1
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Rahman M, Dannatt HRW, Blundell CD, Hughes LP, Blade H, Carson J, Tatman BP, Johnston ST, Brown SP. Polymorph Identification for Flexible Molecules: Linear Regression Analysis of Experimental and Calculated Solution- and Solid-State NMR Data. J Phys Chem A 2024; 128:1793-1816. [PMID: 38427685 PMCID: PMC10945485 DOI: 10.1021/acs.jpca.3c07732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 03/03/2024]
Abstract
The Δδ regression approach of Blade et al. [ J. Phys. Chem. A 2020, 124(43), 8959-8977] for accurately discriminating between solid forms using a combination of experimental solution- and solid-state NMR data with density functional theory (DFT) calculation is here extended to molecules with multiple conformational degrees of freedom, using furosemide polymorphs as an exemplar. As before, the differences in measured 1H and 13C chemical shifts between solution-state NMR and solid-state magic-angle spinning (MAS) NMR (Δδexperimental) are compared to those determined by gauge-including projector augmented wave (GIPAW) calculations (Δδcalculated) by regression analysis and a t-test, allowing the correct furosemide polymorph to be precisely identified. Monte Carlo random sampling is used to calculate solution-state NMR chemical shifts, reducing computation times by avoiding the need to systematically sample the multidimensional conformational landscape that furosemide occupies in solution. The solvent conditions should be chosen to match the molecule's charge state between the solution and solid states. The Δδ regression approach indicates whether or not correlations between Δδexperimental and Δδcalculated are statistically significant; the approach is differently sensitive to the popular root mean squared error (RMSE) method, being shown to exhibit a much greater dynamic range. An alternative method for estimating solution-state NMR chemical shifts by approximating the measured solution-state dynamic 3D behavior with an ensemble of 54 furosemide crystal structures (polymorphs and cocrystals) from the Cambridge Structural Database (CSD) was also successful in this case, suggesting new avenues for this method that may overcome its current dependency on the prior determination of solution dynamic 3D structures.
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Affiliation(s)
- Mohammed Rahman
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | | | | | - Leslie P. Hughes
- Oral
Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Helen Blade
- Oral
Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Jake Carson
- Mathematics
Institute at Warwick, University of Warwick, Coventry CV4 7AL, U.K.
| | - Ben P. Tatman
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | | | - Steven P. Brown
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
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2
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Patyk-Kaźmierczak E, Izquierdo-Ruiz F, Lobato A, Kaźmierczak M, Moszczyńska I, Olejniczak A, Recio JM. The curious case of proton migration under pressure in the malonic acid and 4,4'-bipyridine cocrystal. IUCRJ 2024; 11:168-181. [PMID: 38275161 PMCID: PMC10916288 DOI: 10.1107/s2052252524000344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/09/2024] [Indexed: 01/27/2024]
Abstract
In the search for new active pharmaceutical ingredients, the precise control of the chemistry of cocrystals becomes essential. One crucial step within this chemistry is proton migration between cocrystal coformers to form a salt, usually anticipated by the empirical ΔpKa rule. Due to the effective role it plays in modifying intermolecular distances and interactions, pressure adds a new dimension to the ΔpKa rule. Still, this variable has been scarcely applied to induce proton-transfer reactions within these systems. In our study, high-pressure X-ray diffraction and Raman spectroscopy experiments, supported by DFT calculations, reveal modifications to the protonation states of the 4,4'-bipyridine (BIPY) and malonic acid (MA) cocrystal (BIPYMA) that allow the conversion of the cocrystal phase into ionic salt polymorphs. On compression, neutral BIPYMA and monoprotonated (BIPYH+MA-) species coexist up to 3.1 GPa, where a phase transition to a structure of P21/c symmetry occurs, induced by a double proton-transfer reaction forming BIPYH22+MA2-. The low-pressure C2/c phase is recovered at 2.4 GPa on decompression, leading to a 0.7 GPa hysteresis pressure range. This is one of a few studies on proton transfer in multicomponent crystals that shows how susceptible the interconversion between differently charged species is to even slight pressure changes, and how the proton transfer can be a triggering factor leading to changes in the crystal symmetry. These new data, coupled with information from previous reports on proton-transfer reactions between coformers, extend the applicability of the ΔpKa rule incorporating the pressure required to induce salt formation.
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Affiliation(s)
- Ewa Patyk-Kaźmierczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Fernando Izquierdo-Ruiz
- MALTA-Consolider Team and Departamento de Química Física, University Complutense of Madrid, Avda. de Séneca, 2 Ciudad Universitaria, Madrid 28040, Spain
| | - Alvaro Lobato
- MALTA-Consolider Team and Departamento de Química Física, University Complutense of Madrid, Avda. de Séneca, 2 Ciudad Universitaria, Madrid 28040, Spain
| | - Michał Kaźmierczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Ida Moszczyńska
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Anna Olejniczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - J. Manuel Recio
- MALTA-Consolider Team and Departamento de Química Física y Analítica, University of Oviedo, Julián Clavería n° 8, Oviedo 33006, Spain
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3
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Beran GJO. Frontiers of molecular crystal structure prediction for pharmaceuticals and functional organic materials. Chem Sci 2023; 14:13290-13312. [PMID: 38033897 PMCID: PMC10685338 DOI: 10.1039/d3sc03903j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
The reliability of organic molecular crystal structure prediction has improved tremendously in recent years. Crystal structure predictions for small, mostly rigid molecules are quickly becoming routine. Structure predictions for larger, highly flexible molecules are more challenging, but their crystal structures can also now be predicted with increasing rates of success. These advances are ushering in a new era where crystal structure prediction drives the experimental discovery of new solid forms. After briefly discussing the computational methods that enable successful crystal structure prediction, this perspective presents case studies from the literature that demonstrate how state-of-the-art crystal structure prediction can transform how scientists approach problems involving the organic solid state. Applications to pharmaceuticals, porous organic materials, photomechanical crystals, organic semi-conductors, and nuclear magnetic resonance crystallography are included. Finally, efforts to improve our understanding of which predicted crystal structures can actually be produced experimentally and other outstanding challenges are discussed.
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Affiliation(s)
- Gregory J O Beran
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
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4
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Graf D, Thom AJW. Simple and Efficient Route toward Improved Energetics within the Framework of Density-Corrected Density Functional Theory. J Chem Theory Comput 2023; 19:5427-5438. [PMID: 37525457 PMCID: PMC10448722 DOI: 10.1021/acs.jctc.3c00441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Indexed: 08/02/2023]
Abstract
The crucial step in density-corrected Hartree-Fock density functional theory (DC(HF)-DFT) is to decide whether the density produced by the density functional for a specific calculation is erroneous and, hence, should be replaced by, in this case, the HF density. We introduce an indicator, based on the difference in noninteracting kinetic energies between DFT and HF calculations, to determine when the HF density is the better option. Our kinetic energy indicator directly compares the self-consistent density of the analyzed functional with the HF density, is size-intensive, reliable, and most importantly highly efficient. Moreover, we present a procedure that makes best use of the computed quantities necessary for DC(HF)-DFT by additionally evaluating a related hybrid functional and, in that way, not only "corrects" the density but also the functional itself; we call that procedure corrected Hartree-Fock density functional theory (C(HF)-DFT).
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Affiliation(s)
- Daniel Graf
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Alex J. W. Thom
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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5
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Christian MS, Nenoff TM, Rimsza JM. Effect of Linker Structure and Functionalization on Secondary Gas Formation in Metal-Organic Frameworks. J Phys Chem A 2023; 127:2881-2888. [PMID: 36947182 DOI: 10.1021/acs.jpca.2c07751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Rare-earth terephthalic acid (BDC)-based metal-organic frameworks (MOFs) are promising candidate materials for acid gas separation and adsorption from flue gas streams. However, previous simulations have shown that acid gases (H2O, NO2, and SO2) react with the hydroxyl on the BDC linkers to form protonated acid gases as a potential degradation mechanism. Herein, gas-phase computational approaches were used to identify the formation energies of these secondary protonated acid gases across multiple BDC linker molecules. Formation energies for secondary protonated acid gases were evaluated using both density functional theory (DFT) and correlated wave function methods for varying BDC-gas reaction mechanisms. Upon validation of DFT to reproduce wave function calculation results, rotated conformational linkers and chemically functionalized BDC linkers with -OH, -NH2, and -SH were investigated. The calculations show that the rotational conformation affects the molecule stability. Double-functionalized BDC linkers, where two functional groups are substituted onto BDC, showed varied reaction energies depending on whether the functional groups donate or withdraw electrons from the aromatic system. Based on these results, BDC linker design must balance adsorption performance with degradation via linker dehydrogenation for the design of stable MOFs for acid gas separations.
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Affiliation(s)
- Matthew S Christian
- Geochemistry Department, Sandia National Laboratories, P.O. Box 5800, Eubank Boulevard SE, Albuquerque, New Mexico 87185, United States
| | - Tina M Nenoff
- Advanced Science & Technology, Sandia National Laboratories, P.O. Box 5800, Eubank Boulevard SE, Albuquerque, New Mexico 87185, United States
| | - Jessica M Rimsza
- Geochemistry Department, Sandia National Laboratories, P.O. Box 5800, Eubank Boulevard SE, Albuquerque, New Mexico 87185, United States
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6
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Price AJA, Otero-de-la-Roza A, Johnson ER. XDM-corrected hybrid DFT with numerical atomic orbitals predicts molecular crystal lattice energies with unprecedented accuracy. Chem Sci 2023; 14:1252-1262. [PMID: 36756332 PMCID: PMC9891363 DOI: 10.1039/d2sc05997e] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Molecular crystals are important for many applications, including energetic materials, organic semiconductors, and the development and commercialization of pharmaceuticals. The exchange-hole dipole moment (XDM) dispersion model has shown good performance in the calculation of relative and absolute lattice energies of molecular crystals, although it has traditionally been applied in combination with plane-wave/pseudopotential approaches. This has limited XDM to use with semilocal functional approximations, which suffer from delocalization error and poor quality conformational energies, and to systems with a few hundreds of atoms at most due to unfavorable scaling. In this work, we combine XDM with numerical atomic orbitals, which enable the efficient use of XDM-corrected hybrid functionals for molecular crystals. We test the new XDM-corrected functionals for their ability to predict the lattice energies of molecular crystals for the X23 set and 13 ice phases, the latter being a particularly stringent test. A composite approach using a XDM-corrected, 25% hybrid functional based on B86bPBE achieves a mean absolute error of 0.48 kcal mol-1 per molecule for the X23 set and 0.19 kcal mol-1 for the total lattice energies of the ice phases, compared to recent diffusion Monte-Carlo data. These results make the new XDM-corrected hybrids not only far more computationally efficient than previous XDM implementations, but also the most accurate density-functional methods for molecular crystal lattice energies to date.
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Affiliation(s)
- Alastair J. A. Price
- Department of Chemistry, Dalhousie University6274 Coburg RdHalifaxB3H 4R2Nova ScotiaCanada
| | - Alberto Otero-de-la-Roza
- Departamento de Química Física y Analítica and MALTA-Consolider Team, Facultad de Química, Universidad de Oviedo Oviedo 33006 Spain
| | - Erin R. Johnson
- Department of Chemistry, Dalhousie University6274 Coburg RdHalifaxB3H 4R2Nova ScotiaCanada
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7
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Lonsdale DR, Goerigk L. One-electron self-interaction error and its relationship to geometry and higher orbital occupation. J Chem Phys 2023; 158:044102. [PMID: 36725505 DOI: 10.1063/5.0129820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Density Functional Theory (DFT) sees prominent use in computational chemistry and physics; however, problems due to the self-interaction error (SIE) pose additional challenges to obtaining qualitatively correct results. As an unphysical energy an electron exerts on itself, the SIE impacts most practical DFT calculations. We conduct an in-depth analysis of the one-electron SIE in which we replicate delocalization effects for simple geometries. We present a simple visualization of such effects, which may help in future qualitative analysis of the one-electron SIE. By increasing the number of nuclei in a linear arrangement, the SIE increases dramatically. We also show how molecular shape impacts the SIE. Two- and three-dimensional shapes show an even greater SIE stemming mainly from the exchange functional with some error compensation from the one-electron error, which we previously defined [D. R. Lonsdale and L. Goerigk, Phys. Chem. Chem. Phys. 22, 15805 (2020)]. Most tested geometries are affected by the functional error, while some suffer from the density error. For the latter, we establish a potential connection with electrons being unequally delocalized by the DFT methods. We also show how the SIE increases if electrons occupy higher-lying atomic orbitals; seemingly one-electron SIE free methods in a ground are no longer SIE free in excited states, which is an important insight for some popular, non-empirical density functional approximations (DFAs). We conclude that the erratic behavior of the SIE in even the simplest geometries shows that robust DFAs are needed. Our test systems can be used as a future benchmark or contribute toward DFT development.
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Affiliation(s)
- Dale R Lonsdale
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Lars Goerigk
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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8
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Cook CJ, Li W, Lui BF, Gately TJ, Al-Kaysi RO, Mueller LJ, Bardeen CJ, Beran GJO. A theoretical framework for the design of molecular crystal engines. Chem Sci 2023; 14:937-949. [PMID: 36755715 PMCID: PMC9890974 DOI: 10.1039/d2sc05549j] [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: 10/06/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Photomechanical molecular crystals have garnered attention for their ability to transform light into mechanical work, but difficulties in characterizing the structural changes and mechanical responses experimentally have hindered the development of practical organic crystal engines. This study proposes a new computational framework for predicting the solid-state crystal-to-crystal photochemical transformations entirely from first principles, and it establishes a photomechanical engine cycle that quantifies the anisotropic mechanical performance resulting from the transformation. The approach relies on crystal structure prediction, solid-state topochemical principles, and high-quality electronic structure methods. After validating the framework on the well-studied [4 + 4] cycloadditions in 9-methyl anthracene and 9-tert-butyl anthracene ester, the experimentally-unknown solid-state transformation of 9-carboxylic acid anthracene is predicted for the first time. The results illustrate how the mechanical work is done by relaxation of the crystal lattice to accommodate the photoproduct, rather than by the photochemistry itself. The large ∼107 J m-3 work densities computed for all three systems highlight the promise of photomechanical crystal engines. This study demonstrates the importance of crystal packing in determining molecular crystal engine performance and provides tools and insights to design improved materials in silico.
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Affiliation(s)
- Cameron J. Cook
- Department of Chemistry, University of California RiversideRiverside CA 92521USA
| | - Wangxiang Li
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| | - Brandon F. Lui
- Department of Chemistry, University of California RiversideRiverside CA 92521USA
| | - Thomas J. Gately
- Department of Chemistry, University of California RiversideRiverside CA 92521USA
| | - Rabih O. Al-Kaysi
- College of Science and Health Professions-3124, King Saud Bin Abdulaziz University for Health Sciences, and King Abdullah International Medical Research Center, Ministry of National Guard Health AffairsRiyadh 11426Kingdom of Saudi Arabia
| | - Leonard J. Mueller
- Department of Chemistry, University of California RiversideRiverside CA 92521USA
| | | | - Gregory J. O. Beran
- Department of Chemistry, University of California RiversideRiverside CA 92521USA
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9
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Díaz Mirón JEZ, Stein M. A benchmark for non-covalent interactions in organometallic crystals. Phys Chem Chem Phys 2022; 24:29338-29349. [PMID: 36448535 DOI: 10.1039/d2cp04160j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Organometallic complexes are the basis for homogeneous catalysis, have applications in materials science and are also active pharmaceutical ingredients. The interaction between transition metal complexes in the solid state is determining their thermodynamics and bio-availability. Non-covalent interactions such as hydrogen bonding and van der Waals are stabilizing crystals of transition metal complexes. The variation of ligand field, central metal atoms and their oxidation and spin states are determinants of the magnitude of their inter-molecular interactions. A comparison of a set of 43 manually curated experimental heats of sublimation (the new XTMC43 set) and results from periodic DFT calculations shows that an agreement to within 9% can be achieved using GGA or mGGA functionals with atom-centred Gaussian-type basis functions. The need for careful assessments of consistency, calibration and reproducibility of experimental and computational data is discussed. Results regarding the new XTMC43 benchmark set are suggested to serve as a starting point for further method development, systematic screening and crystal engineering.
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Affiliation(s)
- José Eduardo Zamudio Díaz Mirón
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany.
| | - Matthias Stein
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany.
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10
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Blahut J, Štoček JR, Šála M, Dračínský M. The hydrogen bond continuum in solid isonicotinic acid. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 345:107334. [PMID: 36410062 DOI: 10.1016/j.jmr.2022.107334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
The understanding and correct description of intermolecular hydrogen bonds are crucial in the field of multicomponent pharmaceutical solids, such as salts and cocrystals. Solid isonicotinic acid can serve as a suitable model for the development of methods that can accurately characterize these hydrogen bonds. Experimental solid-state NMR has revealed a remarkable temperature dependence and deuterium-isotope-induced changes of the chemical shifts of the atoms involved in the intermolecular hydrogen bond; these NMR data are related to changes of the average position of the hydrogen atom. These changes of NMR parameters were interpreted using periodic DFT path-integral molecular dynamics (PIMD) simulations. The small size of the unit cell of isonicotinic acid allowed for PIMD simulations with the computationally demanding hybrid DFT functional. Calculations of NMR parameters based on the hybrid-functional PIMD simulations are in excellent agreement with experiment. It is thus demonstrated that an accurate characterization of intermolecular hydrogen bonds can be achieved by a combination of NMR experiments and advanced computations.
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Affiliation(s)
- Jan Blahut
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Jakub Radek Štoček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic; Department of Organic Chemistry, Faculty of Science, Charles University in Prague, 128 40 Prague 2, Czech Republic
| | - Michal Šála
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic.
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11
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Bryenton KR, Adeleke AA, Dale SG, Johnson ER. Delocalization error: The greatest outstanding challenge in density‐functional theory. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kyle R. Bryenton
- Department of Physics and Atmospheric Science Dalhousie University Halifax Nova Scotia Canada
| | | | - Stephen G. Dale
- Queensland Micro‐ and Nanotechnology Centre Griffith University Nathan Queensland Australia
| | - Erin R. Johnson
- Department of Physics and Atmospheric Science Dalhousie University Halifax Nova Scotia Canada
- Department of Chemistry Dalhousie University Halifax Nova Scotia Canada
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12
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Wengert S, Csányi G, Reuter K, Margraf JT. A Hybrid Machine Learning Approach for Structure Stability Prediction in Molecular Co-crystal Screenings. J Chem Theory Comput 2022; 18:4586-4593. [PMID: 35709378 PMCID: PMC9281391 DOI: 10.1021/acs.jctc.2c00343] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Co-crystals are a
highly interesting material class as varying
their components and stoichiometry in principle allows tuning supramolecular
assemblies toward desired physical properties. The in silico prediction of co-crystal structures represents a daunting task,
however, as they span a vast search space and usually feature large
unit cells. This requires theoretical models that are accurate and
fast to evaluate, a combination that can in principle be accomplished
by modern machine-learned (ML) potentials trained on first-principles
data. Crucially, these ML potentials need to account for the description
of long-range interactions, which are essential for the stability
and structure of molecular crystals. In this contribution, we present
a strategy for developing Δ-ML potentials for co-crystals, which
use a physical baseline model to describe long-range interactions.
The applicability of this approach is demonstrated for co-crystals
of variable composition consisting of an active pharmaceutical ingredient
and various co-formers. We find that the Δ-ML approach offers
a strong and consistent improvement over the density functional tight
binding baseline. Importantly, this even holds true when extrapolating
beyond the scope of the training set, for instance in molecular dynamics
simulations under ambient conditions.
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Affiliation(s)
- Simon Wengert
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.,Chair of Theoretical Chemistry, Technische Universitát München, 85747 Garching, Germany
| | - Gábor Csányi
- Engineering Laboratory, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | - Karsten Reuter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Johannes T Margraf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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13
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Cruz-Cabeza AJ, Lusi M, Wheatcroft HP, Bond AD. The role of solvation in proton transfer reactions: implications for predicting salt/co-crystal formation using the Δp Ka rule. Faraday Discuss 2022; 235:446-466. [PMID: 35446321 DOI: 10.1039/d1fd00081k] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ΔpKa rule is commonly applied by chemists and crystal engineers as a guideline for the rational design of molecular salts and co-crystals. For multi-component crystals containing acid and base constituents, empirical evidence has shown that ΔpKa > 4 almost always leads to salts, ΔpKa < -1 almost always leads to co-crystals and ΔpKa between -1 and 4 can be either. This paper reviews the theoretical background of the ΔpKa rule and highlights the crucial role of solvation in determining the outcome of the potential proton transfer from acid to base. New data on the frequency of the occurrence of co-crystals and salts in multi-component crystal structures containing acid and base constituents show that the relationship between ΔpKa and the frequency of salt/co-crystal formation is influenced by the composition of the crystal. For unsolvated co-crystals/salts, containing only the principal acid and base components, the point of 50% probability for salt/co-crystal formation occurs at ΔpKa ≈ 1.4, while for hydrates of co-crystals and salts, this point is shifted to ΔpKa ≈ -0.5. For acid-base crystals with the possibility for two proton transfers, the overall frequency of occurrence of any salt (monovalent or divalent) versus a co-crystal is comparable to that of the whole data set, but the point of 50% probability for observing a monovalent salt vs. a divalent salt lies at ΔpKa,II ≈ -4.5. Hence, where two proton transfers are possible, the balance is between co-crystals and divalent salts, with monovalent salts being far less common. Finally, the overall role played by the "crystal" solvation is illustrated by the fact that acid-base complexes in the intermediate region of ΔpKa tip towards salt formation if ancillary hydrogen bonds can exist. Thus, the solvation strength of the lattice plays a key role in the stabilisation of the ions.
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Affiliation(s)
- Aurora J Cruz-Cabeza
- Department of Chemical Engineering, School of Engineering, University of Manchester, UK. .,Chemical Development, Pharmaceutical Technology & Development, AstraZeneca, Macclesfield, UK
| | - Matteo Lusi
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Helen P Wheatcroft
- Chemical Development, Pharmaceutical Technology & Development, AstraZeneca, Macclesfield, UK
| | - Andrew D Bond
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
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14
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Štoček JR, Socha O, Císařová I, Slanina T, Dračínský M. Importance of Nuclear Quantum Effects for Molecular Cocrystals with Short Hydrogen Bonds. J Am Chem Soc 2022; 144:7111-7116. [PMID: 35394771 DOI: 10.1021/jacs.1c10885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many efforts have been recently devoted to the design and investigation of multicomponent pharmaceutical solids, such as salts and cocrystals. The experimental distinction between these solid forms is often challenging. Here, we show that the transformation of a salt into a cocrystal with a short hydrogen bond does not occur as a sharp phase transition but rather a smooth shift of the positional probability of the hydrogen atoms. A combination of solid-state NMR spectroscopy, X-ray diffraction, and diffuse reflectance measurements with density functional theory calculations that include nuclear quantum effects (NQEs) provides evidence of temperature-induced hydrogen atom shift in cocrystals with short hydrogen bonds. We demonstrate that for the predictions of the salt/cocrystal solid forms with short H-bonds, the computations have to include NQEs (particularly hydrogen nuclei delocalization) and temperature effects.
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Affiliation(s)
- Jakub Radek Štoček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic.,Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2 12840, Czech Republic
| | - Ondřej Socha
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2 12840, Czech Republic
| | - Tomáš Slanina
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
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15
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Beran GJO, Wright SE, Greenwell C, Cruz-Cabeza AJ. The interplay of intra- and intermolecular errors in modeling conformational polymorphs. J Chem Phys 2022; 156:104112. [DOI: 10.1063/5.0088027] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Conformational polymorphs of organic molecular crystals represent a challenging test for quantum chemistry because they require careful balancing of the intra- and intermolecular interactions. This study examines 54 molecular conformations from 20 sets of conformational polymorphs, along with the relative lattice energies and 173 dimer interactions taken from six of the polymorph sets. These systems are studied with a variety of van der Waals-inclusive density functionals theory models; dispersion-corrected spin-component-scaled second-order Møller–Plesset perturbation theory (SCS-MP2D); and domain local pair natural orbital coupled cluster singles, doubles, and perturbative triples [DLPNO-CCSD(T)]. We investigate how delocalization error in conventional density functionals impacts monomer conformational energies, systematic errors in the intermolecular interactions, and the nature of error cancellation that occurs in the overall crystal. The density functionals B86bPBE-XDM, PBE-D4, PBE-MBD, PBE0-D4, and PBE0-MBD are found to exhibit sizable one-body and two-body errors vs DLPNO-CCSD(T) benchmarks, and the level of success in predicting the relative polymorph energies relies heavily on error cancellation between different types of intermolecular interactions or between intra- and intermolecular interactions. The SCS-MP2D and, to a lesser extent, ωB97M-V models exhibit smaller errors and rely less on error cancellation. Implications for crystal structure prediction of flexible compounds are discussed. Finally, the one-body and two-body DLPNO-CCSD(T) energies taken from these conformational polymorphs establish the CP1b and CP2b benchmark datasets that could be useful for testing quantum chemistry models in challenging real-world systems with complex interplay between intra- and intermolecular interactions, a number of which are significantly impacted by delocalization error.
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Affiliation(s)
- Gregory J. O. Beran
- Department of Chemistry, University of California, Riverside, California 92521, USA
| | - Sarah E. Wright
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, United Kingdom
| | - Chandler Greenwell
- Department of Chemistry, University of California, Riverside, California 92521, USA
| | - Aurora J. Cruz-Cabeza
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, United Kingdom
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16
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Dudek MK, Druzbicki K. Along the road to Crystal Structure Prediction (CSP) of pharmaceutical-like molecules. CrystEngComm 2022. [DOI: 10.1039/d1ce01564h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computational methods used for predicting crystal structures of organic compounds are mature enough to be routinely used with many rigid and semi-rigid organic molecules. The usefulness of Crystal Structure Prediction...
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17
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Beran GJO, Sugden IJ, Greenwell C, Bowskill DH, Pantelides CC, Adjiman CS. How many more polymorphs of ROY remain undiscovered. Chem Sci 2022; 13:1288-1297. [PMID: 35222912 PMCID: PMC8809489 DOI: 10.1039/d1sc06074k] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/10/2021] [Indexed: 12/15/2022] Open
Abstract
With 12 crystal forms, 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecabonitrile (a.k.a. ROY) holds the current record for the largest number of fully characterized organic crystal polymorphs. Four of these polymorph structures have been reported since 2019, raising the question of how many more ROY polymorphs await future discovery. Employing crystal structure prediction and accurate energy rankings derived from conformational energy-corrected density functional theory, this study presents the first crystal energy landscape for ROY that agrees well with experiment. The lattice energies suggest that the seven most stable ROY polymorphs (and nine of the twelve lowest-energy forms) on the Z′ = 1 landscape have already been discovered experimentally. Discovering any new polymorphs at ambient pressure will likely require specialized crystallization techniques capable of trapping metastable forms. At pressures above 10 GPa, however, a new crystal form is predicted to become enthalpically more stable than all known polymorphs, suggesting that further high-pressure experiments on ROY may be warranted. This work highlights the value of high-accuracy crystal structure prediction for solid-form screening and demonstrates how pragmatic conformational energy corrections can overcome the limitations of conventional density functionals for conformational polymorphs. Crystal structure prediction suggests that the low-energy polymorphs of ROY have already been found, but a new high-pressure form is predicted.![]()
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Affiliation(s)
- Gregory J. O. Beran
- Department of Chemistry, University of California Riverside, Riverside, CA 92521, USA
| | - Isaac J. Sugden
- Department of Chemical Engineering, Sargent Centre for Process Systems Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Chandler Greenwell
- Department of Chemistry, University of California Riverside, Riverside, CA 92521, USA
| | - David H. Bowskill
- Department of Chemical Engineering, Sargent Centre for Process Systems Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Constantinos C. Pantelides
- Department of Chemical Engineering, Sargent Centre for Process Systems Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Claire S. Adjiman
- Department of Chemical Engineering, Sargent Centre for Process Systems Engineering, Imperial College London, London, SW7 2AZ, UK
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18
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Beran GJO, Greenwell C, Rezac J. Spin-component-scaled and dispersion-corrected second-order Møller-Plesset perturbation theory: A path toward chemical accuracy. Phys Chem Chem Phys 2022; 24:3695-3712. [DOI: 10.1039/d1cp04922d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Second-order Moller-Plesset perturbation theory (MP2) provides a valuable alternative to density functional theory for modeing problems in organic and biological chemistry. However, MP2 suffers from known limitations in the description...
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19
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Mechanochemical Synthesis and Physicochemical Characterization of Previously Unreported Praziquantel Solvates with 2-Pyrrolidone and Acetic Acid. Pharmaceutics 2021; 13:pharmaceutics13101606. [PMID: 34683899 PMCID: PMC8540171 DOI: 10.3390/pharmaceutics13101606] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/26/2022] Open
Abstract
Two new solvates of the widely used anthelminthic Praziquantel (PZQ) were obtained through mechanochemical screening with different liquid additives. Specifically, 2-pyrrolidone and acetic acid gave solvates with 1:1 stoichiometry (PZQ-AA and PZQ-2P, respectively). A wide-ranging characterization of the new solid forms was carried out by means of powder X-ray diffraction, differential scanning calorimetry, FT-IR, solid-state NMR and biopharmaceutical analyses (solubility and intrinsic dissolution studies). Besides, the crystal structures of the two new solvates were solved from their Synchrotron-PXRD pattern: the solvates are isostructural, with equivalent triclinic packing. In both structures acetic acid and 2-pyrrolidone showed a strong interaction with the PZQ molecule via hydrogen bond. Even though previous studies have shown that PZQ is conformationally flexible, the same syn conformation as the PZQ Form A of the C=O groups of the piperazinone-cyclohexylcarbonyl segment is involved in these two new solid forms. In terms of biopharmaceutical properties, PZQ-AA and PZQ-2P exhibited water solubility and intrinsic dissolution rate much greater than those of anhydrous Form A.
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20
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Watts TA, Price LS, Price SL, Niederberger SM, Bertke JA, Swift JA. The Crystal Structure of 5‐Aminouracil and the Ambiguity of Alternative Polymorphs. Isr J Chem 2021. [DOI: 10.1002/ijch.202100062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Taylor A. Watts
- Department of Chemistry Georgetown University 37th and O Sts NW Washington DC 20057–1227 USA
| | - Louise S. Price
- Department of Chemistry University College London 20 Gordon Street London WC1H 0AJ UK
| | - Sarah L. Price
- Department of Chemistry University College London 20 Gordon Street London WC1H 0AJ UK
| | - Sara M. Niederberger
- Department of Chemistry Georgetown University 37th and O Sts NW Washington DC 20057–1227 USA
| | - Jeffery A. Bertke
- Department of Chemistry Georgetown University 37th and O Sts NW Washington DC 20057–1227 USA
| | - Jennifer A. Swift
- Department of Chemistry Georgetown University 37th and O Sts NW Washington DC 20057–1227 USA
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21
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Saunders LK, Pallipurath AR, Gutmann MJ, Nowell H, Zhang N, Allan DR. A quantum crystallographic approach to short hydrogen bonds. CrystEngComm 2021; 23:6180-6190. [PMID: 34588923 PMCID: PMC8436739 DOI: 10.1039/d1ce00355k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/27/2021] [Indexed: 11/21/2022]
Abstract
In this work we use high-resolution synchrotron X-ray diffraction for electron density mapping, in conjunction with ab initio modelling, to study short O-H⋯O and O+-H⋯O- hydrogen bonds whose behaviour is known to be tuneable by temperature. The short hydrogen bonds have donor-acceptor distances in the region of 2.45 Å and are formed in substituted urea and organic acid molecular complexes of N,N'-dimethylurea oxalic acid 2 : 1 (1), N,N-dimethylurea 2,4-dinitrobenzoate 1 : 1 (2) and N,N-dimethylurea 3,5-dinitrobenzoic acid 2 : 2 (3). From the combined analyses, these complexes are found to fall within the salt-cocrystal continuum and exhibit short hydrogen bonds that can be characterised as both strong and electrostatic (1, 3) or very strong with a significant covalent contribution (2). An additional charge assisted component is found to be important in distinguishing the relatively uncommon O-H⋯O pseudo-covalent interaction from a typical strong hydrogen bond. The electron density is found to be sensitive to the extent of static proton transfer, presenting it as a useful parameter in the study of the salt-cocrystal continuum. From complementary calculated hydrogen atom potentials, we attribute changes in proton position to the molecular environment. Calculated potentials also show zero barrier to proton migration, forming an 'energy slide' between the donor and acceptor atoms. The better fundamental understanding of the short hydrogen bond in the 'zone of fluctuation' presented in a salt-cocrystal continuum, enabled by studies like this, provide greater insight into their related properties and can have implications in the regulation of pharmaceutical materials.
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Affiliation(s)
- Lucy K Saunders
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
| | - Anuradha R Pallipurath
- School of Chemical and Process Engineering, University of Leeds Leeds LS2 9JT UK
- Research Complex at Harwell Didcot Oxfordshire OX11 0DE UK
- EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Advanced Crystallization, University of Strathclyde G1 1RD UK
| | - Matthias J Gutmann
- ISIS Pulsed Muon and Neutron Source, Rutherford Appleton Laboratory, Harwell Oxford Didcot OX11 0QX UK
| | - Harriott Nowell
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
| | - Ningjin Zhang
- Chemistry, Faculty of Natural and Environmental Sciences, Highfield Campus, University of Southampton Southampton SO17 1HE UK
| | - David R Allan
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
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22
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Ramos C, Muehlbrad J, Janesko BG. Density functionals with full nonlocal exchange, nonlocal rung-3.5 correlation, and D3 dispersion: Combined accuracy for general main-group thermochemistry, kinetics, and noncovalent interactions. J Comput Chem 2021; 42:1974-1981. [PMID: 34387364 DOI: 10.1002/jcc.26728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/25/2021] [Indexed: 11/11/2022]
Abstract
We introduce the HF-R35-D3(BJ) functional combining full nonlocal exact (Hartree-Fock-like, HF) exchange, inexpensive rung-3.5 correlation constructed from nonlocal one-electron operators, and nonlocal D3 dispersion corrections. HF-R35-D3(BJ) is among the first full-exact-exchange functionals offering competitive accuracy for general main-group thermochemistry, kinetics, and noncovalent interactions. HF-R35-D3(BJ) gives weighted mean absolute deviation WTMAD-2 8.5 kcal/mol across the entire GMTKN55 dataset, outperforming most dispersion-corrected semilocal functionals and approaching the accuracy of dispersion-corrected global hybrids. This requires six fitted parameters, three each in the nonlocal correlation and dispersion corrections. Full nonlocal exchange appears to help give accurate binding energies and reasonable energy orderings for water hexamers. These results motivate continued exploration of inexpensive nonlocal correlation corrections to nonlocal exchange.
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Affiliation(s)
- Chloe Ramos
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, Texas, USA
| | - Jeremiah Muehlbrad
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, Texas, USA
| | - Benjamin G Janesko
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, Texas, USA
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23
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Analyzing Discrepancies in Chemical-Shift Predictions of Solid Pyridinium Fumarates. Molecules 2021; 26:molecules26133857. [PMID: 34202841 PMCID: PMC8270278 DOI: 10.3390/molecules26133857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 01/29/2023] Open
Abstract
Highly accurate chemical-shift predictions in molecular solids are behind the success and rapid development of NMR crystallography. However, unusually large errors of predicted hydrogen and carbon chemical shifts are sometimes reported. An understanding of these deviations is crucial for the reliability of NMR crystallography. Here, recently reported large deviations of predicted hydrogen and carbon chemical shifts of a series of solid pyridinium fumarates are thoroughly analyzed. The influence of the geometry optimization protocol and of the computational level of NMR calculations on the accuracy of predicted chemical shifts is investigated. Periodic calculations with GGA, meta-GGA and hybrid functionals are employed. Furthermore, molecular corrections at the coupled-cluster singles-and-doubles (CCSD) level are calculated. The effect of nuclear delocalization on the structure and NMR shielding is also investigated. The geometry optimization with a computationally demanding hybrid functional leads to a substantial improvement in proton chemical-shift predictions.
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24
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Price AJA, Bryenton KR, Johnson ER. Requirements for an accurate dispersion-corrected density functional. J Chem Phys 2021; 154:230902. [PMID: 34241263 DOI: 10.1063/5.0050993] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Post-self-consistent dispersion corrections are now the norm when applying density-functional theory to systems where non-covalent interactions play an important role. However, there is a wide range of base functionals and dispersion corrections available from which to choose. In this work, we opine on the most desirable requirements to ensure that both the base functional and dispersion correction, individually, are as accurate as possible for non-bonded repulsion and dispersion attraction. The base functional should be dispersionless, numerically stable, and involve minimal delocalization error. Simultaneously, the dispersion correction should include finite damping, higher-order pairwise dispersion terms, and electronic many-body effects. These criteria are essential for avoiding reliance on error cancellation and obtaining correct results from correct physics.
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Affiliation(s)
- Alastair J A Price
- Department of Chemistry, Dalhousie University, 6274 Coburg Rd., Halifax, Nova Scotia B3H 4R2, Canada
| | - Kyle R Bryenton
- Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Rd., Halifax, Nova Scotia B3H 4R2, Canada
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University, 6274 Coburg Rd., Halifax, Nova Scotia B3H 4R2, Canada
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25
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Janesko BG. Replacing hybrid density functional theory: motivation and recent advances. Chem Soc Rev 2021; 50:8470-8495. [PMID: 34060549 DOI: 10.1039/d0cs01074j] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Density functional theory (DFT) is the most widely-used electronic structure approximation across chemistry, physics, and materials science. Every year, thousands of papers report hybrid DFT simulations of chemical structures, mechanisms, and spectra. Unfortunately, hybrid DFT's accuracy is ultimately limited by tradeoffs between over-delocalization and under-binding. This review summarizes these tradeoffs, and introduces six modern attempts to go beyond them while maintaining hybrid DFT's relatively low computational cost: DFT+U, self-interaction corrections, localized orbital scaling corrections, local hybrid functionals, real-space nondynamical correlation, and our rung-3.5 approach. The review concludes with practical suggestions for DFT users to identify and mitigate these tradeoffs' impact on their simulations.
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Affiliation(s)
- Benjamin G Janesko
- Department of Chemistry & Biochemistry, Texas Christian University, 2800 S. University Dr, Fort Worth, TX 76129, USA.
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26
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Ramos C, Janesko BG. Nonlocal rung-3.5 correlation from the density matrix expansion: Flat-plane condition, thermochemistry, and kinetics. J Chem Phys 2020; 153:164116. [PMID: 33138396 DOI: 10.1063/5.0025160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The rung-3.5 approach to density functional theory constructs nonlocal approximate correlation from the expectation values of nonlocal one-electron operators. This offers an inexpensive solution to hybrid functionals' imbalance between exact nonlocal exchange and local approximate correlation. Our rung-3.5 correlation functionals also include a local complement to the nonlocal ingredient, analogous to the local exchange component of a hybrid functional. Here, we use the density matrix expansion (DME) to build rung-3.5 complements. We demonstrate how these provide a measure of local fractional occupancy and use them to approximate the flat-plane condition. We also use these complements in a three-parameter nonlocal correlation functional compatible with full nonlocal exchange. This functional approaches the accuracy of widely used hybrids for molecular thermochemistry and kinetics. The DME provides a foundation for practical, minimally empirical, nonlocal correlation functionals compatible with full nonlocal local exchange.
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Affiliation(s)
- Chloe Ramos
- Department of Chemistry and Biochemistry, Texas Christian University, 2800 S. University Dr., Fort Worth, Texas 76129, USA
| | - Benjamin G Janesko
- Department of Chemistry and Biochemistry, Texas Christian University, 2800 S. University Dr., Fort Worth, Texas 76129, USA
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27
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Egorova O, Hafizi R, Woods DC, Day GM. Multifidelity Statistical Machine Learning for Molecular Crystal Structure Prediction. J Phys Chem A 2020; 124:8065-8078. [PMID: 32881496 DOI: 10.1021/acs.jpca.0c05006] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The prediction of crystal structures from first-principles requires highly accurate energies for large numbers of putative crystal structures. High accuracy of solid state density functional theory (DFT) calculations is often required, but hundreds or more structures can be present in the low energy region of interest, so that the associated computational costs are prohibitive. Here, we apply statistical machine learning to predict expensive hybrid functional DFT (PBE0) calculations using a multifidelity approach to re-evaluate the energies of crystal structures predicted with an inexpensive force field. The method uses an autoregressive Gaussian process, making use of less expensive GGA DFT (PBE) calculations to bridge the gap between the force field and PBE0 energies. The method is benchmarked on the crystal structure landscapes of three small, hydrogen-bonded organic molecules and shown to produce accurate predictions of energies and crystal structure ranking using small numbers of the most expensive calculations; the PBE0 energies can be predicted with errors of less than 1 kJ mol-1 with between 4.2 and 6.8% of the cost of the full calculations. As the model that we have developed is probabilistic, we discuss how the uncertainties in predicted energies impact the assessment of the energetic ranking of crystal structures.
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Affiliation(s)
- Olga Egorova
- Statistical Sciences Research Institute, University of Southampton, Southampton, SO17 1BJ, U.K
| | - Roohollah Hafizi
- Computational Systems Chemistry, School of Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| | - David C Woods
- Statistical Sciences Research Institute, University of Southampton, Southampton, SO17 1BJ, U.K
| | - Graeme M Day
- Computational Systems Chemistry, School of Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
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28
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Chen B, Xu X. XO-PBC: An Accurate and Efficient Method for Molecular Crystals. J Chem Theory Comput 2020; 16:4271-4285. [PMID: 32456429 DOI: 10.1021/acs.jctc.0c00232] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, we propose the XO-PBC method, which combines the eXtended ONIOM method (XO) with the periodic boundary condition (PBC) for the description of molecular crystals. XO-PBC tries to embed a finite cluster cut out from the solid into the periodic environment, making it feasible to employ advanced molecular quantum chemistry methods, which are usually prohibitively expensive for direct PBC calculations. In particular, XO-PBC utilizes the results from force calculations to design the scheme to fragment the molecule when crystals are made of large molecules and to select cluster model systems automatically consisting of dimer up to tetramer interactions for embedding. By applying an appropriate theory to each model, a satisfactory accuracy for the system under study is ensured, while a high efficiency is achieved with massively parallel computing by distributing model systems onto different processors. A comparison of the XO-PBC calculations with the conventional direct PBC calculations at the B3LYP level demonstrates its accuracy at substantially low cost for the description of molecular crystals. The usefulness of the XO-PBC method is further exemplified, showing that XO-PBC is able to predict the lattice energies of various types of molecular crystals within chemical accuracy (<4 kJ/mol) when the doubly hybrid density functional XYG3 is used as the target high level and the periodic PBE as the basic low level. The XO-PBC method provides a general protocol that brings the great predictive power of advanced electronic structure methods from molecular systems to the extended solids.
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Affiliation(s)
- Bozhu Chen
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Ministry of Education Key Laboratory of Computational Physical Sciences, Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Ministry of Education Key Laboratory of Computational Physical Sciences, Department of Chemistry, Fudan University, Shanghai, 200433, China
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29
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Červinka C, Štejfa V. Sublimation Properties of α,ω-Diamines Revisited from First-Principles Calculations. Chemphyschem 2020; 21:1184-1194. [PMID: 32243713 DOI: 10.1002/cphc.202000108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/02/2020] [Indexed: 11/06/2022]
Abstract
Sublimation enthalpies of alkane-α,ω-diamines exhibit an odd-even pattern within their homologous series. First-principles calculations coupled with the quasi-harmonic approximation for crystals and with the conformation mixing model for the ideal gas are used to explain this phenomenon from the theoretical point of view. Crystals of the odd and even alkane-α,ω-diamines distinctly differ in their packing motifs. However, first-principles calculations indicate that it is a delicate interplay of the cohesive forces, phonons, molecular vibrations and conformational equilibrium which governs the odd-even pattern of the sublimation enthalpies within the homologous series. High molecular flexibility of the alkane-α,ω-diamines predetermines higher sensitivity of the computational model to the quality of the optimized geometries and relative conformational energies. Performance of high-throughput computational methods, such as the density functional tight binding (DFTB, GFN2-xTB) and the explicitly correlated dispersion-corrected Møller-Plesset perturbative method (MP2C-F12), are benchmarked against the consistent state-of-the-art calculations of conformational energies and interaction energies, respectively.
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Affiliation(s)
- Ctirad Červinka
- Department of Physical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Vojtěch Štejfa
- Department of Physical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
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30
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Greenwell C, McKinley JL, Zhang P, Zeng Q, Sun G, Li B, Wen S, Beran GJO. Overcoming the difficulties of predicting conformational polymorph energetics in molecular crystals via correlated wavefunction methods. Chem Sci 2020; 11:2200-2214. [PMID: 32190277 PMCID: PMC7059316 DOI: 10.1039/c9sc05689k] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 01/13/2020] [Indexed: 11/21/2022] Open
Abstract
Molecular crystal structure prediction is increasingly being applied to study the solid form landscapes of larger, more flexible pharmaceutical molecules. Despite many successes in crystal structure prediction, van der Waals-inclusive density functional theory (DFT) methods exhibit serious failures predicting the polymorph stabilities for a number of systems exhibiting conformational polymorphism, where changes in intramolecular conformation lead to different intermolecular crystal packings. Here, the stabilities of the conformational polymorphs of o-acetamidobenzamide, ROY, and oxalyl dihydrazide are examined in detail. DFT functionals that have previously been very successful in crystal structure prediction perform poorly in all three systems, due primarily to the poor intramolecular conformational energies, but also due to the intermolecular description in oxalyl dihydrazide. In all three cases, a fragment-based dispersion-corrected second-order Møller-Plesset perturbation theory (MP2D) treatment of the crystals overcomes these difficulties and predicts conformational polymorph stabilities in good agreement with experiment. These results highlight the need for methods which go beyond current-generation DFT functionals to make crystal polymorph stability predictions truly reliable.
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Affiliation(s)
- Chandler Greenwell
- Department of Chemistry , University of California , Riverside , California 92521 , USA . ; Tel: +1-951-827-7869
| | - Jessica L McKinley
- Department of Chemistry , University of California , Riverside , California 92521 , USA . ; Tel: +1-951-827-7869
| | - Peiyu Zhang
- Xtalpi, Inc. , 245 Main St, 12th Floor , Cambridge , MA 02142 , USA
| | - Qun Zeng
- Xtalpi, Inc. , 245 Main St, 12th Floor , Cambridge , MA 02142 , USA
| | - Guangxu Sun
- Xtalpi, Inc. , 245 Main St, 12th Floor , Cambridge , MA 02142 , USA
| | - Bochen Li
- Xtalpi, Inc. , 245 Main St, 12th Floor , Cambridge , MA 02142 , USA
| | - Shuhao Wen
- Xtalpi, Inc. , 245 Main St, 12th Floor , Cambridge , MA 02142 , USA
| | - Gregory J O Beran
- Department of Chemistry , University of California , Riverside , California 92521 , USA . ; Tel: +1-951-827-7869
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31
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Awoonor-Williams E, Isley WC, Dale SG, Johnson ER, Yu H, Becke AD, Roux B, Rowley CN. Quantum Chemical Methods for Modeling Covalent Modification of Biological Thiols. J Comput Chem 2019; 41:427-438. [PMID: 31512279 DOI: 10.1002/jcc.26064] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/24/2019] [Accepted: 08/16/2019] [Indexed: 02/06/2023]
Abstract
Targeted covalent inhibitor drugs require computational methods that go beyond simple molecular-mechanical force fields in order to model the chemical reactions that occur when they bind to their targets. Here, several semiempirical and density-functional theory (DFT) methods are assessed for their ability to describe the potential energy surface and reaction energies of the covalent modification of a thiol by an electrophile. Functionals such as PBE and B3LYP fail to predict a stable enolate intermediate. This is largely due to delocalization error, which spuriously stabilizes the prereaction complex, in which excess electron density is transferred from the thiolate to the electrophile. Functionals with a high-exact exchange component, range-separated DFT functionals, and variationally optimized exact exchange (i.e., the LC-B05minV functional) correct this issue to various degrees. The large gradient behavior of the exchange enhancement factor is also found to significantly affect the results, leading to the improved performance of PBE0. While ωB97X-D and M06-2X were reasonably accurate, no method provided quantitative accuracy for all three electrophiles, making this a very strenuous test of functional performance. Additionally, one drawback of M06-2X was that molecular dynamics (MD) simulations using this functional were only stable if a fine integration grid was used. The low-cost semiempirical methods, PM3, AM1, and PM7, provide a qualitatively correct description of the reaction mechanism, although the energetics is not quantitatively reliable. As a proof of concept, the potential of mean force for the addition of methylthiolate to methylvinyl ketone was calculated using quantum mechanical/molecular mechanical MD in an explicit polarizable aqueous solvent. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Ernest Awoonor-Williams
- Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - William C Isley
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois
| | - Stephen G Dale
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Haibo Yu
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Axel D Becke
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois
| | - Christopher N Rowley
- Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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32
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McKinley JL, Beran GJO. Improving Predicted Nuclear Magnetic Resonance Chemical Shifts Using the Quasi-Harmonic Approximation. J Chem Theory Comput 2019; 15:5259-5274. [PMID: 31442040 DOI: 10.1021/acs.jctc.9b00481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ab initio nuclear magnetic resonance chemical shift prediction plays an important role in the determination or validation of crystal structures. The ability to predict chemical shifts more accurately can translate to increased confidence in the resulting chemical shift or structural assignments. Standard electronic structure predictions for molecular crystal structures neglect thermal expansion, which can lead to an appreciable underestimation of the molar volumes. This study examines this volume error and its impact on 68 13C- and 28 15N-predicted chemical shifts taken from 20 molecular crystals. It assesses the ability to recover more realistic room-temperature crystal structures using the quasi-harmonic approximation and how refining the structures impacts the chemical shifts. Several pharmaceutical molecular crystals are also examined in more detail. On the whole, accounting for quasi-harmonic expansion changes the 13C and 15N chemical shifts by 0.5 and 1.0 ppm on average. This, in turn, reduces the root-mean-square errors relative to experiment by 0.3 ppm for 13C and 0.7 ppm for 15N. Although the statistical impacts are modest, changes in individual chemical shifts can reach multiple ppm. Accounting for thermal expansion in molecular crystal chemical shift prediction may not be needed routinely, but the systematic trend toward improved accuracy with the experiment could be useful in cases where discrimination between structural candidates is challenging, as in the pharmaceutical theophylline.
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Affiliation(s)
- Jessica L McKinley
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - Gregory J O Beran
- Department of Chemistry , University of California , Riverside , California 92521 , United States
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33
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Červinka C, Klajmon M, Štejfa V. Cohesive Properties of Ionic Liquids Calculated from First Principles. J Chem Theory Comput 2019; 15:5563-5578. [DOI: 10.1021/acs.jctc.9b00625] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ctirad Červinka
- Department of Physical Chemistry, University of Chemistry and Technology Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Martin Klajmon
- Department of Physical Chemistry, University of Chemistry and Technology Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Vojtěch Štejfa
- Department of Physical Chemistry, University of Chemistry and Technology Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
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34
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Bhardwaj RM, McMahon JA, Nyman J, Price LS, Konar S, Oswald IDH, Pulham CR, Price SL, Reutzel-Edens SM. A Prolific Solvate Former, Galunisertib, under the Pressure of Crystal Structure Prediction, Produces Ten Diverse Polymorphs. J Am Chem Soc 2019; 141:13887-13897. [DOI: 10.1021/jacs.9b06634] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rajni M. Bhardwaj
- Small Molecule Design & Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Jennifer A. McMahon
- Small Molecule Design & Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Jonas Nyman
- Small Molecule Design & Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
- School of Pharmacy, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Louise S. Price
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Sumit Konar
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Iain D. H. Oswald
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow G4 0RE, U.K
| | - Colin R. Pulham
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Sarah L. Price
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Susan M. Reutzel-Edens
- Small Molecule Design & Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
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35
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Otero-de-la-Roza A, LeBlanc LM, Johnson ER. Dispersion XDM with Hybrid Functionals: Delocalization Error and Halogen Bonding in Molecular Crystals. J Chem Theory Comput 2019; 15:4933-4944. [DOI: 10.1021/acs.jctc.9b00550] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Otero-de-la-Roza
- Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Luc M. LeBlanc
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
| | - Erin R. Johnson
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
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36
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McDonagh D, Skylaris CK, Day GM. Machine-Learned Fragment-Based Energies for Crystal Structure Prediction. J Chem Theory Comput 2019; 15:2743-2758. [PMID: 30817152 DOI: 10.1021/acs.jctc.9b00038] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Crystal structure prediction involves a search of a complex configurational space for local minima corresponding to stable crystal structures, which can be performed efficiently using atom-atom force fields for the assessment of intermolecular interactions. However, for challenging systems, the limitations in the accuracy of force fields prevent a reliable assessment of the relative thermodynamic stability of potential structures, while the cost of fully quantum mechanical approaches can limit applications of the methods. We present a method to rapidly improve force field lattice energies by correcting two-body interactions with a higher level of theory in a fragment-based approach and predicting these corrections with machine learning. Corrected lattice energies with commonly used density functionals and second order perturbation theory (MP2) all significantly improve the ranking of experimentally known polymorphs where the rigid molecule model is applicable. The relative lattice energies of known polymorphs are also found to systematically improve with the fragment corrections. Predicting two-body interactions with atom-centered symmetry functions in a Gaussian process is found to give highly accurate results using as little as 10-20% of the data for training, reducing the cost of the energy correction by up to an order of magnitude. The machine learning approach opens up the possibility of more widespread use of fragment-based methods in crystal structure prediction, whose increased accuracy at a low computational cost will benefit applications in areas such as polymorph screening and computer-guided materials discovery.
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Affiliation(s)
- David McDonagh
- School of Chemistry , University of Southampton , Highfield, Southampton , SO17 1BJ , United Kingdom
| | - Chris-Kriton Skylaris
- School of Chemistry , University of Southampton , Highfield, Southampton , SO17 1BJ , United Kingdom
| | - Graeme M Day
- School of Chemistry , University of Southampton , Highfield, Southampton , SO17 1BJ , United Kingdom
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37
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Dračínský M, Unzueta P, Beran GJO. Improving the accuracy of solid-state nuclear magnetic resonance chemical shift prediction with a simple molecular correction. Phys Chem Chem Phys 2019; 21:14992-15000. [PMID: 31237586 DOI: 10.1039/c9cp01666j] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A fast, straightforward method for computing NMR chemical shieldings of crystalline solids is proposed. The method combines the advantages of both conventional approaches: periodic calculations using plane-wave basis sets and molecular computational approaches. The periodic calculations capture the periodic nature of crystalline solids, but the computational level of the electronic structure calculation is limited to general-gradient-approximation (GGA) density functionals. It is demonstrated that a correction to the GGA result calculated on an isolated molecule at a higher level of theory significantly improves the correlations between experimental and calculated chemical shifts while adding almost no additional computational cost. Corrections calculated with a hybrid density functional improved the accuracy of 13C, 15N and 17O chemical shift predictions significantly and allowed identifying errors in previously published experimental data. Applications of the approach to crystalline isocytosine, methacrylamide, and testosterone are presented.
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Affiliation(s)
- Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, AS CR, Flemingovo 2, Prague, Czech Republic.
| | - Pablo Unzueta
- Department of Chemistry, University of California, Riverside, California 92521, USA
| | - Gregory J O Beran
- Department of Chemistry, University of California, Riverside, California 92521, USA
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