Salt or Co-Crystal? Determination of Protonation State by X-Ray Photoelectron Spectroscopy (XPS)

Stevens, Joanna S.; Byard, Stephen J.; Schroeder, Sven L. M.

doi:10.1002/jps.22164

Cited by 71 publications

(79 citation statements)

References 24 publications

(35 reference statements)

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“…The AMB C 1s core level spectrum (Fig. 12) reveals three types of carbon environment at 287.05 eV (N-C-N/N=C-NH), 284.6 eV (C=C, C-N) and 283 eV from hydrocarbon contamination [32]. Photoemissions from C 1s core level of Glu is more complex and reveals four peaks.…”

Section: Xps Spectroscopymentioning

confidence: 99%

“…Photoemissions from C 1s core level of Glu is more complex and reveals four peaks. The peak at higher binding energy (288 eV) corresponds to carbons with decreased electron density, the two carboxylic acids (COOH) [32], the peak at 285.7 eV may be assigned to C-N, the one at 284.4 eV corresponds to C atoms adjacent to the carboxylic acid (C-COOH) and the peak at lowest binding energy 282.7 eV arise from hydrocarbon also present by contamination.…”

Section: Xps Spectroscopymentioning

confidence: 99%

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Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

et al. 2011

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Abstract. Ambazone monohydrate C 8 H 11 N 7 S · H 2 O (AMB), a well-known antimicrobial compound, was used together with Glutamic Acid C 5 H 9 NO 4 (Glu) to obtain a new solid form using the solvent-drop grinding procedure. The screening of the new solid form was best achieved by the combined use of X-ray Powder Diffraction (XRPD) and several spectroscopic techniques (Fourier Transformed Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Raman and 13 C-NMR spectroscopy) together with Differential Scanning Calorimetry (DSC), Differential thermal analysis and thermogravimetry (DTA-TGA). The combination of the mentioned analytical techniques allows the compound to be assigned to an ambazone-glutamate salt which crystallizes in monoclinic system having the following lattice parameters: a = 9.8352, b = 4.7014, c = 40.0987 Å and β = 94.505• . DSC, TGA data and the before mentioned spectroscopic techniques support the ambazone-glutamate salt formation.

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Section: Xps Spectroscopymentioning

confidence: 99%

Section: Xps Spectroscopymentioning

confidence: 99%

Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

et al. 2011

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“…Thus, SSNMR is an important tool for the identification of cocrystal or salt. SSNMR can also be used to evaluate the cocrystal structure by estimating hydrogen bonding and local conformation changes by couplings [110,111] .…”

Section: Evaluation Of Cocrystalsmentioning

confidence: 99%

Pharmaceutical Cocrystals: An Overview

Kumar¹,

Nanda²

2017

pharmaceutical-sciences

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“…6) with the acquisition of a positive charge. 6 During exposure to X-rays, changes in the peak intensities occurred, indicative of significant radiationinduced degradation. A loss of oxygen was observed by a decrease in the relative oxygen content in the survey spectra.…”

Section: N 1smentioning

confidence: 99%

“…10 The ability of XPS for determining the presence of protonated versus unprotonated nitrogen in pharmaceutical salts and cocrystals has been demonstrated with N 1s chemical shifts. 6,8 The presence of free base at the surface of 1 may therefore be expected to give rise to a decrease in the proportion of the protonated nitrogen signal in XPS and thus a lower NH + /N ratio.…”

Section: Introductionmentioning

confidence: 99%