1
|
Shtukenberg AG, Braun DE, Tan M, Fellah N, Kahr B. Suppression of Disorder in Benzamide and Thiobenzamide Crystals by Fluorine Substitution. CRYSTAL GROWTH & DESIGN 2024; 24:5276-5284. [PMID: 38911134 PMCID: PMC11191397 DOI: 10.1021/acs.cgd.4c00517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/25/2024]
Abstract
Disorder is a common feature of molecular crystals that complicates determination of structures and can potentially affect electric and mechanical properties. Suppression of disorder is observed in otherwise severely disordered benzamide and thiobenzamide crystals by substituting hydrogen with fluorine in the ortho-position of the phenyl ring. Fluorine occupancies of 20-30% are sufficient to suppress disorder without changing the packing motif. Crystal structure prediction calculations reveal a much denser lattice energy landscape for benzamide compared to 2-fluorobenzamide, suggesting that fluorine substitution makes disorder less likely.
Collapse
Affiliation(s)
- Alexander G. Shtukenberg
- Department
of Chemistry and Molecular Design Institute, New York University, New York, New York 10003, United States
| | - Doris E. Braun
- Institute
of Pharmacy, Pharmaceutical Technology, University of Innsbruck, 6020 Innsbruck, Austria
- Christian
Doppler Laboratory for Advanced Crystal Engineering Strategies in
Drug Development, Institute of Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria
| | - Melissa Tan
- Department
of Chemistry and Molecular Design Institute, New York University, New York, New York 10003, United States
| | - Noalle Fellah
- Department
of Chemistry and Molecular Design Institute, New York University, New York, New York 10003, United States
| | - Bart Kahr
- Department
of Chemistry and Molecular Design Institute, New York University, New York, New York 10003, United States
| |
Collapse
|
2
|
Petrick TL, Grünwald A, Braun DE. Flavone Cocrystals: A Comprehensive Approach Integrating Experimental and Virtual Methods. CRYSTAL GROWTH & DESIGN 2024; 24:4195-4212. [PMID: 38766642 PMCID: PMC11099919 DOI: 10.1021/acs.cgd.4c00293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/25/2024] [Accepted: 04/25/2024] [Indexed: 05/22/2024]
Abstract
The dapsone/flavone cocrystal system served as a benchmark for both experimental and virtual screening methods. Expanding beyond this, two additional active pharmaceutical ingredients (APIs), sulfanilamide and sulfaguanidine, structurally related to dapsone were chosen to investigate the impact of substituents on cocrystal formation. The experimental screening involved mechanochemical methods, slurry experiments, hot-melt extrusion, and the contact preparation method. The virtual screening focused on crystal structure prediction (CSP), molecular complementarity, hydrogen-bond propensity, and molecular electrostatic potentials. The CSP studies not only indicated that each of the three APIs should form cocrystals with flavone but also reproduced the known single- and multicomponent phases. Experimentally, dapsone/flavone cocrystals ACC, BCC, CCC, and DCC were reproduced, CCC was identified as a nonstoichiometric hydrate, and a fifth cocrystal (ECC), a t-butanol solvate, was discovered. The cocrystal polymorphs ACC and BCC are enantiotripically related, and DCC, exhibiting a different stoichiometric ratio, is enthalpically stabilized over the other cocrystals. For the sulfaguanidine/flavone system, two novel, enantiotripically related cocrystals were identified. The crystal structures of two cocrystals and a flavone polymorph were solved from powder X-ray diffraction data, and the stability of all cocrystals was assessed through differential scanning calorimetry and lattice energy calculations. Despite computational indications, a diverse array of cocrystallization techniques did not result in a sulfanilamide/flavone cocrystal. The driving force behind dapsone's tendency to cocrystallize with flavone can be attributed to the overall strength of flavone interactions in the cocrystals. For sulfaguanidine, the potential to form strong API···API and API···coformer interactions in the cocrystal is a contributing factor. Furthermore, flavone was found to be trimorphic.
Collapse
Affiliation(s)
- Tom L. Petrick
- Institute of Pharmacy, University
of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Alexandra Grünwald
- Institute of Pharmacy, University
of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Doris E. Braun
- Institute of Pharmacy, University
of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
3
|
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.
Collapse
Affiliation(s)
- Gregory J O Beran
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| |
Collapse
|
4
|
Racher F, Petrick TL, Braun DE. Exploring the Supramolecular Interactions and Thermal Stability of Dapsone:Bipyridine Cocrystals by Combining Computational Chemistry with Experimentation. CRYSTAL GROWTH & DESIGN 2023; 23:4638-4654. [PMID: 37304396 PMCID: PMC10251420 DOI: 10.1021/acs.cgd.3c00387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/21/2023] [Indexed: 06/13/2023]
Abstract
The application of computational screening methodologies based on H-bond propensity scores, molecular complementarity, molecular electrostatic potentials, and crystal structure prediction has guided the discovery of novel cocrystals of dapsone and bipyridine (DDS:BIPY). The experimental screen, which included mechanochemical and slurry experiments as well as the contact preparation, resulted in four cocrystals, including the previously known DDS:4,4'-BIPY (2:1, CC44-B) cocrystal. To understand the factors governing the formation of the DDS:2,2'-BIPY polymorphs (1:1, CC22-A and CC22-B) and the two DDS:4,4'-BIPY cocrystal stoichiometries (1:1 and 2:1), different experimental conditions (such as the influence of solvent, grinding/stirring time, etc.) were tested and compared with the virtual screening results. The computationally generated (1:1) crystal energy landscapes had the experimental cocrystals as the lowest energy structures, although distinct cocrystal packings were observed for the similar coformers. H-bonding scores and molecular electrostatic potential maps correctly indicated cocrystallization of DDS and the BIPY isomers, with a higher likelihood for 4,4'-BIPY. The molecular conformation influenced the molecular complementarity results, predicting no cocrystallization for 2,2'-BIPY with DDS. The crystal structures of CC22-A and CC44-A were solved from powder X-ray diffraction data. All four cocrystals were fully characterized by a range of analytical techniques, including powder X-ray diffraction, infrared spectroscopy, hot-stage microscopy, thermogravimetric analysis, and differential scanning calorimetry. The two DDS:2,2'-BIPY polymorphs are enantiotropically related, with form B being the stable polymorph at room temperature (RT) and form A being the higher temperature form. Form B is metastable but kinetically stable at RT. The two DDS:4,4'-BIPY cocrystals are stable at room conditions; however, at higher temperatures, CC44-A transforms to CC44-B. The cocrystal formation enthalpy order, derived from the lattice energies, was calculated as follows: CC44-B > CC44-A > CC22-A.
Collapse
|
5
|
Xu J, Chen A, Cai T. Polymorphism of Purpurin and Low-level Detection of the Noncentrosymmetric form by Second Harmonic Generation Microscopy. J Pharm Sci 2023; 112:282-289. [PMID: 36257339 DOI: 10.1016/j.xphs.2022.10.011] [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: 07/11/2022] [Revised: 10/08/2022] [Accepted: 10/09/2022] [Indexed: 12/23/2022]
Abstract
Nonlinear optical imaging based on second harmonic generation (SHG) provides rapid and highly selective detection of polar crystals. Purpurin (PUR) is a natural product with multiple pharmacological activities. Two polymorphs of PUR show distinct crystal packing and structural symmetry, where form I crystallizes in a polar space group and form II crystallizes in a centrosymmetric crystal structure. The two polymorphs are monotropically related, with form I being the thermodynamically stable form, as suggested by slurry experiments, in-situ Raman spectroscopy and crystal structure prediction (CSP). The specificity of SHG to the polar crystals of form I allows rapid polymorphism detection at the limit of individual crystals. SHG is also able to detect low levels of form I in a tablet matrix dominated by amorphous excipients. This study shows that SHG microscopy can achieve the rapid and sensitive detection of noncentrosymmetric crystals in solid dosage forms, which is especially helpful for the early detection of unwanted polymorphic conversion or crystallization of amorphous drugs in formulations and final products.
Collapse
Affiliation(s)
- Jia Xu
- State Key Laboratory of Natural Medicines, Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China; School of Pharmacy, Jiangsu Vocational College of Medicine, Yancheng, 224005, China
| | - An Chen
- State Key Laboratory of Natural Medicines, Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Ting Cai
- State Key Laboratory of Natural Medicines, Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| |
Collapse
|
6
|
Wade J, Salerno F, Kilbride RC, Kim DK, Schmidt JA, Smith JA, LeBlanc LM, Wolpert EH, Adeleke AA, Johnson ER, Nelson J, Mori T, Jelfs KE, Heutz S, Fuchter MJ. Controlling anisotropic properties by manipulating the orientation of chiral small molecules. Nat Chem 2022; 14:1383-1389. [PMID: 36302869 DOI: 10.1038/s41557-022-01044-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 08/22/2022] [Indexed: 01/04/2023]
Abstract
Chiral π-conjugated molecules bring new functionality to technological applications and represent an exciting, rapidly expanding area of research. Their functional properties, such as the absorption and emission of circularly polarized light or the transport of spin-polarized electrons, are highly anisotropic. As a result, the orientation of chiral molecules critically determines the functionality and efficiency of chiral devices. Here we present a strategy to control the orientation of a small chiral molecule (2,2'-dicyano[6]helicene) by the use of organic and inorganic templating layers. Such templating layers can either force 2,2'-dicyano[6]helicene to adopt a face-on orientation and self-assemble into upright supramolecular columns oriented with their helical axis perpendicular to the substrate, or an edge-on orientation with parallel-lying supramolecular columns. Through such control, we show that low- and high-energy chiroptical responses can be independently 'turned on' or 'turned off'. The templating methodologies described here provide a simple way to engineer orientational control and, by association, anisotropic functional properties of chiral molecular systems for a range of emerging technologies.
Collapse
Affiliation(s)
- Jessica Wade
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK.
- Centre for Processable Electronics, Imperial College London, London, UK.
| | - Francesco Salerno
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Rachel C Kilbride
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK
| | - Dong Kuk Kim
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK
- Centre for Processable Electronics, Imperial College London, London, UK
| | - Julia A Schmidt
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Joel A Smith
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - Luc M LeBlanc
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Emma H Wolpert
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Adebayo A Adeleke
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jenny Nelson
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Physics, Imperial College London, London, UK
| | - Tadashi Mori
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Kim E Jelfs
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Sandrine Heutz
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK
- Centre for Processable Electronics, Imperial College London, London, UK
| | - Matthew J Fuchter
- Centre for Processable Electronics, Imperial College London, London, UK.
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK.
| |
Collapse
|
7
|
Polyzois H, Guo R, Srirambhatla VK, Warzecha M, Prasad E, Turner A, Halbert GW, Keating P, Price SL, Florence AJ. Crystal Structure and Twisted Aggregates of Oxcarbazepine Form III. CRYSTAL GROWTH & DESIGN 2022; 22:4146-4156. [PMID: 35915669 PMCID: PMC9337787 DOI: 10.1021/acs.cgd.2c00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Polymorphism and crystal habit play vital roles in dictating the properties of crystalline materials. Here, the structure and properties of oxcarbazepine (OXCBZ) form III are reported along with the occurrence of twisted crystalline aggregates of this metastable polymorph. OXCBZ III can be produced by crystallization from the vapor phase and by recrystallization from solution. The crystallization process used to obtain OXCBZ III is found to affect the pitch, with the most prominent effect observed from the sublimation-grown OXCBZ III material where the pitch increases as the length of aggregates increases. Sublimation-grown OXCBZ III follows an unconventional mechanism of formation with condensed droplet formation and coalescence preceding nucleation and growth of aggregates. A crystal structure determination of OXCBZ III from powder X-ray diffraction methods, assisted by crystal structure prediction (CSP), reveals that OXCBZ III, similar to carbamazepine form II, contains void channels in its structure with the channels, aligned along the c crystallographic axis, oriented parallel to the twist axis of the aggregates. The likely role of structural misalignment at the lattice or nanoscale is explored by considering the role of molecular and closely related structural impurities informed by crystal structure prediction.
Collapse
Affiliation(s)
- Hector Polyzois
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
- National
Physical Laboratory, Teddington, Middlesex TW11 0LW, U.K.
| | - Rui Guo
- Department
of Chemistry, University College London, London WC1H 0AJ, U.K.
| | - Vijay K. Srirambhatla
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| | - Monika Warzecha
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| | - Elke Prasad
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| | - Alice Turner
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| | - Gavin W. Halbert
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| | - Patricia Keating
- Department
of Pure and Applied Chemistry, University
of Strathclyde, Glasgow G1 1XL, U.K.
| | - Sarah L. Price
- Department
of Chemistry, University College London, London WC1H 0AJ, U.K.
| | - Alastair J. Florence
- EPSRC
Future CMAC Research Hub, University of
Strathclyde, Glasgow G1 1RD, U.K.
- Strathclyde
Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
| |
Collapse
|
8
|
Yin X, Gounaris CE. Search methods for inorganic materials crystal structure prediction. Curr Opin Chem Eng 2022. [DOI: 10.1016/j.coche.2021.100726] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
9
|
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...
Collapse
|
10
|
Braun DE, Hald P, Kahlenberg V, Griesser UJ. Expanding the Solid Form Landscape of Bipyridines. CRYSTAL GROWTH & DESIGN 2021; 21:7201-7217. [PMID: 34867088 PMCID: PMC8640990 DOI: 10.1021/acs.cgd.1c01045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Two bipyridine isomers (2,2'- and 4,4'-), used as coformers and ligands in coordination chemistry, were subjected to solid form screening and crystal structure prediction. One anhydrate and a formic acid disolvate were crystallized for 2,2'-bipyridine, whereas multiple solid-state forms, anhydrate, dihydrate, and eight solvates with carboxylic acids, including a polymorphic acetic acid disolvate, were found for the 4,4'-isomer. Seven of the solvates are reported for the first time, and structural information is provided for six of the new solvates. All twelve solid-state forms were investigated comprehensively using experimental [thermal analysis, isothermal calorimetry, X-ray diffraction, gravimetric moisture (de)sorption, and IR spectroscopy] and computational approaches. Lattice and interaction energy calculations confirmed the thermodynamic driving force for disolvate formation, mediated by the absence of H-bond donor groups of the host molecules. The exposed location of the N atoms in 4,4'-bipyridine facilitates the accommodation of bigger carboxylic acids and leads to higher conformational flexibility compared to 2,2'-bipyridine. For the 4,4'-bipyridine anhydrate ↔ hydrate interconversion hardly any hysteresis and a fast transformation kinetics are observed, with the critical relative humidity being at 35% at room temperature. The computed anhydrate crystal energy landscapes have the 2,2'-bipyridine as the lowest energy structure and the 4,4'-bipyridine among the low-energy structures and suggest a different crystallization behavior of the two compounds.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute
of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Patricia Hald
- Institute
of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Volker Kahlenberg
- Institute
of Mineralogy and Petrography, University
of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute
of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
11
|
In-silico methods of cocrystal screening: A review on tools for rational design of pharmaceutical cocrystals. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
12
|
Bowskill DH, Sugden IJ, Konstantinopoulos S, Adjiman CS, Pantelides CC. Crystal Structure Prediction Methods for Organic Molecules: State of the Art. Annu Rev Chem Biomol Eng 2021; 12:593-623. [PMID: 33770462 DOI: 10.1146/annurev-chembioeng-060718-030256] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The prediction of the crystal structures that a given organic molecule is likely to form is an important theoretical problem of significant interest for the pharmaceutical and agrochemical industries, among others. As evidenced by a series of six blind tests organized over the past 2 decades, methodologies for crystal structure prediction (CSP) have witnessed substantial progress and have now reached a stage of development where they can begin to be applied to systems of practical significance. This article reviews the state of the art in general-purpose methodologies for CSP, placing them within a common framework that highlights both their similarities and their differences. The review discusses specific areas that constitute the main focus of current research efforts toward improving the reliability and widening applicability of these methodologies, and offers some perspectives for the evolution of this technology over the next decade.
Collapse
Affiliation(s)
- David H Bowskill
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, and Institute for Molecular Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
| | - Isaac J Sugden
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, and Institute for Molecular Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
| | - Stefanos Konstantinopoulos
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, and Institute for Molecular Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
| | - Claire S Adjiman
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, and Institute for Molecular Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
| | - Constantinos C Pantelides
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, and Institute for Molecular Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
| |
Collapse
|
13
|
Aina AA, Misquitta AJ, Price SL. A non-empirical intermolecular force-field for trinitrobenzene and its application in crystal structure prediction. J Chem Phys 2021; 154:094123. [PMID: 33685142 DOI: 10.1063/5.0043746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An anisotropic atom-atom distributed intermolecular force-field (DIFF) for rigid trinitrobenzene (TNB) is developed using distributed multipole moments, dipolar polarizabilities, and dispersion coefficients derived from the charge density of the isolated molecule. The short-range parameters of the force-field are fitted to first- and second-order symmetry-adapted perturbation theory dimer interaction energy calculations using the distributed density-overlap model to guide the parameterization of the short-range anisotropy. The second-order calculations are used for fitting the damping coefficients of the long-range dispersion and polarization and also for relaxing the isotropic short-range coefficients in the final model, DIFF-srL2(rel). We assess the accuracy of the unrelaxed model, DIFF-srL2(norel), and its equivalent without short-range anisotropy, DIFF-srL0(norel), as these models are easier to derive. The model potentials are contrasted with empirical models for the repulsion-dispersion fitted to organic crystal structures with multipoles of iterated stockholder atoms (ISAs), FIT(ISA,L4), and with Gaussian Distributed Analysis (GDMA) multipoles, FIT(GDMA,L4), commonly used in modeling organic crystals. The potentials are tested for their ability to model the solid state of TNB. The non-empirical models provide more reasonable relative lattice energies of the three polymorphs of TNB and propose more sensible hypothetical structures than the empirical force-field (FIT). The DIFF-srL2(rel) model successfully has the most stable structure as one of the many structures that match the coordination sphere of form III. The neglect of the conformational flexibility of the nitro-groups is a significant approximation. This methodology provides a step toward force-fields capable of representing all phases of a molecule in molecular dynamics simulations.
Collapse
Affiliation(s)
- Alex A Aina
- Department of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Alston J Misquitta
- School of Physics and Astronomy and The Thomas Young Centre for Theory and Simulation of Materials at Queen Mary, University of London, London E1 4NS, United Kingdom
| | - Sarah L Price
- Department of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, United Kingdom
| |
Collapse
|
14
|
Francia NF, Price LS, Salvalaglio M. Reducing crystal structure overprediction of ibuprofen with large scale molecular dynamics simulations. CrystEngComm 2021. [DOI: 10.1039/d1ce00616a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reduction of a large dataset of computationally predicted structures of ibuprofen by employing molecular dynamics and biased simulations at finite temperature and pressure.
Collapse
Affiliation(s)
- Nicholas F. Francia
- Thomas Young Centre and Department of Chemical Engineering, University College London, London WC1E 7JE, UK
| | - Louise S. Price
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Matteo Salvalaglio
- Thomas Young Centre and Department of Chemical Engineering, University College London, London WC1E 7JE, UK
| |
Collapse
|
15
|
Braun DE. The trimorphism of 3-hydroxybenzoic acid: an experimental and computational study. CrystEngComm 2021. [DOI: 10.1039/d1ce00159k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A computationally driven experimental search for polymorphs of 3-hydroxybenzoic acid confirmed the third form and the small energy differences between the polymorphs.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy
- University of Innsbruck
- 6020 Innsbruck
- Austria
| |
Collapse
|
16
|
Mazurek AH, Szeleszczuk Ł, Simonson T, Pisklak DM. Application of Various Molecular Modelling Methods in the Study of Estrogens and Xenoestrogens. Int J Mol Sci 2020; 21:E6411. [PMID: 32899216 PMCID: PMC7504198 DOI: 10.3390/ijms21176411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/14/2022] Open
Abstract
In this review, applications of various molecular modelling methods in the study of estrogens and xenoestrogens are summarized. Selected biomolecules that are the most commonly chosen as molecular modelling objects in this field are presented. In most of the reviewed works, ligand docking using solely force field methods was performed, employing various molecular targets involved in metabolism and action of estrogens. Other molecular modelling methods such as molecular dynamics and combined quantum mechanics with molecular mechanics have also been successfully used to predict the properties of estrogens and xenoestrogens. Among published works, a great number also focused on the application of different types of quantitative structure-activity relationship (QSAR) analyses to examine estrogen's structures and activities. Although the interactions between estrogens and xenoestrogens with various proteins are the most commonly studied, other aspects such as penetration of estrogens through lipid bilayers or their ability to adsorb on different materials are also explored using theoretical calculations. Apart from molecular mechanics and statistical methods, quantum mechanics calculations are also employed in the studies of estrogens and xenoestrogens. Their applications include computation of spectroscopic properties, both vibrational and Nuclear Magnetic Resonance (NMR), and also in quantum molecular dynamics simulations and crystal structure prediction. The main aim of this review is to present the great potential and versatility of various molecular modelling methods in the studies on estrogens and xenoestrogens.
Collapse
Affiliation(s)
- Anna Helena Mazurek
- Chair and Department of Physical Pharmacy and Bioanalysis, Department of Physical Chemistry, Medical Faculty of Pharmacy, University of Warsaw, Banacha 1 str., 02-093 Warsaw Poland; (A.H.M.); (D.M.P.)
| | - Łukasz Szeleszczuk
- Chair and Department of Physical Pharmacy and Bioanalysis, Department of Physical Chemistry, Medical Faculty of Pharmacy, University of Warsaw, Banacha 1 str., 02-093 Warsaw Poland; (A.H.M.); (D.M.P.)
| | - Thomas Simonson
- Laboratoire de Biochimie (CNRS UMR7654), Ecole Polytechnique, 91-120 Palaiseau, France;
| | - Dariusz Maciej Pisklak
- Chair and Department of Physical Pharmacy and Bioanalysis, Department of Physical Chemistry, Medical Faculty of Pharmacy, University of Warsaw, Banacha 1 str., 02-093 Warsaw Poland; (A.H.M.); (D.M.P.)
| |
Collapse
|
17
|
Rosbottom I, Cheng TNH, Heng JYY. Computational Analysis of the Solid‐State and Solvation Properties of Carbamazepine in Relation to its Polymorphism. Chem Eng Technol 2020. [DOI: 10.1002/ceat.202000056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ian Rosbottom
- Imperial College LondonDepartment of Chemical Engineering South Kensington Campus SW7 2AZ London United Kingdom
| | - Thomas Nok Hin Cheng
- Imperial College LondonDepartment of Chemical Engineering South Kensington Campus SW7 2AZ London United Kingdom
| | - Jerry Y. Y. Heng
- Imperial College LondonDepartment of Chemical Engineering South Kensington Campus SW7 2AZ London United Kingdom
- Imperial College LondonInstitute for Molecular Science and Engineering South Kensington Campus SW7 2AZ London United Kingdom
| |
Collapse
|
18
|
Braun D, Rivalta A, Giunchi A, Bedoya-Martinez N, Schrode B, Venuti E, Della Valle RG, Werzer O. Surface Induced Phenytoin Polymorph. 1. Full Structure Solution by Combining Grazing Incidence X-ray Diffraction and Crystal Structure Prediction. CRYSTAL GROWTH & DESIGN 2019; 19:6058-6066. [PMID: 31728132 PMCID: PMC6839513 DOI: 10.1021/acs.cgd.9b00857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/15/2019] [Indexed: 05/31/2023]
Abstract
Understanding the behavior and properties of molecules assembled in thin layers requires knowledge of their crystalline packing. The drug phenytoin (5,5-diphenylhydantoin) is one of the compounds that can be grown as a surface induced polymorph. By using grazing incidence X-ray diffraction, the monoclinic unit cell of the new form II can be determined, but, due to crystal size and the low amount of data, a full solution using conventional structure solving strategies fails. In this work, the full solution has been obtained by combining computational structure generation and experimental results. The comparison between the bulk and the new surface induced phase reveals significant packing differences of the hydrogen-bonding network, which might be the reason for the faster dissolution of form II with respect to form I. The results are very satisfactory, and the method might be adapted for other systems, where, due to the limited amount of experimental data, one must rely on additional approaches to gain access to more detailed information to understand the solid-state behavior.
Collapse
Affiliation(s)
- Doris
E. Braun
- Institute
of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Arianna Rivalta
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
| | - Andrea Giunchi
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
| | | | - Benedikt Schrode
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
- Institute
of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz, Univertitaetsplatz 1, 8010 Graz, Austria
| | - Elisabetta Venuti
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
| | - Raffaele Guido Della Valle
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
| | - Oliver Werzer
- Institute
of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz, Univertitaetsplatz 1, 8010 Graz, Austria
| |
Collapse
|
19
|
Braun DE. Experimental and computational approaches to rationalise multicomponent supramolecular assemblies: dapsone monosolvates. Phys Chem Chem Phys 2019; 21:17288-17305. [PMID: 31348477 DOI: 10.1039/c9cp02572c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The monosolvate crystal energy landscapes of dapsone (DDS) including the solvents carbon tetrachloride, acetone, cyclohexanone, dimethyl formamide, tetrahydrofuran, methyl ethyl ketone, 1,2-dichloroethane, 1,4-dioxane, dichloromethane and chloroform were established using experimental and computational approaches. To rationalise and understand solvate formation, solvate stability and desolvation reactions a careful control of the experimental crystallisation and storage conditions, a range of thermoanalytical methods and crystal structure prediction were required. Six of the eight DDS monosolvates are reported and characterised for the first time. Structural similarity and diversity of the at ambient conditions unstable monosolvates were apparent from the computed crystal energy landscapes, which had the experimental packings as lowest energy structures. The computed structures were used as input for Rietveld refinements and isostructurality of four of the monosolvates was confirmed. Packing comparisons of the solvate structures and molecular properties of the solvent molecules indicated that both size/shape of the solvent molecule and the possible DDSsolvent interactions are the important factors for DDS solvate formation. Through the combination of experiment and theory solvate stability and structural features have been rationalised.
Collapse
Affiliation(s)
- Doris E Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
| |
Collapse
|
20
|
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
| |
Collapse
|
21
|
Sugden IJ, Adjiman CS, Pantelides CC. Accurate and efficient representation of intramolecular energy in ab initio generation of crystal structures. II. Smoothed intramolecular potentials. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2019; 75:423-433. [PMID: 32830664 DOI: 10.1107/s2052520619005778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/27/2019] [Indexed: 06/11/2023]
Abstract
The application of crystal structure prediction (CSP) to industrially relevant molecules requires the handling of increasingly large and flexible compounds. A revised model for the effect of molecular flexibility on the lattice energy that removes the discontinuities and non-differentiabilities present in earlier models (Sugden et al., 2016), with a view to improving the performance of CSP is presented. The approach is based on the concept of computing a weighted average of local models, and has been implemented within the CrystalPredictor code. Through the comparative investigation of several compounds studied in earlier literature, it is shown that this new model results in large reductions in computational effort (of up to 65%) and in significant increases in reliability. The approach is further applied to investigate, for the first time, the computational polymorphic landscape of flufenamic acid for Z' = 1 structures, resulting in the successful identification of all three experimentally resolved polymorphs within reasonable computational time.
Collapse
Affiliation(s)
- Isaac J Sugden
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Claire S Adjiman
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Constantinos C Pantelides
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| |
Collapse
|
22
|
Braun DE, Vickers M, Griesser UJ. Dapsone Form V: A Late Appearing Thermodynamic Polymorph of a Pharmaceutical. Mol Pharm 2019; 16:3221-3236. [PMID: 31075201 DOI: 10.1021/acs.molpharmaceut.9b00419] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Five anhydrate polymorphs (forms I-V) and the isomorphic dehydrate (Hydehy) of dapsone (4,4'-diaminodiphenyl sulfone or DDS) were prepared and characterized in an interdisciplinary experimental and computational study, elucidating the kinetic and thermodynamic stabilities, solid form interrelationships, and structural features of the known forms I-IV, the novel polymorph form V, and Hydehy. Calorimetric measurements, solubility experiments, and lattice energy calculations revealed that form V is the thermodynamically stable polymorph from absolute zero to at least 90 °C. At higher temperatures, form II, and then form I, becomes the most stable DDS solid form. The computed 0 K stability order (lattice energy calculations) was confirmed with calorimetric measurements as follows, V (most stable) > III > Hydehy > II > I > IV (least stable). The discovery of form V was complicated by the fact that the metastable but kinetically stabilized form III shows a higher nucleation and growth rate. By combining laboratory powder X-ray diffraction data and ab initio calculations, the crystal structure of form V ( P21/ c, Z' = 4) was solved, with a high energy DDS conformation allowing a denser packing and more stable intermolecular interactions, rationalizing the formation of a high Z' structure. The structures of the forms I and IV, only observed from the melt and showing distinct packing features compared to the forms II, III, and V, were derived from the computed crystal energy landscapes. Dehydration modeling of the DDS hydrate led to the Hydehy structure. This study expands our understanding about the complex crystallization behavior of pharmaceuticals and highlights the big challenge in solid form screening, especially that there is no clear end point.
Collapse
Affiliation(s)
- Doris E Braun
- Institute of Pharmacy , University of Innsbruck , Innrain 52c , 6020 Innsbruck , Austria
| | - Martin Vickers
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , U.K
| | - Ulrich J Griesser
- Institute of Pharmacy , University of Innsbruck , Innrain 52c , 6020 Innsbruck , Austria
| |
Collapse
|
23
|
Cruz-Cabeza AJ, Davey RJ, Oswald IDH, Ward MR, Sugden IJ. Polymorphism in p-aminobenzoic acid. CrystEngComm 2019. [DOI: 10.1039/c8ce01890a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We review the polymorphism of p-aminobenzoic acid (pABA), a model drug compound whose crystallisation and polymorphic behaviour has been extensively studied in recent years.
Collapse
Affiliation(s)
- Aurora J. Cruz-Cabeza
- School of Chemical Engineering and Analytical Science
- University of Manchester
- M13 9PL Manchester
- UK
- Astra Zeneca
| | - Roger J. Davey
- School of Chemical Engineering and Analytical Science
- University of Manchester
- M13 9PL Manchester
- UK
| | - Iain D. H. Oswald
- Strathclyde Institute of Pharmacy & Biomedical Sciences (SIPBS)
- University of Strathclyde
- Glasgow
- UK
| | - Martin R. Ward
- Strathclyde Institute of Pharmacy & Biomedical Sciences (SIPBS)
- University of Strathclyde
- Glasgow
- UK
| | - Isaac J. Sugden
- Molecular Systems Engineering Group
- Centre for Process Systems Engineering
- Department of Chemical Engineering
- Imperial College London
- London SW7 2AZ
| |
Collapse
|
24
|
Gatsiou CA, Adjiman CS, Pantelides CC. Repulsion-dispersion parameters for the modelling of organic molecular crystals containing N, O, S and Cl. Faraday Discuss 2018; 211:297-323. [PMID: 30094433 DOI: 10.1039/c8fd00064f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In lattice energy models that combine ab initio and empirical components, it is important to ensure consistency between these components so that meaningful quantitative results are obtained. A method for deriving parameters of atom-atom repulsion dispersion potentials for crystals, tailored to different ab initio models, is presented. It is based on minimization of the sum of squared deviations between experimental and calculated structures and energies. The solution algorithm is designed to avoid convergence to local minima in the parameter space by combining a deterministic low-discrepancy sequence for the generation of multiple initial parameter guesses with an efficient local minimization algorithm. The proposed approach is applied to derive transferable exp-6 potential parameters suitable for use in conjunction with a distributed multipole electrostatics model derived from isolated molecule charge densities calculated at the M06/6-31G(d,p) level of theory. Data for hydrocarbons, azahydrocarbons, oxohydrocarbons, organosulphur compounds and chlorohydrocarbons are used for the estimation. A good fit is achieved for the new set of parameters with a mean absolute error in sublimation enthalpies of 4.1 kJ mol-1 and an average rmsd15 of 0.31 Å. The parameters are found to perform well on a separate cross-validation set of 39 compounds.
Collapse
Affiliation(s)
- Christina A Gatsiou
- Molecular Systems Engineering Group, Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | | | | |
Collapse
|
25
|
Braun DE, Griesser UJ. Supramolecular Organization of Nonstoichiometric Drug Hydrates: Dapsone. Front Chem 2018; 6:31. [PMID: 29520359 PMCID: PMC5826966 DOI: 10.3389/fchem.2018.00031] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/09/2018] [Indexed: 12/16/2022] Open
Abstract
The observed moisture- and temperature dependent transformations of the dapsone (4,4'-diaminodiphenyl sulfone, DDS) 0. 33-hydrate were correlated to its structure and the number and strength of the water-DDS intermolecular interactions. A combination of characterization techniques was used, including thermal analysis (hot-stage microscopy, differential scanning calorimetry and thermogravimetric analysis), gravimetric moisture sorption/desorption studies and variable humidity powder X-ray diffraction, along with computational modeling (crystal structure prediction and pair-wise intermolecular energy calculations). Depending on the relative humidity the hydrate contains between 0 and 0.33 molecules of water per molecule DDS. The crystal structure is retained upon dehydration indicating that DDS hydrate shows a non-stoichiometric (de)hydration behavior. Unexpectedly, the water molecules are not located in structural channels but at isolated-sites of the host framework, which is counterintuitively for a hydrate with non-stoichiometric behavior. The water-DDS interactions were estimated to be weaker than water-host interactions that are commonly observed in stoichiometric hydrates and the lattice energies of the isomorphic dehydration product (hydrate structure without water molecules) and (form III) differ only by ~1 kJ mol-1. The computational generation of hypothetical monohydrates confirms that the hydrate with the unusual DDS:water ratio of 3:1 is more stable than a feasible monohydrate structure. Overall, this study highlights that a deeper understanding of the formation of hydrates with non-stoichiometric behavior requires a multidisciplinary approach including suitable experimental and computational methods providing a firm basis for the development and manufacturing of high quality drug products.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | | |
Collapse
|
26
|
Rice B, LeBlanc LM, Otero-de-la-Roza A, Fuchter MJ, Johnson ER, Nelson J, Jelfs KE. A computational exploration of the crystal energy and charge-carrier mobility landscapes of the chiral [6]helicene molecule. NANOSCALE 2018; 10:1865-1876. [PMID: 29313040 DOI: 10.1039/c7nr08890f] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The potential of a given π-conjugated organic molecule in an organic semiconductor device is highly dependent on molecular packing, as it strongly influences the charge-carrier mobility of the material. Such solid-state packing is sensitive to subtle differences in their intermolecular interactions and is challenging to predict. Chirality of the organic molecule adds an additional element of complexity to intuitive packing prediction. Here we use crystal structure prediction to explore the lattice-energy landscape of a potential chiral organic semiconductor, [6]helicene. We reproduce the experimentally observed enantiopure crystal structure and explain the absence of an experimentally observed racemate structure. By exploring how the hole and electron-mobility varies across the energy-structure-function landscape for [6]helicene, we find that an energetically favourable and frequently occurring packing motif is particularly promising for electron-mobility, with a highest calculated mobility of 2.9 cm2 V-1 s-1 (assuming a reorganization energy of 0.46 eV). We also calculate relatively high hole-mobility in some structures, with a highest calculated mobility of 2.0 cm2 V-1 s-1 found for chains of helicenes packed in a herringbone fashion. Neither the energetically favourable nor high charge-carrier mobility packing motifs are intuitively obvious, and this demonstrates the utility of our approach to computationally explore the energy-structure-function landscape for organic semiconductors. Our work demonstrates a route for the use of computational simulations to aid in the design of new molecules for organic electronics, through the a priori prediction of their likely solid-state form and properties.
Collapse
Affiliation(s)
- Beth Rice
- Department of Physics, Imperial College London, South Kensington, London, SW7 2AZ, UK and Centre for Plastic Electronics, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Luc M LeBlanc
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Alberto Otero-de-la-Roza
- Department of Chemistry, University of British Columbia, Okanagan, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Matthew J Fuchter
- Centre for Plastic Electronics, Imperial College London, South Kensington, London, SW7 2AZ, UK. and Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jenny Nelson
- Department of Physics, Imperial College London, South Kensington, London, SW7 2AZ, UK and Centre for Plastic Electronics, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Kim E Jelfs
- Centre for Plastic Electronics, Imperial College London, South Kensington, London, SW7 2AZ, UK. and Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| |
Collapse
|
27
|
Iuzzolino L, McCabe P, Price SL, Brandenburg JG. Crystal structure prediction of flexible pharmaceutical-like molecules: density functional tight-binding as an intermediate optimisation method and for free energy estimation. Faraday Discuss 2018; 211:275-296. [PMID: 30035288 DOI: 10.1039/c8fd00010g] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Successful methodologies for theoretical crystal structure prediction (CSP) on flexible pharmaceutical-like organic molecules explore the lattice energy surface to find a set of plausible crystal structures. The initial search stages of CSP studies use relatively simple lattice energy approximations as hundreds of thousands of minima have to be considered. These generated crystal structures often have poor molecular geometries, as well as inaccurate lattice energy rankings, and performing reasonably accurate but computationally affordable optimisations of the crystal structures generated in a search would be highly desirable. Here, we seek to explore whether semi-empirical quantum-mechanical methods can perform this task. We employed the dispersion-corrected tight-binding Hamiltonian (DFTB3-D3) to relax all the inter- and intra-molecular degrees of freedom of several thousands of generated crystal structures of five pharmaceutical-like molecules, saving a large amount of computational effort compared to earlier studies. The computational cost scales better with molecular size and flexibility than other CSP methods, suggesting that it could be extended to even larger and more flexible molecules. On average, this optimisation improved the average reproduction of the eight experimental crystal structures (RMSD15) and experimental conformers (RMSD1) by 4% and 23%, respectively. The intermolecular interactions were then further optimised using distributed multipoles, derived from the molecular wave-functions, to accurately describe the electrostatic components of the intermolecular energies. In all cases, the experimental crystal structures are close to the top of the lattice energy ranking. Phonon calculations on some of the lowest energy structures were also performed with DFTB3-D3 methods to calculate the vibrational component of the Helmholtz free energy, providing further insights into the solid-state behaviour of the target molecules. We conclude that DFTB3-D3 is a cost-effective method for optimising flexible molecules, bridging the gap between the approximate methods used in CSP searches for generating crystal structures and more accurate methods required in the final energy ranking.
Collapse
Affiliation(s)
- Luca Iuzzolino
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | | | | | | |
Collapse
|
28
|
Ruggiero MT, Kölbel J, Li Q, Zeitler JA. Predicting the structures and associated phase transition mechanisms in disordered crystals via a combination of experimental and theoretical methods. Faraday Discuss 2018; 211:425-439. [DOI: 10.1039/c8fd00042e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Experimental terahertz time-domain spectroscopy and theoretical solid-state ab initio density functional theory and molecular dynamics simulations are used to elucidate the structures, dynamics, and phase transformation processes of molecular crystals undergoing a solid-state order–disorder transition.
Collapse
Affiliation(s)
- Michael T. Ruggiero
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge
- UK
| | - Johanna Kölbel
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge
- UK
| | - Qi Li
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge
- UK
| | - J. Axel Zeitler
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge
- UK
| |
Collapse
|
29
|
Braun DE, Raabe K, Schneeberger A, Kahlenberg V, Griesser UJ. New Insights into Solid Form Stability and Hydrate Formation: o-Phenanthroline HCl and Neocuproine HCl. Molecules 2017; 22:molecules22122238. [PMID: 29244765 PMCID: PMC6149885 DOI: 10.3390/molecules22122238] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 11/27/2022] Open
Abstract
The moisture- and temperature dependent stabilities and interrelation pathways of the practically relevant solid forms of o-phenanthroline HCl (1) and neocuproine HCl (2) were investigated using thermal analytical techniques (HSM, DSC and TGA) and gravimetric moisture sorption/desorption studies. The experimental stability data were correlated with the structural changes observed upon dehydration and the pairwise interaction and lattice energies calculated. For 1 the monohydrate was identified as the only stable form under conditions of RH typically found during production and storage, but at RH values >80% deliquescence occurs. The second compound, 2, forms an anhydrate and two different hydrates, mono- (2-Hy1) and trihydrate (2-Hy3). The 2-Hy1 structure was solved from SCXRD data and the anhydrate structure derived from a combination of PXRD and CSP. Depending on the environmental conditions (moisture) either 2-Hy1 or 2-Hy3 is the most sable solid form of 2 at RT. The monohydrates 1-Hy1 and 2-Hy1 show a high enthalpic stabilization (≥20 kJ mol−1) relative to the anhydrates. The anhydrates are unstable at ambient conditions and readily transform to the monohydrates even in the presence of traces of moisture. This study demonstrates how the right combination of experiment and theory can unravel the properties and interconversion pathways of solid forms.
Collapse
Affiliation(s)
- Doris E Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
| | - Katharina Raabe
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
| | - Anna Schneeberger
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
| | - Volker Kahlenberg
- Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria.
| | - Ulrich J Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
| |
Collapse
|
30
|
Braun DE, Schneeberger A, Griesser UJ. Understanding the Role of Water in 1,10-Phenanthroline Monohydrate. CrystEngComm 2017; 19:6133-6145. [PMID: 30344448 PMCID: PMC6195195 DOI: 10.1039/c7ce01371j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solid forms emerging from an experimental screening programme of 1,10-phenanthroline (o-phen), a heavily used bidentate ligand, and interconversion pathways of its two neat forms, the monohdyrate (Hy1) and four solvates with acetone, chloroform, dichloromethane and 1,2-dichloroethane are described. The solvates, identified and characterised with thermoanalyical methods, are unstable when removed from the mother liquor and desolvate at room temperature depending on the relative humidity (RH) to anhydrate I° (AH I°) or transform to Hy1. At ambient conditions Hy1, a stoichiometric channel hydrate, is the thermodynaically most stable o-phen solid form. The enthalpically stabilised Hy1 melts at 102 °C or dehydrates to AH I° at RH < 10% at 25 °C. The potential energy difference between Hy1 and AH I° was calculated to be approx. 15 kJ mol-1. The second anhydrate polymorph (AH II) can be obatined from the quench cooled melt of o-phen, but is unstable at ambient conditions and transforms wihtin minutes to either AH I° or Hy1. The two neat polymorphs are enantiotropically related and water-free o-phen transforms to Hy1 at RH > 16%. The structural and stablity features of the solid forms, in paricular Hy1, are unravelled by a combination of experimental (thermal analysis, moisture sorption/desorption and storage experiments, infrared spectroscopy and powder X-ray diffraction) and computational modelling (crystal structure prediction and lattice energy calculations), providing a consistent picture why o-phen forms a very stable Z' = 3 channel hydrate.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020
Innsbruck, Austria
| | | | | |
Collapse
|
31
|
Aina AA, Misquitta AJ, Price SL. From dimers to the solid-state: Distributed intermolecular force-fields for pyridine. J Chem Phys 2017; 147:161722. [DOI: 10.1063/1.4999789] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexander A. Aina
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | - Alston J. Misquitta
- School of Physics and Astronomy, Queen Mary, University of London, London E1 4NS, United Kingdom
| | - Sarah L. Price
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| |
Collapse
|
32
|
Braun D, Lingireddy SR, Beidelschies MD, Guo R, Müller P, Price SL, Reutzel-Edens SM. Unraveling Complexity in the Solid Form Screening of a Pharmaceutical Salt: Why so Many Forms? Why so Few? CRYSTAL GROWTH & DESIGN 2017; 17:5349-5365. [PMID: 29018305 PMCID: PMC5629560 DOI: 10.1021/acs.cgd.7b00842] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/28/2017] [Indexed: 06/07/2023]
Abstract
The solid form landscape of 5-HT2a antagonist 3-(4-(benzo[d]isoxazole-3-yl)piperazin-1-yl)-2,2-dimethylpropanoic acid hydrochloride (B5HCl) proved difficult to establish. Many crystalline materials were produced by solid form screening, but few forms readily grew high quality crystals to afford a clear picture or understanding of the solid form landscape. Careful control of crystallization conditions, a range of experimental methods, computational modeling of solvate structures, and crystal structure prediction were required to see potential arrangements of the salt in its crystal forms. Structural diversity in the solid form landscape of B5HCl was apparent in the layer structures for the anhydrate polymorphs (Forms I and II), dihydrate and a family of solvates with alcohols. The alcohol solvates, which provided a distinct packing from the neat forms and the dihydrate, form layers with conserved hydrogen bonding between B5HCl and the solvent, as well as stacking of the aromatic rings. The ability of the alcohol hydrocarbon moieties to efficiently pack between the layers accounted for the difficulty in growing some solvate crystals and the inability of other solvates to crystallize altogether. Through a combination of experiment and computation, the crystallization problems, form stability, and desolvation pathways of B5HCl have been rationalized at a molecular level.
Collapse
Affiliation(s)
- Doris
E. Braun
- Institute
of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | | | - Mark D. Beidelschies
- Eurofins
Lancaster Laboratories, PSS, Indianapolis, Indiana 46285, United States
| | - Rui Guo
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Peter Müller
- X-Ray Diffraction
Facility, MIT Department of Chemistry, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sarah L. Price
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | | |
Collapse
|
33
|
Iuzzolino L, Reilly AM, McCabe P, Price SL. Use of Crystal Structure Informatics for Defining the Conformational Space Needed for Predicting Crystal Structures of Pharmaceutical Molecules. J Chem Theory Comput 2017; 13:5163-5171. [PMID: 28892623 DOI: 10.1021/acs.jctc.7b00623] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Determining the range of conformations that a flexible pharmaceutical-like molecule could plausibly adopt in a crystal structure is a key to successful crystal structure prediction (CSP) studies. We aim to use conformational information from the crystal structures in the Cambridge Structural Database (CSD) to facilitate this task. The conformations produced by the CSD Conformer Generator are reduced in number by considering the underlying rotamer distributions, an analysis of changes in molecular shape, and a minimal number of molecular ab initio calculations. This method is tested for five pharmaceutical-like molecules where an extensive CSP study has already been performed. The CSD informatics-derived set of crystal structure searches generates almost all the low-energy crystal structures previously found, including all experimental structures. The workflow effectively combines information on individual torsion angles and then eliminates the combinations that are too high in energy to be found in the solid state, reducing the resources needed to cover the solid-state conformational space of a molecule. This provides insights into how the low-energy solid-state and isolated-molecule conformations are related to the properties of the individual flexible torsion angles.
Collapse
Affiliation(s)
- Luca Iuzzolino
- Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, England
| | - Anthony M Reilly
- The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England
| | - Patrick McCabe
- The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England
| | - Sarah L Price
- Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, England
| |
Collapse
|
34
|
Yang Y, Rice B, Shi X, Brandt JR, Correa da Costa R, Hedley GJ, Smilgies DM, Frost JM, Samuel IDW, Otero-de-la-Roza A, Johnson ER, Jelfs KE, Nelson J, Campbell AJ, Fuchter MJ. Emergent Properties of an Organic Semiconductor Driven by its Molecular Chirality. ACS NANO 2017; 11:8329-8338. [PMID: 28696680 DOI: 10.1021/acsnano.7b03540] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chiral molecules exist as pairs of nonsuperimposable mirror images; a fundamental symmetry property vastly underexplored in organic electronic devices. Here, we show that organic field-effect transistors (OFETs) made from the helically chiral molecule 1-aza[6]helicene can display up to an 80-fold difference in hole mobility, together with differences in thin-film photophysics and morphology, solely depending on whether a single handedness or a 1:1 mixture of left- and right-handed molecules is employed under analogous fabrication conditions. As the molecular properties of either mirror image isomer are identical, these changes must be a result of the different bulk packing induced by chiral composition. Such underlying structures are investigated using crystal structure prediction, a computational methodology rarely applied to molecular materials, and linked to the difference in charge transport. These results illustrate that chirality may be used as a key tuning parameter in future device applications.
Collapse
Affiliation(s)
| | | | | | | | - Rosenildo Correa da Costa
- Faculty of Computing, Engineering and Science, University of South Wales , Cemetery Road, Glyntaff, Pontypridd CF37 4BD, United Kingdom
| | - Gordon J Hedley
- University of St. Andrews , North Haugh, Fife KY16 9SS, United Kingdom
| | - Detlef-M Smilgies
- Cornell High Energy Synchrotron Source (CHESS), Wilson Laboratory, Cornell University , Ithaca, New York 14853, United States
| | - Jarvist M Frost
- Department of Chemistry, University of Bath , Bath BA2 7AY, United Kingdom
- Department of Materials, Imperial College London , London SW7 2AZ, United Kingdom
| | - Ifor D W Samuel
- University of St. Andrews , North Haugh, Fife KY16 9SS, United Kingdom
| | - Alberto Otero-de-la-Roza
- Department of Chemistry, University of British Columbia, Okanagan , 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | | | | | | | | |
Collapse
|
35
|
Braun DE, Kahlenberg V, Griesser UJ. Experimental and Computational Hydrate Screening: Cytosine, 5-Flucytosine and Their Solid Solution. CRYSTAL GROWTH & DESIGN 2017; 17:4347-4364. [PMID: 30344452 PMCID: PMC6193535 DOI: 10.1021/acs.cgd.7b00664] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The structural, temperature- and moisture dependent stability features of cytosine and 5-flucytosine monohydrates, two pharmaceutically important compounds, were rationalized using complementary experimental and computational approaches. Moisture sorption/desorption, water activity, thermal analysis and calorimetry were applied to determine the stability ranges of hydrate ↔ anhydrate systems, while X-ray diffraction, IR spectroscopy and crystal structure prediction provided the molecular level understanding. At 25 °C, the critical water activity for the cytosine hydrate ↔ anhydrate system is ~0.43 and for 5-flucytosine ~0.41. In 5-flucytosine the water molecules are arranged in open channels, therefore the kinetic desorption data, dehydration < 40% relative humidity (RH), conform with the thermodynamic data, whereas for the cytosine isolated site hydrate dehydration was observed at RH < 15%. Peritectic dissociation temperatures of the hydrates were measured to be 97 °C and 84.2 °C for cytosine and 5-flucytosine, respectively, and the monohydrate to anhydrate transition enthalpies to be around 10 kJ mol-1. Computed crystal energy landscapes not only revealed that the substitution of C5 (H or F) controls the packing and properties of cytosine/5-flucytosine solid forms, but also have enabled the finding of a monohydrate solid solution of the two substances which shows increased thermal- and moisture-dependent stability compared to 5-flucytosine monohydrate.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Volker Kahlenberg
- Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
36
|
Braun DE, Griesser UJ. Prediction and experimental validation of solid solutions and isopolymorphs of cytosine/5-flucytosine. CrystEngComm 2017; 19:3566-3572. [PMID: 30405321 PMCID: PMC6218006 DOI: 10.1039/c7ce00939a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
A computational search for polymorphs of cytosine, 5-flucytosine and a 1 : 1 mixture of the two substances not only rationalised the preferred packing arrangements but also enabled the finding and characterisation of cytosine/5-flucytosine solid solutions. The structures of the new solid forms were determined by combining laboratory powder X-ray diffraction data and computational modelling.
Collapse
Affiliation(s)
| | - U. J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
37
|
Sugden I, Adjiman CS, Pantelides CC. Accurate and efficient representation of intramolecular energy in ab initio generation of crystal structures. I. Adaptive local approximate models. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2016; 72:864-874. [PMID: 27910837 PMCID: PMC5134761 DOI: 10.1107/s2052520616015122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/26/2016] [Indexed: 05/14/2023]
Abstract
The global search stage of crystal structure prediction (CSP) methods requires a fine balance between accuracy and computational cost, particularly for the study of large flexible molecules. A major improvement in the accuracy and cost of the intramolecular energy function used in the CrystalPredictor II [Habgood et al. (2015). J. Chem. Theory Comput. 11, 1957-1969] program is presented, where the most efficient use of computational effort is ensured via the use of adaptive local approximate model (LAM) placement. The entire search space of the relevant molecule's conformations is initially evaluated using a coarse, low accuracy grid. Additional LAM points are then placed at appropriate points determined via an automated process, aiming to minimize the computational effort expended in high-energy regions whilst maximizing the accuracy in low-energy regions. As the size, complexity and flexibility of molecules increase, the reduction in computational cost becomes marked. This improvement is illustrated with energy calculations for benzoic acid and the ROY molecule, and a CSP study of molecule (XXVI) from the sixth blind test [Reilly et al. (2016). Acta Cryst. B72, 439-459], which is challenging due to its size and flexibility. Its known experimental form is successfully predicted as the global minimum. The computational cost of the study is tractable without the need to make unphysical simplifying assumptions.
Collapse
Affiliation(s)
- Isaac Sugden
- Molecular Systems Engineering Group Centre for Process Systems Engineering Department of Chemical Engineering, Imperial College London, London SW7 2AZ, England
| | - Claire S. Adjiman
- Molecular Systems Engineering Group Centre for Process Systems Engineering Department of Chemical Engineering, Imperial College London, London SW7 2AZ, England
| | - Constantinos C. Pantelides
- Molecular Systems Engineering Group Centre for Process Systems Engineering Department of Chemical Engineering, Imperial College London, London SW7 2AZ, England
| |
Collapse
|
38
|
Braun DE, Griesser UJ. Why do Hydrates (Solvates) Form in Small Neutral Organic Molecules? Exploring the Crystal Form Landscapes of the Alkaloids Brucine and Strychnine. CRYSTAL GROWTH & DESIGN 2016; 16:6405-6418. [PMID: 28670205 PMCID: PMC5486441 DOI: 10.1021/acs.cgd.6b01078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Computational methods were used to generate and explore the crystal structure landscapes of the two alkaloids strychnine and brucine. The computed structures were analyzed and rationalized by correlating the modelling results to a rich pool of available experimental data. Despite their structural similarity, the two compounds show marked differences in the formation of solid forms. For strychnine only one anhydrous form is reported in the literature and two new solvates from 1,4-dioxane were detected in the course of this work. In contrast, 22 solid forms are so far known to exist for brucine, comprising two anhydrates, four hydrates (HyA - HyC and a 5.25-hydrate), twelve solvates (alcohols and acetone) and four heterosolvates (mixed solvates with water and alcohols). For strychnine it is hard to produce any solid form other than the stable anhydrate while the formation of specific solid state forms of brucine is governed by a complex interplay between temperature and relative humidity/water activity and it is rather a challenging to avoid hydrate formation. Differences in crystal packing and the high tendency for brucine to form hydrates are not intuitive from the molecular structure alone, as both molecules have hydrogen bond acceptor groups but lack hydrogen bond donor groups. Only the evaluation of the crystal energy landscapes, in particular the close-packed crystal structures and high-energy open frameworks containing voids of molecular (water) dimensions, allowed us to unravel the diverse solid state behavior of the two alkaloids at a molecular level. In this study we demonstrate that expanding the analysis of anhydrate crystal energy landscapes to higher energy structures and calculating the solvent-accessible volume can be used to estimate non-stoichiometric or channel hydrate (solvate) formation, without explicitly computing the hydrate/solvate crystal energy landscapes.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
39
|
Elking DM, Fusti-Molnar L, Nichols A. Crystal structure prediction of rigid molecules. ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE CRYSTAL ENGINEERING AND MATERIALS 2016; 72:488-501. [DOI: 10.1107/s2052520616010118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/21/2016] [Indexed: 11/11/2022]
Abstract
A non-polarizable force field based on atomic multipoles fit to reproduce experimental crystal properties andab initiogas-phase dimers is described. The Ewald method is used to calculate both long-range electrostatic and 1/r6dispersion energies of crystals. The dispersion energy of a crystal calculated by a cutoff method is shown to converge slowly to the exact Ewald result. A method for constraining space-group symmetry during unit-cell optimization is derived. Results for locally optimizing 4427 unit cells including volume, cell parameters, unit-cell r.m.s.d. and CPU timings are given for both flexible and rigid molecule optimization. An algorithm for randomly generating rigid molecule crystals is described. Using the correct experimentally determined space group, the average and maximum number of random crystals needed to find the correct experimental structure is given for 2440 rigid single component crystals. The force field energy rank of the correct experimental structure is presented for the same set of 2440 rigid single component crystals assuming the correct space group. A complete crystal prediction is performed for two rigid molecules by searching over the 32 most probable space groups.
Collapse
|
40
|
Brandenburg JG, Grimme S. Organic crystal polymorphism: a benchmark for dispersion-corrected mean-field electronic structure methods. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2016; 72:502-513. [PMID: 27484372 DOI: 10.1107/s2052520616007885] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/13/2016] [Indexed: 06/06/2023]
Abstract
We analyze the energy landscape of the sixth crystal structure prediction blind test targets with various first principles and semi-empirical quantum chemical methodologies. A new benchmark set of 59 crystal structures (termed POLY59) for testing quantum chemical methods based on the blind test target crystals is presented. We focus on different means to include London dispersion interactions within the density functional theory (DFT) framework. We show the impact of pairwise dispersion corrections like the semi-empirical D2 scheme, the Tkatchenko-Scheffler (TS) method, and the density-dependent dispersion correction dDsC. Recent methodological progress includes higher-order contributions in both the many-body and multipole expansions. We use the D3 correction with Axilrod-Teller-Muto type three-body contribution, the TS based many-body dispersion (MBD), and the nonlocal van der Waals density functional (vdW-DF2). The density functionals with D3 and MBD correction provide an energy ranking of the blind test polymorphs in excellent agreement with the experimentally found structures. As a computationally less demanding method, we test our recently presented minimal basis Hartree-Fock method (HF-3c) and a density functional tight-binding Hamiltonian (DFTB). Considering the speed-up of three to four orders of magnitudes, the energy ranking provided by the low-cost methods is very reasonable. We compare the computed geometries with the corresponding X-ray data where TPSS-D3 performs best. The importance of zero-point vibrational energy and thermal effects on crystal densities is highlighted.
Collapse
Affiliation(s)
- Jan Gerit Brandenburg
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4-6, 53115 Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4-6, 53115 Bonn, Germany
| |
Collapse
|
41
|
Braun DE, Oberacher H, Arnhard K, Orlova M, Griesser UJ. 4-Aminoquinaldine monohydrate polymorphism: Prediction and impurity aided discovery of a difficult to access stable form. CrystEngComm 2016; 18:4053-4067. [PMID: 28649176 PMCID: PMC5482396 DOI: 10.1039/c5ce01758k] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Crystal structure prediction studies indicated the existence of an unknown high density monohydrate structure (Hy1B°) as global energy minimum for 4-aminoquinaldine (4-AQ). We thus performed an interdisciplinary experimental and computational study elucidating the crystal structures, solid form inter-relationships, kinetic and thermodynamic stabilities of the stable anhydrate (AH I°), the kinetic monohydrate (Hy1A ) and this novel monohydrate polymorph (Hy1B°) of 4-AQ. The crystal structure of Hy1B° was determined by combining laboratory powder X-ray diffraction data and ab initio calculations. Dehydration studies with differential scanning calorimetry and solubility measurements confirmed the result of the lattice energy calculations, which identified Hy1B° as the thermodynamically most stable hydrate form. At 25 °C the equilibrium of the 4-AQ hydrate/anhydrate system was observed at an aw (water activity) of 0.14. The finding of Hy1B° was complicated by the fact that the metastable but kinetically stable Hy1A shows a higher nucleation and growth rate. The presence of an impurity in an available 4-AQ sample facilitated the nucleation of Hy1B°, whose crystallisation is favored under hydrothermal conditions. The value of combining experimental with theoretical studies in hydrate screening and characterisation, as well as the reasons for hydrate formation in 4-AQ, are discussed.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Herbert Oberacher
- Institute of Legal Medicine, Innsbruck Medical University, Muellerstr. 44, 6020 Innsbruck, Austria
| | - Kathrin Arnhard
- Institute of Legal Medicine, Innsbruck Medical University, Muellerstr. 44, 6020 Innsbruck, Austria
| | - Maria Orlova
- Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
42
|
Braun DE, Gelbrich T, Wurst K, Griesser UJ. Computational and Experimental Characterization of Five Crystal Forms of Thymine: Packing Polymorphism, Polytypism/Disorder and Stoichiometric 0.8-Hydrate. CRYSTAL GROWTH & DESIGN 2016; 16:3480-3496. [PMID: 28663717 PMCID: PMC5486440 DOI: 10.1021/acs.cgd.6b00459] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
New polymorphs of thymine emerged in an experimental search for solid forms, which was guided by the computationally generated crystal energy landscape. Three of the four anhydrates (AH) are homeoenergetic (A° - C) and their packing modes differ only in the location of oxygen and hydrogen atoms. AHs A° and B are ordered phases, whereas AH C shows disorder (X-ray diffuse scattering). Anhydrates AHs A° and B are ordered phases, whereas AH C shows disorder (X-ray diffuse scattering). Analysis of the crystal energy landscape for alternative AH C hydrogen bonded ribbon motifs identified a number of different packing modes, whose 3D structures were calculated to deviate by less than 0.24 kJ mol-1 in lattice energy. These structures provide models for stacking faults. The three anhydrates A° - C show strong similarity in their powder X-ray diffraction, thermoanalytical and spectroscopic (IR and Raman) characteristics. The already known anhydrate AH A° was identified as the thermodynamically most stable form at ambient conditions; AH B and AH C are metastable but show high kinetic stability. The hydrate of thymine is stable only at water activities (aw) > 0.95 at temperatures ≤ 25 °C. It was found to be a stoichiometric hydrate despite being a channel hydrate with an unusual water:thymine ratio of 0.8:1. Depending on the dehydration conditions, either AH C or AH D is obtained. The hydrate is the only known precursor to AH D. This study highlights the value and complementarity of simultaneous explorations of computationally and experimentally generated solid form landscapes of a small molecule anhydrate ↔ hydrate system.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Thomas Gelbrich
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
43
|
Abstract
Interest in molecular crystals has grown thanks to their relevance to pharmaceuticals, organic semiconductor materials, foods, and many other applications. Electronic structure methods have become an increasingly important tool for modeling molecular crystals and polymorphism. This article reviews electronic structure techniques used to model molecular crystals, including periodic density functional theory, periodic second-order Møller-Plesset perturbation theory, fragment-based electronic structure methods, and diffusion Monte Carlo. It also discusses the use of these models for predicting a variety of crystal properties that are relevant to the study of polymorphism, including lattice energies, structures, crystal structure prediction, polymorphism, phase diagrams, vibrational spectroscopies, and nuclear magnetic resonance spectroscopy. Finally, tools for analyzing crystal structures and intermolecular interactions are briefly discussed.
Collapse
Affiliation(s)
- Gregory J O Beran
- Department of Chemistry, University of California , Riverside, California 92521, United States
| |
Collapse
|
44
|
Braun DE, Nartowski KP, Khimyak YZ, Morris KR, Byrn SR, Griesser UJ. Structural Properties, Order-Disorder Phenomena, and Phase Stability of Orotic Acid Crystal Forms. Mol Pharm 2016; 13:1012-29. [PMID: 26741914 PMCID: PMC4783786 DOI: 10.1021/acs.molpharmaceut.5b00856] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Orotic acid (OTA) is reported to
exist in the anhydrous (AH), monohydrate
(Hy1), and dimethyl sulfoxide monosolvate (SDMSO) forms.
In this study we investigate the (de)hydration/desolvation behavior,
aiming at an understanding of the elusive structural features of anhydrous
OTA by a combination of experimental and computational techniques,
namely, thermal analytical methods, gravimetric moisture (de)sorption
studies, water activity measurements, X-ray powder diffraction, spectroscopy
(vibrational, solid-state NMR), crystal energy landscape, and chemical
shift calculations. The Hy1 is a highly stable hydrate, which dissociates
above 135 °C and loses only a small part of the water when stored
over desiccants (25 °C) for more than one year. In Hy1, orotic
acid and water molecules are linked by strong hydrogen bonds in nearly
perfectly planar arranged stacked layers. The layers are spaced by
3.1 Å and not linked via hydrogen bonds. Upon dehydration the
X-ray powder diffraction and solid-state NMR peaks become broader,
indicating some disorder in the anhydrous form. The Hy1 stacking reflection
(122) is maintained, suggesting that the OTA molecules are still arranged
in stacked layers in the dehydration product. Desolvation of SDMSO, a nonlayer structure, results in the same AH phase as
observed upon dehydrating Hy1. Depending on the desolvation conditions,
different levels of order–disorder of layers present in anhydrous
OTA are observed, which is also suggested by the computed low energy
crystal structures. These structures provide models for stacking faults
as intergrowth of different layers is possible. The variability in
anhydrate crystals is of practical concern as it affects the moisture
dependent stability of AH with respect to hydration.
Collapse
Affiliation(s)
- Doris E Braun
- Institute of Pharmacy, University of Innsbruck , Innrain 52c, 6020 Innsbruck, Austria
| | - Karol P Nartowski
- School of Pharmacy, University of East Anglia , Norwich, Norfolk NR4 7TJ, United Kingdom
| | - Yaroslav Z Khimyak
- School of Pharmacy, University of East Anglia , Norwich, Norfolk NR4 7TJ, United Kingdom
| | - Kenneth R Morris
- Lachman Institute for Pharmaceutical Analysis, Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University-Brooklyn Campus , 75 DeKalb Avenue, Brooklyn, New York 11201, United States
| | - Stephen R Byrn
- Department of Industrial and Physical Pharmacy, Purdue University , 575 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
| | - Ulrich J Griesser
- Institute of Pharmacy, University of Innsbruck , Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
45
|
Hylton RK, Tizzard GJ, Threlfall TL, Ellis AL, Coles SJ, Seaton CC, Schulze E, Lorenz H, Seidel-Morgenstern A, Stein M, Price SL. Are the Crystal Structures of Enantiopure and Racemic Mandelic Acids Determined by Kinetics or Thermodynamics? J Am Chem Soc 2015; 137:11095-104. [DOI: 10.1021/jacs.5b05938] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Rebecca K. Hylton
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Graham J. Tizzard
- Chemistry,
Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Terence L. Threlfall
- Chemistry,
Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Amy L. Ellis
- Chemistry,
Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Simon J. Coles
- Chemistry,
Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Colin C. Seaton
- School of
Chemical Engineering and Analytical Science, University of Manchester, The Mill, Oxford Road, Manchester M13 9PL, U.K
| | - Eric Schulze
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, D-39106 Magdeburg, Germany
| | - Heike Lorenz
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, D-39106 Magdeburg, Germany
| | - Andreas Seidel-Morgenstern
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, D-39106 Magdeburg, Germany
- Otto-von-Guericke-Universität, Chemische Verfahrenstechnik, D-39106 Magdeburg, Germany
| | - Matthias Stein
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, D-39106 Magdeburg, Germany
| | - Sarah L. Price
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| |
Collapse
|
46
|
Braun DE, Gelbrich T, Kahlenberg V, Griesser UJ. Solid state forms of 4-aminoquinaldine - From void structures with and without solvent inclusion to close packing. CrystEngComm 2015; 17:2504-2516. [PMID: 26726294 PMCID: PMC4693969 DOI: 10.1039/c5ce00118h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Polymorphs of 4-aminoquinaldine (4-AQ) have been predicted in silico and experimentally identified and characterised. The two metastable forms, AH (anhydrate) II and AH III, crystallise in the trigonal space group [Formula: see text] and are less densely packed than the thermodynamically most stable phase AH I° (P21/c ). AH II can crystallise and exist both, as a solvent inclusion compound and as an unsolvated phase. The third polymorph, AH III, is exclusively obtained by desolvation of a carbon tetrachloride solvate. Theoretical calculations correctly estimated the experimental 0K stability order, confirmed that AH II can exist without solvents, gave access to the AH III structure, and identified that there exists a subtle balance between close packing and number of hydrogen bonding interactions in the solid state of anhydrous 4-AQ. Furthermore, the prevalence of void space and solvent inclusion in [Formula: see text] structures is discussed.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Thomas Gelbrich
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Volker Kahlenberg
- Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| |
Collapse
|
47
|
Habgood M, Sugden IJ, Kazantsev AV, Adjiman CS, Pantelides CC. Efficient Handling of Molecular Flexibility in Ab Initio Generation of Crystal Structures. J Chem Theory Comput 2015; 11:1957-69. [DOI: 10.1021/ct500621v] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Matthew Habgood
- Molecular Systems Engineering
Group, Centre for Process Systems Engineering, Department of Chemical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Isaac J. Sugden
- Molecular Systems Engineering
Group, Centre for Process Systems Engineering, Department of Chemical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Andrei V. Kazantsev
- Molecular Systems Engineering
Group, Centre for Process Systems Engineering, Department of Chemical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Claire S. Adjiman
- Molecular Systems Engineering
Group, Centre for Process Systems Engineering, Department of Chemical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Constantinos C. Pantelides
- Molecular Systems Engineering
Group, Centre for Process Systems Engineering, Department of Chemical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| |
Collapse
|
48
|
Vasileiadis M, Pantelides CC, Adjiman CS. Prediction of the crystal structures of axitinib, a polymorphic pharmaceutical molecule. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.08.058] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
49
|
Uzoh OG, Galek PTA, Price SL. Analysis of the conformational profiles of fenamates shows route towards novel, higher accuracy, force-fields for pharmaceuticals. Phys Chem Chem Phys 2015; 17:7936-48. [DOI: 10.1039/c4cp05525j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conformational barriers of the fenamates which lead to conformational polymorphism can be represented by a novel, physically motivated, model intramolecular potential suitable for extension to other pharmaceuticals.
Collapse
Affiliation(s)
- Ogaga G. Uzoh
- Department of Chemistry
- University College London
- London
- UK
| | | | - Sarah L. Price
- Department of Chemistry
- University College London
- London
- UK
| |
Collapse
|
50
|
Braun DE, Orlova M, Griesser U. Creatine: Polymorphs Predicted and Found. CRYSTAL GROWTH & DESIGN 2014; 14:4895-4900. [PMID: 26722225 PMCID: PMC4693963 DOI: 10.1021/cg501159c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hydrate and anhydrate crystal structure prediction (CSP) of creatine (CTN), a heavily used, badly water soluble, zwitterionic compound, has enabled the finding and characterization of its anhydrate polymorphs, including the thermodynamic room temperature form. Crystal structures of the novel forms were determined by combining laboratory powder X-ray diffraction data and ab initio generated structures. The computational method not only revealed all experimental forms but predicted the correct stability order, which was experimentally confirmed by measurements of the heat of hydration.
Collapse
Affiliation(s)
- Doris E. Braun
- Institute of Pharmacy and Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
- Tel: +43(0)512 507 58653; E-mail:
| | - Maria Orlova
- Institute of Pharmacy and Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich
J. Griesser
- Institute of Pharmacy and Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| |
Collapse
|