Molecular and NLO Properties of Red Fluorescent Coumarins - DFT Computations Using Long-Range Separated and Conventional Functionals

Nagaiyan Sekar; Santosh Katariya; Lydia Rhyman; Ibrahim A Alswaidan; Ponnadurai Ramasami

doi:10.1007/s10895-018-2333-1

Molecular and NLO Properties of Red Fluorescent Coumarins - DFT Computations Using Long-Range Separated and Conventional Functionals

J Fluoresc. 2019 Jan;29(1):241-253. doi: 10.1007/s10895-018-2333-1. Epub 2018 Dec 15.

Authors

Nagaiyan Sekar¹, Santosh Katariya², Lydia Rhyman^{3

4}, Ibrahim A Alswaidan⁵, Ponnadurai Ramasami^{6

7}

Affiliations

¹ Department of Dyestuff Technology, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai, 400 019, India. n.sekar@ictmumbai.edu.in.
² Department of Dyestuff Technology, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai, 400 019, India.
³ Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80832, Mauritius.
⁴ Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, Johannesburg, 2028, South Africa.
⁵ Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia.
⁶ Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80832, Mauritius. p.ramasami@uom.ac.mu.
⁷ Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, Johannesburg, 2028, South Africa. p.ramasami@uom.ac.mu.

PMID: 30554293
DOI: 10.1007/s10895-018-2333-1

Abstract

Comparative study of nonlinear optical properties of red fluorescent coumarins was carried out with density functional theory based ab initio method using the popular global hybrid (GH) and range separated hybrid (RSH) functionals and correlated with the spectroscopic values. The GHs - M06 L, PBE1PBE, M06, BHHLYP, M062X and M06HF and RSHs - HISSbPBE, wB97, wB97X, HSEH1PBE, CAM-B3LYP and wB97XD in combination with the double zeta basis function 6-311 + G(d,p) were used. The computed polarizability (α₀), hyperpolarizability of the first order (β₀) and second order (γ) computed by the RSHs are closer to the spectroscopic values compared to GHs. Polarizabilities computed with the functionals BHHLYP and M06-2X are closer with the spectroscopic values. Incorporation of additional cyano group enhances the NLO response. An increase in electrophilic nature contributed from the reduced orbital band gap culminating an increase in α₀, β₀, and γ in all the cases. The NLO response was found to be highly solvent dependent that is the polarity of the micro environment created by the solvents. To understand the agreement and accuracy among the NLO parameters obtained from the selected DFT functionals and the spectroscopic values, the mean absolute error (MAE) and vibrational contribution parameters are presented. Two photon absorption (TPA) cross section depends upon the molecular structure where π-framework is an important factor rather than number of acceptors.

Keywords: DFT; GHs and RSHs; Nonlinear optical properties; Red fluorescent coumarins.

Grants and funding

Faculty Improvement Program/University Grants Commission