Concomitant Effects of Transition Metal Chelation and Solvent Polarity on the First Molecular Hyperpolarizability of 4-Methoxyacetophenone Thiosemicarbazone: A DFT Study

Abstract

Nonlinear optical (NLO) properties of organic and metal-organic materials are of considerable interest to emerging optoelectronic and photonic technologies. Much work has been carried out on the former materials but the latter ones have received less attention till date. Herein, a density functional theory (DFT) study on the combined effects of transition metal chelation and solvent polarity on the first hyperpolarizability ( tot ) of 4-methoxyacetophenone thiosemicarbazone (MAPTSC) is reported. MAPTSC exhibits a tautomeric form with higher optical nonlinearity rendering its NLO response in polar solvents potentially switchable. Our results have revealed significant modifications of the first hyperpolarizability of MAPTSC upon complexation with different transition metal chlorides in the presence of solvents with varying dielectric constants. Therefore, its second-order NLO response is highly tunable by the synergy of transition metal chelation and solvent polarity. MAPTSC and its Zn(II) and Pt(II) chloride complexes are promising NLO materials because their gas-phase tot values are larger than those of the prototype push-pull molecules, paranitroaniline (PNA) and urea, by factors of about 1. 40-1.76 and 19.57-37.24, respectively; these factors greatly increase in polar solvent medium. Moreover, they possess high optical transparencies in the visible region of the electromagnetic spectrum which mitigate transparency/nonlinearity trade-offs, thereby increasing the likelihood of broad band NLO response.

Effects of Changing Substituents on the Non-Linear Optical Properties of Two Coumarin Derivatives

“…It has been used frequently as a threshold value of the NLO parameters. As can be noted, the values of all parameters for the compounds studied here are greater than those values found for the urea parameters (µ = 1.37D, α = 3.83 × 10 −24 esu, and γ = 4.16 × 10 −36 esu) [37][38][39]. When our results are compared with those of urea, compound I is 3.1 times greater for the dipole moment, 8.8 times greater for the average linear polarizability and 20.5 times greater for the second hyperpolarizability, while compound II is 2.3 times larger for the dipole moment, 9.0 times greater for linear polarizability, and 19.5 times greater for the average value of the second hyperpolarizability.…”

Third-Order Nonlinear Optical Properties of a Carboxylic Acid Derivative

“…As shown in the Table 2 the values of the average second hyperpolarizability (in units of 10 -36 esu) are 5.39 and 4.77 for isolated molecule and embedded molecule respectively. Although the values of the average dipole moment and average linear polarizability for the CAD were two and three times the urea values respectively, [50][51][52] the values of average second hyperpolarizability are found almost similar to urea (4.16 × 10 -36 esu) and smaller than the value for the L-arginine phosphate monohydrate crystal (14.16 × 10 -36 esu). 34 The calculations for the linear refractive index (n) via Eq.…”

Determination of the structural, electronic, optoelectronic and thermodynamic properties of the methylxanthine molecules theophylline and theobromine

“… 2019b , Fonkem et al. 2019 , 2020 ; Nkungli and Ghogomu 2016 ; Song and Farwell 2004 ). Urea is one of a prototype molecule used for the purpose of comparison in the study of nonlinear optical (NLO) properties of molecular systems.…”

“…Hence, the molecules may equally have applications in linear and nonlinear optical active devices, photonic devices and in molecular electronics (Livshits et al 2014). This is due to the fact that the value of the dipole moment, the average polarizability, molar refractivity and second hyperpolarizability of the molecules at the RHF and DFT levels are larger than the corresponding value of Urea as reported in literature (Tadjouteu Assatse et al 2019b, Fonkem et al 2019Nkungli and Ghogomu 2016;Song and Farwell 2004). Urea is one of a prototype molecule used for the purpose of comparison in the study of nonlinear optical (NLO) properties of molecular systems.…”