ePrints@IIScePrints@IISc Home | About | Browse | Latest Additions | Advanced Search | Contact | Help

Supramolecular Synthon Identification in Azelaic Acid – Isonicotinamide Cocrystal by Solid-State NMR

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 .

[img]
Preview
PDF
jou_mag_res_10-11_2022.pdf - Published Version

Download (2MB) | Preview
Official URL: https://doi.org/10.1016/j.jmro.2022.100056

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
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

Actions (login required)

View Item View Item