Theoretical insights into the static chemical reactivity and NLO properties of some conjugated carbonyl compounds: case of 5-aminopenta-2,4-dienal derivatives

Remarkable enhancement of the nonlinear optical behavior towards asymmetric substituted D-π-A dithiophene-based compounds

CONTEXT

Nonlinear optics (NLO) is an interesting field that discloses the interaction between intense light and matter, leading to a deeper understanding of NLO phenomena. Organic chromophores are considered as promising materials for NLO due to their exceptional structural versatility, ease of processing, and rapid response to NLO effects. Functional materials based on thiophene have been indispensable in advancing organic optoelectronics. Specifically, dithiophene-based compounds display weaker aromaticity, reduced steric hindrance, and additional sulfur-sulfur interactions. Hence, by utilizing dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) as the core structure, designing of a set of organic compounds with D1-π-D2-π-A-type framework, namely ZR1D1-ZR1D8, was carried out in this study. The analysis of frontier molecular orbitals (FMOs) revealed that compound ZR1D2 has the lowest band gap of 1.922 eV among all the investigated chromophores. The correlation of global reactivity parameters (GRPs) with the band gap values indicates that ZR1D2 displays a hardness of 0.961 eV and a softness of 0.520 eV-1. Among the studied compounds, ZR1D2 demonstrated a broad absorption spectrum that extended across the visible region. The maximum absorption wavelengths were observed at 766.470 nm for ZR1D2 and 749.783 nm for ZR1D5. These DTBDT-based dyes exhibit a remarkable NLO response with exceptionally high first hyperpolarizability (βtot) values. Among them, compound ZR1D2 stands out with the highest average linear polarizability (⟨α⟩ = 3.0 × 10-22 esu), first hyperpolarizability (βtot = 4.1 × 10-27 esu), and second hyperpolarizability (γtot = 7.5 × 10-32 esu) values. In summary, this investigation offers valuable insights into the potential use of DTBDT-based organic chromophores, particularly ZR1D2, for advanced applications in NLO. These findings suggest promising opportunities for researchers to synthesize these molecules and utilize these compounds in hi-tech NLO-based applications.

METHODOLOGY

The density functional theory computations were performed at the M06/6-311G(d,p) functional to explore their structural effects on electronic and NLO findings. Various analyses like highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps, absorption maxima, density of states, open circuit voltage, binding energies of electrons and holes, and transition density matrix are employed to investigate photovoltaic efficiencies of the derivatives. Different software packages like Avogadro, Multiwfn, Origin, GaussSum, PyMOlyze, and Chemcraft were used to deduce conclusions from the output files.

Nonlinear optical properties of azo sulfonamide derivatives

CONTEXT

The present work deals with the linear and nonlinear optical properties such as the dipole moment, polarizability, total hyperpolarizability, electric field-induced second harmonic generation, and hyper-Rayleigh scattering first hyperpolarizability of four heterocyclic azo compounds containing the sulfonamide group considered promise in nonlinear optic. The obtained polarizability and hyperpolarizability were supported by the frontier molecular orbital analysis. The properties have been effectively estimated and thoroughly examined to shed light on the nonlinear optical activity based on the density functional theory. The observed results show a high total first hyperpolarizability β tot up to 2503 a.u. and a low energy gap E g less than 1.41 eV. An inverse relationship has been obtained between the β tot and E g . The calculated E g values confirm that charge occurs within the azo sulfonamides. The new study provides a promising avenue for the development of these azo sulfonamides as novel NLO materials.

METHODS

The molecular modeling and the theoretical studies were performed with Gaussian software packages. The B3LYP/6-311 + G** level was used for optimization. All the linear and nonlinear optical properties reported here are obtained using the DFT. The optimized structures and their frontier molecular orbitals were plotted using the GaussView 5.1 program.

Comprehensive quantum chemical study of the associative complex of para-aminobenzoic acid and 7-diethylamino 4-methyl coumarin by adsorption and aromatic bridges

CONTEXT

The present study accounts for the quantum chemical and nonlinear optical properties of the combination of para-aminobenzoic acid and 7-diethylamino 4-methyl coumarin. Three different complexes were designed, surface interaction (adsorption) and two by connecting both molecules with π-bridge benzene and biphenyl. The amino and carboxyl groups were observed to behave as strong donor and acceptor sites in all the complexes. The band gap of the adsorbed complex was found more suitable. The absorption wavelength and intensity both were seen to increase with the increase in the number of benzene rings in the π-bridge. The values of first- and second-order hyperpolarizability suggest the improved nonlinear optical responses of the introduced complexes. Additionally, the negative value of second-order hyperpolarizability suggests the possibility of the occurrence of reverse saturable absorption in these combinations. The reported work gives theoretical insights into the nonlinear optical properties of the combination of para-aminobenzoic acid and 7-diethylamino 4-methyl coumarin.

METHODS

The molecular modeling and the quantum chemical studies were performed with Gaussian software packages. The standard B3LYP-6-311++G(d,p) basis functionals were used for energy minimization and other spectral calculations. All the surface analyses reported here are obtained by employing Multiwfn software. The chemical reactivity was established by the global reactivity descriptors. The intramolecular interactions and charge localization were stated using inter-fragment charge transfer analysis.

Theoretical design of transition metal-doped oxo-triarylmethyl as a disposable platform for adsorption of ibuprofen

Emerging environmental contaminants have become a crucial environmental issue because of the highly toxic effluents emitted by factories. Ibuprofen (IBP), as a typical anti-inflammatory drug, is frequently detected in water sources. Therefore, its removal using various adsorbents has drawn great interest. Herein, the structural, electronic, energetic, and optical properties of pristine oxo-triarylmethyl (oxTAM) and transition metal-doped oxo-triarylmethyl (TM@oxTAM, TM = Sc, Ti, V, Cr, and Mn) for adsorption of the IBU drug were investigated using density functional theory (DFT) calculations implemented in Gaussian and VASP codes. Frontier molecular orbital (FMO), density of states (DOS), and electronic band structure results demonstrated that transition metal-doped oxTAM causes a significant reduction in the energy band gap (Eg) value of pristine oxTAM, with the highest decrease (30.14 %) in the case of Mn@oxTAM. It was found that transition metal doping onto oxTAM leads to an increase in the adsorption energies (1.20-2.64 eV) and charge density between transition metal and IBU. Natural bond orbital (NBO) analysis revealed that charge was effectively transferred from the IBU towards the transition metal, which was further analyzed by charge decomposition analysis (CDA). Furthermore, quantum theory of atoms in molecules (QTAIM), interaction region indicator (IRI), electron localization function (ELF), and radial distribution function (RDF) analyses revealed that the IBU is adsorbed on the Sc@oxTAM surface via covalent interactions, while electrostatic with partially covalent interactions are dominated in other IBU/TM@oxTAM complexes. The results suggest that TM doping on the oxTAM provides a new insight for developing photocatalyst-based covalent organic frameworks (COFs) to remove emerging pollutants in wastewater.

Theoretical study of the Tetraaminelithium and Tetraaminesodium molecules complexed with H-, Li- and Na- anions: static and dynamic NLO parameters

CONTEXT

This work focuses on the study of six molecules composed of the TetraAmineLithium (TALi+) and TetraAmineSodium (TANa+) structures linked with the anions H-, Li- and Na-. The NLO results obtained by these calculations showed significant values of static first hyperpolarizabilities (βtot) ranging from 8.74 * 10-30 to 691.99 * 10-30 esu. The two molecules TALi-Li and TALi-Na gave the highest values of static βtot equal to 563.20 and 691.99 * 10-30 esu respectively and static second hyperpolarizabilities (γav) of 680.02 and 779.05 * 10-35 esu. The highest dynamic first hyperpolarizabilities (β||) values are around 1474080.00 * 10-30 esu and 6,145,080.00 * 10-30 esu at 720 nm lasers and which are attributed to the two molecules TANa-Li and TANa-Na respectively. Four molecules have push-pull behavior where the anions are donor groups, the Li+-NH3 and Na+-NH3 groups are acceptor groups and a bridge composed by the three remaining NH3 ligands. The maximum wavelengths (λmax) in vacuum and in the presence of solvents for all molecules are in the range 240 to 870 nm.

METHOD

The software used in this study is Gaussian 16. The optimizations of the molecules were calculated by B3LYP-D3/6-31 +  + G(d,p). The static first hyperpolarizability (βtot) was calculated by different functionals: CAM-B3LYP, LC-wPBE, LC-BLYP, M11, wB97X, HSEh1PBE and M06-2X and the MP2 method, the basis-set used is 6-31 +  + G(d,p). Other calculations of static βtot were carried out by the CAM-B3LYP functional combined with several basis-sets: 6-31G(d,p), 6-31 +  + G(d,p), cc-pVDZ, AUG-cc- pVDZ, 6-311G(d,p), 6-311 +  + G(d,p), cc-pVTZ and AUG-cc-pVTZ. The calculations of the first (β||) and second (γ||) hyperpolarizabilities in second harmonic generation (SHG) were calculated by CAM-B3LYP/6-31 +  + G(d,p). The delocalization energies (E(2)) were determined by the NBO approach and calculated by the same functional and basis-set cited before. The solvation Gibbs energies (ΔGsolv) were calculated using the implicit SMD model. Maximum wavelengths (λmax) and oscillator strengths ([Formula: see text]) were calculated by TD-CAM-B3LYP/6-31 +  + G(d,p) in the presence of the implicit CPCM model.

Oxo-Carotenoids as Efficient Superoxide Radical Scavengers

Oxo-carotenoids containing conjugated carbonyl groups in their chains were designed to be more efficient superoxide radical scavengers than natural carotenoids, β-carotene and canthaxanthin. A practical chain-extension method for polyene dials (e.g., crocetin dial) was also proposed based on Horner–Wadsworth–Emmons olefination. Double aldol condensation between polyene dials and acetophenones with ring substituents produced oxo-carotenoids with substituted benzene rings. The antioxidant activity of oxo-carotenoids was measured using DPPH (radical) and ABTS (cationic radical) scavenging assays and compared with the analysis with the superoxide (anionic radical) probe. An effective conjugation length by carbon–carbon double bonds is important to provide superior antioxidant activity for oxo-carotenoids, regardless of the type of radical probe used in the assay. Increasing electron density is favorable to strong antioxidant activity in DPPH, and the phenol group is favored in ABTS, whereas electron deficient oxo-carotenoids are very potent in the superoxide radical assay. All oxo-carotenoids exhibited 105~151% better superoxide radical scavenging activity compared to beta-carotene (100%), whereas 38~155% in DPPH and 16~96% in ABTS radical scavenging activities were observed.