Yarava, JR and Potnuru, LR and Pahari, B and Tothadi, S and Ramanathan, KV (2022) Supramolecular Synthon Identification in Azelaic Acid – Isonicotinamide Cocrystal by Solid-State NMR. In: Journal of Magnetic Resonance Open, 10-11 .
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Abstract
Supramolecular synthons are the smallest structural units that contain the information inherent in building large molecular assemblies. Here, we apply solid-state NMR methods for the identification of the synthon in a cocrystal of Azelaic acid [(CH2)7(COOH)2]– Isonicotinamide [C6H6N2O]. It is observed that the spin-lattice relaxation time of protons in the cocrystal is long, implying that the choice of experiments, particularly those that involve low-sensitivity nuclei, could be time consuming. It is noticed that the two dimensional 1H double quantum (DQ) – 1H single quantum (SQ) correlation experiment at very fast MAS (60 kHz) is able to provide information on proton-proton proximities that leads to an understanding of the synthon structure. Experiments such as the CP-Reverse CP and 1H–13C HETCOR have been used to obtain spectral assignment which was additionally confirmed by first-principle GIPAW NMR chemical shift calculations. Present study indicates the basic unit to be a heterosynthon in Azelaic acid (AZA) – Isonicotinamide (INIC) cocrystal formed by two different modes of intermolecular connectivity, viz. acid–pyridine and acid–amide hydrogen bonding interactions. The presence of a CH…O type bond involving a hydrogen of INIC is also indicated from the observation of a larger chemical shift of the corresponding proton. The experimental protocol presented in this paper is expected to be a useful tool for the estimation of the basic structural arrangement of the synthons in a rapid fashion.
Item Type: | Journal Article |
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Publication: | Journal of Magnetic Resonance Open |
Publisher: | Elsevier Inc. |
Additional Information: | The copyright for this article belongs to the Author. |
Keywords: | Cocrystal; GIPAW Calculations; Hydrogen bonding; Proton Double Quantum Experiment; Solid State NMR; Supramolecular Synthons |
Department/Centre: | Division of Chemical Sciences > NMR Research Centre (Formerly Sophisticated Instruments Facility) Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Physical & Mathematical Sciences > Physics |
Date Deposited: | 25 Jul 2023 09:24 |
Last Modified: | 25 Jul 2023 09:24 |
URI: | https://eprints.iisc.ac.in/id/eprint/82652 |
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