Proton Transfer on the Edge of the Salt/Cocrystal Continuum: X-Ray Photoelectron Spectroscopy of Three Isonicotinamide Salts
Autor: | Elizabeth J. Shotton, Lucy K. Saunders, Andrew J. Britton, Anuradha R. Pallipurath, Paul T. Edwards, Elizabeth A. Willneff, Sven L. M. Schroeder |
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Rok vydání: | 2021 |
Předmět: | |
Zdroj: | Crystal Growth & Design. 21:6332-6340 |
ISSN: | 1528-7505 1528-7483 |
Popis: | X-ray photoelectron spectroscopy (XPS) has emerged as a technique that allows for characterization and classification of hydrogen bonding and proton transfer interactions in organic crystal structures, in a way that is complementary to crystallography by X-ray or neutron diffraction. Here, we analyze the nitrogen 1s core-level binding energies (BEs) of isonicotinamide (IN) systems with proton transfer between donor and acceptor groups at short distances. We show how a careful calibration of the BE scale places these salt systems correctly on the edge of the so-called salt–cocrystal continuum. We show how performing a fitting analysis of the data that is consistent with elemental analysis, expected stoichiometry, and quantification of adventitious carbon contamination facilitates the determination of absolute BEs with accuracy and reproducibility within ±0.1 eV. The determined N 1s core-level BEs of the protonated IN acceptors suggest that the local geometric arrangements of the donor, acceptor, and proton can influence the N 1s core-level BE significantly. |
Databáze: | OpenAIRE |
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