Experimental and Theoretical Charge Density Study of the Neurotransmitter Taurine

Hibbs, David E.; Austin-Woods, Charles J.; Platts, James Alexis; Overgaard, Jacob; Turner, Peter

doi:10.1002/chem.200390100

Cited by 47 publications

(56 citation statements)

References 45 publications

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“…This is discussed in more detail below. This effect has been seen before in polar bonds 21,22 , but the non-polar nature of this bond appears to rule this out as an explanation. To further check the agreement between experiment and theory, we also plotted the total electron density in the same plane ( Figure S1): as with topological data, this shows excellent agreement between experiment and theory.…”

Section: Hydrogen Atom Treatmentsupporting

confidence: 57%

Experimental and theoretical charge density distribution in Pigment Yellow 101

Váradi

Tan

et al. 2015

Phys. Chem. Chem. Phys.

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The charge density distribution in 2,2'-Dihydroxy-1,1'-naphthalazine (Pigment Yellow 101; P.Y.101) has been determined using high-resolution X-ray diffraction and multipole refinement, along with density functional theory calculations. Topological analysis of the resulting densities highlights the localisation of single/double bonds in the central C=N-N=C moiety of the molecule in its ground state. The density in the N-N is examined in detail, where we show that very small differences between experiment and theory are amplified by use of the Laplacian of the density. Quantification of hydrogen bonds highlights the importance of the intramolecular N-H…O interaction, known to be vital for retention of fluorescence in the solid state, relative to the many but weak intermolecular contacts located.However, a popular method for deriving H-bond strengths from density data appears to struggle with the intramolecular N-H…O interaction. We also show that theoretical estimation of anisotropic displacements for hydrogen atoms brings little benefit overall, and degrades agreement with experiment for one intra-molecular contact.2

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Section: Hydrogen Atom Treatmentsupporting

confidence: 57%

Experimental and theoretical charge density distribution in Pigment Yellow 101

Váradi

Tan

et al. 2015

Phys. Chem. Chem. Phys.

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“…In addition to the 33 S data, experimentally determined 14 N EFG parameters measured from the static 14 N powder pattern ( Figure 4) are also considered. The comparison between the experimental NMR parameters and those calculated from the various taurine structures 31,[50][51][52][53][54][55][56] are shown as graphical plots in Figure 5 (all calculated parameters are given in the Supporting Information). Three of the structures, TAURIN03, 09, and 10, give a better agreement with the experimental parameters than the others.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure Based Design of Signal Enhancement Schemes for Solid-State NMR of Insensitive Half-Integer Quadrupolar Nuclei

O’Dell

Ratcliffe

2010

J. Phys. Chem. A

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=eedeb6cd-a761-47eb-8177-bc997d8891e2 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=eedeb6cd-a761-47eb-8177-bc997d8891e2 ABSTRACT: A combination of density functional and optimal control theory has been used to generate amplitude-and phase-modulated excitation pulses tailored specifically for the 33 S nuclei in taurine, based on one of several reported crystal structures. The pulses resulted in significant signal enhancement (stemming from population transfer from the satellite transitions) without the need for any experimental optimization. This allowed an accurate determination of the 33 S NMR interaction parameters at natural abundance and at a moderate magnetic field strength (11.7 T). The 33 S NMR parameters, along with those measured from 14 N using frequency-swept pulses, were then used to assess the accuracy of various proposed crystal structures.

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“…In both molecules, differences of around 0.2 e were seen consistently across the sulfonyl oxygen atoms, with those in (3) being the more negative; this is possibly due to the large number of weak interactions in the co-crystal. density studies previously, 23 and it is generally found that the changes in charge are 'delocalised' across neighbouring atoms.…”

Section: Atomic Chargesmentioning

confidence: 92%

“…The large discrepancies here may be attributed to the inability of the experimental model to properly account for the valence electrons of heavy atoms such as sulfur, further compounded by the proximity of two oxygen atoms which may also contribute to a large amount of unaccounted for electrons. Thus, very small differences in the total electron density, of the same magnitude as the residual errors stemming from the multipole model, are amplified in the Laplacian into apparently major discrepancies between experiment and theory 23,24,43 . It should be noted here that there is no appreciable difference between the Exp and the Shade refinements, across all datasets the maximum differences are 0.30eÅ -3 for ρ bcp and -1.5 eÅ -5 in ł 2 ρ bcp .…”

Section: Topological Analysismentioning

confidence: 99%

“…The coefficients n l are chosen so that the maximum of the radial function is at the peak density position for each shell. We and others have previously shown that this standard description is particularly troublesome for sulfur [23][24][25] and usually results in high residual electron density in the proximity of the sulfur atoms at the completion of the refinement. To address this issue we adopted a model where the n l -set for sulfur used in this work was (4,4,4,5,5) 26 .…”

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confidence: 99%

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An analysis of the experimental and theoretical charge density distributions of the piroxicam–saccharin co-crystal and its constituents

Váradi

Williams

et al. 2016

RSC Adv.

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Experimental and theoretical charge density analyses of piroxicam (1), saccharin (2) and their 1:1 co-crystal complex (3) have been carried out. Electron density distribution (EDD) was determined through the use of high-resolution single crystal X-ray diffraction and the data were modelled using the conventional multipole model of electron density according to the Hansen-Coppens formalism. A method for optimising the core density refinement of sulfur atoms is discussed, with emphasis on the reduction of residual electron density that is typically associated with this atom. The asymmetric unit of complex (3) contains single molecules of saccharin and the zwitterionic form of piroxicam. These are held together by weak interactions (hydrogen bonds, π-π and van der Waals interactions), ranging in strength from 4 to 160 kJmol -1 , working together to stabilise the complex;. analysis of the molecular electrostatic potential (MEP) of the complexes showed electron redistribution within the cocrystal, facilitating the formation of these generally weak interactions. Interestingly, in the zwitterionic form of piroxicam, the charge distribution reveals that the positive and negative charges are not associated with the formal charges normally associated with this description, but are distributed over adjacent molecular fragments. The use of anisotropic displacement parameters (ADPs) for hydrogen atoms in the multipole model was also investigated but no improvement in the quality of the topological analysis was found.3

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Experimental and Theoretical Charge Density Study of the Neurotransmitter Taurine

Cited by 47 publications

References 45 publications

Experimental and theoretical charge density distribution in Pigment Yellow 101

Experimental and theoretical charge density distribution in Pigment Yellow 101

Crystal Structure Based Design of Signal Enhancement Schemes for Solid-State NMR of Insensitive Half-Integer Quadrupolar Nuclei

An analysis of the experimental and theoretical charge density distributions of the piroxicam–saccharin co-crystal and its constituents

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