Exploration of Chromone-Based Thiosemicarbazone Derivatives: SC-XRD/DFT, Spectral (IR, UV–Vis) Characterization, and Quantum Chemical Analysis

Abstract

By the condensation of thiosemicarbazide with coumarin aldehyde, two novel substituted thiosemicarbazones with chemical formulae C24H25N3O3S (3a) and C26H23N3O3S (3b) have been synthesized. The synthesized compounds were resolved using SC-XRD, and structure elucidation was carried out using 1H NMR, 13C NMR, UV–visible, and FT-IR spectroscopic analyses. Computational calculations at the B3LYP/6-311+G­(d,p) level of theory were performed to countercheck the experimental (UV–vis, FT-IR) findings and explore the electronic (FMO, NBO, MEP) properties of 3a–b. The nonlinear optical (NLO) properties of 3a–b were estimated using B3LYP, HF, LC-BLYP, CAM-B3LYP, M062X, and M06 functionals in combination with the 6-311+G­(d,p) basis set. The crystallographic data revealed that compounds were crystallized as an orthorhombic crystal lattice with the Pbcn space group and the triclinic crystal lattice with the P̅1 space group. A good concurrence among experimental SC-XRD-generated bond lengths, bond angles, FT-IR, UV–vis, and corresponding DFT results was found, which confirms the purity of both compounds. The NBO analysis confirmed the presence of intramolecular hydrogen bonding and hyperconjugative interactions, which not only were the pivotal cause of stability of the investigated compounds but also led to an overwhelming NLO response. The energy differences calculated for HOMO/LUMO are 3.053 and 3.118 eV in 3a and 3b, respectively. The crystal 3b showed a higher value of first-order polarizability at all levels of theory than 3a. Overall results show that the crystals under investigation are polarized in nature with a good dipole moment. A comparative analysis with urea molecules clearly indicates that the studied compounds are acceptable NLO candidates and they can be used for future technological applications.

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

“…Similarly, the γ amplitudes of BTCC and MBTB are also larger than the ferrocenylethyl-thiosemicarbazone derivatives (1, 2, and 3) studied by Jawaria et al 45 and Shkir et al 46 Furthermore, a comparison with hydrazinecarbothioamide derivatives shows that compound MBTB possesses slightly larger amplitudes than the reported derivatives. 47 These comparable γ amplitudes indicate that the above-entitled compounds will be penitential candidates for efficient thirdorder NLO applications. 3.3.…”

Facile Synthesis of Diversely Functionalized Peptoids, Spectroscopic Characterization, and DFT-Based Nonlinear Optical Exploration

“…FMO analysis is mostly used to explain different properties like reactivity, molecular interactions, electronic features, chemical stability, and charge transfer in different compounds. − Various chemists and physicists have exercised FMO investigation to expose the structural and geometrical characteristics of investigated systems. − The aptitude of a molecule to donate or accept the charge density is estimated through FMOs (HOMO and LUMO) energies. , Moreover, the energy gap between HOMO and LUMO ( E g = E LUMO – E HOMO ) is a key sign for nonlinear optical behavior of a compound and also used to gauge several parameters including chemical reactivity, ionization potential, chemical hardness, and chemical softness. A compound is considered soft, least stable, and highly reactive if it has a narrow HOMO–LUMO energy gap and vice versa. , FMO results of 1–4 are presented in Table .…”

Structural, Electronic, Reactivity, and Conformational Features of 2,5,5-Trimethyl-1,3,2-diheterophosphinane-2-sulfide, and Its Derivatives: DFT, MEP, and NBO Calculations

“…Hence, MEP has mainly been employed to describe the chemical reactivity of several biological systems involved in electrophilic and hydrogen bonding interactions [59,60]. MEP diagram is essential for researchers looking into the physicochemical characteristics of molecules since it shows the molecule size, shape, and negative, positive, and natural electrostatic potentials [61]. It was used to figure out where nucleophilic and electrophilic attacks will most likely [62].…”