Determination of H-atom positions in organic crystal structures by NEXAFS combined with density functional theory: a study of two-component systems containing isonicotinamide

DOI: 10.1021/acs.jpca.2c00439

Authors: Paul T. Edwards (University Of Leeds; Diamond Light Source) , Lucy K. Saunders (Diamond Light Source) , David C. Grinter (Diamond Light Source) , Pilar Ferrer (Diamond Light Source) , Georg Held (Diamond Light Source) , Elizabeth J. Shotton (Diamond Light Source) , Sven L. M. Schroeder (University of Leeds; Diamond Light Source; Research Complex at Harwell (RCaH))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry A

State: Published (Approved)
Published: May 2022
Diamond Proposal Number(s): 29334

Abstract: It is important to be able to identify the precise position of H-atoms in hydrogen bonding interactions to fully understand the effects on the structure and properties of organic crystals. Using a combination of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory (DFT) quantum chemistry calculations, we demonstrate the sensitivity of core-level X-ray spectroscopy to the precise H-atom position within a donor-proton-acceptor system. Exploiting this sensitivity, we then combine the predictive power of DFT with the experimental NEXAFS, confirming the H-atom position identified using single-crystal X-ray diffraction (XRD) techniques more easily than using other H-atom sensitive techniques, such as neutron diffraction. This proof of principle experiment confirms the H-atom positions in structures obtained from XRD, providing evidence for the potential use of NEXAFS as a more accurate and easier method of locating H-atoms within organic crystals.

Journal Keywords: Nitrogen; Amides; Energy; Crystal structure; X-ray absorption near edge spectroscopy

Subject Areas: Chemistry, Technique Development


Instruments: B07-B-Versatile Soft X-ray beamline: High Throughput

Added On: 12/05/2022 09:59

Documents:
acs.jpca.2c00439.pdf

Discipline Tags:

Physical Chemistry Technique Development - Chemistry Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Near Edge X-ray Absorption Fine Structures (NEXAFS)