1
|
Erastova V, Evans IR, Glossop WN, Guryel S, Hodgkinson P, Kerr HE, Oganesyan VS, Softley LK, Wickins HM, Wilson MR. Unravelling Guest Dynamics in Crystalline Molecular Organics Using 2H Solid-State NMR and Molecular Dynamics Simulation. J Am Chem Soc 2024. [PMID: 38935813 DOI: 10.1021/jacs.4c03246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
2H solid-state NMR and atomistic molecular dynamics (MD) simulations are used to understand the disorder of guest solvent molecules in two cocrystal solvates of the pharmaceutical furosemide. Traditional approaches to interpreting the NMR data fail to provide a coherent model of molecular behavior and indeed give misleading kinetic data. In contrast, the direct prediction of the NMR properties from MD simulation trajectories allows the NMR data to be correctly interpreted in terms of combined jump-type and libration-type motions. Time-independent component analysis of the MD trajectories provides additional insights, particularly for motions that are invisible to NMR. This allows a coherent picture of the dynamics of molecules restricted in molecular-sized cavities to be determined.
Collapse
Affiliation(s)
- Valentina Erastova
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
- Department of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Ivana R Evans
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - William N Glossop
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - Songül Guryel
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - Hannah E Kerr
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | | | - Lorna K Softley
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - Helen M Wickins
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| | - Mark R Wilson
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K
| |
Collapse
|
2
|
Szell PMJ, Rehman Z, Tatman BP, Hughes LP, Blade H, Brown SP. Exploring the Potential of Multinuclear Solid-State 1 H, 13 C, and 35 Cl Magnetic Resonance To Characterize Static and Dynamic Disorder in Pharmaceutical Hydrochlorides. Chemphyschem 2023; 24:e202200558. [PMID: 36195553 PMCID: PMC10099218 DOI: 10.1002/cphc.202200558] [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: 07/28/2022] [Revised: 09/30/2022] [Indexed: 02/04/2023]
Abstract
Crystallographic disorder, whether static or dynamic, can be detrimental to the physical and chemical stability, ease of crystallization and dissolution rate of an active pharmaceutical ingredient. Disorder can result in a loss of manufacturing control leading to batch-to-batch variability and can lengthen the process of structural characterization. The range of NMR active nuclei makes solid-state NMR a unique technique for gaining nucleus-specific information about crystallographic disorder. Here, we explore the use of high-field 35 Cl solid-state NMR at 23.5 T to characterize both static and dynamic crystallographic disorder: specifically, dynamic disorder occurring in duloxetine hydrochloride (1), static disorder in promethazine hydrochloride (2), and trifluoperazine dihydrochloride (3). In all structures, the presence of crystallographic disorder was confirmed by 13 C cross-polarization magic-angle spinning (CPMAS) NMR and supported by GIPAW-DFT calculations, and in the case of 3, 1 H solid-state NMR provided additional confirmation. Applying 35 Cl solid-state NMR to these compounds, we show that higher magnetic fields are beneficial for resolving the crystallographic disorder in 1 and 3, while broad spectral features were observed in 2 even at higher fields. Combining the data obtained from 1 H, 13 C, and 35 Cl NMR, we show that 3 exhibits a unique case of disorder involving the + N-H hydrogen positions of the piperazinium ring, driving the chloride anions to occupy three distinct sites.
Collapse
Affiliation(s)
| | - Zainab Rehman
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Ben P Tatman
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Leslie P Hughes
- Oral Product Development Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Helen Blade
- Oral Product Development Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| |
Collapse
|
3
|
Al-Ani A, Szell PMJ, Rehman Z, Blade H, Wheatcroft HP, Hughes LP, Brown SP, Wilson CC. Combining X-ray and NMR Crystallography to Explore the Crystallographic Disorder in Salbutamol Oxalate. CRYSTAL GROWTH & DESIGN 2022; 22:4696-4707. [PMID: 35971412 PMCID: PMC9374327 DOI: 10.1021/acs.cgd.1c01093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Salbutamol is an active pharmaceutical ingredient commonly used to treat respiratory distress and is listed by the World Health Organization as an essential medicine. Here, we establish the crystal structure of its oxalate form, salbutamol oxalate, and explore the nature of its crystallographic disorder by combined X-ray crystallography and 13C cross-polarization (CP) magic-angle spinning (MAS) solid-state NMR. The *C-OH chiral center of salbutamol (note that the crystal structures are a racemic mixture of the two enantiomers of salbutamol) is disordered over two positions, and the tert-butyl group is rotating rapidly, as revealed by 13C solid-state NMR. The impact of crystallization conditions on the disorder was investigated, finding variations in the occupancy ratio of the *C-OH chiral center between single crystals and a consistency across samples in the bulk powder. Overall, this work highlights the contrast between investigating crystallographic disorder by X-ray diffraction and solid-state NMR experiment, and gauge-including projector-augmented-wave (GIPAW) density functional theory (DFT) calculations, with their combined use, yielding an improved understanding of the nature of the crystallographic disorder between the local (i.e., as viewed by NMR) and longer-range periodic (i.e., as viewed by diffraction) scale.
Collapse
Affiliation(s)
- Aneesa
J. Al-Ani
- Centre
for Sustainable and Circular Technologies (CSCT), University of Bath, Claverton Down, Bath BA2
7AY, U.K.
| | | | - Zainab Rehman
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
| | - Helen Blade
- Oral
Product Development, Pharmaceutical Technology & Development,
Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Helen P. Wheatcroft
- Chemical
Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Leslie P. Hughes
- Oral
Product Development, Pharmaceutical Technology & Development,
Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Steven P. Brown
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
| | - Chick C. Wilson
- Centre
for Sustainable and Circular Technologies (CSCT), University of Bath, Claverton Down, Bath BA2
7AY, U.K.
| |
Collapse
|
4
|
De Nicola A, Correa A, Bracco S, Perego J, Sozzani P, Comotti A, Milano G. Collective dynamics of molecular rotors in periodic mesoporous organosilica: a combined solid-state 2H-NMR and molecular dynamics simulation study. Phys Chem Chem Phys 2022; 24:666-673. [PMID: 34904981 DOI: 10.1039/d1cp05013c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular rotors offer a platform to realize controlled dynamics and modulate the functions of solids. The motional mechanisms in arrays of rotors have not been explored in depth. Crystal-like porous organosilicas, comprising p-phenylene rotators pivoted onto a siloxane scaffold, were modelled using molecular dynamics (MD) simulations. Long simulations, on a microsecond scale, allowed to follow the reorientation statistics of rotor collections and single out group configurations and frequency distributions as a function of temperature. The motions observed in the MD simulations support a multiple-site model for rotor reorientations. Computed motional frequencies revealed a complex rotatory phenomenon combining an ultra-fast libration motion (oscillation up to 30°) with a slow and fast 180° flip reorientation. Adopting a multiple-site model provides a more accurate simulation of the 2H-NMR spectra and a rationalization of their temperature dependence. In particular, rotators endowed with distinct rates could be explained by the presence of slower rings locked in a T-shaped conformation.
Collapse
Affiliation(s)
- Antonio De Nicola
- Scuola Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy.
| | - Andrea Correa
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, Complesso Monte S. Angelo, 80126, Napoli, Italy
| | - Silvia Bracco
- Department of Materials Science, University of Milano - Bicocca, Via R. Cozzi 55, 20125, Milano, Italy.
| | - Jacopo Perego
- Department of Materials Science, University of Milano - Bicocca, Via R. Cozzi 55, 20125, Milano, Italy.
| | - Piero Sozzani
- Department of Materials Science, University of Milano - Bicocca, Via R. Cozzi 55, 20125, Milano, Italy.
| | - Angiolina Comotti
- Department of Materials Science, University of Milano - Bicocca, Via R. Cozzi 55, 20125, Milano, Italy.
| | - Giuseppe Milano
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naploli, Italy
| |
Collapse
|
5
|
Liepuoniute I, Jellen MJ, Garcia-Garibay MA. Correlated motion and mechanical gearing in amphidynamic crystalline molecular machines. Chem Sci 2020; 11:12994-13007. [PMID: 34094484 PMCID: PMC8163207 DOI: 10.1039/d0sc04495d] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 10/15/2020] [Indexed: 12/21/2022] Open
Abstract
In this review we highlight the recent efforts towards the development of molecular gears with an emphasis on building molecular gears in the solid state and the role that molecular gearing and correlated motions may play in the function of crystalline molecular machines. We discuss current molecular and crystal engineering strategies, challenges associated with engineering correlated motion in crystals, and outline experimental and theoretical tools to explore gearing dynamics while highlighting key advances made to date.
Collapse
Affiliation(s)
- Ieva Liepuoniute
- Department of Chemistry and Biochemistry, University of California Los Angeles CA 90095-1569 USA
| | - Marcus J Jellen
- Department of Chemistry and Biochemistry, University of California Los Angeles CA 90095-1569 USA
| | - Miguel A Garcia-Garibay
- Department of Chemistry and Biochemistry, University of California Los Angeles CA 90095-1569 USA
| |
Collapse
|
6
|
Rodríguez-Fortea A, Canadell E, Wzietek P, Lemouchi C, Allain M, Zorina L, Batail P. Nanoscale rotational dynamics of four independent rotators confined in crowded crystalline layers. NANOSCALE 2020; 12:8294-8302. [PMID: 32236227 DOI: 10.1039/d0nr00858c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report a study where Car-Parrinello molecular dynamics simulations and variable-temperature (30-300 K) 1H spin-lattice relaxation time experiments nicely complement each other to characterize the dynamics within a set of four crystalline 1,4-diethynylbicyclo[2.2.2]octane (BCO) rotors assembled in the metal-organic rotor, {Li+4(-CO2-Ph-BCO-py)4(H2O)8}·2DMF. The remarkable finding of this work is that, despite the individual rotational barriers of four rotors being indiscernible and superimposed in a broad relaxation process, we were able to unravel a strongly interrelated series of rotational motions involving disrotatory and conrotatory motions in pairs as well as rotational steps of single rotators, all three processes with similar, sizeable rotational barriers of 6 kcal mol-1. It is noteworthy that DFT molecular dynamics simulations and variable-temperature (30-300 K) proton spin-lattice relaxation time experiments deliver the same high value for the rotational barriers stressing the potential of the combined use of the two techniques in understanding rotational motion at the nanoscale.
Collapse
Affiliation(s)
- Antonio Rodríguez-Fortea
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel.lí Domingo 1, 43007 Tarragona, Spain. antonio.rodriguezf@urv
| | | | | | | | | | | | | |
Collapse
|
7
|
Ashbrook SE, Hodgkinson P. Perspective: Current advances in solid-state NMR spectroscopy. J Chem Phys 2018; 149:040901. [PMID: 30068173 DOI: 10.1063/1.5038547] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In contrast to the rapid and revolutionary impact of solution-state Nuclear Magnetic Resonance (NMR) on modern chemistry, the field of solid-state NMR has matured more slowly. This reflects the major technical challenges of much reduced spectral resolution and sensitivity in solid-state as compared to solution-state spectra, as well as the relative complexity of the solid state. In this perspective, we outline the technique developments that have pushed resolution to intrinsic limits and the approaches, including ongoing major developments in the field of Dynamic Nuclear Polarisation, that have enhanced spectral sensitivity. The information on local structure and dynamics that can be obtained using these gains in sensitivity and resolution is illustrated with a diverse range of examples from large biomolecules to energy materials and pharmaceuticals and from both ordered and highly disordered materials. We discuss how parallel developments in quantum chemical calculation, particularly density functional theory, have enabled experimental data to be translated directly into information on local structure and dynamics, giving rise to the developing field of "NMR crystallography."
Collapse
Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Paul Hodgkinson
- Department of Chemistry, Durham University, Durham DH1 4RD, United Kingdom
| |
Collapse
|
8
|
Moran RF, Dawson DM, Ashbrook SE. Exploiting NMR spectroscopy for the study of disorder in solids. INT REV PHYS CHEM 2017. [DOI: 10.1080/0144235x.2017.1256604] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Robert F. Moran
- School of Chemistry, EaStCHEM and St Andrews Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Daniel M. Dawson
- School of Chemistry, EaStCHEM and St Andrews Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Sharon E. Ashbrook
- School of Chemistry, EaStCHEM and St Andrews Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| |
Collapse
|
9
|
Colombo V, Presti LL, Gavezzotti A. Two-component organic crystals without hydrogen bonding: structure and intermolecular interactions in bimolecular stacking. CrystEngComm 2017. [DOI: 10.1039/c7ce00311k] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
10
|
Sarkar S, Row TNG. A heuristic approach to evaluate peri interactions versus intermolecular interactions in an overcrowded naphthalene. IUCRJ 2017; 4:37-49. [PMID: 28250940 PMCID: PMC5331464 DOI: 10.1107/s205225251601808x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/10/2016] [Indexed: 05/14/2023]
Abstract
Octachloronaphthalene (OCN), a serious environmental pollutant, has been investigated by charge density analysis to unravel several unexplored factors responsible for steric overcrowding. The topological features of the enigmatic peri interactions contributing to steric overcrowding are qualified and quantified from experimental and theoretical charge-density studies. A new facet in the fundamental understanding of peri interactions is revealed by NCI (non-covalent interaction) analysis. The potential role of these interactions in deforming the molecular geometry and subsequent effect on aromaticity are substantiated from NICS (Nuclear Independent Chemical Shift) and QTAIM (Quantum Theory of Atoms in Molecules) calculations. The eye-catching dissimilarity in the out-of-plane twisting of OCN renders the molecule in an asymmetric geometry in the crystalline phase compared with symmetric geometry in the optimized solvated phase. This is uniquely characterized by their molecular electrostatic potential (MESP), respectively, and is explained in terms of conflict between two opposing forces - peri interactions, and symbiotic intermolecular Cl⋯Cl and Cl⋯π contacts.
Collapse
Affiliation(s)
- Sounak Sarkar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, C. V. Raman Avenue, Bangalore, Karnataka 560012, India
| | - Tayur N. Guru Row
- Solid State and Structural Chemistry Unit, Indian Institute of Science, C. V. Raman Avenue, Bangalore, Karnataka 560012, India
| |
Collapse
|
11
|
Abraham A, Apperley DC, Byard SJ, Ilott AJ, Robbins AJ, Zorin V, Harris RK, Hodgkinson P. Characterising the role of water in sildenafil citrate by NMR crystallography. CrystEngComm 2016. [DOI: 10.1039/c5ce02234g] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A combination of solid-state NMR techniques, including 13C/1H correlation, 2H magic-angle spinning NMR and first principles calculation are employed to characterise the role of water in different hydration states of sildenafil citrate.
Collapse
Affiliation(s)
- Anuji Abraham
- Department of Chemistry
- University of Durham
- Durham DH1 3LE, UK
| | | | | | - Andrew J. Ilott
- Department of Chemistry
- University of Durham
- Durham DH1 3LE, UK
| | | | - Vadim Zorin
- Department of Chemistry
- University of Durham
- Durham DH1 3LE, UK
| | - Robin K. Harris
- Department of Chemistry
- University of Durham
- Durham DH1 3LE, UK
| | - Paul Hodgkinson
- Department of Chemistry
- University of Durham
- Durham DH1 3LE, UK
| |
Collapse
|
12
|
|
13
|
Owens AR, Saunders GC, Thomas HP, Wehr-Candler TT. Solvent-free mechanochemical syntheses and reactions of π–π stacked arene–perfluoroarene co-crystals. J Fluor Chem 2015. [DOI: 10.1016/j.jfluchem.2015.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
14
|
Yi H, Albrecht M, Valkonen A, Rissanen K. Perfluoro-1,1′-biphenyl and perfluoronaphthalene and their derivatives as π-acceptors for anions. NEW J CHEM 2015. [DOI: 10.1039/c4nj01654h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Perfluoro-1,1′-biphenyl and perfluoronaphthalene are identified experimentally as π-acceptors for anions by studying the parent systems as well as cationic derivatives.
Collapse
Affiliation(s)
- Hai Yi
- Institut für Organische Chemie
- RWTH Aachen
- 52074 Aachen
- Germany
| | - Markus Albrecht
- Institut für Organische Chemie
- RWTH Aachen
- 52074 Aachen
- Germany
| | - Arto Valkonen
- Department of Chemistry
- Nanoscience Center
- University of Jyväskylä
- 40014 Jyväskylä
- Finland
| | - Kari Rissanen
- Department of Chemistry
- Nanoscience Center
- University of Jyväskylä
- 40014 Jyväskylä
- Finland
| |
Collapse
|
15
|
Ilott AJ, Palucha S, Hodgkinson P, Wilson MR. Well-tempered metadynamics as a tool for characterizing multi-component, crystalline molecular machines. J Phys Chem B 2013; 117:12286-95. [PMID: 24028495 DOI: 10.1021/jp4045995] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The well-tempered, smoothly converging form of the metadynamics algorithm has been implemented in classical molecular dynamics simulations and used to obtain an estimate of the free energy surface explored by the molecular rotations in the plastic crystal, octafluoronaphthalene. The biased simulations explore the full energy surface extremely efficiently, more than 4 orders of magnitude faster than unbiased molecular dynamics runs. The metadynamics collective variables used have also been expanded to include the simultaneous orientations of three neighboring octafluoronaphthalene molecules. Analysis of the resultant three-dimensional free energy surface, which is sampled to a very high degree despite its significant complexity, demonstrates that there are strong correlations between the molecular orientations. Although this correlated motion is of limited applicability in terms of exploiting dynamical motion in octafluoronaphthalene, the approach used is extremely well suited to the investigation of the function of crystalline molecular machines.
Collapse
Affiliation(s)
- Andrew J Ilott
- Department of Chemistry, University of Durham , South Road, Durham, U.K. DH1 3LE
| | | | | | | |
Collapse
|
16
|
Saunders GC, Wehr-Candler TT. Solvent-free mechanochemical synthesis of π–π stacked arene–perfluoroarene co-crystals. J Fluor Chem 2013. [DOI: 10.1016/j.jfluchem.2013.05.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
17
|
Apperley DC, Markwell AF, Frantsuzov I, Ilott AJ, Harris RK, Hodgkinson P. NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate. Phys Chem Chem Phys 2013; 15:6422-30. [DOI: 10.1039/c3cp50180a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
18
|
Dračínský M, Hodgkinson P. A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters. CrystEngComm 2013. [DOI: 10.1039/c3ce40612a] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
19
|
Rossini AJ, Zagdoun A, Hegner F, Schwarzwälder M, Gajan D, Copéret C, Lesage A, Emsley L. Dynamic nuclear polarization NMR spectroscopy of microcrystalline solids. J Am Chem Soc 2012; 134:16899-908. [PMID: 22967206 DOI: 10.1021/ja308135r] [Citation(s) in RCA: 192] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dynamic nuclear polarization (DNP) solid-state NMR has been applied to powdered microcrystalline solids to obtain sensitivity enhancements on the order of 100. Glucose, sulfathiazole, and paracetamol were impregnated with bis-nitroxide biradical (bis-cyclohexyl-TEMPO-bisketal, bCTbK) solutions of organic solvents. The organic solvents were carefully chosen to be nonsolvents for the compounds, so that DNP-enhanced solid-state NMR spectra of the unaltered solids could be acquired. A theoretical model is presented that illustrates that for externally doped organic solids characterized by long spin-lattice relaxation times (T(1)((1)H) > 200 s), (1)H-(1)H spin diffusion can relay enhanced polarization over micrometer length scales yielding substantial DNP enhancements (ε). ε on the order of 60 are obtained for microcrystalline glucose and sulfathiazole at 9.4 T and with temperatures of ca. 105 K. The large gain in sensitivity enables the rapid acquisition of (13)C-(13)C correlation spectra at natural isotopic abundance. It is anticipated that this will be a general method for enhancing the sensitivity of solid-state NMR experiments of organic solids.
Collapse
Affiliation(s)
- Aaron J Rossini
- Centre de RMN a Tres Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Dračínský M, Bouř P. Vibrational averaging of the chemical shift in crystalline α-glycine. J Comput Chem 2012; 33:1080-9. [PMID: 22410968 DOI: 10.1002/jcc.22940] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/04/2012] [Accepted: 01/04/2012] [Indexed: 11/06/2022]
Abstract
Averaging of the chemical shift over the molecular motion improves the simulated data and provides additional information about the temperature dependence and system dynamics. However, crystal modeling is difficult due to the limited precision of the plane-wave density functional theory (DFT) methods and approximate vibrational schemes. On the glycine example, we investigate how the averaging can be achieved within the periodic boundary conditions at the DFT level. The nuclear motion is modeled with the vibrational configuration interaction, with other simplified quantum anharmonic schemes, and the classical Born-Oppenheimer molecular dynamics (BOMD). The results confirm a large vibrational contribution to the isotropic shielding values. Both the first and second derivatives of the shielding were found important for the quantum averaging. The first derivatives influence the shielding mostly due to the anharmonic character of the CH and NH stretching modes, whereas second derivatives produce most vibrational corrections associated with the lower-frequency vibrational modes. Temperature excitations of the lowest-frequency vibrational states and the expansion of the crystal cell both determine the temperature dependence of nuclear magnetic resonance parameters. The vibrational quantum approach as well as classical BOMD schemes provided temperature dependencies of the chemical shifts that are consistent with the previous experimental data.
Collapse
Affiliation(s)
- Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, Prague 166 10, Czech Republic.
| | | |
Collapse
|
21
|
Kuprusevicius E, Edge R, Gopee H, Cammidge AN, McInnes EJL, Wilson MR, Oganesyan VS. Prediction of EPR Spectra of Liquid Crystals with Doped Spin Probes from Fully Atomistic Molecular Dynamics Simulations: Exploring Molecular Order and Dynamics at the Phase Transition. Chemistry 2010; 16:11558-62. [DOI: 10.1002/chem.201001439] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Indexed: 11/10/2022]
|