Nonempirical Quantification of Molecular Interactions in Supramolecular Assemblies

Henry, Marc

doi:10.1002/1439-7641(20020715)3:7<561::aid-cphc561>3.0.co;2-e

Cited by 82 publications

(72 citation statements)

References 45 publications

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“…48 Since the hydrogenatom positions of these structures suffer from the usual X-ray distortion, all hydrogen atoms were added in calculated positions with optimised bond lengths 52 and their position subsequently optimised sterically and electrostatically. The PACHA algorithm is a fast, ab initio method that treats atoms as point charges and is thus a simple approximation to the calculation of lattice energies compared to the high-level algorithms used for polymorph prediction.…”

Section: Energy Calculations Of the Polymorphsmentioning

confidence: 99%

New Insights into an Old Molecule: Interaction Energies of Theophylline Crystal Forms

Fucke

McIntyre

Wilkinson

et al. 2012

Crystal Growth & Design

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'New insights into an old molecule : interaction energies of theophylline crystal forms.', Crystal growth design., 12 (3). pp. 1395-1401. Further information on publisher's website:http://dx.doi.org/10.1021/cg201499sPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Crystal growth design, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/cg201499sAdditional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The asthma therapeutic theophylline exists in at least three anhydrous polymorphs and a monohydrate. The single-crystal X-ray structure of the high-temperature polymorph form I is presented for the first time and the energetic relationship between forms I and II is investigated using the partial charges and chemical hardness analysis (PACHA) algorithm. It is shown that the interactions in the form I crystal network are stronger, especially the hydrogen bond. The singlecrystal neutron structure of the monohydrate demonstrates static disorder of the water molecule as well as dynamic disorder of the methyl groups. PACHA investigations based on the neutron coordinates reveal that the homomeric interactions in this form are stronger than the interaction of the water with the host molecules. The dehydration of the hydrate should thus leave the theophylline network intact, explaining the isomorphic powder X-ray diffractograms of the monohydrate and its dehydrated form III.

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Section: Energy Calculations Of the Polymorphsmentioning

confidence: 99%

New Insights into an Old Molecule: Interaction Energies of Theophylline Crystal Forms

Fucke

McIntyre

Wilkinson

et al. 2012

Crystal Growth & Design

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“…In a previous paper, [1] we have presented the nonempirical PACHA formalism based on a spherical approximation of DFT equations, which allows us to treat considerably larger-sized objects than what can be achieved by standard quantum mechanics computations. Therefore, it allows us to explore the domain of organization that spans from clusters to crystals, a critical scale range involved in many processes.…”

Section: Introductionmentioning

confidence: 89%

“…Earlier in this issue, [1] it was shown that the experimental hydrogen bond energy, E HB À 22.6 AE 2.9 kJ mol À1 , deduced from the microwave spectrum of the (H 2 O) 2 dimer in the gas phase, [4] was very close to the value E HB À 22.8 AE 1.0 kJ mol À1 computed by insertion of the experimental geometry of the water dimer [5] into the PACHA equations. Even if the dimer is a very limited test compound, it was of crucial importance to check that we were able to reproduce quantitatively, without any adjustable parameters, the well known hydrogen bond interaction energy.…”

Section: Ice Polymorphsmentioning

confidence: 99%

“…Application of the same formalism to the disordered hexagonal ice network [6] has led to a predicted sublimation enthalpy DH subl 55 AE 5 kJ mol À1 , which compares very favorably with the thermochemical experimental value. [1] Assuming that the total sum of van der Waals contributions for this network was E VdW À 11.1 kJ mol À1 , we have been able to show that the overall hydrogen bond energy was very similar in hexagonal ice (E HB À 21.7 AE 0.5 kJ mol À1 ) [1] and in the water dimer.…”

Section: Ice Polymorphsmentioning

confidence: 99%

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Thermodynamics of Hydrogen Bond Patterns in Supramolecular Assemblies of Water Molecules

Henry¹

2002

ChemPhysChem

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“…Each sandwich then connects with another through two hydrogen bonds per piroxicam molecule from the amide carbonyl O1A to the amide H2NB-N2B and from the second deprotonated hydroxyl oxygen O2B to the protonated pyridyl nitrogen atom N1A-H1NA. Interestingly, these hydrogen bonds result in the formation of infinite chains of sandwiches along (101), which do not have strong interactions (hydrogen bonds) with each other (Figure 4).The accurate atomic coordinates obtained from the neutron diffraction experiments were submitted to non-empirical lattice energy calculations [14] to assign interaction energies to the hydrogen bonds found in the crystal network (see ESI Table S4). The hydrogen bonds donated by the O1W water molecule yield the strongest interactions with energies of -33.7 and -28.6 kJ mol -1 .…”

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Unexpected Low‐Temperature Behaviour of Piroxicam Monohydrate

et al. 2012

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(2013) 'Unexpected low temperature behaviour of piroxicam monohydrate. ', ChemPhysChem., 14 (4). pp. 675-679.Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. MonohydrateKatharina Fucke, [a] Alison J. Edwards, [b] Michael R.Probert, [a] Sarah E. Tallentire, [a] Judith A. K. Howard, [a] and Jonathan W. Steed* [a] Pharmaceutical compounds can crystallise in different polymorphic forms with the same chemical composition; a phenomenon that has been studied for almost 200 years, [1] and remains a major issue in the pharmaceutical industry. Additional problems arise from solvated crystal forms, which incorporate one or more types of solvent from the crystallisation medium into the crystal. [2] In the special case of water incorporation, the crystal form is called a hydrate. Pharmaceutical hydrates, which can vary widely in both composition and stability, are simultaneously favoured and feared. Hydrates exhibit the lowest solubility in water of all crystal forms of a compound and hence hydrate formation can seriously influence the bioavailability and thus the safety and efficacy of a medication.[3] As a result there is considerable current interest in the study of water clusters in crystalline hydrates. [4] Hydrated crystal structures also shed light on the fundamental nature of homomeric interactions between water molecules and heteromeric interactions between water and host molecules in molecular solids. [4b, 5] With the help of modern diffraction techniques and computational studies, these interactions can now be accurately structurally characterised, [6] making essential information available for ab initio crystal structure prediction of hydrates. [7] We have focussed on the neutron structural characterisation of a range of pharmaceutically relevant hydrates. [5b, 8] As part of this study we have investigated piroxicam (PIR, Figure 1), which is a non-steroidal anti-inflammatory drug (NSAID) used in the treatment of chronic pain in rheumatoid arthritis and osteoarthritis. PIR is listed in both the European [9] and the US Pharmacopoeias, [10] and is reported to exist in three different unsolvated crystal forms, [11] a monohydrate, [12] and several multicomponent crystals and salt forms. [13] Our interest lies mainly in the interaction of water of crystallisation with the host molecule in the monohydrate structure. We now report accurate hydrogen atom positions for PIR monohydrate derived from neutron diffraction data as well as the substance's remarkable behaviou...

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Nonempirical Quantification of Molecular Interactions in Supramolecular Assemblies

Cited by 82 publications

References 45 publications

New Insights into an Old Molecule: Interaction Energies of Theophylline Crystal Forms

New Insights into an Old Molecule: Interaction Energies of Theophylline Crystal Forms

Thermodynamics of Hydrogen Bond Patterns in Supramolecular Assemblies of Water Molecules

Unexpected Low‐Temperature Behaviour of Piroxicam Monohydrate

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