Towards a better comprehension of interactions in the crystalline N-acetylbenzylamine and its sulphur analogue N-benzyl-ethanethioamide. IR, Raman, DFT studies and Hirshfeld surfaces analysis

Wioleta Edyta Śmiszek-Lindert; Elżbieta Chełmecka; Olaf Lindert; Anna Dudzińska; Ilona Kaczmarczyk-Sedlak

doi:10.1016/j.saa.2018.05.021

Towards a better comprehension of interactions in the crystalline N-acetylbenzylamine and its sulphur analogue N-benzyl-ethanethioamide. IR, Raman, DFT studies and Hirshfeld surfaces analysis

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Aug 5:201:328-338. doi: 10.1016/j.saa.2018.05.021. Epub 2018 May 8.

Authors

Wioleta Edyta Śmiszek-Lindert¹, Elżbieta Chełmecka², Olaf Lindert³, Anna Dudzińska⁴, Ilona Kaczmarczyk-Sedlak⁵

Affiliations

¹ Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellońska 4, 41-200 Sosnowiec, Poland. Electronic address: wlindert@sum.edu.pl.
² Department of Statistics, School of Pharmacy with Division of Laboratory Medicine, Medical University of Silesia, 30 Ostrogórska Street, 41-200 Sosnowiec, Poland.
³ Clinic of Infertility Treatment, Gynecology and Obstetrics, Bocian Clinic in Katowice, Dąbrówki 13, 40-081 Katowice, Poland.
⁴ Institute of Building Materials and Structures, Faculty of Civil Engineering, Cracow University of Technology, 31-155 Cracow, Poland.
⁵ Department of Pharmacognosy and Phytochemistry, Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Jagiellońska 4, 41-200 Sosnowiec, Poland.

PMID: 29763826
DOI: 10.1016/j.saa.2018.05.021

Abstract

This paper presents the investigation results of the polarized IR spectra of the hydrogen bond in crystals of N-acetylbenzylamine and its sulphur analogue N-benzyl-ethanethioamide. The spectra were measured at 298 and 77 K by a transmission method, with the use of polarized light. The Raman spectroscopy, Hirshfeld surfaces analysis and DFT studies have been also reported. Theoretical calculations of the isolated molecule were performed by using density functional theory (DFT) method at B3LYP/6-311(d,p), B3LYP/6-311++G(d,p) and B3LYP/6-311++G(3df,2pd) basis set levels. The geometrical parameters of analyzed compounds are in good agreement with the XRD experiment. The vibrational frequencies were calculated and subsequently values have been compared with the experimental Infrared and Raman spectra. It has been shown that the observed and calculated frequencies are found to be in good agreement, as well as the analysis of the Hirshfeld surface has been well correlated to the spectroscopic studies. Additionally, the highest occupied molecular orbital energy (E_HOMO), lowest unoccupied molecular orbital energy (E_LUMO), the energy gap between E_HOMO and E_LUMO (ΔE_HOMO-LUMO), molecular electrostatic potential and global reactivity descriptors viz. chemical potential, global hardness and electrophilicity have been calculated. In N-acetylbenzylamine the presence of the N-benzylamide fragment is essential for activity.

Keywords: DFT calculations; HOMO and LUMO; Hirshfeld surfaces; Hydrogen bond; IR and Raman spectra.