51
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Zhao D, Shen X, Cheng Z, Li W, Dong H, Li S. Accurate and Efficient Prediction of NMR Parameters of Condensed-Phase Systems with the Generalized Energy-Based Fragmentation Method. J Chem Theory Comput 2020; 16:2995-3005. [DOI: 10.1021/acs.jctc.9b01298] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Dongbo Zhao
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, People’s Republic of China
- Kuang Yaming Honors School, Nanjing University, 210023 Nanjing, People’s Republic of China
| | - Xiaoling Shen
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, People’s Republic of China
| | - Zheng Cheng
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, People’s Republic of China
| | - Wei Li
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, People’s Republic of China
| | - Hao Dong
- Kuang Yaming Honors School, Nanjing University, 210023 Nanjing, People’s Republic of China
- Institute for Brain Sciences, Nanjing University, 210023 Nanjing, People’s Republic of China
| | - Shuhua Li
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, People’s Republic of China
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52
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Holmes ST, Engl OG, Srnec MN, Madura JD, Quiñones R, Harper JK, Schurko RW, Iuliucci RJ. Chemical Shift Tensors of Cimetidine Form A Modeled with Density Functional Theory Calculations: Implications for NMR Crystallography. J Phys Chem A 2020; 124:3109-3119. [DOI: 10.1021/acs.jpca.0c00421] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sean T. Holmes
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Olivia G. Engl
- Department of Chemistry, Washington and Jefferson College, Washington, Pennsylvania 15301, United States
| | - Matthew N. Srnec
- Department of Chemistry, Physics, & Engineering, Franciscan University, Steubenville, Ohio 43952, United States
| | - Jeffry D. Madura
- Department of Chemistry & Biochemistry, Center for Computational Sciences, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
| | - Rosalynn Quiñones
- Department of Chemistry, Marshall University, Huntington, West Virginia 25755, United States
| | - James K. Harper
- Department of Chemistry & Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Robert W. Schurko
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Robbie J. Iuliucci
- Department of Chemistry, Washington and Jefferson College, Washington, Pennsylvania 15301, United States
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53
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Gregorovič A. The many-body expansion approach to ab initio calculation of electric field gradients in molecular crystals. J Chem Phys 2020; 152:124105. [PMID: 32241128 DOI: 10.1063/1.5144735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accurate calculation of electric field gradients (EFGs) in molecular crystals, despite big advances in ab initio techniques, is still a challenge. Here, we present a new approach to calculate the EFGs in molecular crystals by employing the many-body expansion (MBE) technique with electrostatic embedding. This allows for (i) a reduction in the computational cost or an alternative increase in the level of theory (we use the MP2/6-311++G) and (ii) the ability to monitor EFG convergence by progressively adding more surrounding molecules and/or adding higher many-body interactions. We focus on the 14N EFG and study four (model) compounds in more detail: solid nitrogen, ethylamine, methylamine, and ammonia. Solid nitrogen is rather insensitive to neighbors; for ethylamine and methylamine, the 3-body interactions are found sufficient for a converged EFG, whereas for ammonia, even the inclusion of 5-body interactions is insufficient although convergence is anticipated. We then validate our technique by comparing the experimental and ab initio14N EFGs for 116 organic compounds utilizing their known crystal structures and published EFG. Overall, we find a very good agreement, with a small EFG rms error, which is probably due to other sources, rather than the MBE approximation.
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Affiliation(s)
- Alan Gregorovič
- Institute "Jožef Stefan", Jamova 39, 1000 Ljubljana, Slovenia
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54
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Zanolla D, Hasa D, Arhangelskis M, Schneider-Rauber G, Chierotti MR, Keiser J, Voinovich D, Jones W, Perissutti B. Mechanochemical Formation of Racemic Praziquantel Hemihydrate with Improved Biopharmaceutical Properties. Pharmaceutics 2020; 12:pharmaceutics12030289. [PMID: 32210129 PMCID: PMC7151222 DOI: 10.3390/pharmaceutics12030289] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 11/16/2022] Open
Abstract
Praziquantel (PZQ) is the first-line drug used against schistosomiasis, one of the most common parasitic diseases in the world. A series of crystalline structures including two new polymorphs of the pure drug and a series of cocrystals of PZQ have been discovered and deposited in the Cambridge Structural Database (CSD). This work adds to the list of multicomponent forms of PZQ a relevant example of a racemic hemihydrate (PZQ-HH), obtainable from commercial PZQ (polymorphic Form A) through mechanochemistry. Noteworthy, the formation of the new hemihydrate strongly depends on the initial polymorphic form of PZQ and on the experimental conditions used. The new PZQ-HH has been fully characterized by means of HPLC, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Hot-Stage Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), FT-IR, polarimetry, solid-state NMR (SS-NMR), solubility and intrinsic dissolution rate (IDR), and in vitro tests on Schistosoma mansoni adults. The crystal structure was solved from the powder X-ray diffraction pattern and validated by periodic-DFT calculations. The new bioactive hemihydrate was physically stable for three months and showed peculiar biopharmaceutical features including enhanced solubility and a double intrinsic dissolution rate in water in comparison to the commercially available PZQ Form A.
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Affiliation(s)
- Debora Zanolla
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, P.le Europa 1, 34127 Trieste, Italy; (D.Z.); (D.H.)
| | - Dritan Hasa
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, P.le Europa 1, 34127 Trieste, Italy; (D.Z.); (D.H.)
| | - Mihails Arhangelskis
- Faculty of Chemistry, University of Warsaw, 1 Pasteura Street, 02-093 Warsaw, Poland;
| | - Gabriela Schneider-Rauber
- Department of Chemistry, University of Cambridge, Lensfield Road, CB2-1EW Cambridge, UK; (G.S.-R.); (W.J.)
| | - Michele R. Chierotti
- Department of Chemistry and NIS Centre, University of Torino, V. Giuria 7, 10125 Torino, Italy;
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, P.O. Box, CH-4002 Basel; Switzerland;
- Universität Basel, Petersplatz 1, P.O. Box, CH-4001 Basel, Switzerland
| | - Dario Voinovich
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, P.le Europa 1, 34127 Trieste, Italy; (D.Z.); (D.H.)
- Correspondence: (D.V.); (B.P.); Tel.: +39-040-558-3106 (D.V. & B.P.)
| | - William Jones
- Department of Chemistry, University of Cambridge, Lensfield Road, CB2-1EW Cambridge, UK; (G.S.-R.); (W.J.)
| | - Beatrice Perissutti
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, P.le Europa 1, 34127 Trieste, Italy; (D.Z.); (D.H.)
- Correspondence: (D.V.); (B.P.); Tel.: +39-040-558-3106 (D.V. & B.P.)
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55
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Ludwig M, Himmel D, Hillebrecht H. GIAO versus GIPAW: Comparison of Methods To Calculate 11B NMR Shifts of Icosahedral Closo-Heteroboranes toward Boron-Rich Borides. J Phys Chem A 2020; 124:2173-2185. [PMID: 31999459 DOI: 10.1021/acs.jpca.9b06582] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, we perform first-principle density functional theory calculations with the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional to compare the results of the gauge-including atomic orbital (GIAO) method with the gauge-including projector-augmented wave (GIPAW) approach for isotropic 11B nuclear magnetic resonance shifts. GIPAW had been used successfully for the theoretical calculation of nuclear magnetic parameters of 11B species in strong ionic solid-phase compounds such as borates but had been applied very rarely to structures where boron is mainly involved in complex covalent bonding situations, for example, in icosahedra of boron-rich borides. Thus, we investigate the accuracy of both well-known methods and reliability of the effective treatment of core electrons on a test set containing 16 experimentally known closo-(hetero)dodecaboranes. In general, we find very good agreement between GIAO and GIPAW when compared to experimental observations. However, accidental degeneracies of the shift values are better predicted by GIPAW. The optimized molecular geometries on the PBE level agree well with gaseous electron diffraction data and lead to theoretical isotropic chemical 11B shifts with root-mean-square errors of 2.1 and 1.0 ppm depending on the used model of converting absolute shieldings to chemical shifts. The comparison with results from hybrid functionals (B3LYP, B3LYP-D2, and PBE0) shows a minor improvement in accuracy, which is in agreement with 13C shifts of sp3-hybridized species. In order to prove the reliability of the conversion parameters obtained by PBE, we report the calculated 11B shifts of 1,2-, 1,7-, and 1,12-PCB10H11 with GIAO and GIPAW to our knowledge for the first time. Additionally, Bader's analysis is carried out on the converged electron density for all boron species within the molecular test set, yielding no simple direct relation between charge and isotropic shifts.
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Affiliation(s)
- Martin Ludwig
- Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität, Albertstraße 21, 79104 Freiburg, Germany
| | - Daniel Himmel
- Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität, Albertstraße 21, 79104 Freiburg, Germany
| | - Harald Hillebrecht
- Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität, Albertstraße 21, 79104 Freiburg, Germany
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56
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Zanolla D, Perissutti B, Vioglio PC, Chierotti MR, Gigli L, Demitri N, Passerini N, Albertini B, Franceschinis E, Keiser J, Voinovich D. Exploring mechanochemical parameters using a DoE approach: Crystal structure solution from synchrotron XRPD and characterization of a new praziquantel polymorph. Eur J Pharm Sci 2019; 140:105084. [PMID: 31626966 DOI: 10.1016/j.ejps.2019.105084] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/11/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022]
Abstract
A rotated Doehlert matrix was utilized to explore the experimental design space around the milling parameters of Praziquantel (PZQ) polymorph B formation in terms of frequency and milling time. Three experimental responses were evaluated on the resulting ground samples: two quantitative responses, i.e. median particle size by Laser Light scattering (LLS) and drug recovery by HPLC, and one qualitative dependent variable, i.e. the obtained PZQ crystalline form, characterized through X-Ray Powder Diffraction (XRPD) and confirmed by Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). Temperature inside the jars was kept under constant control during the milling process by using temperature sensor equipped jars (thermojars), thus allowing evaluation of the obtained solid states at each experimental point, considering the specific temperature of the process. This explorative analysis led to the finding of a novel PZQ polymorph, named "Form C", produced without degradation, then fully characterized, including by means of Synchrotron XRPD, Polarimetric, FT-IR, SS-NMR, ESEM and saturation solubility. Crystal structure was solved from XRPD data and its geometry was optimized by DFT calculations (CASTEP). Finally, Form C and Form A activity against adult schistosoma mansoni were compared through in vitro testing, and Form C's physical stability checked. The new polymorph, crystallizing in space group I2/c, physically stable for approximately 2 months, showed a m.p. of 106.84 °C and displayed excellent biopharmaceutical properties (water solubility of 382.69±9.26 mg/l), while preserving excellent activity levels against adult schistosoma mansoni.
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Affiliation(s)
- Debora Zanolla
- University of Trieste, Dept. of Chemical and Pharmaceutical Sciences, P.le Europa 1, Trieste, Italy
| | - Beatrice Perissutti
- University of Trieste, Dept. of Chemical and Pharmaceutical Sciences, P.le Europa 1, Trieste, Italy.
| | | | - Michele R Chierotti
- University of Torino, Dept. of Chemistry and NIS Centre, V. Giuria 7, Torino, Italy
| | - Lara Gigli
- Elettra-Sincrotrone Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza-Trieste, Italy
| | - Nicola Demitri
- Elettra-Sincrotrone Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza-Trieste, Italy
| | - Nadia Passerini
- University of Bologna Dept. of Pharmacy and BioTechnology, Via S. Donato 19/2, Bologna, Italy
| | - Beatrice Albertini
- University of Bologna Dept. of Pharmacy and BioTechnology, Via S. Donato 19/2, Bologna, Italy
| | - Erica Franceschinis
- University of Padova Dept. of Pharmaceutical and Pharmacological Sciences, via Marzolo 5, Padova, Italy
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute Helminth Drug Development Unit, Dept. Medical Parasitology and Infection Biology, Basel, Switzerland; Universität Basel, Petersplatz 1, P.O. Box, CH-4001 Basel, Switzerland
| | - Dario Voinovich
- University of Trieste, Dept. of Chemical and Pharmaceutical Sciences, P.le Europa 1, Trieste, Italy
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57
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Engel EA, Anelli A, Hofstetter A, Paruzzo F, Emsley L, Ceriotti M. A Bayesian approach to NMR crystal structure determination. Phys Chem Chem Phys 2019; 21:23385-23400. [PMID: 31631196 DOI: 10.1039/c9cp04489b] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nuclear Magnetic Resonance (NMR) spectroscopy is particularly well suited to determine the structure of molecules and materials in powdered form. Structure determination usually proceeds by finding the best match between experimentally observed NMR chemical shifts and those of candidate structures. Chemical shifts for the candidate configurations have traditionally been computed by electronic-structure methods, and more recently predicted by machine learning. However, the reliability of the determination depends on the errors in the predicted shifts. Here we propose a Bayesian framework for determining the confidence in the identification of the experimental crystal structure, based on knowledge of the typical errors in the electronic structure methods. We demonstrate the approach on the determination of the structures of six organic molecular crystals. We critically assess the reliability of the structure determinations, facilitated by the introduction of a visualization of the similarity between candidate configurations in terms of their chemical shifts and their structures. We also show that the commonly used values for the errors in calculated 13C shifts are underestimated, and that more accurate, self-consistently determined uncertainties make it possible to use 13C shifts to improve the accuracy of structure determinations. Finally, we extend the recently-developed ShiftML model to render it more efficient, accurate, and, most importantly, to evaluate the uncertainties in its predictions. By quantifying the confidence in structure determinations based on ShiftML predictions we further substantiate that it provides a valid replacement for first-principles calculations in NMR crystallography.
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Affiliation(s)
- Edgar A Engel
- Laboratory of Computational Science and Modeling, Institut des Matériaux, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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58
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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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59
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Liu S, Li J, Bennett KC, Ganoe B, Stauch T, Head-Gordon M, Hexemer A, Ushizima D, Head-Gordon T. Multiresolution 3D-DenseNet for Chemical Shift Prediction in NMR Crystallography. J Phys Chem Lett 2019; 10:4558-4565. [PMID: 31305081 PMCID: PMC6922005 DOI: 10.1021/acs.jpclett.9b01570] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed a deep learning algorithm for chemical shift prediction for atoms in molecular crystals that utilizes an atom-centered Gaussian density model for the 3D data representation of a molecule. We define multiple channels that describe different spatial resolutions for each atom type that utilizes cropping, pooling, and concatenation to create a multiresolution 3D-DenseNet architecture (MR-3D-DenseNet). Because the training and testing time scale linearly with the number of samples, the MR-3D-DenseNet can exploit data augmentation that takes into account the property of rotational invariance of the chemical shifts, thereby also increasing the size of the training data set by an order of magnitude without additional cost. We obtain very good agreement for 13C, 15N, and 17O chemical shifts when compared to ab initio quantum chemistry methods, with the highest accuracy found for 1H chemical shifts that is comparable to the error between the ab initio results and experimental measurements. Principal component analysis (PCA) is used to both understand these greatly improved predictions for 1H , as well as indicating that chemical shift prediction for 13C, 15N, and 17O, which have far fewer training environments than the 1H atom type, will improve once more unique training samples are made available to exploit the deep network architecture.
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Affiliation(s)
- Shuai Liu
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Jie Li
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Kochise C Bennett
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Brad Ganoe
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Tim Stauch
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Martin Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Alexander Hexemer
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Daniela Ushizima
- Computational Research Division, Center for Advanced Mathematics for Energy Research Applications (CAMERA) , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Teresa Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, Department of Bioengineering, Department of Chemical and Biomolecular Engineering , University of California , Berkeley , California 94720 , United States
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60
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Hofstetter A, Balodis M, Paruzzo FM, Widdifield CM, Stevanato G, Pinon AC, Bygrave PJ, Day GM, Emsley L. Rapid Structure Determination of Molecular Solids Using Chemical Shifts Directed by Unambiguous Prior Constraints. J Am Chem Soc 2019; 141:16624-16634. [PMID: 31117663 PMCID: PMC7540916 DOI: 10.1021/jacs.9b03908] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
NMR-based crystallography approaches involving the combination of crystal structure prediction methods, ab initio calculated chemical shifts and solid-state NMR experiments are powerful methods for crystal structure determination of microcrystalline powders. However, currently structural information obtained from solid-state NMR is usually included only after a set of candidate crystal structures has already been independently generated, starting from a set of single-molecule conformations. Here, we show with the case of ampicillin that this can lead to failure of structure determination. We propose a crystal structure determination method that includes experimental constraints during conformer selection. In order to overcome the problem that experimental measurements on the crystalline samples are not obviously translatable to restrict the single-molecule conformational space, we propose constraints based on the analysis of absent cross-peaks in solid-state NMR correlation experiments. We show that these absences provide unambiguous structural constraints on both the crystal structure and the gas-phase conformations, and therefore can be used for unambiguous selection. The approach is parametrized on the crystal structure determination of flutamide, flufenamic acid, and cocaine, where we reduce the computational cost by around 50%. Most importantly, the method is then shown to correctly determine the crystal structure of ampicillin, which would have failed using current methods because it adopts a high-energy conformer in its crystal structure. The average positional RMSE on the NMR powder structure is ⟨rav⟩ = 0.176 Å, which corresponds to an average equivalent displacement parameter Ueq = 0.0103 Å2.
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Affiliation(s)
- Albert Hofstetter
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
| | - Martins Balodis
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
| | - Federico M Paruzzo
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
| | - Cory M Widdifield
- Department of Chemistry, Mathematics and Science Center , Oakland University , 146 Library Drive , Rochester , Michigan 48309-4479 , United States
| | - Gabriele Stevanato
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
| | - Arthur C Pinon
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
| | - Peter J Bygrave
- 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
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques , École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne , Switzerland
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61
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Young RP, Lewis CR, Yang C, Wang L, Harper JK, Mueller LJ. TensorView: A software tool for displaying NMR tensors. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:211-223. [PMID: 30230009 PMCID: PMC6736611 DOI: 10.1002/mrc.4793] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 05/29/2023]
Abstract
The representation of nuclear magnetic resonance (NMR) tensors as surfaces on three-dimensional molecular models is an information-rich presentation that highlights the geometric relationship between tensor principal components and the underlying molecular and electronic structure. Here, we describe a new computational tool, TensorView, for depicting NMR tensors on the molecular framework. This package makes use of the graphical interface and built-in molecular display functionality present within the Mathematica programming environment and is robust for displaying tensor properties from a broad range of commercial and user-specific computational chemistry packages. Two mathematical forms for representing tensor interaction surfaces are presented, the popular ellipsoidal construct and the more technically correct "ovaloid" form. Examples are provided for chemical shielding and shift tensors, dipole-dipole and quadrupolar couplings, and atomic anisotropic displacement parameters (thermal ellipsoids) derived from NMR crystallography.
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Affiliation(s)
- Robert P. Young
- Department of Chemistry, University of California, Riverside, California 92521
| | - Corbin R. Lewis
- Department of Chemistry, University of California, Riverside, California 92521
| | - Chen Yang
- Department of Chemistry, University of California, Riverside, California 92521
| | - Luther Wang
- Department of Chemistry, University of Central Florida, 4111 Libra Drive, Orlando, FL 32816
| | - James K. Harper
- Department of Chemistry, University of Central Florida, 4111 Libra Drive, Orlando, FL 32816
| | - Leonard J. Mueller
- Department of Chemistry, University of California, Riverside, California 92521
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62
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Dale BL, Halcovitch NR, Peach MJG, Griffin JM. Investigation of structure and dynamics in a photochromic molecular crystal by NMR crystallography. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:230-242. [PMID: 30452093 DOI: 10.1002/mrc.4805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/01/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
A photochromic anil, N-(3,5-di-t-butylsalicylidene)-4-amino-pyridine, has been studied by single-crystal X-ray diffraction, multinuclear magic-angle spinning NMR, and first-principles density functional theory (DFT) calculations. Interpretation of the solid-state NMR data on the basis of calculated chemical shifts confirms the structure is primarily composed of molecules in the ground-state enol tautomer, whereas thermally activated cis-keto and photoisomerised trans-keto states exist as low-level defects with populations that are too low to detect experimentally. Variable temperature 13 C NMR data reveal evidence for solid-state dynamics, which is found to be associated with fast rotational motion of t-butyl groups and 180° flips of the pyridine ring, contrasting the time-averaged structure obtained by X-ray diffraction. Comparison of calculated chemical shifts for the full crystal structure and an isolated molecule also reveals evidence for an intermolecular hydrogen bond involving the pyridine ring and an adjacent imine carbon, which facilitates the flipping motion. The DFT calculations also reveal that the molecular conformation in the crystal structure is very close to the energetic minimum for an isolated molecule, indicating that the ring dynamics arise as a result of considerable steric freedom of the pyridine ring and which also allows the molecule to adopt a favourable conformation for photochromism.
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Affiliation(s)
- Benjamin L Dale
- Department of Chemistry, Lancaster University, Lancaster, UK
| | | | | | - John M Griffin
- Department of Chemistry, Lancaster University, Lancaster, UK
- Materials Science Institute, Lancaster University, Lancaster, UK
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63
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Chernyshov IY, Vener MV, Shenderovich IG. Local-structure effects on 31P NMR chemical shift tensors in solid state. J Chem Phys 2019; 150:144706. [PMID: 30981271 DOI: 10.1063/1.5075519] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The effect of the local structure on the 31P NMR chemical shift tensor (CST) has been studied experimentally and simulated theoretically using the density functional theory gauge-independent-atomic-orbital approach. It has been shown that the dominating impact comes from a small number of noncovalent interactions between the phosphorus-containing group under question and the atoms of adjacent molecules. These interactions can be unambiguously identified using the Bader analysis of the electronic density. A robust and computationally effective approach designed to attribute a given experimental 31P CST to a certain local morphology has been elaborated. This approach can be useful in studies of surfaces, complex molecular systems, and amorphous materials.
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Affiliation(s)
- Ivan Yu Chernyshov
- Department of Quantum Chemistry, D. Mendeleev University of Chemical Technology, Moscow 125047, Russia
| | - Mikhail V Vener
- Department of Quantum Chemistry, D. Mendeleev University of Chemical Technology, Moscow 125047, Russia
| | - Ilya G Shenderovich
- Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany
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64
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Holmes ST, Schurko RW. A DFT/ZORA Study of Cadmium Magnetic Shielding Tensors: Analysis of Relativistic Effects and Electronic-State Approximations. J Chem Theory Comput 2019; 15:1785-1797. [PMID: 30721042 DOI: 10.1021/acs.jctc.8b01296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Theoretical considerations are discussed for the accurate prediction of cadmium magnetic shielding tensors using relativistic density functional theory (DFT). Comparison is made between calculations that model the extended lattice of the cadmium-containing solids using periodic boundary conditions and pseudopotentials with calculations that use clusters of atoms. The all-electron cluster-based calculations afford an opportunity to examine the importance of (i) relativistic effects on cadmium magnetic shielding tensors, as introduced through the ZORA Hamiltonian at either the scalar (SC) or spin-orbit (SO) levels and (ii) variation in the class of the DFT approximation. Twenty-three combinations of pseudopotentials or all-electron methods, DFT functionals, and relativistic treatments are assessed for the prediction of the principal components of the magnetic shielding tensors of 30 cadmium sites. We find that the inclusion of SO coupling can increase the cadmium magnetic shielding by as much as ca. 1100 ppm for a certain principal values; these effects are most pronounced for cadmium sites featuring bonds to other heavy atoms such as cadmium, iodine, or selenium. The best agreement with experimental values is found at the ZORA SO level in combination with a hybrid DFT method featuring a large admixture of Hartree-Fock exchange such as BH&HLYP. Finally, a theoretical examination is presented of the magnetic shielding tensor of the Cd(I) site in Cd2(AlCl4)2.
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Affiliation(s)
- Sean T Holmes
- Department of Chemistry and Biochemistry , University of Windsor , Windsor , ON , Canada N9B 3P4
| | - Robert W Schurko
- Department of Chemistry and Biochemistry , University of Windsor , Windsor , ON , Canada N9B 3P4
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65
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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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66
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Corlett EK, Blade H, Hughes LP, Sidebottom PJ, Walker D, Walton RI, Brown SP. An XRD and NMR crystallographic investigation of the structure of 2,6-lutidinium hydrogen fumarate. CrystEngComm 2019. [DOI: 10.1039/c9ce00633h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A crystallographic study highlighting the benefits of a combined XRD and NMR approach in investigating both stability and variation within an organic multicomponent crystal.
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Affiliation(s)
| | - Helen Blade
- Pharmaceutical Development
- AstraZeneca
- Macclesfield
- UK
| | | | | | - David Walker
- Department of Physics
- University of Warwick
- Coventry
- UK
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67
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Sexton TM, Tschumper GS. 2-body:Many-body QM:QM study of structures, energetics, and vibrational frequencies for microhydrated halide ions. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1554827] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Thomas More Sexton
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, USA
| | - Gregory S. Tschumper
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, USA
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68
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Carnahan SL, Lampkin BJ, Naik P, Hanrahan MP, Slowing II, VanVeller B, Wu G, Rossini AJ. Probing O–H Bonding through Proton Detected 1H–17O Double Resonance Solid-State NMR Spectroscopy. J Am Chem Soc 2018; 141:441-450. [DOI: 10.1021/jacs.8b10878] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Scott L. Carnahan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
| | - Bryan J. Lampkin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Pranjali Naik
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
| | - Michael P. Hanrahan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
| | - Igor I. Slowing
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Gang Wu
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - Aaron J. Rossini
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
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69
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Hartman JD, Beran GJO. Accurate 13-C and 15-N molecular crystal chemical shielding tensors from fragment-based electronic structure theory. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 96:10-18. [PMID: 30273904 DOI: 10.1016/j.ssnmr.2018.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
Standard nuclear magnetic resonance (NMR) spectroscopy experiments measure isotropic chemical shifts, but measuring the chemical shielding anisotropy (CSA) tensor can provide additional insights into solid state chemical structures. Interpreting the principal components of these tensors is facilitated by first-principles chemical shielding tensor predictions. Here, the ability to predict molecular crystal CSA tensor components for 13C and 15N nuclei with fragment-based electronic structure techniques is explored. Similar to what has been found previously for isotropic chemical shifts, the benchmarking demonstrates that fragment-based techniques can accurately reproduce CSA tensor components. The use of hybrid density functionals like PBE0 or B3LYP provide higher accuracy than generalized gradient approximation functionals like PBE. Unlike for planewave density functional techniques, hybrid density functionals can be employed routinely with modest computational cost in fragment approaches. Finally, good consistency between the regression parameters used to map either isotropic shieldings or CSA tensor components is demonstrated, providing further evidence for the quality of the models and highlighting that models trained for isotropic shifts can also be applied to CSA tensor components.
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Affiliation(s)
- Joshua D Hartman
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
| | - Gregory J O Beran
- Department of Chemistry, University of California, Riverside, CA, 92521, USA.
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70
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Paruzzo FM, Hofstetter A, Musil F, De S, Ceriotti M, Emsley L. Chemical shifts in molecular solids by machine learning. Nat Commun 2018; 9:4501. [PMID: 30374021 PMCID: PMC6206069 DOI: 10.1038/s41467-018-06972-x] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 09/26/2018] [Indexed: 02/02/2023] Open
Abstract
Due to their strong dependence on local atonic environments, NMR chemical shifts are among the most powerful tools for strucutre elucidation of powdered solids or amorphous materials. Unfortunately, using them for structure determination depends on the ability to calculate them, which comes at the cost of high accuracy first-principles calculations. Machine learning has recently emerged as a way to overcome the need for quantum chemical calculations, but for chemical shifts in solids it is hindered by the chemical and combinatorial space spanned by molecular solids, the strong dependency of chemical shifts on their environment, and the lack of an experimental database of shifts. We propose a machine learning method based on local environments to accurately predict chemical shifts of molecular solids and their polymorphs to within DFT accuracy. We also demonstrate that the trained model is able to determine, based on the match between experimentally measured and ML-predicted shifts, the structures of cocaine and the drug 4-[4-(2-adamantylcarbamoyl)-5-tert-butylpyrazol-1-yl]benzoic acid. Solid-state nuclear magnetic resonance combined with quantum chemical shift predictions is limited by high computational cost. Here, the authors use machine learning based on local atomic environments to predict experimental chemical shifts in molecular solids with accuracy similar to density functional theory.
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Affiliation(s)
- Federico M Paruzzo
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Albert Hofstetter
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Félix Musil
- Institut des Sciences et Génie Matériaux, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Sandip De
- Institut des Sciences et Génie Matériaux, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Michele Ceriotti
- Institut des Sciences et Génie Matériaux, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
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71
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Nilsson Lill SO, Widdifield CM, Pettersen A, Svensk Ankarberg A, Lindkvist M, Aldred P, Gracin S, Shankland N, Shankland K, Schantz S, Emsley L. Elucidating an Amorphous Form Stabilization Mechanism for Tenapanor Hydrochloride: Crystal Structure Analysis Using X-ray Diffraction, NMR Crystallography, and Molecular Modeling. Mol Pharm 2018; 15:1476-1487. [PMID: 29490140 DOI: 10.1021/acs.molpharmaceut.7b01047] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
By the combined use of powder and single-crystal X-ray diffraction, solid-state NMR, and molecular modeling, the crystal structures of two systems containing the unusually large tenapanor drug molecule have been determined: the free form, ANHY, and a dihydrochloride salt form, 2HCl. Dynamic nuclear polarization (DNP) assisted solid-state NMR (SSNMR) crystallography investigations were found essential for the final assignment and were used to validate the crystal structure of ANHY. From a structural informatics analysis of ANHY and 2HCl, conformational ring differences in one part of the molecule were observed which influence the relative orientation of a methyl group on a ring nitrogen and thereby impact the crystallizability of the dihydrochloride salt. From quantum chemistry calculations, the dynamics between different ring conformations in tenapanor is predicted to be fast. Addition of HCl to tenapanor results in general in a mixture of protonated ring conformers and hence a statistical mix of diastereoisomers which builds up the amorphous form, a-2HCl. This was qualitatively verified by 13C CP/MAS NMR investigations of the amorphous form. Thus, to form any significant amount of the crystalline material 2HCl, which originates from the minor (i.e., energetically less stable) ring conformations, one needs to involve nitrogen deprotonation to allow exchange between the minor and major conformations of ANHY in solution. Thus, by controlling the solution pH value to well below the p Ka of ANHY, the equilibrium between ANHY and 2HCl can be controlled and by this mechanism the crystallization of 2HCl can be avoided and the amorphous form of the dichloride salt can therefore be stabilized.
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Affiliation(s)
- Sten O Nilsson Lill
- Early Product Development, Pharmaceutical Sciences, IMED Biotech Unit , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Cory M Widdifield
- Institut des Sciences Analytiques (CNRS/ENS de Lyon/UCB Lyon 1), Centre de RMN à Très Hauts Champs , Université de Lyon , 69100 Villeurbanne , France
| | - Anna Pettersen
- Early Product Development, Pharmaceutical Sciences, IMED Biotech Unit , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Anna Svensk Ankarberg
- Pharmaceutical Technology & Development , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Maria Lindkvist
- Pharmaceutical Technology & Development , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Peter Aldred
- Pharmaceutical Technology & Development , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Sandra Gracin
- Pharmaceutical Technology & Development , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Norman Shankland
- CrystallografX Ltd , 2 Stewart Street , Milngavie, Glasgow G62 6BW , United Kingdom
| | - Kenneth Shankland
- CrystallografX Ltd , 2 Stewart Street , Milngavie, Glasgow G62 6BW , United Kingdom.,School of Pharmacy , University of Reading , Whiteknights, P.O. Box 224, Reading , RG6 6AD , United Kingdom
| | - Staffan Schantz
- Pharmaceutical Technology & Development , AstraZeneca Gothenburg , SE-431 83 , Mölndal , Sweden
| | - Lyndon Emsley
- Institut des Sciences Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
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72
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Hartman JD, Balaji A, Beran GJO. Improved Electrostatic Embedding for Fragment-Based Chemical Shift Calculations in Molecular Crystals. J Chem Theory Comput 2017; 13:6043-6051. [PMID: 29139294 DOI: 10.1021/acs.jctc.7b00677] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fragment-based methods predict nuclear magnetic resonance (NMR) chemical shielding tensors in molecular crystals with high accuracy and computational efficiency. Such methods typically employ electrostatic embedding to mimic the crystalline environment, and the quality of the results can be sensitive to the embedding treatment. To improve the quality of this embedding environment for fragment-based molecular crystal property calculations, we borrow ideas from the embedded ion method to incorporate self-consistently polarized Madelung field effects. The self-consistent reproduction of the Madelung potential (SCRMP) model developed here constructs an array of point charges that incorporates self-consistent lattice polarization and which reproduces the Madelung potential at all atomic sites involved in the quantum mechanical region of the system. The performance of fragment- and cluster-based 1H, 13C, 14N, and 17O chemical shift predictions using SCRMP and density functionals like PBE and PBE0 are assessed. The improved embedding model results in substantial improvements in the predicted 17O chemical shifts and modest improvements in the 15N ones. Finally, the performance of the model is demonstrated by examining the assignment of the two oxygen chemical shifts in the challenging γ-polymorph of glycine. Overall, the SCRMP-embedded NMR chemical shift predictions are on par with or more accurate than those obtained with the widely used gauge-including projector augmented wave (GIPAW) model.
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Affiliation(s)
- Joshua D Hartman
- Department of Chemistry, University of California, Riverside , Riverside, California 92521, United States
| | - Ashwin Balaji
- Department of Chemistry, University of California, Riverside , Riverside, California 92521, United States
| | - Gregory J O Beran
- Department of Chemistry, University of California, Riverside , Riverside, California 92521, United States
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73
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Zhao D, Song R, Li W, Ma J, Dong H, Li S. Accurate Prediction of NMR Chemical Shifts in Macromolecular and Condensed-Phase Systems with the Generalized Energy-Based Fragmentation Method. J Chem Theory Comput 2017; 13:5231-5239. [DOI: 10.1021/acs.jctc.7b00380] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dongbo Zhao
- Key
Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute
of Theoretical and Computational Chemistry, School of Chemistry and
Chemical Engineering, Nanjing University, Nanjing 210023, People’s Republic of China
- Kuang
Yaming Honors School, Nanjing University, Nanjing 210023, People’s Republic of China
| | - Ruiheng Song
- Kuang
Yaming Honors School, Nanjing University, Nanjing 210023, People’s Republic of China
| | - Wei Li
- Key
Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute
of Theoretical and Computational Chemistry, School of Chemistry and
Chemical Engineering, Nanjing University, Nanjing 210023, People’s Republic of China
| | - Jing Ma
- Key
Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute
of Theoretical and Computational Chemistry, School of Chemistry and
Chemical Engineering, Nanjing University, Nanjing 210023, People’s Republic of China
| | - Hao Dong
- Kuang
Yaming Honors School, Nanjing University, Nanjing 210023, People’s Republic of China
| | - Shuhua Li
- Key
Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute
of Theoretical and Computational Chemistry, School of Chemistry and
Chemical Engineering, Nanjing University, Nanjing 210023, People’s Republic of China
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74
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Zilka M, Dudenko DV, Hughes CE, Williams PA, Sturniolo S, Franks WT, Pickard CJ, Yates JR, Harris KDM, Brown SP. Ab initio random structure searching of organic molecular solids: assessment and validation against experimental data. Phys Chem Chem Phys 2017; 19:25949-25960. [PMID: 28944393 PMCID: PMC5779078 DOI: 10.1039/c7cp04186a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/30/2017] [Indexed: 02/03/2023]
Abstract
This paper explores the capability of using the DFT-D ab initio random structure searching (AIRSS) method to generate crystal structures of organic molecular materials, focusing on a system (m-aminobenzoic acid; m-ABA) that is known from experimental studies to exhibit abundant polymorphism. Within the structural constraints selected for the AIRSS calculations (specifically, centrosymmetric structures with Z = 4 for zwitterionic m-ABA molecules), the method is shown to successfully generate the two known polymorphs of m-ABA (form III and form IV) that have these structural features. We highlight various issues that are encountered in comparing crystal structures generated by AIRSS to experimental powder X-ray diffraction (XRD) data and solid-state magic-angle spinning (MAS) NMR data, demonstrating successful fitting for some of the lowest energy structures from the AIRSS calculations against experimental low-temperature powder XRD data for known polymorphs of m-ABA, and showing that comparison of computed and experimental solid-state NMR parameters allows different hydrogen-bonding motifs to be discriminated.
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Affiliation(s)
- Miri Zilka
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | - Dmytro V Dudenko
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK. and School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK.
| | - Colan E Hughes
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK.
| | - P Andrew Williams
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK.
| | - Simone Sturniolo
- Scientific Computing Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
| | - W Trent Franks
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
| | - Jonathan R Yates
- Department of Materials, University of Oxford, Oxford OX1 3PH, UK.
| | - Kenneth D M Harris
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK.
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
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75
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Giese TJ, York DM. Quantum mechanical force fields for condensed phase molecular simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:383002. [PMID: 28817382 PMCID: PMC5821073 DOI: 10.1088/1361-648x/aa7c5c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Molecular simulations are powerful tools for providing atomic-level details into complex chemical and physical processes that occur in the condensed phase. For strongly interacting systems where quantum many-body effects are known to play an important role, density-functional methods are often used to provide the model with the potential energy used to drive dynamics. These methods, however, suffer from two major drawbacks. First, they are often too computationally intensive to practically apply to large systems over long time scales, limiting their scope of application. Second, there remain challenges for these models to obtain the necessary level of accuracy for weak non-bonded interactions to obtain quantitative accuracy for a wide range of condensed phase properties. Quantum mechanical force fields (QMFFs) provide a potential solution to both of these limitations. In this review, we address recent advances in the development of QMFFs for condensed phase simulations. In particular, we examine the development of QMFF models using both approximate and ab initio density-functional models, the treatment of short-ranged non-bonded and long-ranged electrostatic interactions, and stability issues in molecular dynamics calculations. Example calculations are provided for crystalline systems, liquid water, and ionic liquids. We conclude with a perspective for emerging challenges and future research directions.
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76
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Presti D, Pedone A, Licari D, Barone V. A Modular Implementation for the Simulation of 1D and 2D Solid-State NMR Spectra of Quadrupolar Nuclei in the Virtual Multifrequency Spectrometer-Draw Graphical Interface. J Chem Theory Comput 2017; 13:2215-2229. [PMID: 28402672 DOI: 10.1021/acs.jctc.7b00154] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present the implementation of the solid state (SoS)NMR module for the simulation of several 1D and 2D NMR spectra of all the elements in the periodic table in the virtual multifrequency spectrometer (VMS). This module is fully integrated with the graphical user interface of VMS (VMS-Draw) [Licari et al., J. Comput. Chem. 36, 2015, 321-334], a freeware tool which allows a user-friendly handling of structures and analyses of advanced spectroscopical properties of chemical compounds-from model systems to real-world applications. Besides the numerous modules already available in VMS for the study of electronic, optical, vibrational, vibronic, and EPR properties, here the simulation of NMR spectra is presented with a particular emphasis on those techniques usually employed to investigate solid state systems. The SoSNMR module benefits from its ability to work under both periodic and nonperiodic conditions, such that small molecules/molecular clusters can be treated, as well as extended three-dimensional systems enforcing (or not) translational periodicity. These features allow VMS to simulate spectra resulting from NMR calculations by some popular quantum chemistry codes, namely Gaussian09/16, Castep, and Quantum Espresso. The effectiveness of the SoSNMR module of VMS is examined throughout the manuscript, and applied to simulate 1D static, MAS, and VAS NMR spectra as well as 2D correlation (90°, MAS) and MQMAS spectra of active NMR nuclei embedded in different amorphous and crystalline systems of actual interest in chemistry and material science. Finally, the program is able to simulate the spectra of both the total ensemble of spin-active nuclei present in the system and of subensembles differentiated depending on the chemical environment of the first and second coordination sphere in a very general way applicable to any kind of systems.
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Affiliation(s)
- Davide Presti
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio-Emilia , 103 via G. Campi, I-41125 Modena, Italy
| | - Alfonso Pedone
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio-Emilia , 103 via G. Campi, I-41125 Modena, Italy
| | - Daniele Licari
- Scuola Normale Superiore di Pisa , Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore di Pisa , Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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77
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Li X, Neumann MA, van de Streek J. The application of tailor-made force fields and molecular dynamics for NMR crystallography: a case study of free base cocaine. IUCRJ 2017; 4:175-184. [PMID: 28250956 PMCID: PMC5330528 DOI: 10.1107/s2052252517001415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 01/27/2017] [Indexed: 05/04/2023]
Abstract
Motional averaging has been proven to be significant in predicting the chemical shifts in ab initio solid-state NMR calculations, and the applicability of motional averaging with molecular dynamics has been shown to depend on the accuracy of the molecular mechanical force field. The performance of a fully automatically generated tailor-made force field (TMFF) for the dynamic aspects of NMR crystallography is evaluated and compared with existing benchmarks, including static dispersion-corrected density functional theory calculations and the COMPASS force field. The crystal structure of free base cocaine is used as an example. The results reveal that, even though the TMFF outperforms the COMPASS force field for representing the energies and conformations of predicted structures, it does not give significant improvement in the accuracy of NMR calculations. Further studies should direct more attention to anisotropic chemical shifts and development of the method of solid-state NMR calculations.
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Affiliation(s)
- Xiaozhou Li
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
| | - Marcus A. Neumann
- Avant-garde Materials Simulation Deutschland GmbH, Rosa-Luxemberg-Strasse 14, Freiburg D-79100, Germany
| | - Jacco van de Streek
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
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78
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Holmes ST, Bai S, Iuliucci RJ, Mueller KT, Dybowski C. Calculations of solid‐state
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Ca NMR parameters: A comparison of periodic and cluster approaches and an evaluation of DFT functionals. J Comput Chem 2017; 38:949-956. [DOI: 10.1002/jcc.24763] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/29/2016] [Accepted: 01/30/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Sean T. Holmes
- Department of Chemistry and BiochemistryUniversity of DelawareNewark Delaware19716
| | - Shi Bai
- Department of Chemistry and BiochemistryUniversity of DelawareNewark Delaware19716
| | - Robbie J. Iuliucci
- Department of ChemistryWashington and Jefferson CollegeWashington Pennsylvania15301
| | - Karl T. Mueller
- Department of ChemistryPennsylvania State University, University Park Pennsylvania16802
- Physical and Computational Sciences Directorate, Pacific Northwest National LaboratoryRichland Washington99352
| | - Cecil Dybowski
- Department of Chemistry and BiochemistryUniversity of DelawareNewark Delaware19716
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Holmes ST, Iuliucci RJ, Mueller KT, Dybowski C. Semi-empirical refinements of crystal structures using 17O quadrupolar-coupling tensors. J Chem Phys 2017; 146:064201. [DOI: 10.1063/1.4975170] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Sean T. Holmes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Robbie J. Iuliucci
- Department of Chemistry, Washington and Jefferson College, Washington, Pennsylvania 15301, USA
| | - Karl T. Mueller
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Cecil Dybowski
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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80
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Caulkins BG, Young RP, Kudla RA, Yang C, Bittbauer T, Bastin B, Hilario E, Fan L, Marsella MJ, Dunn MF, Mueller LJ. NMR Crystallography of a Carbanionic Intermediate in Tryptophan Synthase: Chemical Structure, Tautomerization, and Reaction Specificity. J Am Chem Soc 2016; 138:15214-15226. [PMID: 27779384 PMCID: PMC5129030 DOI: 10.1021/jacs.6b08937] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Indexed: 12/22/2022]
Abstract
Carbanionic intermediates play a central role in the catalytic transformations of amino acids performed by pyridoxal-5'-phosphate (PLP)-dependent enzymes. Here, we make use of NMR crystallography-the synergistic combination of solid-state nuclear magnetic resonance, X-ray crystallography, and computational chemistry-to interrogate a carbanionic/quinonoid intermediate analogue in the β-subunit active site of the PLP-requiring enzyme tryptophan synthase. The solid-state NMR chemical shifts of the PLP pyridine ring nitrogen and additional sites, coupled with first-principles computational models, allow a detailed model of protonation states for ionizable groups on the cofactor, substrates, and nearby catalytic residues to be established. Most significantly, we find that a deprotonated pyridine nitrogen on PLP precludes formation of a true quinonoid species and that there is an equilibrium between the phenolic and protonated Schiff base tautomeric forms of this intermediate. Natural bond orbital analysis indicates that the latter builds up negative charge at the substrate Cα and positive charge at C4' of the cofactor, consistent with its role as the catalytic tautomer. These findings support the hypothesis that the specificity for β-elimination/replacement versus transamination is dictated in part by the protonation states of ionizable groups on PLP and the reacting substrates and underscore the essential role that NMR crystallography can play in characterizing both chemical structure and dynamics within functioning enzyme active sites.
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Affiliation(s)
- Bethany G. Caulkins
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Robert P. Young
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Ryan A. Kudla
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Chen Yang
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Thomas
J. Bittbauer
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Baback Bastin
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Eduardo Hilario
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Li Fan
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Michael J. Marsella
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Michael F. Dunn
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Leonard J. Mueller
- Department of Chemistry, and Department of Biochemistry, University of California, Riverside, California 92521, United States
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81
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Beran GJO, Hartman JD, Heit YN. Predicting Molecular Crystal Properties from First Principles: Finite-Temperature Thermochemistry to NMR Crystallography. Acc Chem Res 2016; 49:2501-2508. [PMID: 27754668 DOI: 10.1021/acs.accounts.6b00404] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Molecular crystals occur widely in pharmaceuticals, foods, explosives, organic semiconductors, and many other applications. Thanks to substantial progress in electronic structure modeling of molecular crystals, attention is now shifting from basic crystal structure prediction and lattice energy modeling toward the accurate prediction of experimentally observable properties at finite temperatures and pressures. This Account discusses how fragment-based electronic structure methods can be used to model a variety of experimentally relevant molecular crystal properties. First, it describes the coupling of fragment electronic structure models with quasi-harmonic techniques for modeling the thermal expansion of molecular crystals, and what effects this expansion has on thermochemical and mechanical properties. Excellent agreement with experiment is demonstrated for the molar volume, sublimation enthalpy, entropy, and free energy, and the bulk modulus of phase I carbon dioxide when large basis second-order Møller-Plesset perturbation theory (MP2) or coupled cluster theories (CCSD(T)) are used. In addition, physical insight is offered into how neglect of thermal expansion affects these properties. Zero-point vibrational motion leads to an appreciable expansion in the molar volume; in carbon dioxide, it accounts for around 30% of the overall volume expansion between the electronic structure energy minimum and the molar volume at the sublimation point. In addition, because thermal expansion typically weakens the intermolecular interactions, neglecting thermal expansion artificially stabilizes the solid and causes the sublimation enthalpy to be too large at higher temperatures. Thermal expansion also frequently weakens the lower-frequency lattice phonon modes; neglecting thermal expansion causes the entropy of sublimation to be overestimated. Interestingly, the sublimation free energy is less significantly affected by neglecting thermal expansion because the systematic errors in the enthalpy and entropy cancel somewhat. Second, because solid state nuclear magnetic resonance (NMR) plays an increasingly important role in molecular crystal studies, this Account discusses how fragment methods can be used to achieve higher-accuracy chemical shifts in molecular crystals. Whereas widely used plane wave density functional theory models are largely restricted to generalized gradient approximation (GGA) functionals like PBE in practice, fragment methods allow the routine use of hybrid density functionals with only modest increases in computational cost. In extensive molecular crystal benchmarks, hybrid functionals like PBE0 predict chemical shifts with 20-30% higher accuracy than GGAs, particularly for 1H, 13C, and 15N nuclei. Due to their higher sensitivity to polarization effects, 17O chemical shifts prove slightly harder to predict with fragment methods. Nevertheless, the fragment model results are still competitive with those from GIPAW. The improved accuracy achievable with fragment approaches and hybrid density functionals increases discrimination between different potential assignments of individual shifts or crystal structures, which is critical in NMR crystallography applications. This higher accuracy and greater discrimination are highlighted in application to the solid state NMR of different acetaminophen and testosterone crystal forms.
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Affiliation(s)
- Gregory J. O. Beran
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Joshua D. Hartman
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yonaton N. Heit
- Department of Chemistry, University of California, Riverside, California 92521, United States
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82
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Hartman J, Day GM, Beran GJO. Enhanced NMR Discrimination of Pharmaceutically Relevant Molecular Crystal Forms through Fragment-Based Ab Initio Chemical Shift Predictions. CRYSTAL GROWTH & DESIGN 2016; 16:6479-6493. [PMID: 27829821 PMCID: PMC5095663 DOI: 10.1021/acs.cgd.6b01157] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/09/2016] [Indexed: 05/10/2023]
Abstract
Chemical shift prediction plays an important role in the determination or validation of crystal structures with solid-state nuclear magnetic resonance (NMR) spectroscopy. One of the fundamental theoretical challenges lies in discriminating variations in chemical shifts resulting from different crystallographic environments. Fragment-based electronic structure methods provide an alternative to the widely used plane wave gauge-including projector augmented wave (GIPAW) density functional technique for chemical shift prediction. Fragment methods allow hybrid density functionals to be employed routinely in chemical shift prediction, and we have recently demonstrated appreciable improvements in the accuracy of the predicted shifts when using the hybrid PBE0 functional instead of generalized gradient approximation (GGA) functionals like PBE. Here, we investigate the solid-state 13C and 15N NMR spectra for multiple crystal forms of acetaminophen, phenobarbital, and testosterone. We demonstrate that the use of the hybrid density functional instead of a GGA provides both higher accuracy in the chemical shifts and increased discrimination among the different crystallographic environments. Finally, these results also provide compelling evidence for the transferability of the linear regression parameters mapping predicted chemical shieldings to chemical shifts that were derived in an earlier study.
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Affiliation(s)
- Joshua
D. Hartman
- Department
of Chemistry, University of California, Riverside, California 92521 United States
| | - Graeme M. Day
- School
of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Gregory J. O. Beran
- Department
of Chemistry, University of California, Riverside, California 92521 United States
- E-mail:
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