New look at the Badger-Bauer rule: Correlations of spectroscopic IR and NMR parameters with hydrogen bond energy and geometry. FHF complexes
Abstract
In this work correlation dependencies between hydrogen bond energy ΔE for complexes with Fsbnd H⋯F hydrogen bond and their spectroscopic characteristics of the IR and NMR spectra are presented. We considered 26 complexes in a wide hydrogen bond energy range 0.2-47 kcal/mol. For each complex we calculated complexation energy (MP2/6-311++G(d,p)), IR spectroscopic parameters (FH stretching frequency ν, FH stretching frequency in local mode approximation νLM at MP2/6-311++G(d,p) level) and NMR parameters (chemical shift of hydrogen δH and fluorine nuclei δF, Nuclear Independent Chemical Shielding and spin-spin coupling constants 1JFH, 1hJH...F, 2hJFF at B3LYP/pcSseg-2 level). It was shown that changes of parameters upon complexation, i.e. changes of the stretching frequency in local mode approximation ΔνLM, change of the proton chemical shift ΔδH and change of the absolute value of spin-spin coupling constant 1JFH could be used for estimation of corresponding hydrogen bond strength. Furthermore, we build correlation dependencies between abovementioned spectroscopic characteristics and geometric ones, such as the asymmetry of bridging proton position q1 = 0.5·(rFH - rH…F).
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- July 2018
- DOI:
- 10.1016/j.molstruc.2018.03.018
- Bibcode:
- 2018JMoSt1164..129T
- Keywords:
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- Badger-Bauer rule;
- Hydrogen bond energy;
- Vibrational local mode;
- NMR spectroscopy;
- IR spectroscopy;
- FHF complexes