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Crystal size, shape, and conformational changes drive both the disappearance and reappearance of ritonavir polymorphs in the mill. (2024)
Journal Article
Sacchi, P., Wright, S. E., Neoptolemou, P., Lampronti, G. I., Rajagopalan, A. K., Kras, W., …Cruz-Cabeza, A. J. (2024). Crystal size, shape, and conformational changes drive both the disappearance and reappearance of ritonavir polymorphs in the mill. Proceedings of the National Academy of Sciences, 121(15), Article e2319127121. https://doi.org/10.1073/pnas.2319127121

Organic compounds can crystallize in different forms known as polymorphs. Discovery and control of polymorphism is crucial to the pharmaceutical industry since different polymorphs can have significantly different physical properties which impacts th... Read More about Crystal size, shape, and conformational changes drive both the disappearance and reappearance of ritonavir polymorphs in the mill..

Revisiting the Van Vleck second moment for characterizing molecular motion in organic solids (2023)
Journal Article
Sturniolo, S., Wickins, H. M., & Hodgkinson, P. (2023). Revisiting the Van Vleck second moment for characterizing molecular motion in organic solids. The Journal of Chemical Physics, 158(24), https://doi.org/10.1063/5.0151022

Van Vleck’s classic theory of the second moment of lineshapes in 1H nuclear magnetic resonance (NMR) is reworked in a form that allows the effect of rapid molecular motion on second moments to be calculated in a semi-analytical fashion. This is much... Read More about Revisiting the Van Vleck second moment for characterizing molecular motion in organic solids.

A new avenue to relaxor-like ferroelectric behaviour found by probing the structure and dynamics of [NH3NH2]Mg(HCO2)3 (2023)
Journal Article
Hitchings, T. J., Wickins, H. M., Peat, G. U. L., Hodgkinson, P., Srivastava, A. K., Lu, T., …Saines, P. J. (2023). A new avenue to relaxor-like ferroelectric behaviour found by probing the structure and dynamics of [NH3NH2]Mg(HCO2)3. Journal of Materials Chemistry C Materials for optical and electronic devices, 11(28), 9695-9706. https://doi.org/10.1039/d3tc00480e

The field of relaxor ferroelectrics has long been dominated by ceramic oxide materials exhibiting large polarisations with temperature and frequency dependence. Intriguingly, the dense metal–organic framework (MOF) [NH3NH2]Mg(HCO2)3 was reported as o... Read More about A new avenue to relaxor-like ferroelectric behaviour found by probing the structure and dynamics of [NH3NH2]Mg(HCO2)3.

Structured ternary fluids as nanocrystal incubators for enhanced crystallization control (2022)
Journal Article
Maunder, J., Aguilar, J., Hodgkinson, P., & Cooper, S. (2022). Structured ternary fluids as nanocrystal incubators for enhanced crystallization control. Chemical Science, 13(44), 13132-13140. https://doi.org/10.1039/d2sc04413g

In crystallization from solution, a ubiquitous process in both industry and the natural world, nucleation is usually the rate-determining step, followed by faster crystal growth. Consequently, crystals typically exist in the nm-size range for such li... Read More about Structured ternary fluids as nanocrystal incubators for enhanced crystallization control.

Resolving alternative structure determinations of indapamide using 13C solid-state NMR​ (2022)
Journal Article
Evans, C. L., Evans, I. R., & Hodgkinson, P. (2022). Resolving alternative structure determinations of indapamide using 13C solid-state NMR​. Chemical Communications, 58(30), 4767-4770. https://doi.org/10.1039/d1cc06256e

The conflict between alternative crystal structures in the Cambridge Structural Database for the diuretic drug indapamide hemihydrate (IND) has been resolved with the aid of 13C solid-state NMR. IND is seen to contain multiple distinct molecules in t... Read More about Resolving alternative structure determinations of indapamide using 13C solid-state NMR​.

Characterization of crystalline and amorphous forms of irbesartan by multi-nuclear solid-state NMR (2022)
Journal Article
Skotnicki, M., & Hodgkinson, P. (2022). Characterization of crystalline and amorphous forms of irbesartan by multi-nuclear solid-state NMR. Solid State Nuclear Magnetic Resonance, 118, https://doi.org/10.1016/j.ssnmr.2022.101783

Irbesartan (IRB) is an antihypertensive drug which exhibits the rare phenomenon of desmotropy; its 1H- and 2H- tetrazole tautomers can be isolated as distinct crystalline forms. The crystalline forms of IRB are poorly soluble, hence the amorphous for... Read More about Characterization of crystalline and amorphous forms of irbesartan by multi-nuclear solid-state NMR.

A study of the dynamics and structure of the dielectric anomaly within the molecular solid TEA(TCNQ)2 (2022)
Journal Article
Berlie, A., Terry, I., Szablewski, M., Telling, M., Apperley, D., Hodgkinson, P., & Zeller, D. (2022). A study of the dynamics and structure of the dielectric anomaly within the molecular solid TEA(TCNQ)2. Physical Chemistry Chemical Physics, 24(12), 7481-7492. https://doi.org/10.1039/d2cp00142j

With rising interest in organic-based functional materials, it is important to understand the nature of magnetic and electrical transitions within these types of systems. One intriguing material is triethylammonium bis-7,7,8,8-tetracyanoquinodimethan... Read More about A study of the dynamics and structure of the dielectric anomaly within the molecular solid TEA(TCNQ)2.

Paramagnetic solid-state NMR assignment and novel chemical conversion of the aldehyde group to dihydrogen ortho ester and hemiacetal moieties in copper(ii)- and cobalt(ii)-pyridinecarboxaldehyde complexes (2021)
Journal Article
Crespi, A. F., Sánchez, V. M., Vega, D., Pérez, A. L., Brondino, C. D., Linck, Y. G., …Lázaro-Martínez, J. M. (2021). Paramagnetic solid-state NMR assignment and novel chemical conversion of the aldehyde group to dihydrogen ortho ester and hemiacetal moieties in copper(ii)- and cobalt(ii)-pyridinecarboxaldehyde complexes. RSC Advances, 11(33), 20216-20231. https://doi.org/10.1039/d1ra02512k

The complex chemical functionalization of aldehyde moieties in Cu(II)- and Co(II)-pyridinecarboxaldehyde complexes was studied. X-ray studies demonstrated that the aldehyde group (RCHO) of the four pyridine molecules is converted to dihydrogen ortho... Read More about Paramagnetic solid-state NMR assignment and novel chemical conversion of the aldehyde group to dihydrogen ortho ester and hemiacetal moieties in copper(ii)- and cobalt(ii)-pyridinecarboxaldehyde complexes.

Towards accurate predictions of proton NMR parameters in molecular solids (2020)
Journal Article
Dracinsky, M., Vícha, J., Bártová, K., & Hodgkinson, P. (2020). Towards accurate predictions of proton NMR parameters in molecular solids. ChemPhysChem, 21(18), 2075-2083. https://doi.org/10.1002/cphc.202000629

The factors contributing to the accuracy of quantum‐chemical calculations of proton NMR chemical shifts in molecular solids are systematically investigated. Proton chemical shifts of six solid amino acids with hydrogen atoms in various bonding enviro... Read More about Towards accurate predictions of proton NMR parameters in molecular solids.

Synthesis and structural characterization of cocrystals of isoniazid and cinnamic acid derivatives (2020)
Journal Article
Mashhadi, S. M. A., Yufit, D., Liu, H., Hodgkinson, P., & Yunus, U. (2020). Synthesis and structural characterization of cocrystals of isoniazid and cinnamic acid derivatives. Journal of Molecular Structure, 1219, Article 128621. https://doi.org/10.1016/j.molstruc.2020.128621

Isoniazid is a key antitubercular agent which exhibits poor chemical stability in the solid state. Cocrystallization with hydroxyl derivatives of cinnamic acid, which themselves possesses antitubercular and antioxidant activity, may produce solid for... Read More about Synthesis and structural characterization of cocrystals of isoniazid and cinnamic acid derivatives.

NMR Crystallography of Molecular Organics (2020)
Journal Article
Hodgkinson, P. (2020). NMR Crystallography of Molecular Organics. Progress in Nuclear Magnetic Resonance Spectroscopy, 118-119, 10-53. https://doi.org/10.1016/j.pnmrs.2020.03.001

Developments of NMR methodology to characterise the structures of molecular organic structures are reviewed, concentrating on the previous decade of research in which density functional theory-based calculations of NMR parameters in periodic solids h... Read More about NMR Crystallography of Molecular Organics.

Resolving Alternative Organic Crystal Structures using Density Functional Theory and NMR Chemical Shifts (2020)
Journal Article
Widdifield, C., Farrell, J., Cole, J., Howard, J., & Hodgkinson, P. (2020). Resolving Alternative Organic Crystal Structures using Density Functional Theory and NMR Chemical Shifts. Chemical Science, 11(11), 2987-2992. https://doi.org/10.1039/c9sc04964a

Alternative (‘repeat’) determinations of organic crystal structures deposited in the Cambridge Structural Database are analysed to characterise the nature and magnitude of the differences between structure solutions obtained by diffraction methods. O... Read More about Resolving Alternative Organic Crystal Structures using Density Functional Theory and NMR Chemical Shifts.

Shape-Selective Crystallisation of Fluxional Carbon Cages (2018)
Journal Article
Bismillah, A., Sturala, J., Chapin, B., Yufit, D., Hodgkinson, P., & McGonigal, P. (2018). Shape-Selective Crystallisation of Fluxional Carbon Cages. Chemical Science, 9(46), 8631-8636. https://doi.org/10.1039/c8sc04303e

Dynamic covalent rearrangements of fluxional carbon cages, such as bullvalenes and barbaralanes, impart ‘shapeshifting’ molecular properties. Here, a series of five barbaralanes each interconvert dynamically between two constitutional isomers in solu... Read More about Shape-Selective Crystallisation of Fluxional Carbon Cages.

Perspective: Current advances in solid-state NMR spectroscopy (2018)
Journal Article
Ashbrook, S. E., & Hodgkinson, P. (2018). Perspective: Current advances in solid-state NMR spectroscopy. The Journal of Chemical Physics, 149(4), Article 040901. https://doi.org/10.1063/1.5038547

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 reso... Read More about Perspective: Current advances in solid-state NMR spectroscopy.

Proton transfer in guanine–cytosine base pair analogues studied by NMR spectroscopy and PIMD simulations (2018)
Journal Article
Pohl, R., Socha, O., Slavíček, P., Šála, M., Hodgkinson, P., & Dračínský, M. (2018). Proton transfer in guanine–cytosine base pair analogues studied by NMR spectroscopy and PIMD simulations. Faraday Discussions, 212, 331-344. https://doi.org/10.1039/c8fd00070k

It has been hypothesised that proton tunnelling between paired nucleobases significantly enhances the formation of rare tautomeric forms and hence leads to errors in DNA replication. Here, we study nuclear quantum effects (NQEs) using deuterium isoto... Read More about Proton transfer in guanine–cytosine base pair analogues studied by NMR spectroscopy and PIMD simulations.

Improving Confidence in Crystal Structure Solutions Using NMR Crystallography: The Case of β-Piroxicam (2018)
Journal Article
Tatton, A. S., Blade, H., Brown, S. P., Hodgkinson, P., Hughes, L. P., Lill, S. O. N., & Yates, J. R. (2018). Improving Confidence in Crystal Structure Solutions Using NMR Crystallography: The Case of β-Piroxicam. Crystal Growth and Design, 18(6), 3339-3351. https://doi.org/10.1021/acs.cgd.8b00022

NMR crystallographic techniques are used to validate a structure of β-piroxicam determined from powder X-ray diffraction (PXRD) with a relatively poor R-factor. Geometry optimization of PXRD- and single-crystal XRD- derived structures results in conv... Read More about Improving Confidence in Crystal Structure Solutions Using NMR Crystallography: The Case of β-Piroxicam.

Exploring Systematic Discrepancies in DFT Calculations of Chlorine Nuclear Quadrupole Couplings (2017)
Journal Article
Socha, O., Hodgkinson, P., Widdifield, C. M., Yates, J. R., & Dračínský, M. (2017). Exploring Systematic Discrepancies in DFT Calculations of Chlorine Nuclear Quadrupole Couplings. The Journal of Physical Chemistry A, 121(21), 4103-4113. https://doi.org/10.1021/acs.jpca.7b02810

Previous studies have revealed significant discrepancies between density functional theory (DFT)-calculated and experimental nuclear quadrupolar coupling constants (CQ) for chlorine atoms, particularly in ionic solids. Various aspects of the computat... Read More about Exploring Systematic Discrepancies in DFT Calculations of Chlorine Nuclear Quadrupole Couplings.

Structure and Physicochemical Characterization of a Naproxen-Picolinamide Cocrystal (2017)
Journal Article
Kerr, H., Softley, L., Suresh, K., Hodgkinson, P., & Evans, I. (2017). Structure and Physicochemical Characterization of a Naproxen-Picolinamide Cocrystal. Acta Crystallographica Section C: Structural Chemistry, C73(3), https://doi.org/10.1107/s2053229616011980

Naproxen (NPX) is a nonsteroidal anti-inflammatory drug with pain- and fever-relieving properties, currently marketed in the sodium salt form to overcome solubility problems; however, alternative solutions for improving its solubility across all pH v... Read More about Structure and Physicochemical Characterization of a Naproxen-Picolinamide Cocrystal.

Rationalising heteronuclear decoupling in refocussing applications of solid-state NMR (2017)
Journal Article
Frantsuzov, I., Vasa, S. K., Ernst, M. E., Brown, S. P., Zorin, V., Kentgens, A. P., & Hodgkinson, P. (2017). Rationalising heteronuclear decoupling in refocussing applications of solid-state NMR. ChemPhysChem, 18(4), 394-405. https://doi.org/10.1002/cphc.201601003

Factors affecting the performance of 1H heteronuclear decoupling sequences for magic-angle spinning (MAS) NMR spectroscopy of organic solids are explored, as observed by time constants for the decay of nuclear magnetisation under a spin-echo (math fo... Read More about Rationalising heteronuclear decoupling in refocussing applications of solid-state NMR.

Testing the limits of NMR crystallography: the case of caffeine-citric acid hydrate (2016)
Journal Article
Kerr, H. E., Mason, H. E., Sparkes, H. A., & Hodgkinson, P. (2016). Testing the limits of NMR crystallography: the case of caffeine-citric acid hydrate. CrystEngComm, 18(35), 6700-6707. https://doi.org/10.1039/c6ce01453d

The crystal structure of a new 1 : 2 caffeine–citric acid hydrate cocrystal is presented. The caffeine molecules are disordered over two positions, with the nature of the disorder confirmed to be static by 13C solid-state NMR. NMR linewidths in stati... Read More about Testing the limits of NMR crystallography: the case of caffeine-citric acid hydrate.

Visualization and processing of computed solid-state NMR parameters: MagresView and MagresPython (2016)
Journal Article
Sturniolo, S., Green, T., Hanson, R., Zilka, M., Refson, K., Hodgkinson, P., …Yates, J. (2016). Visualization and processing of computed solid-state NMR parameters: MagresView and MagresPython. Solid State Nuclear Magnetic Resonance, 78, 64-70. https://doi.org/10.1016/j.ssnmr.2016.05.004

We introduce two open source tools to aid the processing and visualisation of ab-initio computed solid-state NMR parameters. The Magres file format for computed NMR parameters (as implemented in CASTEP v8.0 and QuantumEspresso v5.0.0) is implemented.... Read More about Visualization and processing of computed solid-state NMR parameters: MagresView and MagresPython.

Stray-field NMR diffusion q-space diffraction imaging of monodisperse coarsening foams (2016)
Journal Article
Smith, K., Burbidge, A., Apperley, D. C., Hodgkinson, P., Markwell, F. A., Topgaard, D., & Hughes, E. (2016). Stray-field NMR diffusion q-space diffraction imaging of monodisperse coarsening foams. Journal of Colloid and Interface Science, 476, 20-28. https://doi.org/10.1016/j.jcis.2016.04.053

The technique of stray field diffusion NMR is adapted to study the diffusion properties of water in monodisperse wet foams. We show for the first time, that the technique is capable of observing q-space diffusion diffraction peaks in monodisperse aqu... Read More about Stray-field NMR diffusion q-space diffraction imaging of monodisperse coarsening foams.

Furosemide’s One Little Hydrogen Atom: NMR Crystallography Structure Verification of Powdered Molecular Organics (2016)
Journal Article
Widdifield, C. M., Robson, H., & Hodgkinson, P. (2016). Furosemide’s One Little Hydrogen Atom: NMR Crystallography Structure Verification of Powdered Molecular Organics. Chemical Communications, 52(40), 6685-6688. https://doi.org/10.1039/c6cc02171a

The potential of NMR crystallography to verify molecular crystal structures deposited in structural databases is evaluated, with two structures of the pharmaceutical furosemide serving as examples. While the structures differ in the placement of one... Read More about Furosemide’s One Little Hydrogen Atom: NMR Crystallography Structure Verification of Powdered Molecular Organics.

Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations (2016)
Journal Article
Dračínský, M., Bour, P., & Hodgkinson, P. (2016). Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations. Journal of Chemical Theory and Computation, 12(3), 968-973. https://doi.org/10.1021/acs.jctc.5b01131

The influence of temperature on NMR chemical shifts and quadrupolar couplings in model molecular organic solids is explored using path integral molecular dynamics (PIMD) and density functional theory (DFT) calculations of shielding and electric field... Read More about Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations.

Characterising the role of water in sildenafil citrate by NMR crystallography (2016)
Journal Article
Abraham, A., Apperley, D., Byard, S., Ilott, A., Robbins, A., Zorin, V., …Hodgkinson, P. (2016). Characterising the role of water in sildenafil citrate by NMR crystallography. CrystEngComm, 18(6), 1054-1063. https://doi.org/10.1039/c5ce02234g

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. The 13C spectr... Read More about Characterising the role of water in sildenafil citrate by NMR crystallography.

Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR (2016)
Journal Article
Skotnicki, M., Apperley, D., Aguilar, J., Milanowski, B., Pyda, M., & Hodgkinson, P. (2016). Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR. Molecular Pharmaceutics, 13(1), 211-222. https://doi.org/10.1021/acs.molpharmaceut.5b00646

Valsartan (VAL) is an antihypertensive drug marketed in an amorphous form. Amorphous materials can have different physicochemical properties depending on preparation method, thermal history, etc., but the nature of such materials is difficult to stud... Read More about Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR.

A furosemide – isonicotinamide cocrystal: An investigation of properties and extensive structural disorder (2015)
Journal Article
Kerr, H. E., Softley, L. K., Kuthuru, S., Nangia, A., Hodgkinson, P., & Evans, I. R. (2015). A furosemide – isonicotinamide cocrystal: An investigation of properties and extensive structural disorder. CrystEngComm, 17(35), 6707-6715. https://doi.org/10.1039/c5ce01183c

Furosemide is a loop diuretic drug marketed in solid form which suffers from low solubility and low permeability. The pharmaceutically relevant properties of a recently described furosemide-isonicotinamide 2:1 cocrystal (2FS-INA) were investigated an... Read More about A furosemide – isonicotinamide cocrystal: An investigation of properties and extensive structural disorder.

Resonance-assisted stabilisation of hydrogen bonds probed by NMR spectroscopy and path integral molecular dynamics (2015)
Journal Article
Dračínský, M., Čechová, L., Hodgkinson, P., Procházková, E., & Janeba, Z. (2015). Resonance-assisted stabilisation of hydrogen bonds probed by NMR spectroscopy and path integral molecular dynamics. Chemical Communications, 51(73), 13986-13989. https://doi.org/10.1039/c5cc05199a

Path integral molecular dynamics and experimental NMR data are used to investigate resonance-assisted hydrogen bonds (RAHBs). When nuclear delocalisation is included in chemical shift calculations, the agreement with experiment is excellent, while st... Read More about Resonance-assisted stabilisation of hydrogen bonds probed by NMR spectroscopy and path integral molecular dynamics.

Simulating spin dynamics in organic solids under heteronuclear decoupling (2015)
Journal Article
Frantsuzov, I., Ernst, M., Brown, S. P., & Hodgkinson, P. (2015). Simulating spin dynamics in organic solids under heteronuclear decoupling. Solid State Nuclear Magnetic Resonance, 70, 28-37. https://doi.org/10.1016/j.ssnmr.2015.05.003

Although considerable progress has been made in simulating the dynamics of multiple coupled nuclear spins, predicting the evolution of nuclear magnetisation in the presence of radio-frequency decoupling remains challenging. We use exact numerical sim... Read More about Simulating spin dynamics in organic solids under heteronuclear decoupling.

Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol (2015)
Journal Article
Bērziņš, A., & Hodgkinson, P. (2015). Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol. Solid State Nuclear Magnetic Resonance, 65, 12-20. https://doi.org/10.1016/j.ssnmr.2014.09.001

13C, 15N and 2H solid-state NMR spectroscopy have been used to rationalize arrangement and dynamics of solvent molecules in a set of isostructural solvates of droperidol. The solvent molecules are determined to be dynamically disordered in the methan... Read More about Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol.

Solid-state NMR studies of nucleic acid components (2015)
Journal Article
Dračínský, M., & Hodgkinson, P. (2015). Solid-state NMR studies of nucleic acid components. RSC Advances, 5(16), 12300-12310. https://doi.org/10.1039/c4ra14404j

Recent applications of solid-state NMR to the characterisation of nucleic acid systems are reviewed. Developments in NMR methodology and DFT-based first-principles calculations have led to the emergence of “NMR crystallography”, where solid-state NMR... Read More about Solid-state NMR studies of nucleic acid components.

Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry (2014)
Journal Article
Skotnicki, M., Aguilar, J. A., Pyda, M., & Hodgkinson, P. (2015). Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry. Pharmaceutical Research, 32(2), 414-429. https://doi.org/10.1007/s11095-014-1471-7

Purpose The objective of this study was to evaluate the thermal behavior of crystalline and amorphous bisoprolol fumarate and its compatibility with amorphous valsartan. This pharmacologically relevant drug combination is a potential candidate for fi... Read More about Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry.

Dynamics of water molecules and sodium ions in solid hydrates of nucleotides (2014)
Journal Article
Dračínský, M., Šála, M., & Hodgkinson, P. (2014). Dynamics of water molecules and sodium ions in solid hydrates of nucleotides. CrystEngComm, 16(29), 6756-6764. https://doi.org/10.1039/c4ce00727a

Nuclear magnetic resonance experiments, together with molecular dynamics simulations and NMR calculations, are used to investigate mobility of water molecules and sodium ions in solid hydrates of two nucleotides. The structure of guanosine monophosph... Read More about Dynamics of water molecules and sodium ions in solid hydrates of nucleotides.

Effects of Quantum Nuclear Delocalisation on NMR Parameters from Path Integral Molecular Dynamics (2014)
Journal Article
Dračínský, M., & Hodgkinson, P. (2014). Effects of Quantum Nuclear Delocalisation on NMR Parameters from Path Integral Molecular Dynamics. Chemistry - A European Journal, 20(8), 2201-2207. https://doi.org/10.1002/chem.201303496

The influence of nuclear delocalisation on NMR chemical shifts in molecular organic solids is explored using path integral molecular dynamics (PIMD) and density functional theory calculations of shielding tensors. Nuclear quantum effects are shown to... Read More about Effects of Quantum Nuclear Delocalisation on NMR Parameters from Path Integral Molecular Dynamics.

A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters (2013)
Journal Article
Dračínský, M., & Hodgkinson, P. (2013). A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters. CrystEngComm, 15(43), 8705-8712. https://doi.org/10.1039/c3ce40612a

The influence of fast molecular motions on NMR parameters in molecular organic solids is explored on a set of amino acids and nucleic acid bases. A combination of DFT molecular dynamics and calculations of shielding and electric field gradient (EFG)... Read More about A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters.

Well-Tempered Metadynamics as a Tool for Characterizing Multi-Component, Crystalline Molecular Machines (2013)
Journal Article
Ilott, A. J., Palucha, S., Hodgkinson, P., & Wilson, M. R. (2013). Well-Tempered Metadynamics as a Tool for Characterizing Multi-Component, Crystalline Molecular Machines. Journal of Physical Chemistry B (Soft Condensed Matter and Biophysical Chemistry), 117(40), 12286-12295. https://doi.org/10.1021/jp4045995

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 cr... Read More about Well-Tempered Metadynamics as a Tool for Characterizing Multi-Component, Crystalline Molecular Machines.

NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate (2013)
Journal Article
Apperley, D., Markwell, A., Frantsuzov, I., Ilott, A., Harris, R., & Hodgkinson, P. (2013). NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate. Physical Chemistry Chemical Physics, 15(17), 6422-6430. https://doi.org/10.1039/c3cp50180a

Solid-state NMR is used to characterise dynamics in the ethanol solvate of the pharmaceutical material formoterol fumarate and its associated desolvate. Jump rates and activation barriers for dynamic processes such as phenyl ring rotation and methyl... Read More about NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate.

Unexpected effects of third-order cross-terms in heteronuclear spin systems under simultaneous radio-frequency irradiation and magic-angle spinning NMR (2012)
Journal Article
Tatton, A., Frantsuzov, I., Brown, S., & Hodgkinson, P. (2012). Unexpected effects of third-order cross-terms in heteronuclear spin systems under simultaneous radio-frequency irradiation and magic-angle spinning NMR. The Journal of Chemical Physics, 136(8), Article 084503. https://doi.org/10.1063/1.3684879

We recently noted [R. K. Harris, P. Hodgkinson, V. Zorin, J.-N. Dumez, B. Elena, L. Emsley, E. Salager, and R. Stein, Magn. Reson. Chem. 48, S103 (2010)10.1002/mrc.2636] anomalous shifts in apparent 1H chemical shifts in experiments using 1H homonucl... Read More about Unexpected effects of third-order cross-terms in heteronuclear spin systems under simultaneous radio-frequency irradiation and magic-angle spinning NMR.

Towards homonuclear J solid-state NMR correlation experiments for half-integer quadrupolar nuclei: experimental and simulated B-11 MAS spin-echo dephasing and calculated (2)J(BB) coupling constants for lithium diborate (2011)
Journal Article
Barrow, N. S., Yates, J. R., Feller, S. A., Holland, D., Ashbrook, S. E., Hodgkinson, P., & Brown, S. P. (2011). Towards homonuclear J solid-state NMR correlation experiments for half-integer quadrupolar nuclei: experimental and simulated B-11 MAS spin-echo dephasing and calculated (2)J(BB) coupling constants for lithium diborate. Physical Chemistry Chemical Physics, 13(13), 5778-5789. https://doi.org/10.1039/c0cp02343d

Structures and Phase Transitions in (MoO2)2P2O7 (2010)
Journal Article
Lister, S., Soleilhavoup, A., Withers, R., Hodgkinson, P., & Evans, J. (2010). Structures and Phase Transitions in (MoO2)2P2O7. Inorganic Chemistry, 49(5), 2290-2301. https://doi.org/10.1021/ic902166j

We report structural investigations into (MoO2)2P2O7 using a combination of X-ray, neutron and electron diffraction, and solid-state NMR supported by first principles quantum chemical calculations. These reveal a series of phase transitions on coolin... Read More about Structures and Phase Transitions in (MoO2)2P2O7.

Elucidation of Structure and Dynamics in Solid Octafluoronaphthalene from Combined NMR, Diffraction, And Molecular Dynamics Studies (2010)
Journal Article
Ilott, A., Palucha, S., Batsanov, A., Wilson, M., & Hodgkinson, P. (2010). Elucidation of Structure and Dynamics in Solid Octafluoronaphthalene from Combined NMR, Diffraction, And Molecular Dynamics Studies. Journal of the American Chemical Society, 132(14), 5179-5185. https://doi.org/10.1021/ja910526z

X-ray diffraction (XRD), molecular dynamics simulations (MD), and 19F NMR have been used to investigate structure and dynamics in solid octafluoronaphthalene, C10F8. Two distinct processes are observed via measurements of 19F relaxation times as a fu... Read More about Elucidation of Structure and Dynamics in Solid Octafluoronaphthalene from Combined NMR, Diffraction, And Molecular Dynamics Studies.

Understanding two-pulse phase-modulated decoupling in solid-state NMR (2009)
Journal Article
Scholz, I., Hodgkinson, P., Meier, B., & Ernst, M. (2009). Understanding two-pulse phase-modulated decoupling in solid-state NMR. The Journal of Chemical Physics, 130(11), Article 114510. https://doi.org/10.1063/1.3086936

A theoretical description of the two-pulse phase-modulated (TPPM) decoupling sequence in magic-angle spinning NMR is presented using a triple-mode Floquet approach. The description is formulated in the radio-frequency interaction-frame representation... Read More about Understanding two-pulse phase-modulated decoupling in solid-state NMR.

Characterization of Polymorphs and Solvates of Terbutaline Sulfate (2008)
Journal Article
Harris, R., Hodgkingson, P., Larsson, T., Muruganantham, A., Ymen, I., Yufit, D., & Zorin, V. (2008). Characterization of Polymorphs and Solvates of Terbutaline Sulfate. Crystal Growth and Design, 8(1), 80-90. https://doi.org/10.1021/cg700840j

Five different crystalline modifications (two anhydrates, a monohydrate, a higher hydrate, and an acetic acid solvate) of an asthma-therapy drug, terbutaline sulfate, have been identified and characterized by several solid-state techniques. X-ray pow... Read More about Characterization of Polymorphs and Solvates of Terbutaline Sulfate.

Quantifying hydrogen-bonding strength: the measurement of (2h)J(NN) couplings in self-assembled guanosines by solid-state (15)N spin-echo MAS NMR (2007)
Journal Article
Pham, T. N., Griffin, J. M., Masiero, S., Lena, S., Gottarelli, G., Hodgkinson, P., …Brown, S. P. (2007). Quantifying hydrogen-bonding strength: the measurement of (2h)J(NN) couplings in self-assembled guanosines by solid-state (15)N spin-echo MAS NMR. Physical Chemistry Chemical Physics, 9(26), 3416-3423. https://doi.org/10.1039/b703513f

Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene (2007)
Journal Article
Robbins, A., Ng, W., Jochym, D., Keal, T., Clark, S., Tozer, D., & Hodgkinson, P. (2007). Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene. Physical Chemistry Chemical Physics, 9(19), 2389-2396. https://doi.org/10.1039/b701291h

Advances in solid-state NMR methodology and computational chemistry are applied to the 19F NMR of solid octafluoronaphthalene. It is demonstrated experimentally, and confirmed by density functional theory (DFT) calculations, that the spectral resolut... Read More about Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene.

Origins of linewidth in ¹H magic-angle spinning NMR (2006)
Journal Article
Zorin, V., Brown, S., & Hodgkinson, P. (2006). Origins of linewidth in ¹H magic-angle spinning NMR. The Journal of Chemical Physics, 125(14), https://doi.org/10.1063/1.2357602

A detailed study of the factors determining the linewidth (and hence resolution) in 1H solid-state magic-angle spinning NMR is described. Although it has been known from the early days of magic-angle spinning (MAS) that resolution of spectra from abu... Read More about Origins of linewidth in ¹H magic-angle spinning NMR.

Quantitative analysis of 17O exchange and T1 relaxation data : Application to zirconium tungstate. (2006)
Journal Article
Hodgkinson, P., & Hampson, M. (2006). Quantitative analysis of 17O exchange and T1 relaxation data : Application to zirconium tungstate. Solid State Nuclear Magnetic Resonance, 30(2), 98-105. https://doi.org/10.1016/j.ssnmr.2006.04.001

The theoretical basis behind a recent quantitative analysis of 17O exchange in ZrW2O8 [M.R. Hampson, J.S.O. Evans, P. Hodgkinson, J. Am. Chem. Soc. 127 (2005) 15175–15181] is set out. Despite the complexities of combining the multi-exponential relaxa... Read More about Quantitative analysis of 17O exchange and T1 relaxation data : Application to zirconium tungstate..

Quantification of homonuclear dipolar coupling networks from magic-angle spinning 1H NMR (2006)
Journal Article
Zorin, V., Brown, S., & Hodgkinson, P. (2006). Quantification of homonuclear dipolar coupling networks from magic-angle spinning 1H NMR. Molecular Physics, 104(2), 293-304. https://doi.org/10.1080/00268970500351052

Numerical simulations of magic-angle spinning (MAS) spectra of dipolar-coupled nuclear spins have been used to assess different approaches to the quantification of dipolar couplings from 1H solid-state NMR. Exploiting the translational symmetry of pe... Read More about Quantification of homonuclear dipolar coupling networks from magic-angle spinning 1H NMR.

Hydrogen bonding and dynamic behaviour in crystals and polymorphs of dicarboxylic-diamine adducts: A comparison between NMR parameters and X-ray diffraction studies (2005)
Journal Article
Gobetto, R., Nervi, C., Chierotti, M., Braga, D., Maini, L., Grepioni, F., …Hodgkinson, P. (2005). Hydrogen bonding and dynamic behaviour in crystals and polymorphs of dicarboxylic-diamine adducts: A comparison between NMR parameters and X-ray diffraction studies. Chemistry - A European Journal, 11(24), 7461-7471. https://doi.org/10.1002/chem.200500616

Characterisation of indomethacin and nifedipine using variable-temperature solid-state NMR (2005)
Journal Article
Apperley, D. C., Forster, A. H., Fournier, R., Harris, R. K., Hodgkinson, P., Lancaster, R. W., & Rades, T. (2005). Characterisation of indomethacin and nifedipine using variable-temperature solid-state NMR. Magnetic Resonance in Chemistry, 43(11), 881-892. https://doi.org/10.1002/mrc.1643

We have characterised the stable polymorphic forms of two drug molecules, indomethacin (1) and nifedipine (2) by C-13 CPMAS NMR and the resonances have been assigned. The signal for the C-Cl carbon of indomethacin has been studied as a function of ap... Read More about Characterisation of indomethacin and nifedipine using variable-temperature solid-state NMR.

Characterization of oxygen dynamics in ZrW₂O₈ (2005)
Journal Article
Hampson, M., Evans, J., & Hodgkinson, P. (2005). Characterization of oxygen dynamics in ZrW₂O₈. Journal of the American Chemical Society, 127(43), 15175-15181. https://doi.org/10.1021/ja054063z

The dynamics of oxygen motion in ZrW2O8 have been characterized using O-17 solid-state NMR. Rates of dynamic exchange have been extracted from magnetization transfer experiments over a temperature range of 40 to 226 degrees C, and distinct values for... Read More about Characterization of oxygen dynamics in ZrW₂O₈.

Quantification of bambuterol hydrochloride in a formulated product using solid-state NMR (2005)
Journal Article
Harris, R., Hodgkinson, P., Larsson, T., & Muruganantham, A. (2005). Quantification of bambuterol hydrochloride in a formulated product using solid-state NMR. Journal of Pharmaceutical and Biomedical Analysis, 38(5), 858-864

Carbon-13 NMR spectra of the stable polymorphs of solid bambuterol hydrochloride (BHC) and terbutaline sulfate (TBS) are reported and the resonances assigned with the aid of solution-state spectra. A protocol is presented for quantification of BHC in... Read More about Quantification of bambuterol hydrochloride in a formulated product using solid-state NMR.

Synthesis and NMR studies of O-17 enriched AM(2)O(8) phases (2005)
Journal Article
Hampson, M., Allen, S., King, I., Crossland, C., Hodgkinson, P., Harris, R., …Evans, J. (2005). Synthesis and NMR studies of O-17 enriched AM(2)O(8) phases. Solid State Sciences, 7(7), 819-826

This paper describes synthetic routes to produce highly O-17 enriched samples of the negative thermal expansion materials ZrW2O8 and ZrMo2O8. In the case of ZrW2O8 enriched samples can be produced either via enriched Zr-17 O-2 and (WO3)-O-17, which h... Read More about Synthesis and NMR studies of O-17 enriched AM(2)O(8) phases.

Solid-state NMR studies of some tin(II) compounds (2004)
Journal Article
Amornsakchai, P., Apperley, D., Harris, R., Hodgkinson, P., & Waterfield, P. (2004). Solid-state NMR studies of some tin(II) compounds. Solid State Nuclear Magnetic Resonance, 26(3-4), 160-171

High-resolution NMR spectra of spin-1/2 nuclei, particularly Sn-119 and insolid tin(II) phosphite, SnHPO3,and tin(II) phosphate, SnHPO4, are presented. The results are discussed in relation to the crystal structures. Spinning sideband analysis has be... Read More about Solid-state NMR studies of some tin(II) compounds.

Solid-state Ag-109 CP/MAS NMR spectroscopy of some diammine silver(I) complexes (2004)
Journal Article
Bowmaker, G., Harris, R., Assadollahzadeh, B., Apperley, D., Hodgkinson, P., & Amornsakchai, P. (2004). Solid-state Ag-109 CP/MAS NMR spectroscopy of some diammine silver(I) complexes. Magnetic Resonance in Chemistry, 42(9), 819-826

Solid-state cross-polarization magic-angle spinning (CP/MAS) NMR spectra were recorded for the compounds [Ag(NH3)(2)](2)SO4, [Ag(NH3)(2)](2)SeO4 and [Ag(NH3)(2)]NO3, all of which contain the linear or nearly linear two-coordinate [Ag(NH3)(2)](+) ion.... Read More about Solid-state Ag-109 CP/MAS NMR spectroscopy of some diammine silver(I) complexes.

Resolution of C-13-F-19 interactions in the C-13 NMR of spinning solids and liquid crystals (2004)
Journal Article
Antonioli, G., & Hodgkinson, P. (2004). Resolution of C-13-F-19 interactions in the C-13 NMR of spinning solids and liquid crystals. Journal of Magnetic Resonance, 168(1), 124-131

Anomalous line-broadenings of carbon resonances close to F-19 have commonly been reported in the C-13 NMR of liquid crystals and solids. We have previously shown that these effects in static liquid-crystal samples are related to the difficulty of H-1... Read More about Resolution of C-13-F-19 interactions in the C-13 NMR of spinning solids and liquid crystals.

NMR studies of P-31, H-1 spin pairs in solid tin(II) phosphite and tin(II) hydrogen phosphate (2004)
Journal Article
Amornsakchai, P., Hodgkinson, P., & Harris, R. (2004). NMR studies of P-31, H-1 spin pairs in solid tin(II) phosphite and tin(II) hydrogen phosphate. Molecular Physics, 102(9-10), 877-882

We show how the spin dynamics in isolated spin systems presents both opportunities and complications, using the H-1, P-31 pair encountered in solid SnHPO3 and SnHPO4. Transient oscillations observed in the build-up of P-31 magnetization, during cross... Read More about NMR studies of P-31, H-1 spin pairs in solid tin(II) phosphite and tin(II) hydrogen phosphate.

The nature of oxygen exchange in ZrW2O8 revealed by two-dimensional solid-state O-17 NMR (2004)
Journal Article
Hampson, M., Hodgkinson, P., Evans, J., Harris, R., King, I., Allen, S., & Fayon, F. (2004). The nature of oxygen exchange in ZrW2O8 revealed by two-dimensional solid-state O-17 NMR. Chemical Communications, 392-393

O-17 magic angle spinning (MAS) NMR has been used to determine the nature of oxygen exchange in ZrW2O8. A highly effective isotopic labelling technique has been developed and 1D NMR and 2D exchange spectroscopy (EXSY) experiments have revealed that m... Read More about The nature of oxygen exchange in ZrW2O8 revealed by two-dimensional solid-state O-17 NMR.

Transverse dephasing optimized solid-state NMR spectroscopy (2003)
Journal Article
De Paepe, G., Giraud, N., Lesage, A., Hodgkinson, P., Bockmann, A., & Emsley, L. (2003). Transverse dephasing optimized solid-state NMR spectroscopy. Journal of the American Chemical Society, 125(46), 13938-13939

Improved heteronuclear decoupling schemes for solid-state magic angle spinning NMR by direct spectral optimization (2003)
Journal Article
De Paepe, G., Hodgkinson, P., & Emsley, L. (2003). Improved heteronuclear decoupling schemes for solid-state magic angle spinning NMR by direct spectral optimization. Chemical Physics Letters, 376(3-4), 259-267

It is shown that a direct spectral optimization scheme can be implemented to obtain improved heteronuclear dipolar decoupling schemes for solid-state magic-angle-spinning NMR experiments. The resulting schemes, which turn out to have a particularly s... Read More about Improved heteronuclear decoupling schemes for solid-state magic angle spinning NMR by direct spectral optimization.

Interference of homonuclear decoupling and exchange in the solid-state NMR of perfluorocyclohexane (2003)
Journal Article
McMillan, D., Hazendonk, P., & Hodgkinson, P. (2003). Interference of homonuclear decoupling and exchange in the solid-state NMR of perfluorocyclohexane. Journal of Magnetic Resonance, 161(2), 234-241

We observe an interference between RF irradiation used for homonuclear decoupling of F-19 and conformational exchange in the C-13 spectrum of perfluorocyclohexane. We show that these effects can be readily reproduced in simulation, and characterise t... Read More about Interference of homonuclear decoupling and exchange in the solid-state NMR of perfluorocyclohexane.

Heteronuclear decoupling in NMR of Liquid Crystals using continuous phase modulation (2003)
Journal Article
De Paepe, G., Sakellariou, D., Hodgkinson, P., Hediger, S., & Emsley, L. (2003). Heteronuclear decoupling in NMR of Liquid Crystals using continuous phase modulation. Chemical Physics Letters, 368(5-6), 511-522

In this Letter we present a framework for the use of continuously phase modulated radio-frequency pulses for heteronuclear decoupling in NMR of Liquid Crystals. Within this framework, we found new sets of heteronuclear decoupling sequences using nume... Read More about Heteronuclear decoupling in NMR of Liquid Crystals using continuous phase modulation.

Improved proton decoupling in NMR spectroscopy of crystalline solids using the SPINAL-64 sequence (2002)
Journal Article
Brauniger, T., Wormald, P., & Hodgkinson, P. (2002). Improved proton decoupling in NMR spectroscopy of crystalline solids using the SPINAL-64 sequence. Monatshefte für Chemie - Chemical Monthly, 133(12), 1549-1554

The performance of three different spin decoupling schemes, CW, TPPM, and SPINAL-64 is compared, by recording proton decoupled C-13 NMR spectra of a crystalline glycine sample, with 20% isotopic labelling. At a magnetic field of B-0 = 14.1 T, the two... Read More about Improved proton decoupling in NMR spectroscopy of crystalline solids using the SPINAL-64 sequence.

Line-splitting and broadening effects from F-19 in the C-13 NMR of liquid crystals and solids (2001)
Journal Article
Antonioli, G., McMillan, D., & Hodgkinson, P. (2001). Line-splitting and broadening effects from F-19 in the C-13 NMR of liquid crystals and solids. Chemical Physics Letters, 344(1-2), 68-74

The NMR resonances of C-13 spins in proximity to F-19 are often unusually broad, degrading resolution and limiting the ability to quantify the C-F interactions. We observe line-splittings and selective broadenings in a liquid crystal sample that stro... Read More about Line-splitting and broadening effects from F-19 in the C-13 NMR of liquid crystals and solids.