1
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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; 25: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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2
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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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3
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Capone M, Romanelli M, Castaldo D, Parolin G, Bello A, Gil G, Vanzan M. A Vision for the Future of Multiscale Modeling. ACS PHYSICAL CHEMISTRY AU 2024; 4:202-225. [PMID: 38800726 PMCID: PMC11117712 DOI: 10.1021/acsphyschemau.3c00080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 05/29/2024]
Abstract
The rise of modern computer science enabled physical chemistry to make enormous progresses in understanding and harnessing natural and artificial phenomena. Nevertheless, despite the advances achieved over past decades, computational resources are still insufficient to thoroughly simulate extended systems from first principles. Indeed, countless biological, catalytic and photophysical processes require ab initio treatments to be properly described, but the breadth of length and time scales involved makes it practically unfeasible. A way to address these issues is to couple theories and algorithms working at different scales by dividing the system into domains treated at different levels of approximation, ranging from quantum mechanics to classical molecular dynamics, even including continuum electrodynamics. This approach is known as multiscale modeling and its use over the past 60 years has led to remarkable results. Considering the rapid advances in theory, algorithm design, and computing power, we believe multiscale modeling will massively grow into a dominant research methodology in the forthcoming years. Hereby we describe the main approaches developed within its realm, highlighting their achievements and current drawbacks, eventually proposing a plausible direction for future developments considering also the emergence of new computational techniques such as machine learning and quantum computing. We then discuss how advanced multiscale modeling methods could be exploited to address critical scientific challenges, focusing on the simulation of complex light-harvesting processes, such as natural photosynthesis. While doing so, we suggest a cutting-edge computational paradigm consisting in performing simultaneous multiscale calculations on a system allowing the various domains, treated with appropriate accuracy, to move and extend while they properly interact with each other. Although this vision is very ambitious, we believe the quick development of computer science will lead to both massive improvements and widespread use of these techniques, resulting in enormous progresses in physical chemistry and, eventually, in our society.
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Affiliation(s)
- Matteo Capone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, L’Aquila 67010, Italy
| | - Marco Romanelli
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
| | - Davide Castaldo
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
| | - Giovanni Parolin
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
| | - Alessandro Bello
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
- Department
of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Gabriel Gil
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
- Instituto
de Cibernética, Matemática y Física (ICIMAF), La Habana 10400, Cuba
| | - Mirko Vanzan
- Department
of Chemical Sciences, University of Padova, Padova 35131, Italy
- Department
of Physics, University of Milano, Milano 20133, Italy
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4
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Giovannini T, Scavino M, Koch H. Time-Dependent Multilevel Density Functional Theory. J Chem Theory Comput 2024; 20:3601-3612. [PMID: 38648031 DOI: 10.1021/acs.jctc.4c00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
We present a novel three-layer approach based on multilevel density functional theory (MLDFT) and polarizable molecular mechanics to simulate the electronic excitations of chemical systems embedded in an external environment within the time-dependent DFT formalism. In our method, the electronic structure of a target system, the chromophore, is determined in the field of an embedded inactive layer, which is treated as frozen. Long-range interactions are described by employing the polarizable fluctuating charge (FQ) force field. The resulting MLDFT/FQ thus accurately describes both electrostatics (and polarization) and non-electrostatic target-environment interactions. The robustness and reliability of the approach are demonstrated by comparing our results with experimental data reported for various organic molecules in solution.
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Affiliation(s)
| | - Marco Scavino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Henrik Koch
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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5
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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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6
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Lafiosca P, Rossi F, Egidi F, Giovannini T, Cappelli C. Multiscale Frozen Density Embedding/Molecular Mechanics Approach for Simulating Magnetic Response Properties of Solvated Systems. J Chem Theory Comput 2024; 20:266-279. [PMID: 38109486 PMCID: PMC10782454 DOI: 10.1021/acs.jctc.3c00850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/06/2023] [Accepted: 11/10/2023] [Indexed: 12/20/2023]
Abstract
We present a three-layer hybrid quantum mechanical/quantum embedding/molecular mechanics approach for calculating nuclear magnetic resonance (NMR) shieldings and J-couplings of molecular systems in solution. The model is based on the frozen density embedding (FDE) and polarizable fluctuating charges (FQ) and fluctuating dipoles (FQFμ) force fields and permits the accurate ab initio description of short-range nonelectrostatic interactions by means of the FDE shell and cost-effective treatment of long-range electrostatic interactions through the polarizable force field FQ(Fμ). Our approach's accuracy and potential are demonstrated by studying NMR spectra of Brooker's merocyanine in aqueous and nonaqueous solutions.
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Affiliation(s)
- Piero Lafiosca
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Federico Rossi
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Franco Egidi
- Software
for Chemistry and Materials BV, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | | | - Chiara Cappelli
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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7
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Tran VA, Teucher M, Galazzo L, Sharma B, Pongratz T, Kast SM, Marx D, Bordignon E, Schnegg A, Neese F. Dissecting the Molecular Origin of g-Tensor Heterogeneity and Strain in Nitroxide Radicals in Water: Electron Paramagnetic Resonance Experiment versus Theory. J Phys Chem A 2023; 127:6447-6466. [PMID: 37524058 PMCID: PMC10424240 DOI: 10.1021/acs.jpca.3c02879] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/01/2023] [Indexed: 08/02/2023]
Abstract
Nitroxides are common EPR sensors of microenvironmental properties such as polarity, numbers of H-bonds, pH, and so forth. Their solvation in an aqueous environment is facilitated by their high propensity to form H-bonds with the surrounding water molecules. Their g- and A-tensor elements are key parameters to extracting the properties of their microenvironment. In particular, the gxx value of nitroxides is rich in information. It is known to be characterized by discrete values representing nitroxide populations previously assigned to have different H-bonds with the surrounding waters. Additionally, there is a large g-strain, that is, a broadening of g-values associated with it, which is generally correlated with environmental and structural micro-heterogeneities. The g-strain is responsible for the frequency dependence of the apparent line width of the EPR spectra, which becomes evident at high field/frequency. Here, we address the molecular origin of the gxx heterogeneity and of the g-strain of a nitroxide moiety (HMI: 2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water. To treat the solvation effect on the g-strain, we combined a multi-frequency experimental approach with ab initio molecular dynamics simulations for structural sampling and quantum chemical EPR property calculations at the highest realistically affordable level, including an explicitly micro-solvated HMI ensemble and the embedded cluster reference interaction site model. We could clearly identify the distinct populations of the H-bonded nitroxides responsible for the gxx heterogeneity experimentally observed, and we dissected the role of the solvation shell, H-bond formation, and structural deformation of the nitroxide in the creation of the g-strain associated with each nitroxide subensemble. Two contributions to the g-strain were identified in this study. The first contribution depends on the number of hydrogen bonds formed between the nitroxide and the solvent because this has a large and well-understood effect on the gxx-shift. This contribution can only be resolved at high resonance frequencies, where it leads to distinct peaks in the gxx region. The second contribution arises from configurational fluctuations of the nitroxide that necessarily lead to g-shift heterogeneity. These contributions cannot be resolved experimentally as distinct resonances but add to the line broadening. They can be quantitatively analyzed by studying the apparent line width as a function of microwave frequency. Interestingly, both theory and experiment confirm that this contribution is independent of the number of H-bonds. Perhaps even more surprisingly, the theoretical analysis suggests that the configurational fluctuation broadening is not induced by the solvent but is inherently present even in the gas phase. Moreover, the calculations predict that this broadening decreases upon solvation of the nitroxide.
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Affiliation(s)
- Van Anh Tran
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Markus Teucher
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Laura Galazzo
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Bikramjit Sharma
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Tim Pongratz
- Fakultät
für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Stefan M. Kast
- Fakultät
für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Dominik Marx
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Enrica Bordignon
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Alexander Schnegg
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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8
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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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9
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Csizi K, Reiher M. Universal
QM
/
MM
approaches for general nanoscale applications. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2023. [DOI: 10.1002/wcms.1656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
| | - Markus Reiher
- Laboratorium für Physikalische Chemie ETH Zürich Zürich Switzerland
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10
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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: 6] [Impact Index Per Article: 3.0] [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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11
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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: 14] [Impact Index Per Article: 7.0] [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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12
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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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Indexed: 11/30/2022]
Abstract
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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13
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Gómez S, Bottari C, Egidi F, Giovannini T, Rossi B, Cappelli C. Amide Spectral Fingerprints are Hydrogen Bonding-Mediated. J Phys Chem Lett 2022; 13:6200-6207. [PMID: 35770492 PMCID: PMC9272440 DOI: 10.1021/acs.jpclett.2c01277] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The origin of the peculiar amide spectral features of proteins in aqueous solution is investigated, by exploiting a combined theoretical and experimental approach to study UV Resonance Raman (RR) spectra of peptide molecular models, namely N-acetylglycine-N-methylamide (NAGMA) and N-acetylalanine-N-methylamide (NALMA). UVRR spectra are recorded by tuning Synchrotron Radiation at several excitation wavelengths and modeled by using a recently developed multiscale protocol based on a polarizable QM/MM approach. Thanks to the unparalleled agreement between theory and experiment, we demonstrate that specific hydrogen bond interactions, which dominate hydration dynamics around these solutes, play a crucial role in the selective enhancement of amide signals. These results further argue the capability of vibrational spectroscopy methods as valuable tools for refined structural analysis of peptides and proteins in aqueous solution.
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Affiliation(s)
- Sara Gómez
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Cettina Bottari
- Elettra
Sincrotrone Trieste S.C.p.A., S. S. 14 Km 163.5 in Area Science Park, I-34149, Trieste, Italy
| | - Franco Egidi
- 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
| | - Barbara Rossi
- Elettra
Sincrotrone Trieste S.C.p.A., S. S. 14 Km 163.5 in Area Science Park, I-34149, Trieste, Italy
- Department
of Physics, University of Trento, via Sommarive 14, I-38123 Povo, Trento, Italy
| | - Chiara Cappelli
- Scuola
Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
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14
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Serrano-Aparicio N, Ferrer S, Świderek K. Covalent Inhibition of the Human 20S Proteasome with Homobelactosin C Inquired by QM/MM Studies. Pharmaceuticals (Basel) 2022; 15:ph15050531. [PMID: 35631358 PMCID: PMC9143130 DOI: 10.3390/ph15050531] [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] [Received: 03/31/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 12/02/2022] Open
Abstract
20S proteasome is a main player in the protein degradation pathway in the cytosol, thus intervening in multiple pivotal cellular processes. Over the years the proteasome has emerged as a crucial target for the treatment of many diseases such as neurodegenerative diseases, cancer, autoimmune diseases, developmental disorders, cystic fibrosis, diabetes, cardiac diseases, atherosclerosis, and aging. In this work, the mechanism of proteasome covalent inhibition with bisbenzyl-protected homobelactosin C (hBelC) was explored using quantum mechanics/molecular mechanics (QM/MM) methods. Molecular dynamic simulations were used to describe key interactions established between the hBelC and its unique binding mode in the primed site of the β5 subunit. The free energy surfaces were computed to characterize the kinetics and thermodynamics of the inhibition process. This study revealed that although the final inhibition product for hBelC is formed according to the same molecular mechanism as one described for hSalA, the free energy profile of the reaction pathway differs significantly from the one previously reported for γ-lactam-β-lactone containing inhibitors in terms of the height of the activation barrier as well as the stabilization of the final product. Moreover, it was proved that high stabilization of the covalent adduct formed between β5-subunit and hBelC, together with the presence of aminocarbonyl side chain in the structure of the inhibitor which prevents the hydrolysis of the ester bond from taking place, determines its irreversible character.
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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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Gómez S, Rojas-Valencia N, Giovannini T, Restrepo A, Cappelli C. Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman. Molecules 2022; 27:molecules27020442. [PMID: 35056755 PMCID: PMC8780161 DOI: 10.3390/molecules27020442] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/31/2021] [Accepted: 01/04/2022] [Indexed: 12/07/2022] Open
Abstract
We unravel the potentialities of resonance Raman spectroscopy to detect ibuprofen in diluted aqueous solutions. In particular, we exploit a fully polarizable quantum mechanics/molecular mechanics (QM/MM) methodology based on fluctuating charges coupled to molecular dynamics (MD) in order to take into account the dynamical aspects of the solvation phenomenon. Our findings, which are discussed in light of a natural bond orbital (NBO) analysis, reveal that a selective enhancement of the Raman signal due to the normal mode associated with the C-C stretching in the ring, νC=C, can be achieved by properly tuning the incident wavelength, thus facilitating the recognition of ibuprofen in water samples.
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Affiliation(s)
- Sara Gómez
- Classe di Scienze, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy;
- Correspondence: (S.G.); (C.C.)
| | - Natalia Rojas-Valencia
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellin 050010, Colombia; (N.R.-V.); (A.R.)
| | - Tommaso Giovannini
- Classe di Scienze, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy;
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellin 050010, Colombia; (N.R.-V.); (A.R.)
| | - Chiara Cappelli
- Classe di Scienze, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy;
- Correspondence: (S.G.); (C.C.)
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17
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Barone V, Fusè M, Pinto SMV, Tasinato N. A Computational Journey across Nitroxide Radicals: From Structure to Spectroscopic Properties and Beyond. Molecules 2021; 26:molecules26237404. [PMID: 34885980 PMCID: PMC8659111 DOI: 10.3390/molecules26237404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/25/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022] Open
Abstract
Nitroxide radicals are characterized by a long-lived open-shell electronic ground state and are strongly sensitive to the chemical environment, thus representing ideal spin probes and spin labels for paramagnetic biomolecules and materials. However, the interpretation of spectroscopic parameters in structural and dynamic terms requires the aid of accurate quantum chemical computations. In this paper we validate a computational model rooted into double-hybrid functionals and second order vibrational perturbation theory. Then, we provide reference quantum chemical results for the structures, vibrational frequencies and other spectroscopic features of a large panel of nitroxides of current biological and/or technological interest.
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18
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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: 13] [Impact Index Per Article: 4.3] [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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19
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Jadoon T, Ahsin A, Ullah F, Mahmood T, Ayub K. Adsorption mechanism of p- aminophenol over silver-graphene composite: A first principles study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117415] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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20
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Sharma B, Tran VA, Pongratz T, Galazzo L, Zhurko I, Bordignon E, Kast SM, Neese F, Marx D. A Joint Venture of Ab Initio Molecular Dynamics, Coupled Cluster Electronic Structure Methods, and Liquid-State Theory to Compute Accurate Isotropic Hyperfine Constants of Nitroxide Probes in Water. J Chem Theory Comput 2021; 17:6366-6386. [PMID: 34516119 PMCID: PMC8515807 DOI: 10.1021/acs.jctc.1c00582] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 01/11/2023]
Abstract
The isotropic hyperfine coupling constant (HFCC, Aiso) of a pH-sensitive spin probe in a solution, HMI (2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water, is computed using an ensemble of state-of-the-art computational techniques and is gauged against X-band continuous wave electron paramagnetic resonance (EPR) measurement spectra at room temperature. Fundamentally, the investigation aims to delineate the cutting edge of current first-principles-based calculations of EPR parameters in aqueous solutions based on using rigorous statistical mechanics combined with correlated electronic structure techniques. In particular, the impact of solvation is described by exploiting fully atomistic, RISM integral equation, and implicit solvation approaches as offered by ab initio molecular dynamics (AIMD) of the periodic bulk solution (using the spin-polarized revPBE0-D3 hybrid functional), embedded cluster reference interaction site model integral equation theory (EC-RISM), and polarizable continuum embedding (using CPCM) of microsolvated complexes, respectively. HFCCs are obtained from efficient coupled cluster calculations (using open-shell DLPNO-CCSD theory) as well as from hybrid density functional theory (using revPBE0-D3). Re-solvation of "vertically desolvated" spin probe configuration snapshots by EC-RISM embedding is shown to provide significantly improved results compared to CPCM since only the former captures the inherent structural heterogeneity of the solvent close to the spin probe. The average values of the Aiso parameter obtained based on configurational statistics using explicit water within AIMD and from EC-RISM solvation are found to be satisfactorily close. Using either such explicit or RISM solvation in conjunction with DLPNO-CCSD calculations of the HFCCs provides an average Aiso parameter for HMI in aqueous solution at 300 K and 1 bar that is in good agreement with the experimentally determined one. The developed computational strategy is general in the sense that it can be readily applied to other spin probes of similar molecular complexity, to aqueous solutions beyond ambient conditions, as well as to other solvents in the longer run.
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Affiliation(s)
- Bikramjit Sharma
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Van Anh Tran
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Tim Pongratz
- Physikalische
Chemie III, Technische Universität
Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Laura Galazzo
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, 44780 Bochum, Germany
| | - Irina Zhurko
- Laboratory
of Nitrogen Compounds, N.N. Vorozhtsov Novosibirsk Institute of Organic
Chemistry, NIOCH SB RAS, 9 Lavrentiev Avenue, 630090, Novosibirsk, Russia
| | - Enrica Bordignon
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, 44780 Bochum, Germany
| | - Stefan M. Kast
- Physikalische
Chemie III, Technische Universität
Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dominik Marx
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
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21
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Barone V, Puzzarini C, Mancini G. Integration of theory, simulation, artificial intelligence and virtual reality: a four-pillar approach for reconciling accuracy and interpretability in computational spectroscopy. Phys Chem Chem Phys 2021; 23:17079-17096. [PMID: 34346437 DOI: 10.1039/d1cp02507d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The established pillars of computational spectroscopy are theory and computer based simulations. Recently, artificial intelligence and virtual reality are becoming the third and fourth pillars of an integrated strategy for the investigation of complex phenomena. The main goal of the present contribution is the description of some new perspectives for computational spectroscopy, in the framework of a strategy in which computational methodologies at the state of the art, high-performance computing, artificial intelligence and virtual reality tools are integrated with the aim of improving research throughput and achieving goals otherwise not possible. Some of the key tools (e.g., continuous molecular perception model and virtual multifrequency spectrometer) and theoretical developments (e.g., non-periodic boundaries, joint variational-perturbative models) are shortly sketched and their application illustrated by means of representative case studies taken from recent work by the authors. Some of the results presented are already well beyond the state of the art in the field of computational spectroscopy, thereby also providing a proof of concept for other research fields.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
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22
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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: 12] [Impact Index Per Article: 4.0] [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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23
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Kooi DP, Weckman T, Gori-Giorgi P. Dispersion without Many-Body Density Distortion: Assessment on Atoms and Small Molecules. J Chem Theory Comput 2021; 17:2283-2293. [PMID: 33689322 PMCID: PMC8047766 DOI: 10.1021/acs.jctc.1c00102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Indexed: 11/28/2022]
Abstract
The "fixed diagonal matrices" (FDM) dispersion formalism [Kooi, D. P.; et al. J. Phys. Chem. Lett. 2019, 10, 1537] is based on a supramolecular wave function constrained to leave the diagonal of the many-body density matrix of each monomer unchanged, reducing dispersion to a balance between kinetic energy and monomer-monomer interaction. The corresponding variational optimization leads to expressions for the dispersion energy in terms of the ground-state pair densities of the isolated monomers only, providing a framework to build new approximations without the need for polarizabilities or virtual orbitals. Despite the underlying microscopic real space mechanism being incorrect, as in the exact case there is density relaxation, the formalism has been shown to give extremely accurate (or even exact) dispersion coefficients for H and He. The question we answer in this work is how accurate the FDM expressions can be for isotropic and anisotropic C6 dispersion coefficients when monomer pair densities are used from different levels of theory, namely Hartree-Fock, MP2, and CCSD. For closed-shell systems, FDM with CCSD monomer pair densities yield a mean average percent error for isotropic C6 dispersion coefficients of about 7% and a maximum absolute error within 18%, with a similar accuracy for anisotropies. The performance for open-shell systems is less satisfactory, with CCSD pair densities performing sometimes worse than Hartree-Fock or MP2. In the present implementation, the computational cost on top of the monomer's ground-state calculations is O(N4). The results show little sensitivity to the basis set used in the monomer's calculations.
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Affiliation(s)
- Derk P. Kooi
- Department of Chemistry & Pharmaceutical
Sciences and Amsterdam Institute of Molecular and Life Sciences (AIMMS),
Faculty of Science, Vrije Universiteit, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands
| | - Timo Weckman
- Department of Chemistry & Pharmaceutical
Sciences and Amsterdam Institute of Molecular and Life Sciences (AIMMS),
Faculty of Science, Vrije Universiteit, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands
| | - Paola Gori-Giorgi
- Department of Chemistry & Pharmaceutical
Sciences and Amsterdam Institute of Molecular and Life Sciences (AIMMS),
Faculty of Science, Vrije Universiteit, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands
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24
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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: 17] [Impact Index Per Article: 5.7] [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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25
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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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26
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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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27
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Marrazzini G, Giovannini T, Egidi F, Cappelli C. Calculation of Linear and Non-linear Electric Response Properties of Systems in Aqueous Solution: A Polarizable Quantum/Classical Approach with Quantum Repulsion Effects. J Chem Theory Comput 2020; 16:6993-7004. [PMID: 33058671 PMCID: PMC8015238 DOI: 10.1021/acs.jctc.0c00674] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Indexed: 01/10/2023]
Abstract
We present a computational study of polarizabilities and hyperpolarizabilities of organic molecules in aqueous solutions, focusing on solute-water interactions and the way they affect a molecule's linear and non-linear electric response properties. We employ a polarizable quantum mechanics/molecular mechanics (QM/MM) computational model that treats the solute at the QM level while the solvent is treated classically using a force field that includes polarizable charges and dipoles, which dynamically respond to the solute's quantum-mechanical electron density. Quantum confinement effects are also treated by means of a recently implemented method that endows solvent molecules with a parametric electron density, which exerts Pauli repulsion forces upon the solute. By applying the method to a set of aromatic molecules in solution we show that, for both polarizabilities and first hyperpolarizabilities, observed solution values are the result of a delicate balance between electrostatics, hydrogen-bonding, and non-electrostatic solute solvent interactions.
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Affiliation(s)
- Gioia Marrazzini
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, Pisa 56126, Italy
| | - Tommaso Giovannini
- Department
of Chemistry, Norwegian University of Science
and Technology, Trondheim 7491, Norway
| | - Franco Egidi
- 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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28
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Giovannini T, Egidi F, Cappelli C. Theory and algorithms for chiroptical properties and spectroscopies of aqueous systems. Phys Chem Chem Phys 2020; 22:22864-22879. [PMID: 33043930 DOI: 10.1039/d0cp04027d] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Chiroptical properties and spectroscopies are valuable tools to study chiral molecules and assign absolute configurations. The spectra that result from chiroptical measurements may be very rich and complex, and hide much of their information content. For this reason, the interplay between experiments and calculations is especially useful, provided that all relevant physico-chemical interactions that are present in the experimental sample are accurately modelled. The inherent difficulty associated to the calculation of chiral signals of systems in aqueous solutions requires the development of specific tools, able to account for the peculiarities of water-solute interactions, and especially its ability to form hydrogen bonds. In this perspective we discuss a multiscale approach, which we have developed and challenged to model the most used chiroptical techniques.
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Affiliation(s)
- Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
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29
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Vogler S, Dietschreit JCB, Peters LDM, Ochsenfeld C. Important components for accurate hyperfine coupling constants: electron correlation, dynamic contributions, and solvation effects. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1772515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Sigurd Vogler
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Munich, Germany
| | | | - Laurens D. M. Peters
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Munich, Germany
| | - Christian Ochsenfeld
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Munich, Germany
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30
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Giovannini T, Egidi F, Cappelli C. Molecular spectroscopy of aqueous solutions: a theoretical perspective. Chem Soc Rev 2020; 49:5664-5677. [PMID: 32744278 DOI: 10.1039/c9cs00464e] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Computational spectroscopy is an invaluable tool to both accurately reproduce the spectra of molecular systems and provide a rationalization for the underlying physics. However, the inherent difficulty to accurately model systems in aqueous solutions, owing to water's high polarity and ability to form hydrogen bonds, has severely hampered the development of the field. In this tutorial review we present a technique developed and tested in recent years based on a fully atomistic and polarizable classical modeling of water coupled with a quantum mechanical description of the solute. Thanks to its unparalleled accuracy and versatility, this method can change the perspective of computational and experimental chemists alike.
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Affiliation(s)
| | - Franco Egidi
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
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31
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Auer AA, Tran VA, Sharma B, Stoychev GL, Marx D, Neese F. A case study of density functional theory and domain-based local pair natural orbital coupled cluster for vibrational effects on EPR hyperfine coupling constants: vibrational perturbation theory versus ab initio molecular dynamics. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1797916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Van Anh Tran
- MPI für Kohlenforschung, Mülheim an der Ruhr, Germany
| | - Bikramjit Sharma
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum, Germany
| | | | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum, Germany
| | - Frank Neese
- MPI für Kohlenforschung, Mülheim an der Ruhr, Germany
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32
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Folkestad SD, Kjønstad EF, Myhre RH, Andersen JH, Balbi A, Coriani S, Giovannini T, Goletto L, Haugland TS, Hutcheson A, Høyvik IM, Moitra T, Paul AC, Scavino M, Skeidsvoll AS, Tveten ÅH, Koch H. e T 1.0: An open source electronic structure program with emphasis on coupled cluster and multilevel methods. J Chem Phys 2020; 152:184103. [PMID: 32414265 DOI: 10.1063/5.0004713] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The eT program is an open source electronic structure package with emphasis on coupled cluster and multilevel methods. It includes efficient spin adapted implementations of ground and excited singlet states, as well as equation of motion oscillator strengths, for CCS, CC2, CCSD, and CC3. Furthermore, eT provides unique capabilities such as multilevel Hartree-Fock and multilevel CC2, real-time propagation for CCS and CCSD, and efficient CC3 oscillator strengths. With a coupled cluster code based on an efficient Cholesky decomposition algorithm for the electronic repulsion integrals, eT has similar advantages as codes using density fitting, but with strict error control. Here, we present the main features of the program and demonstrate its performance through example calculations. Because of its availability, performance, and unique capabilities, we expect eT to become a valuable resource to the electronic structure community.
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Affiliation(s)
- Sarai D Folkestad
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Eirik F Kjønstad
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Rolf H Myhre
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Josefine H Andersen
- DTU Chemistry-Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Alice Balbi
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, IT-56126 Pisa, PI, Italy
| | - Sonia Coriani
- DTU Chemistry-Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Linda Goletto
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Tor S Haugland
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Anders Hutcheson
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Ida-Marie Høyvik
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Torsha Moitra
- DTU Chemistry-Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Alexander C Paul
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Marco Scavino
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, IT-56126 Pisa, PI, Italy
| | - Andreas S Skeidsvoll
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Åsmund H Tveten
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Henrik Koch
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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33
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Gómez S, Giovannini T, Cappelli C. Absorption spectra of xanthines in aqueous solution: a computational study. Phys Chem Chem Phys 2020; 22:5929-5941. [PMID: 32115599 DOI: 10.1039/c9cp05420k] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We present a detailed computational analysis of the UV/Vis spectra of caffeine, paraxanthine and theophylline in aqueous solution. A hierarchy of solvation approaches for modeling the aqueous environment have been tested, ranging from the continuum model to the non-polarizable and polarizable quantum mechanical (QM)/molecular mechanics (MM) models, with and without the explicit inclusion of water molecules in the QM portion. The computed results are directly compared with the experimental data, thus highlighting the role of electrostatic, polarization and hydrogen boding solute-solvent interactions.
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Affiliation(s)
- Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
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34
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Giovannini T, Riso RR, Ambrosetti M, Puglisi A, Cappelli C. Electronic transitions for a fully polarizable QM/MM approach based on fluctuating charges and fluctuating dipoles: Linear and corrected linear response regimes. J Chem Phys 2019; 151:174104. [PMID: 31703497 DOI: 10.1063/1.5121396] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The fully polarizable Quantum Mechanics/Molecular Mechanics (QM/MM) approach based on fluctuating charges and fluctuating dipoles, named QM/FQFμ [T. Giovannini et al., J. Chem. Theory Comput. 15, 2233 (2019)], is extended to the calculation of vertical excitation energies of solvated molecular systems. Excitation energies are defined within two different solvation regimes, i.e., linear response (LR), where the response of the MM portion is adjusted to the QM transition density, and corrected-Linear Response (cLR) in which the MM response is adjusted to the relaxed QM density, thus being able to account for charge equilibration in the excited state. The model, which is specified in terms of three physical parameters (electronegativity, chemical hardness, and polarizability) is applied to vacuo-to-water solvatochromic shifts of aqueous solutions of para-nitroaniline, pyridine, and pyrimidine. The results show a good agreement with their experimental counterparts, thus highlighting the potentialities of this approach.
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Affiliation(s)
- 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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35
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Giovannini T, Ambrosetti M, Cappelli C. Quantum Confinement Effects on Solvatochromic Shifts of Molecular Solutes. J Phys Chem Lett 2019; 10:5823-5829. [PMID: 31518133 DOI: 10.1021/acs.jpclett.9b02318] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We demonstrate the pivotal role of quantum mechanics density confinement effects on solvatochromic shifts. In particular, by resorting to a quantum mechanics/molecular mechanics (QM/MM) approach capable of accounting for confinement effects we successfully reproduce vacuo-to-water solvatochromic shifts for dark n → π* and bright π → π* transitions of acrolein and dark n → π* transitions of pyridine and pyrimidine without the need of including explicit water molecules in the QM portion. Remarkably, our approach is also able to dissect the effects of the single forces acting on the solute-solvent couple and allows for a rationalization of the experimental findings in terms of physicochemical quantities.
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Affiliation(s)
- Tommaso Giovannini
- Department of Chemistry , Norwegian University of Science and Technology , 7491 Trondheim , Norway
| | - Matteo Ambrosetti
- 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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36
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Giovannini T, Grazioli L, Ambrosetti M, Cappelli C. Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles. J Chem Theory Comput 2019; 15:5495-5507. [DOI: 10.1021/acs.jctc.9b00574] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tommaso Giovannini
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim 7491, Norway
| | - Laura Grazioli
- 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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37
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Di Remigio R, Giovannini T, Ambrosetti M, Cappelli C, Frediani L. Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions. J Chem Theory Comput 2019; 15:4056-4068. [DOI: 10.1021/acs.jctc.9b00305] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Roberto Di Remigio
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, N-9037 Tromsø, Norway
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - 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
| | - Luca Frediani
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, N-9037 Tromsø, Norway
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38
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Giovannini T, Puglisi A, Ambrosetti M, Cappelli C. Polarizable QM/MM Approach with Fluctuating Charges and Fluctuating Dipoles: The QM/FQFμ Model. J Chem Theory Comput 2019; 15:2233-2245. [DOI: 10.1021/acs.jctc.8b01149] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | | | | | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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39
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Puglisi A, Giovannini T, Antonov L, Cappelli C. Interplay between conformational and solvent effects in UV-visible absorption spectra: curcumin tautomers as a case study. Phys Chem Chem Phys 2019; 21:15504-15514. [PMID: 31259324 DOI: 10.1039/c9cp00907h] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We present a combined theoretical and experimental study on the UV-vis spectra of enol-keto (EK) and keto-keto (KK) tautomeric forms of curcumin dissolved in aqueous solution. Solvent effects have been investigated by resorting to the implicit polarizable continuum model (QM/PCM) and non-polarizable and fully polarizable QM/MM approaches, the latter based on the fluctuating charges (FQ) force-field. In particular, all methods are challenged to rationalize the contribution of conformational, electrostatic and polarization effects in the calculation of the vertical excitation spectra of curcumin tautomers. The obtained results highlight that for both tautomers specific solute-solvent hydrogen-bond interactions play a minor role with respect to conformational and electrostatic effects.
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Affiliation(s)
| | | | - Liudmil Antonov
- Bulgarian Academy of Sciences, Institute of Organic Chemistry with Centre of Phytochemistry, Acad. G. Bonchev str., Bldg. 9, Sofia 1113, Bulgaria
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
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