Color properties and non-covalent interactions in hydrated (Z)-4-(1-cyano-2-(2,4,5-trimethoxyphenyl)-vinyl)pyridin-1-ium chloride salt: Insights from experimental and theoretical studies

Enrique Pérez-Gutiérrez; Atazaz Ahsin; Youness El Bakri; Perumal Venkatesan; S Thamotharan; M Judith Percino

doi:10.1016/j.heliyon.2023.e21040

Color properties and non-covalent interactions in hydrated (Z)-4-(1-cyano-2-(2,4,5-trimethoxyphenyl)-vinyl)pyridin-1-ium chloride salt: Insights from experimental and theoretical studies

Heliyon. 2023 Oct 18;9(11):e21040. doi: 10.1016/j.heliyon.2023.e21040. eCollection 2023 Nov.

Authors

Enrique Pérez-Gutiérrez¹, Atazaz Ahsin^{2

3}, Youness El Bakri⁴, Perumal Venkatesan^{1

5}, S Thamotharan⁶, M Judith Percino¹

Affiliations

¹ Unidad de Polímeros y Electrónica Orgánica, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Val3, Eco-campus Valsequillo, Independencia O2 Sur 50, San Pedro Zacachimalpa, Pue. Mexico.
² Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
³ School of chemical sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Department of Theoretical and Applied Chemistry, South Ural State University, Lenin prospect 76, Chelyabinsk, 454080, Russian Federation.
⁵ Department of Chemistry, Srimad Andavan Arts and Science College (Autonomous), T.V. Koil, Tiruchirappalli 620 005, India.
⁶ Biomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613 401, India.

Abstract

The optical charge-transfer (CT) property and the crystal structure of (Z)-4-(1-cyano-2-(2,4,5-trimethoxyphenyl)vinyl)pyridin-1-ium chloride monohydrate salt (I), which belongs to an acrylonitrile family, was studied. The title salt, I, was characterized using different spectroscopy techniques and a single-crystal X-ray diffraction study combined with quantum chemical computations. The results showed that the color properties of I are determined by the CT, changes in bandgap, optical absorption, and various non-covalent interactions. The HOMO-LUMO energy gaps are 5.41 eV and 5.23 eV for the precursor and salt, respectively. It was demonstrated that π-π stacking interactions lead to the formation of intercalated dimers and donor-acceptor interactions assisted by hydrogen bonds; the dimers and interactions are different between the precursor and the salt. The cation moiety is mainly stabilized by N(1)⁺-H···Cl, and the anion is predominantly stabilized by strong O(1W)- H⋯ Cl^- bonds as well as the hydrogen bonds with the MeO group O(2W)-H⋯O(1) and O(2W)-H⋯O(1W). The charge transfer between cation and anion moieties in the structure is established through NBO analysis.

Keywords: Charge transfer; Non-covalent interactions; Pyridinium-quaternary salts; Spectroscopic characterization; computational methods.