Single-Crystal Investigation, Hirshfeld Surface Analysis, and DFT Study of Third-Order NLO Properties of Unsymmetrical Acyl Thiourea Derivatives

Muhammad Ashfaq; Muhammad Nawaz Tahir; Shabbir Muhammad; Khurram Shahzad Munawar; Akbar Ali; Georgii Bogdanov; Saleh S Alarfaji

doi:10.1021/acsomega.1c04884

Single-Crystal Investigation, Hirshfeld Surface Analysis, and DFT Study of Third-Order NLO Properties of Unsymmetrical Acyl Thiourea Derivatives

ACS Omega. 2021 Nov 12;6(46):31211-31225. doi: 10.1021/acsomega.1c04884. eCollection 2021 Nov 23.

Authors

Muhammad Ashfaq¹, Muhammad Nawaz Tahir¹, Shabbir Muhammad², Khurram Shahzad Munawar³, Akbar Ali⁴, Georgii Bogdanov⁵, Saleh S Alarfaji⁶

Affiliations

¹ Department of Physics, University of Sargodha, Sargodha 40100, Pakistan.
² Department of Physics, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
³ Department of Chemistry, University of Sargodha, Sargodha 40100, Pakistan.
⁴ Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan.
⁵ Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, California 92697, United States.
⁶ Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.

Abstract

In the current research work, unsymmetrical acyl thiourea derivatives, 4-((3-benzoylthioureido)methyl)cyclohexane-1-carboxylic acid (BTCC) and methyl 2-(3-benzoylthioureido)benzoate (MBTB), have been synthesized efficiently. The structures of these crystalline thioureas were unambiguously confirmed by single-crystal diffractional analysis. The crystallographic investigation showed that the molecular configuration of both compounds is stabilized by intramolecular N-H···O bonding. The crystal packing of BTCC is stabilized by strong N-H···O bonding and comparatively weak O-H···S, C-H···O, C-H···π, and C-O···π interactions, whereas strong N-H···O bonding and comparatively weak C-H···O, C-H···S, and C-H···π interactions are responsible for the crystal packing of MBTB. The noncovalent interactions that are responsible for the crystal packing are explored by the Hirshfeld surface analysis for both compounds. The void analysis is performed to find the quantitative strength of crystal packing in both compounds. Additionally, state-of-the-art applied quantum chemical techniques are used to further explore the structure-property relationship in the above-entitled molecules. The optimization of molecular geometries showed a reasonably good correlation with their respective experimental structures. Third-order nonlinear optical (NLO) polarizability calculations were performed to see the advanced functional application of entitled compounds as efficient NLO materials. The average static γ amplitudes are found to be 27.30 × 10^-36 and 102.91 × 10^-36 esu for the compounds BTCC and MBTB, respectively. The γ amplitude of MBTB is calculated to be 3.77 times larger, which is probably due to better charge-transfer characteristics in MBTB. The quantum chemical analysis in the form of 3-D plots was also performed for their frontier molecular orbitals and molecular electrostatic potentials for understanding charge-transfer characteristics. We believe that the current investigation will not only report the new BTCC and MBTB compounds but also evoke the interest of the materials science community in their potential use in NLO applications.