Multiple Intramolecular Hydrogen Bonding in Large Biomolecules: DFT Calculations and Deuterium Isotope Effects on 13C Chemical Shifts as a Tool in Structural Studies

Poul Erik Hansen, Fadhil S. Kamounah

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstract

Large biomolecules often have multiple intramolecular hydrogen bonds. In the cases where these interact, it requires special tools to disentangle the patterns. Such a tool could be deuterium isotope effects on chemical shifts. The use of theoretical calculations is an indispensable tool in such studies. The present paper illustrates how DFT calculations of chemical shifts and deuterium isotope effects on chemical shifts in combination with measurements of these effects can establish the complex intramolecular hydrogen bond patterns of rifampicin as an example) The structures were calculated using DFT theoretical calculations, performed with the Gaussian 16 software. The geometries were optimized using the B3LYP functional and the Pople basis set 6-31G(d) and the solvent (DMSO) was taken into account in the PCM approach. Besides the 6-31G(d) basis set, the 6-31 G(d,p) and the 6-3111G(d,p) basis sets were also tested. The nuclear shieldings were calculated using the GIAO approach. Deuteriation was simulated by shortening the X-H bond lengths by 0.01 Å.

OriginalsprogEngelsk
TidsskriftChemistry
Vol/bind5
Udgave nummer2
Sider (fra-til)1317–1328
Antal sider12
ISSN2624-8549
DOI
StatusUdgivet - 1 mar. 2023

Emneord

  • density functional calculations
  • Hydrogen binding
  • deuterium isotope effects on chemical shifts
  • large biomolecules

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