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

Retention of strong intramolecular hydrogen bonds in high polarity solvents in binaphthalene-benzamide derivatives: extensive NMR studies

Patel, Arun Kumar and Mishra, Sandeep Kumar and Krishnamurthy, Kiran and Suryaprakash, N (2019) Retention of strong intramolecular hydrogen bonds in high polarity solvents in binaphthalene-benzamide derivatives: extensive NMR studies. In: RSC ADVANCES, 9 (56). pp. 32759-32770.

[img]
Preview
PDF
RSC_Adv_9-50_32759_2019.pdf - Published Version

Download (1MB) | Preview
[img]
Preview
PDF
c9ra07299c1.pdf - Published Supplemental Material

Download (2MB) | Preview
Official URL: https://dx.doi.org/10.1039/c9ra07299c

Abstract

Advanced multidimensional NMR techniques have been employed to investigate the intramolecular hydrogen bonds (HBs) in a series of N,N `-(1,1 `-binaphthalene]-2,2 `-diyl)bis(benzamide) derivatives, with the site-specific substitution of different functional groups. The existence of intramolecular HBs and the elimination of any molecular aggregation and possible intermolecular HBs are ascertained by various experimental NMR techniques, including solvent polarity dependent modifications of HB strengths. In the fluorine substituted derivative, direct evidence for the engagement of organic fluorine in HB is obtained by the detection of heteronuclear through-space correlation and the coupling between two NMR active nuclei where the transmission of spin polarization is mediated through HBs ((1h)J(FH)). The extent of reduction in the strength of (1h)J(FH) on dilution with high polarity solvents directly provided the qualitative measure of HB strength. The HB, although becoming weakened, does not get nullified even in pure high polarity solvent, which is attributed to the structural constraints. The rate of exchange of a labile hydrogen atom with the deuterium of the solvent permitted the measurement of their half-lives, that are correlated to the relative strengths of HBs. The experimental NMR findings are further validated by XRD and DFT-based theoretical computations, such as, NCI and QTAIM.

Item Type: Journal Article
Additional Information: copyright for this article belongs to Royal Society of Chemistry
Department/Centre: Division of Chemical Sciences > NMR Research Centre (Formerly Sophisticated Instruments Facility)
Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Depositing User: Id for Latest eprints
Date Deposited: 29 Nov 2019 12:11
Last Modified: 29 Nov 2019 12:11
URI: http://eprints.iisc.ac.in/id/eprint/64018

Actions (login required)

View Item View Item