate obtained via the asymmetrization of a light-driven biomimetic molecular switch. We show that the achieved motor has an ECD band that is remarkably sensitive to the isomerization motion, and it is therefore suitable for time-resolved ECD studies. However, we also find that, unexpectedly, the synthesized motor isomerizes on a time scale longer than the subpicosecond time measured for the achiral parent, a result that points to alternative candidates conserving a high reaction speed.
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Affiliation(s)
- Marco Paolino
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | | | - Madushanka Manathunga
- Chemistry Department, Bowling Green State University, Bowling Green, Ohio 43403-0001, United States
| | - Loredana Latterini
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 8, 06123 Perugia, Italy
| | - Giulia Zampini
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 8, 06123 Perugia, Italy
| | - Robin Pierron
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Jérémie Léonard
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Stefania Fusi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Gianluca Giorgi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Germano Giuliani
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Andrea Cappelli
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Massimo Olivucci
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
- Chemistry Department, Bowling Green State University, Bowling Green, Ohio 43403-0001, United States
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22
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Egidi F, Angelico S, Lafiosca P, Giovannini T, Cappelli C. A polarizable three-layer frozen density embedding/molecular mechanics approach. J Chem Phys 2021; 154:164107. [PMID: 33940798 DOI: 10.1063/5.0045574] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We present a novel multilayer polarizable embedding approach in which the system is divided into three portions, two of which are treated using density functional theory and their interaction is based on frozen density embedding (FDE) theory, and both also mutually interact with a polarizable classical layer described using an atomistic model based on fluctuating charges (FQ). The efficacy of the model is demonstrated by extending the formalism to linear response properties and applying it to the simulation of the excitation energies of organic molecules in aqueous solution, where the solute and the first solvation shell are treated using FDE, while the rest of the solvent is modeled using FQ charges.
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Affiliation(s)
- Franco Egidi
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Sara Angelico
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Piero Lafiosca
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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23
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Marrazzini G, Giovannini T, Scavino M, Egidi F, Cappelli C, Koch H. Multilevel Density Functional Theory. J Chem Theory Comput 2021; 17:791-803. [PMID: 33449681 PMCID: PMC7880574 DOI: 10.1021/acs.jctc.0c00940] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
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Following recent
developments in multilevel embedding methods,
we introduce a novel density matrix-based multilevel approach within
the framework of density functional theory (DFT). In this multilevel
DFT, the system is partitioned in an active and an inactive fragment,
and all interactions are retained between the two parts. The decomposition
of the total system is performed upon the density matrix. The orthogonality
between the two parts is maintained by solving the Kohn–Sham
equations in the MO basis for the active part only, while keeping
the inactive density matrix frozen. This results in the reduction
of computational cost. We outline the theory and implementation and
discuss the differences and similarities with state-of-the-art DFT
embedding methods. We present applications to aqueous solutions of
methyloxirane and glycidol.
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Affiliation(s)
- Gioia Marrazzini
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Marco Scavino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Franco Egidi
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Henrik Koch
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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24
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Giovannini T, Koch H. Energy-Based Molecular Orbital Localization in a Specific Spatial Region. J Chem Theory Comput 2021; 17:139-150. [PMID: 33337150 DOI: 10.1021/acs.jctc.0c00737] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We present a novel energy-based localization procedure able to localize molecular orbitals into predefined spatial regions. The method is defined in a multiscale framework based on the multilevel Hartree-Fock approach. In particular, the system is partitioned into active and inactive fragments. The localized molecular orbitals are obtained maximizing the repulsion between the two fragments. The method is applied to several cases including both conjugated and non-conjugated systems. Our multiscale approach is compared with reference values for both ground-state properties, such as dipole moments, and local excitation energies. The proposed approach is useful to extend the application range of high-level electron correlation methods. In fact, the reduced number of molecular orbitals can lead to a large reduction in the computational cost of correlated calculations.
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Affiliation(s)
- Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Henrik Koch
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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25
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Goletto L, Giovannini T, Folkestad SD, Koch H. Combining multilevel Hartree–Fock and multilevel coupled cluster approaches with molecular mechanics: a study of electronic excitations in solutions. Phys Chem Chem Phys 2021; 23:4413-4425. [DOI: 10.1039/d0cp06359b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the coupling of different quantum-embedding approaches with a third molecular-mechanics layer, which can be either polarizable or non-polarizable.
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Affiliation(s)
- Linda Goletto
- Department of Chemistry
- Norwegian University of Science and Technology (NTNU)
- 7491 Trondheim
- Norway
| | - Tommaso Giovannini
- Department of Chemistry
- Norwegian University of Science and Technology (NTNU)
- 7491 Trondheim
- Norway
| | - Sarai D. Folkestad
- Department of Chemistry
- Norwegian University of Science and Technology (NTNU)
- 7491 Trondheim
- Norway
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26
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Skoko S, Ambrosetti M, Giovannini T, Cappelli C. Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study. Molecules 2020; 25:E5853. [PMID: 33322361 PMCID: PMC7764712 DOI: 10.3390/molecules25245853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 11/16/2022] Open
Abstract
We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.
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Affiliation(s)
- Sulejman Skoko
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; (S.S.); (M.A.)
| | - Matteo Ambrosetti
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; (S.S.); (M.A.)
| | - Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway;
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; (S.S.); (M.A.)
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