Crystallography Aided by Atomic Core‐Level Binding Energies: Proton Transfer versus Hydrogen Bonding in Organic Crystal Structures

Abstract

Ionisch oder H‐verbrückt? Der Transfer von Brønsted‐Protonen zu Stickstoffakzeptoren in organischen Kristallen verursacht starke Verschiebungen der Bindungsenergien des N1s‐Rumpfniveaus. Eine Untersuchung von 15 organischen Cokristall‐ und Salzsystemen zeigt, dass Röntgen‐Photoelektronenspektroskopie ergänzend zur Röntgenkristallographie genutzt werden kann, um Protonentransfer von Wasserstoffbrücken in kondensierter Materie zu unterscheiden (siehe Bild).

Nucleation of Organic Crystals—A Molecular Perspective

“…[71] The ability of core-level spectroscopic methods to probe local chemical interactions even more incisively, especially in the presence of hydrogen bonding and protonation, [72][73][74][75] has been explored in studies of imidazole solutions with X-ray photoelectron spectroscopy. UV/Vis spectroscopy yields information with respect to solute dimerization versus higher-order aggregation, as demonstrated, for example, for the case of imidazole solutions.…”

“…From a CNT perspective, this research direction reveals the nature of the building units of the [86,88] 5-fluorouracil (nitromethane/water) molecular modeling yes (exp. XPS studies of core-level binding energies associated with hydrogen bonding and protonation have already been carried out [72][73][74][75][76][77][78]97] and together with previous studies of core-level shifts caused by van der Waals and dipole interactions [98][99][100] have prepared the ground for more detailed structural studies of solute-solvent interactions, self-association, and cluster formation. [94] benzophenone (methanol, toluene) NMR yes [91] diphenylamine (methanol, toluene) NMR yes [91] p-acetanisidide (chloroform) NMR yes [84] isonicotinamide (methanol, nitromethane) FTIR, Raman yes [89] carbamazepine (methanol, chloroform) NMR yes [105,106] nucleus, and the nature of the building units is related to the attachment frequency of the molecules.…”

Incisive Probing of Intermolecular Interactions in Molecular Crystals: Core Level Spectroscopy Combined with Density Functional Theory

“…6−14 They are very sensitive probes of hydrogen-bonding, 6,7,11,12,15−18 which has a strong effect on physical properties. To give one example, we have applied XPS to the characterization of crystalline organic materials, [7][8][9][10]19 distinguishing Brønsted proton transfer from hydrogen-bonding through chemical shifts in the nitrogen core level photoemission, and relating them to differences between the acidity constants of Brønsted donor and acceptor sites in two-component organic crystals. 7,8 NEXAFS yields additional information through probing of unoccupied valence orbitals, 20 enabling incisive characterization of the local electronic state of functional groups and their interaction with other moieties in the solid.…”

“…To give one example, we have applied XPS to the characterization of crystalline organic materials, 7−10,19 distinguishing Brønsted proton transfer from hydrogen-bonding through chemical shifts in the nitrogen core level photoemission, and relating them to differences between the acidity constants of Brønsted donor and acceptor sites in two-component organic crystals. 7,8 NEXAFS yields additional information through probing of unoccupied valence orbitals, 20 enabling incisive characterization of the local electronic state of functional groups and their interaction with other moieties in the solid. Interpretation of NEXAFS spectra is facilitated by computational methodologies such as modern density functional theory (DFT), 21−25 static exchange (STEX), 26 algebraic diagrammatic construction (ADC(2)), 27,28 and restricted active space self-consistent field (RASSCF).…”

Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) yields better Hydrolytical Stability of Biocompatible SiOx Thin Films on Implant Alumina Ceramics compared to Rapid Thermal Evaporation Physical Vapor Deposition (PVD)

“…The recorded N 1s elemental core spectrum was fitted with one major contributing peak around 399.5 eV, which is characteristic for an unprotonated amino group, and a shoulder peak at 401.9 eV, which is characteristic for a hydrogen bonded amino group, suggesting a high density of amino functionalities on the surface able to interact with each other via H-bonding. 37 The Si 2p spectrum core levels reveal two different chemical oxidation states. In addition, due to the spin-orbit coupling each oxidation state of the Si2p core are represented with a doublet, Si 2p 1/2 and Si 2p 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 4...…”