Original scientific paper

https://doi.org/10.5562/cca3820

Experimental and Theoretical IR Spectra of 2-Nitrosopyridines

Katarina Varga ; Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 542/2, 160 00 Praha 6, Czech Republic
Hrvoj Vančik ; Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
Zlatko Mihalić ; Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia

Abstract

Previously unknown IR spectra of 2-nitrosopyridines 1−3 were recorded in the solid phase after cryogenic photolysis of their dimers, and identified by the comparison with the corresponding theoretical spectra. Optimal results were obtained with double-hybrid (DH) density functionals and def2-TZVP basis set, the best being DSD-PBEP86-D3(BJ), B2GP-PLYP-D3(BJ) and mPW2-PLYP-D2. Experimental frequencies were obtained by scaling harmonic frequencies with appropriate scaling factors, either taken from the literature or calculated using modified HFREQ2014 dataset. In the case of DH functionals, anharmonic frequencies do not offer any advantage in comparison with the scaled harmonic ones. Unexpectedly, all non-DH density functionals, including highly praised ωB97X-V and ωB97M-V, have serious problems with normal modes containing N=O bond stretching vibration. It was concluded that the origin of the problem is in the nitroso group itself, most likely caused by its multireference character. The best results among non-DH functionals were achieved at TPSSh-D3(BJ)/def2-TZVP level of theory.

This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords

cryogenic photolysis; 2-nitrosopyridine; nitroso monomers; vibrational spectra; double-hybrid density functionals; DSD-PBEP86-D3(BJ); harmonic frequencies; anharmonic frequencies; scaling factors

Hrčak ID:

268046

URI

https://hrcak.srce.hr/268046

Publication date:

25.4.2021.

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