𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Salt or co-crystal? determination of protonation state by X-ray photoelectron spectroscopy (XPS)

✍ Scribed by Joanna S. Stevens; Stephen J. Byard; Sven L.M. Schroeder

Publisher
John Wiley and Sons
Year
2010
Tongue
English
Weight
180 KB
Volume
99
Category
Article
ISSN
0022-3549

No coin nor oath required. For personal study only.

✦ Synopsis

Combined 15 N ssNMR and X-ray photoelectron spectroscopy (XPS) investigations for theophylline, a theophylline co-crystal, and a theophyllinium salt demonstrate that XPS allows direct observation of the degree of proton transfer, and thus identification of whether a salt or a co-crystal has been formed. The presence of a strongly binding-energy-shifted N 1s XPS peak with protonation indicates a salt (C --NH þ ), while this peak is unmistakably absent in the co-crystal. XPS should be considered as an alternative and complementary technique to single crystal X-ray diffraction and solid-state nuclear magnetic resonance spectroscopy (ssNMR).

📜 SIMILAR VOLUMES

Detection of free base surface enrichmen
Detection of free base surface enrichment of a pharmaceutical salt by X-ray photoelectron spectroscopy (XPS)
✍ Joanna S. Stevens; Stephen J. Byard; Evgeny Zlotnikov; Sven L. M. Schroeder 📂 Article 📅 2011 🏛 John Wiley and Sons 🌐 English ⚖ 415 KB

Yellow discoloration was observed at the surface of normally white crystals of a development pharmaceutical fumarate salt, tentatively ascribed to the presence of trace amounts of free base. The impact of impurities on sample properties and behavior can be significant, especially if localized at the

The oxidation state of tungsten in NaxWO
The oxidation state of tungsten in NaxWO3 bronzes as determined by X-ray photoelectron spectroscopy
✍ B.A. De Angelis; M. Schiavello 📂 Article 📅 1976 🏛 Elsevier Science 🌐 English ⚖ 213 KB

## Recciwd 4 August 197.5 Revised manuscript rcccivcd 29 Scptcmbcr 1975 The XPS spectrum of the 4fIzvels of W in N+\VOJ bronzes is explained by sssurning the prescnca of three oxidation states (WG+, Wsc nnd \V4'). Tetravslcnt tungsten is formed by dismutation of W 5+. The partial reduction of W6+

Ti and Fe Speciation by X-Ray Photoelect
Ti and Fe Speciation by X-Ray Photoelectron Spectroscopy(XPS) and Mössbauer Spectroscopy for a Full Crystal Chemical Characterisation of Ti-Garnets from Colli Albani (Italy)
✍ Emanuela Schingaro; Fernando Scordari; Giuseppe Pedrazzi; Cosimino Malitesta 📂 Article 📅 2004 🏛 John Wiley and Sons 🌐 English ⚖ 233 KB

## Abstract Different analytical and structural methods (Electron Probe Micro‐ Analysis, Single Crystal X‐ray diffraction, X‐ray Photoelectron Spectroscopy, Mössbauer spectroscopy) were combined to fully characterise the crystal chemistry of natural Ti‐bearing garnets from Colli Albani (Lazio, Ital