Ensemble-averaged ab initio magnetic resonance and double resonance spectra and line shapes in heterogenous condensed phase systems.
Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
Final Report Abstract
The granted research proposal was composed of three sub-projects, all under the broad umbrella of atomistic/molecular simulations of magnetic resonance signals, with the aim of understanding the underlying relation to molecular structure and dynamics. In one of the sub-projects (Overhauser effect dynamic nuclear polarization in insulating solids), the initially planned objective was to improve our understanding of the theory underlying the effect. Here, not only have we achieved the initially desired objectives, but we have achieved several other milestones beyond that, which in the initial planning of the project were only conceived to be possible in a second funding period. Thus, we have used a high level multireference quantum chemical method to validate our initially proposed hypothesis which was based on density functional theory. We have furthermore calculated important vibronic coupling parameters, enabling us to develop some intuitive understanding of the structure-efficiency relationship. We have then put these new developments to work, and screened several candidate novel polarizing agents, and in collaboration with several experimental groups (organic synthesis, EPR spectroscopy, DNP), we were able to synthesize two successfull novel OE-DNP polarizing agents. This research grant has thus enabled a true advancement in the state of the art, starting from a situation when there was only one molecule which was known to exhibit OE-DNP in insulating solids, with an unknown underlying mechanism, to the current state where we have a falsifiable theoretical explanation that has succesfully resulted in obtaining two new polarizing agents, and draws a roadmap for the design of novel agents with the desirable properties. With our work, the quest to optimally design OE-DNP polarizing agents has become that of designing MV compounds with the desired electron hopping rate under a particular experimental setup, a quest that can be pursued building upon the enormous existing literature on MV compounds, for instance for designing polarizing agents that are suitable for biological samples close to physiological conditions. The extra time dedicated to the OE-DNP project was taken away from the ENDOR sub-project, to which there was no tine to dedicate a significant effort. Regarding the third sub-project, where we investigated the relationship between NMR scalar jcouplings and hydrogen bond characteristics, in particular its covalency, we have achieved the first desired milestone and obtained the desired relationships for a model system, namely amorphous ice. The next step is applying this knowledge to a globular protein, and investigate the extent one can use experimentally measured j-couplings to more broadly understand intramolecular hydrogen bonds.
Publications
- Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation, Sci. Adv., 2020, 6, eaay7074
H. Elgabarty, T. Kampfrath, D. J. Bonthuis, V. Balos, N. K. Kaliannan, P. Loche, R. R. Netz, M. Wolf, T. D. Kühne and M. Sajadi
(See online at https://doi.org/10.1126/sciadv.aay7074) - Mixed-Valence Compounds as Polarizing Agents for Overhauser Dynamic Nuclear Polarization in Solids, Angew. Chem. Int. Ed., 2021, 60, 15371–15375
A. Gurinov, B. Sieland, A. Kuzhelev, H. Elgabarty, T. D. Kühne, T. Prisner, J. Paradies, M. Baldus, K. L. Ivanov and S. Pylaeva
(See online at https://doi.org/10.1002/anie.202103215) - Organic Mixed-Valence Compounds and the Overhauser Effect in Insulating Solids, J. Phys. Chem. A, 2021, 125, 867–874
S. Pylaeva, P. Marx, G. Singh, T. D. Kühne, M. Roemelt and H. Elgabarty
(See online at https://doi.org/10.1021/acs.jpca.0c11296) - Time-resolved terahertz–Raman spectroscopy reveals that cations and anions distinctly modify intermolecular interactions of water, Nat. Chem., 2022, 14, 1031–1037
V. Balos, N. K. Kaliannan, H. Elgabarty, M. Wolf, T. D. Kühne and M. Sajadi
(See online at https://doi.org/10.1038/s41557-022-00977-2)
