Spectroscopic, XRD, Hirshfeld surface and DFT approach (chemical activity, ECT, NBO, FFA, NLO, MEP, NPA& MPA) of (E)-4-bromo-2-[(4-bromophenylimino)methyl]-6-ethoxyphenol

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.

Quantum chemical, spectroscopic and molecular docking studies on methyl 2-chloro-6-methyl pyridine-4-carboxylate: A potential inhibitor for irritable bowel syndrome

The methyl 2-chloro-6-methyl pyridine-4-carboxylate (MCMP) was studied using quantum chemical density functional theory (DFT) approach. The DFT/B3LYP method with cc-pVTZ basis set was employed to obtain the optimized stable structure and vibrational frequencies. The potential energy distribution (PED) calculations were used to assign the vibrational bands. The ¹³C NMR spectrum of MCMP molecule was simulated by the Gauge-Invariant-atomic orbital (GIAO) method using DMSO solution and the corresponding chemical shift values were calculated and observed. The maximum absorption wavelength was obtained using TD-DFT method and were compared with the experimental values. The bioactive nature of the MCMP compound was identified using the FMO analysis. The possible sites of electrophilic and nucleophilic attack were predicted using the MEP analysis and local descriptor analysis. The pharmaceutical activity of the MCMP molecule is validated through the NBO analysis. The molecular docking analysis confirms that the MCMP molecule can be used in the drug designing for the treatment of irritable bowel syndrome (IBS).

Antioxidant activity of novel nitrogen scaffold with docking investigation and correlation of DFT stimulation

Heterocyclic scaffolds are frequently employed in drug development to treat a variety of conditions, including cancers. These substances have the ability to engage covalently or non-covalently with particular residues in the target proteins, inhibiting them. In this study, the formation of N-, S-, and O-containing heterocycles by the interaction of chalcone with nitrogen-containing nucleophiles such as hydrazine, hydroxyl amine, guanidine, urea, and aminothiourea was explored. FT-IR, UV-visible, NMR, and mass spectrometric studies were used to confirm the heterocyclic compounds that were produced. These substances were tested for their antioxidant activity by their capacity to scavenge the artificial radicals 2,2-diphenyl-1-picrylhydrazyl (DPPH). The strongest antioxidant activity was demonstrated by compound 3 (IC₅₀ = 93.4 μM), whereas compound 8 (IC₅₀ = 448.70 μM) had the lowest activity when compared to vitamin C (IC₅₀ 141.9 μM). Also, the experimental findings and the docking estimation of these heterocyclic compounds with PDBID:3RP8 were in agreement. Additionally, the compounds' global reactivity characteristics, such as HOMO-LUMO gaps, electronic hardness, chemical potential, electrophilicity index, and Mulliken charges, were identified using DFT/B3LYP/6-31G(d,p) basis sets. The two chemicals that displayed the best antioxidant activity also had their molecular electrostatic potential (MEP) ascertained using DFT simulations.

Microwave-assisted synthesis, antioxidant activity, docking simulation, and DFT analysis of different heterocyclic compounds

In this investigation, pressure microwave irradiation was used to clarify the activity of 1-(2-hydroxyphenyl)-3-(4-methylphenyl)prop-2-en-1-one (3) towards several active methylene derivatives utilized the pressurized microwave irradiation as green energy resource . Chalcone 3 was allowed to react with ethyl cyanoacetate, acetylacetone, and thioglycolic acid; respectively, at 70 °C with pressure under microwave reaction condition to afford the corresponding 2-hydroxyphenylcyanopyridone, 2-hydroxyphenyl acetylcyclohexanone, and thieno[2,3-c]chromen-4-one derivatives respectively. Moreover, the reaction of chalcone 3 with hydrogen peroxide with stirring affords the corresponding chromen-4-one derivative. All the synthesized compounds were confirmed through spectral tools such as FT-IR, ¹HNMR, ¹³CNMR, and mass spectrum. Furthermore, the synthesized heterocycles were exhibited excellent antioxidant activity and comparable with vitamin C, where the presence of the OH group increases the scavenger radical inhibition. Furthermore, the biological activity of compound 12 was demonstrated through molecular docking stimulation using two proteins, PDBID: 1DH2 and PDBID: 3RP8, which showed that compound 12 possesses greater binding energy and a shorter bond length comparable with ascorbic acid. Also, the compounds were optimized through DFT/B3LYP/6-31G (d,p) basis set and identification of their physical descriptors, whereas the compound 12 was confirmed through X-Ray single structure with Hirsh field analysis of the compound to know the hydrogen electrostatic bond interaction, and correlated with the optimized structure by comparing their bond length, bond angle, FT-IR, and NMR, which gave excellent correlation.

Role of donors in triggering second order non-linear optical properties of non-fullerene FCO-2FR1 based derivatives: A theoretical perspective

The organic compounds are known as an emerging class in the field of nonlinear optical (NLO) materials. In this paper, D-π-A configured oxygen containing organic chromophores (FD2-FD6) were designed by incorporating various donors in the chemical structure of FCO-2FR1. This work is also inspired by the feasibility of FCO-2FR1 as an efficient solar cell. Theoretical approach involving DFT functional i.e., B3LYP/6-311G(d,p) was utilized to achieve useful information regarding their electronic, structural, chemical and photonic properties. The structural modifications revealed significant electronic contribution in designing HOMOs and LUMOs for the derivatives with lowered energy gaps. The lowest HOMO-LUMO band gap obtained was 1.223 eV for FD2 compound in comparison to the reference molecule (FCO-2FR1) i.e., 2.053 eV. Moreover, the DFT findings revealed that the end-capped substituents play a key role in enhancing the NLO response of these push-pull chromophores. The UV-Vis spectra of tailored molecules revealed larger λ _max values than the reference compound. Furthermore, strong intramolecular interactions showed the highest stabilization energy (28.40 kcal mol^-1) for FD2 in the natural bond orbitals (NBOs) transitions, combined with the least binding energy (-0.432 eV). Successfully, the NLO results were favorable for the same chromophore (FD2) which showed the highest value for dipole moment (μ _tot = 20.049 D) and first hyper-polarizability (β _tot = 11.22 × 10^-27 esu). Similarly, the largest value for linear polarizability ⟨α⟩ was obtained as 2.936 × 10^-22 esu for FD3 compound. Overall, the designed compounds were calculated with greater NLO values as compared to FCO-2FR1. The current study may provoke the researchers towards designing of highly efficient NLO materials via using the suitable organic linking species.

Synthesis, nonlinear optical analysis and DFT studies of D-π-D and A-π-A configured Schiff bases derived from bis-phenylenediamine

Herein, an integral approach has been made towards the exploration of electronic and structural parameters of four synthesized (DMA with an A-π-A configuration and DMM, DAM, and DMD with a D-π-D configuration) and one designed (DMB-D) novel Schiff base compounds. Bis phenylenediamine derivatives were prepared by condensation of 4,5-dimethyl-o-phenylenediamine (1) with various substituted benzaldehydes (2a-d). The structures of compounds were confirmed by spectroscopic techniques, i.e., UV-visible, FT-IR, and NMR spectroscopy. The DFT-based analysis of entitled compounds was performed via density functional theory utilizing the M06-2X functional in conjugation with the 6-311G(d,p) basis set to acquire geometrical parameters, natural bonding orbital (NBO), the density of states (DOS), non-linear optical (NLO), molecular electrostatic potential (MESP), and natural population analyses. The smallest band gap of (5.446 eV) was noted for DMAvia frontier molecular orbital (FMO) analysis. GRPs were obtained with the aid of E gap values as DMA with the lowest band gap displayed a small magnitude of hardness (2.723 eV) and a large magnitude of softness (0.183 eV). The β tot values of DMA, DMM, DMB-D, DAM, and DMD were 56.95, 0.43, 2.53, 8.98, and 68.47 times larger than urea (β tot = 3.71 × 10-31 e.s.u.), respectively. The observed fascinating NLO properties of these novel compounds might be helpful for further advancement in non-linear optics.

Crystal structure and Hirshfeld surface analysis of 2-{[(E)-(3-cyclo-butyl-1H-1,2,4-triazol-5-yl)imino]-meth-yl}phenol

The title compound, C13H14N4O, was developed using the reaction of salicyl-aldehyde and 3-amino-5-cyclo-butyl-1,2,4-triazole in ethanol under microwave irradiation. This eco-friendly microwave-promoted method proved to be efficient in the synthesis of 2-{[(E)-(3-cyclo-butyl-1H-1,2,4-triazol-5-yl)imino]-meth-yl}phenol in good yields and purity. The title compound is a Schiff base that exists in the phenol-imine tautomeric form and adopts an E configuration. The three independent mol-ecules in the asymmetric unit (A, B and C) are not planar, the cyclo-butyl and the phenol-imine rings are twisted to each other making a dihedral angle of 67.8 (4)° in mol-ecule A, 69.1 (2)° in mol-ecule B and 89.1 (2)° in mol-ecule C. In each mol-ecule an intra-molecular O-H⋯N hydrogen bond is present, forming an S(6) ring motif. A Hirshfeld surface analysis was performed to investigate the contributions of the different inter-molecular contacts within the supra-molecular structure. The major inter-actions are H⋯H (53%), C⋯H (19%) and N⋯H (17%) for mol-ecule A, H⋯H (50%), N⋯H (20%) and C⋯H (20%) for mol-ecule B and H⋯H (57%), C⋯H (14%) and N⋯H (13%) for mol-ecule C.

Crystal structure and Hirshfeld surface analysis of (Z)-2-{[(2,4-di-methyl-phen-yl)imino]-meth-yl}-4-methyl-phenol

The title compound, C16H17NO, is a Schiff base that exists in the enol-imine tautomeric form and adopts a Z configuration. The mol-ecule is non-planar, with the twisted rings making a dihedral angle of 39.92 (4)°. The intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯π inter-actions and very weak π-π stacking inter-actions also help to consolidate the crystal packing. A Hirshfeld surface analysis was performed to investigate the contributions of different inter-molecular contacts within the supra-molecular structure. The major contributions are from H⋯H (65%), C⋯H (19.2%) and O⋯H (6.6%) inter-actions.

Synthesis, Spectroscopic Characterization (FT-IR, NMR, UV), NPA, NBO, NLO, Thermochemical Analysis and Molecular Docking Studies of 2-((4-hydroxyphenyl)(piperidin-1-yl)methyl)phenol

In this study, a new alkylaminophenol compound was synthesized and characterized by spectroscopic techniques (FT-IR, NMR, UV). The optimized molecular geometry and the vibrational wavenumbers were calculated using density functional theory (DFT) B3LYP/WB97XD and HF methods with 6-311++ G([Formula: see text], [Formula: see text]) basis set. Thus, theoretical data were compared within themselves before comparing with experimental data. The detailed interpretation of the vibrational spectra has been carried out by VEDA program. 1H-NMR and [Formula: see text]C-NMR chemical shifts of the compound were calculated using GIAO/IEFPCM method in CDCl3. Using time-dependent (TD-DFT) approach electronic properties such as HOMO and LUMO energies, the electronic spectrum of the title compound has been studied and reported. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Linear polarizability, anisotropic linear polarizability and hyperpolarizability values of the title compound were found to be higher than the values of the pNA compound that are used as a standard substance in the NLO analysis. Molecular electrostatic potential (MEP), the thermodynamic properties (heat capacity, entropy and enthalpy) were calculated. Also, to investigate the biological properties of the title compound, molecular docking was done with DNA(PDB ID: 414D). It has been observed that the effective interaction is hydrogen bonds.

Crystal structure and Hirshfeld surface analysis of a copper(II) complex containing 2-nitro-benzoate and tetra-methyl-ethylenedi-amine ligands

The reaction of copper(II) sulfatepentahydrate with 2-nitro-benzoic acid and N,N,N',N'-tetra-methyl-ethylenedi-amine (TMEDA) in basic solution produces the complex bis-(2-nitro-benzoato-κO)(N,N,N',N'-tetra-methyl-ethylenedi-amine-κ2 N,N')copper(II), [Cu(C7H4NO4)2(C6H16N2)] or [Cu(2-nitro-benzoate)2(tmeda)]. Each carboxyl-ate group of the 2-nitro-benzoate ligand is coordinated by CuII atom in a monodentate fashion and two TMEDA ligand nitro-gen atoms are coordinate by the metal center, giving rise to a distorted square-planar coordination environment. In the crystal, metal complexes are linked by centrosymmetric C-H⋯O hydrogen bonds, forming ribbons via a R 2 2(10) ring motif. These ribbons are linked by further C-H⋯O hydrogen bonds, leading to two-dimensional hydrogen-bonded arrays parallel to the bc plane. Weak π-π stacking inter-actions provide additional stabilization of the crystal structure. Hirshfeld surface analysis, dnorm and two-dimensional fingerprint plots were examined to verify the contributions of the different inter-molecular contacts within the supra-molecular structure. The major inter-actions of the complex are O⋯H/H⋯O (44.9%), H⋯H (34%) and C⋯H (14.5%).

Molecular docking of potential cytotoxic alkylating carmustine derivatives 2-chloroethylnitrososulfamides analogues of 2-chloroethylnitrosoureas

The objective of this work was the molecular modelling by bio-isostery of 2-chloroethylnitrosoureas CENU into 2-chloroethylnitrososulfamides CENS derived from Carmustine. We evaluated the pharmacodynamic profile of the new chemical class by studying molecular docking using innovative software. Good molecular docking scores were obtained through Auto-dock vina of the PyRx 0.8 software, the energy of the complexes formed (Target-Ligand) during the interaction varies from - 5,400 to -5,700 Kcal/mol, the total average between the 45 conformers is -5,213 Kcal/mol. The results were validated by Auto-dock vina 1.5.6 in collaboration with the Molecular Chemistry and Natural Substances Laboratory at the Meknes Faculty of Science - Morocco, a range of -4,900 to -5,100 Kcal/mol was noted for CENS complexes derived from Carmustine with the 2DND target, reflecting a better CENS chemical affinity to the biological target and the stability of the ligand-DNA complex, compared with the analogue reference Carmustine with a score of - 4,700 Kcal/mol. By superimposing the results of molecular docking, analysis of data from the study of electrophilia based on load transfer ECT and publications on CENS, we can predict that inter-strand crosslink is likely to occur between the Guanine dG22 of strand B and the Cytosine dC3 of strand A, located in the poly dA-poly dT segment end within the narrow minor groove of the DNA target (2DND). The molecular docking study was a preliminary approach to understand the therapeutic mode of action of CENS.Communicated by Ramaswamy H. Sarma.