Molecular Electrostatic Potential Maps Research Articles

Computational, Investigational Explorations on Structural, Electro-Optic Behavior of Pelargonidin Organic Colorant for TiO2 Based DSSCs

In an expedition for green-energy generation and to lower the cost per watt of solar energy, environmentally friendly biotic colorants were separated from Tectona grandis seeds. The prime colorant in the extract is pelargonidin which sensitizes titanium dioxide (TiO2)-based photo anodes. The pelargonidin-sensitized TiO2 nanomaterials endured structural, photosensitive, spectral and current-voltage interpretations. Frontier molecular orbital analysis, physicochemical and electronic parameter computation, UV–visible and DOS spectral analysis, van der Waals prediction and molecular electrostatic potential map were performed theoretically with Gaussian tools, and IR symmetry response was computed using the crystal maker software package. The pelargonidin-sensitized TiO2-created dye-sensitized solar cells which exhibited capable solar light energy to photon conversion proficiency. For comparative purposes, the commercial P25 Degussa TiO2-based DSSC was also fabricated and its proficiency was analyzed. The commercial TiO2 exhibited 57 % higher proficiency in comparison to the sol-gel-derived TiO2-based DSSC.

Density Functional Theory and Ab Initio Hartree-Fock Computational Study of 2-[1-Acetyl-3-Methyl-4,5-Dihydro-1H-1,2,4-Triazol-5-One-4-Yl]-Phenoxyacetic Acide

In the present theoretical study, the 2-[1-acetyl-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl]-phenoxyacetic acide was optimized by B3PW91 and HF methods 6-311+G (d.p) basis set using the Gaussian G09W program. The molecular structure, HOMO and LUMO energy analysis, electronic transitions, total static dipole moment, the mean polarizability, the anisotropy of the polarizability, the mean first-order hyperpolarizability, electronegativity, chemical hardness, molecular electrostatic potential maps (MEP) and Mulliken charges of 2-[1-acetyl-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl]-phenoxyacetic acide molecule have been investigated by using B3PW91 and HF methods with the 6-311+G (d, p) basis set. The calculated IR data of titled compound were calculated in gas phase by using of 6311+G (d, p) basis sets of B3PW91 and HF methods and are multiplied with appropriate adjustment factors. Theoretical infrared spectrums are formed from the data obtained according to B3PW91 method. In the identification of calculated IR data was used the veda4f program. 1H-NMR and 13C-NMR spectral data values were calculated according to the method of GIAO using the program package Gaussian G09W Software. Experimental data were obtained from the literature. Experimental and theoretical values were inserted into the graphic according to equitation of δ exp=a+b. δ calc. The standard error values were found via SigmaPlot program with regression coefficient of a and b constants. In addition, in vitro antioxidant properties of this compound was investigated.

Alkali and Transition Metal-Doped 15-Crown-5 with Enhanced Nonlinear Optical Response: A DFT Study

In this study, geometries, electronic structure and first hyperpolarizability of metals doped 15-crown-5 (C5M) were explored through the density functional theory (DFT) method. Alkali metals (Li, Na, K) and silver (Ag) were placed inside and outside of the crown ether, respectively, to deliver three compounds designated as Li[C5M]Ag, Na[C5M]Ag and K[C5M]Ag. All designed complexes were optimized at singlet, triplet, quintet and septet states, where the singlet state was identified as the stable state. The influence of doping on C5M can be investigated by energy gap fluctuation and it was noted that the smallest energy gap (4.68[Formula: see text]eV) was exhibited by K[C5M]Ag among all the intentional complexes, in contrast to reference C5M (12.73[Formula: see text]eV). Moreover, the density of state (DOS), transition density matrix (TDM), noncovalent interaction (NCI), molecular electrostatic potential (MESP) and electron density distribution map (EDDM) analysis were implemented. Static isotropic polarizability values were observed in the range of [Formula: see text]–[Formula: see text] esu which were comparable to dynamic isotropic polarizability values; [Formula: see text]–[Formula: see text]. Li[C5M]Ag revealed maximum first hyperpolarizability ([Formula: see text]) of [Formula: see text][Formula: see text]esu with the minimum transition energy ([Formula: see text]) of 2.93[Formula: see text]eV.

Analysis of the Comparative Growth Kinetics of Paenarthrobacter ureafaciens YL1 in the Biodegradation of Sulfonamide Antibiotics Based on Substituent Structures and Substrate Toxicity

The high consumption and emission of sulfonamide antibiotics (SAs) have a considerable threat to humans and ecosystems, so there is a need to develop safer and more effective methods than conventional strategies for the optimal removal of these compounds. In this study, four SAs with different substituents, sulfadiazine (SDZ), sulfamerazine (SMR), sulfamethoxazole (SMX), and sulfamethazine (SMZ) were removed by a pure culture of Paenarthrobacter ureafaciens YL1. The effect of the initial SAs concentration on the growth rate of strain YL1 was investigated. The results showed that the strain YL1 effectively removed various SAs in the concentration range of 0.05–2.4 mmol·L−1. The Haldane model was used to perform simulations of the experimental data, and the regression coefficient of the model indicated that the model had a good predictive ability. During SAs degradation, the maximum specific growth rate of strain YL1 was ranked as SMX > SDZ > SMR > SMZ with constants of 0.311, 0.304, 0.302, and 0.285 h−1, respectively. In addition, the biodegradation of sulfamethoxazole (SMX) with a five-membered substituent was the fastest, while the six-membered substituent of SMZ was the slowest based on the parameters of the kinetic equation. Also, density functional theory (DFT) calculations such as frontier molecular orbitals (FMOs), and molecular electrostatic potential map analysis were performed. It was evidenced that different substituents in SAs can affect the molecular orbital distribution and their stability, which led to the differences in the growth rate of strain YL1 and the degradation rate of SAs. Furthermore, the toxicity of P. ureafaciens is one of the crucial factors affecting the biodegradation rate: the more toxic the substrate and the degradation product are, the slower the microorganism grows. This study provides a theoretical basis for effective bioremediation using microorganisms in SAs-contaminated environments.

Structure property relationship of two pyrazole derivatives: Insights from crystal structure and computational studies

Single crystal X-ray diffraction method was employed to characterize the pyrazole derivatives 5-(4-Methoxyphenyl)-3-(thiophen-2-yl)-4, 5-dihydro-1H-pyrazole-1-carboxamide (A), and 3-(Thiophen-2-yl)-5-(4-(trifluoromethyl)phenyl)-4, 5-dihydro-1H-pyrazole-1-carboxamide (B). The compound A crytallizes in the orthorhombic crystal system with space group P212121 and B crytallizes in the monoclinic crystal system with space group P21. NH...O type of interaction is responsible for the crystal packing in both the molecules. Compound A is also reinforced by CH...O interaction. The intermolecular interactions present in the crystals were validated by Hirshfeld surface analysis. Geometry optimization was performed by Density Functional Theory (DFT) calculations. The electrophillic and nucleophillic regions are shown using Molecular Electrostatic Potential (MEP) map. The 2D scattered plot were generated by RDG analysis which reveal the weak and noncovalent interactions in the compounds A and B.

Synthesis, single crystal X-ray, DFT, spectroscopic, molecular docking studies and in vitro biological evaluation of compound N-benzyl-4-(4-chlorophenyl)-2-oxobutanamide

Several α-ketoamides from natural as well as synthetic sources have been shown to possess multitude of biological activities due to their versatile nature and presence of multiple reactive centres giving them both electrophilic and nucleophilic characters. This makes them a key scaffold in chemistry and chemical biology. In this paper, we have reported the synthesis of N-benzyl-4-(4-chlorophenyl)-2-oxobutanamide (1) from β,γ-unsaturated α-hydroxythioester. Single crystal X-ray diffraction study was performed to determine the three-dimensional (3D) structure of the compound 1. Further, the 3D structure was optimised through DFT calculations using B3LYP/6-311G(d,p) basis set, followed by FTIR and NMR spectra calculation. The wavelength of maximum absorbance (λ) and the band gap energy of compound 1 were derived for methanol using the TD-DFT/6-311G(d,p) approach and compared to experimental results. The different intermolecular and intramolecular interactions such as H-O, H-Cl, H-C, H-N, and other possible interactions in the crystal structure were explored using Hirsfeld surfaces analysis and fingerprint plots. Additionally, Coulomb energy, dispersion energy, total energy, and total energy annotated were calculated by energy framework calculations demonstrating that electrostatic and repulsion forces are relevant to the topology of the overall interaction energies in the crystal. Finally, from the DFT optimized structure, the molecular electrostatic potential (MEP) map and Mulliken charges were generated and the natural bond (NBO) analysis was performed in order to investigate the interaction between various orbital and lone pairs occurring within the compounds. Based on the geometric and spectroscopic parameters, the experimental and theoretical results were indistinguishable. Additionally, in vitro amyloid beta 1-42 (Aβ42) aggregation assay revealed that the compound 1 modulated the aggregation profile of Aβ42 and the MTT cellular cytotoxicity assay showed that the compound is not toxic to cells. Further, molecular docking study resulted in the determination of interaction of compound 1 with the Aβ42 fibrils. In summary, the present work can be helpful for the design, and synthesis of novel α-ketoamides as potential modulators of amyloid beta aggregation.

Synthesis and computational investigation of N,N-dimethyl-4-[(Z)-(phenylimino)methyl]aniline derivatives: Biological and quantitative structural activity relationship studies

This study describes the synthesis, characterisation and biological activities of four Schiff base compounds, namely: N, N-dimethyl-4-(((4-nitrophenyl)imino)methyl)aniline (ABS1), 4-(((2-chlorophenyl)imino)methyl)-N,N-dimethylaniline (ABS2), 4‑bromo-2‑chloro-N-(4-dimethylamino)benzylidene) aniline (ABS3), and N,N-dimethyl-4-(((2-(trifluoromethyl)phenyl)imino)methyl)aniline (ABS4). These compounds were characterised by UV–Visible, FTIR, CHN-elemental analysis, PXRD, HRMS, and NMR (1H, 13C, DEPT, 1H1H– COSY, NOESY, HSQC, and HBMC) spectroscopic techniques. Furthermore, compounds ABS2–4 were suitable for single crystal X-ray diffraction analysis, and support the structures proposed. The antibacterial, antifungal and antioxidant activities of the compounds were investigated using both micro dilution and DPPH radical scavenging assays, showing a broad range of activity from high to moderate. Computational chemistry (molecular electrostatic potential maps, conceptual density functional theory calculations and non-covalent-interactions analysis) correlates with the experimental electronic properties as well as structure-reactivity relationship for the drug-likeness properties of the compounds. Molecular docking studies identified potential binding modes of the compounds, and the results corroborate with those obtained from MIC and MFC studies. The lead compounds (ABS1 and ABS3) exhibit outstanding drug-like properties.

A comparative structural analysis of arylsulfonamide chalcones with potential as a biofuel additive

Biodiesel has a significant added value compared to petrodiesel regarding a series of improved properties such as biodegradability and reduction of most regulated exhaust emissions. However, some challenges associated with biodiesel include physicochemical improvements in oxidative stability, which can be addressed by antioxidants. In this aspect, chalcone derivatives are simple chemical scaffolds with industrial applications that can be boosted by the insertion of a sulfonamide group. An extensive structure characterization was carried out for arylsulfonamide chalcone N-(2-(3–4-methoxyphenyl-propanoyl)-phenyl)-benzenesulfonamide and its isomer, to describe their supramolecular arrangements and conformational changes. Solid state arrangements were described by XRD and stabilized by C–H⋯O and π⋯π stacking interactions. Theoretical calculations were carried out by DFT using the M06-2X/6-311++G(d,p) level of theory to identify the reactive sites of arylsulfonamide chalcones and their molecular electrostatic potential maps. The fundamental factors were correlated to antioxidant molecules and commercial additives found in the literature. The analysis carried out in this work will be a gateway to confirm the relationship between the structure of arylsulfonamide chalcones and their additive properties as biofuels.

Design and structural analysis of centrosymmetric and non-centrosymmetric Zn(II) complexes by the host-guest complexation method

Crystalline molecular complexes of 2-salicylichydrazono-1,3-dithiolane-based Zn(II) coordination complexes analogues [Zn(H2L)2(Cl)2].(MeOH); (complex 1), [Zn(H2L)2(H2O)2].(ClO4); (complex 2) and [Zn(HL)2]n (complex 3) have been synthesized and characterized by spectroscopic methods and single-crystal XRD analysis. The XRD-structure of the desired complexes were unravelled in that the complexes (1) and (2) possess centrosymmetric form in which Zn(II) metal centre had octahedral coordination environment, while the non-centrosymmetric complex 3 is a coordination polymer with a square pyramidal geometry around the metal centre. The coordination-driven supramolecular self-assembly through distinct intermolecular interactions is observed in the three Zn(II) complexes which are achieved by the host-guest complexation. In the solid state, the coordination geometry and molecular packing by various non-covalent interactions are discussed qualitatively using crystal structure analysis. Graphical tools based on 3-D Hirshfeld surface (dnorm and shape index), 2-D fingerprint plots, RDG-based NCI isosurface embedded with QTAIM and molecular electrostatic potential map are shown to be valuable for visualizing and analyzing intermolecular interactions in different crystal forms of Zn(II) complexes and allows easier and rapid comparison. In addition, the geometrical optimization of the Zn(II) complexes was realized by the electronic structure method using density functional theory (DFT) to identify the active sites and the chemically reactive parameters of the three Zn(II) complexes.

A new halide hybrid compound based on Zn (II) and 3,3′-diaminodiphenylsulfone: A combined experimental and theoretical study

• Slowly evaporation method was used to synthesize a new tetrachlorozincate hybrid compound. • Hirshfeld surfaces and their associated two-dimensional fingerprint plots provides information about the intermolecular interactions. • Vibrational study was realized based on the calculated frequencies. • HOMO-LUMO band gap energy of the crystal is 4.96 eV. • The optical properties were performed. A new organic-inorganic hybrid compound of formula (C 12 H 14 N 2 O 2 S)(ZnCl 4 ) . 1.33H 2 O was obtained by slow evaporation of a H 2 O/EtOH solution at room temperature. The solid-state structure, determined by single X-ray crystal diffraction, indicates that the synthesized compound crystallizes in the triclinic system with P-1 space group. The title compound was further characterized by spectroscopies analysis (Infrared, Raman and UV-Visible) and its thermal behavior was investigated by using TGA and DSC. In the crystal packing ZnCl 4 2- anions, (C 12 H 14 N 2 O 2 S) 2+ cations and water molecules are present. The stability of the three-dimensional framework is assured via intermolecular hydrogen bonds, which were analyzed by using Hirshfeld Surface analysis. Vibrational and UV-vis spectra of the investigated compound were recorded and discussed. Theoretical calculations were carried out by using the PM6 semiempirical model. Moreover, Molecular Electrostatic Potential (MEP) map and the frontier molecular orbitals (HOMO-LUMO) of the compound were calculated and discussed using the optimized structure.

Synthesis, spectroscopic characterization, DNA binding and DFT/PCM calculations of new Hydrogen-bonded charge transfer complex between 4-dimethylaminopyridine and Chloranilic acid

A charge transfer hydrogen bonded complex between the electron donor 4-dimethylaminopyridine (4-DMAP) and the electron acceptor Chloranilic acid (CLA) has been synthesized. The complex was studied experimentally and theoretically. A chemical reaction developed due to strong H-bonding, followed by proton transfer from the CLA to the 4-DMAP in acetonitrile medium (ACN). The straight line approach was employed to verify the 1:1 M ratio of the synthesised CT complex. The Benesi-Hildebrand equation was employed to compute the association constant (KCT), molar absorptivity (εCT), and other physical parameters. The synthesized complex was characterized spectroscopically. The presence of proton and charge transfers in the resultant complex was supported by 1H NMR, FT-IR and SEM-EDX investigations. The complex DNA binding ability of complex was investigated using electron absorption spectroscopy to reveal that the CT complex binding mechanism is intercalative and the intrinsic binding constant (Kb) value is 6.7 × 104 M−1. Theoretical calculations using DFT at the basis set CAM-B3LYP/6–31 G (d, p) were used to validate the experimental outcomes. The Mullikan atomic charges, geometrical parameters, and molecular electrostatic potential maps (MEPs) were computed and interpreted in conformity with the experimental results. In addition to e-transfer, the presence of an H-bond influences complex stability. There is good agreement between experimental results and DFT calculations.

New Insights on Glutathione's Supramolecular Arrangement and Its In Silico Analysis as an Angiotensin-Converting Enzyme Inhibitor.

Angiotensin-converting enzyme (ACE) inhibitors are one of the most active classes for cardiovascular diseases and hypertension treatment. In this regard, developing active and non-toxic ACE inhibitors is still a continuous challenge. Furthermore, the literature survey shows that oxidative stress plays a significant role in the development of hypertension. Herein, glutathione's molecular structure and supramolecular arrangements are evaluated as a potential ACE inhibitor. The tripeptide molecular modeling by density functional theory, the electronic structure by the frontier molecular orbitals, and the molecular electrostatic potential map to understand the biochemical processes inside the cell were analyzed. The supramolecular arrangements were studied by Hirshfeld surfaces, quantum theory of atoms in molecules, and natural bond orbital analyses. They showed distinct patterns of intermolecular interactions in each polymorph, as well as distinct stabilizations of these. Additionally, the molecular docking study presented the interactions between the active site residues of the ACE and glutathione via seven hydrogen bonds. The pharmacophore design indicated that the hydrogen bond acceptors are necessary for the interaction of this ligand with the binding site. The results provide useful information for the development of GSH analogs with higher ACE inhibitor activity.

Теоретическое квантово-химическое моделирование структуры и свойств дипептида карнозина методом DFT

The spatial and electronic structure of the natural carnosine dipeptide in the N3H tautomeric form of its imidazole ring in gas and water environment was studied by the quantum-chemical method in the framework of the electron density functional theory (DFT) with the three-parameter B3LYP hybrid functional. The sufficiently reliable and time-saving extended basis set, taking into account the polarization and diffuse functions 6-31+G (d, p) was used for calculations. All calculations were carried our using the Gaussian 09 software package. GaussView 6.0.16 was used to visualize the obtained results. Geometrical parameters, values of electronic energy, energies of HOMO and LUMO orbitals and the energy gap between them, reactivity descriptors, values of dipole moments, partial charges on atoms, and theoretical IR spectra for gaseous and aqueous media are obtained. Calculations show that the proposed model of the molecule forms a stable structure. The resulting structure is stabilized due to non-covalent interactions in the dipeptide. Molecular electrostatic potential maps (MEP) are constructed to identify potential binding sites. To study the charge transfer and intramolecular interactions that determine the stability of the molecule, an analysis of natural bond orbitals (NBOs) was carried out. Structural rearrangements and changes in various parameters depending on the dielectric constant of the medium are analyzed.

Molecular geometry, spectroscopic and NLO studies of 1-(chloromethyl)-4-fluorobenzene – A DFT study

The vibrational spectra of 1-(chloromethyl)-4-fluorobenzene have been studied in the 4000 - 400 cm -1 and 3500 - 50 cm -1 range, by FTIR and FT-Raman, respectively. In this work, structural analysis and vibrational frequencies are performed utilizing the GAUSSIAN 09W program with DFT/B3LYP strategy with basis set 6-311++G (d, p). Least differences are noted between the measured and scaled wavenumbers. The molecular vibrational assignments are confirmed by the PED (potential energy distribution) percentage. Frontier molecular orbital, natural bond orbital and Mullikan charge examinations are employed to explain the reason for intra and intermolecular charge exchange of the molecule. Reactive sites and chemical shifts are investigated by molecular electrostatic potential map and nuclear magnetic resonance analysis. Besides, the polarizability, the first hyperpolarizability, and total dipole moment of the molecule have been computed for describing its NLO activity.

Investigating the X-aminopyridine (X = 2 and 3) molecules sensing by Al12N12 and B12N12 fullerene-like nanocages: DFT, QTAIM, RDG and TD-DFT insights

DeThe adsorption of 2-aminopyridine (2-AP) and 3-aminopyridine (3-AP) on the external surface of B12N12 and Al12N12 fullerene-like nanocages (FLNs) is probed herein via DFT/M06-2X/6-311G(d,p) level of theory. It came out from the study that all FLN@X-AP states investigated are spontaneously formed. Moreover, topological analysis demonstrated that the boron nitride FLN can strongly adsorbed the APs through B-N covalent interactions. A significant change in the HOMO-LUMO band gap of B12N12, with values of 22.01 and 32.71% have been obtained following the adsorption of 2-AP and 3-AP respectively. Accordingly, the conductivity of B12N12 is greatly enhanced by the adsorption of the APs. The above mentioned observations, combined with those found from the analysis of dipole moments and molecular electrostatic potential maps predict B12N12 to be more sensitive to the aminopyridines investigated than the Al12N12 FLN from the theoretical point of view. Communicated by Ramaswamy H. Sarma

A COMPREHENSIVE ELECTRONIC, VIBRATIONAL, NATURAL BOND ORBITAL AND REACTIVITY DESCRIPTOR ANALYSIS OF PHARMACOLOGICALLY IMPORTANT MOLECULE MIGALASTAT: A THEORETICAL STUDY

Migalastat (Galafold) is a pharmacological chaperone indicated for the long term treatment for fabry disease a rare genetic disorder in adults. Quantum chemical calculations of energy, geometrical shape and vibrational wavenumbers of Migalastat have been accomplished by the usage of DFT method. The specific exploration of the infrared spectra of the compound underneath have a look at is centered on potential energy distribution (PED). Dipole moment, polarizability and first order static hyperpolarizability calculation using DFT/B3LYP/6-311G(d,p) level of theory outlined the nonlinear optical behavior of the underlying molecule. The frontier molecular orbitals and molecular electrostatic potential map were additionally given to clarify the molecular characteristics of the compound. To show the chemical activity of the chemical compound, reactivity descriptors and thermodynamic properties were also calculated utilizing 6-311G(d,p) basis set. Electron density distribution on atoms and bonds of given molecule was interpreted by its complete NBO analysis.

Structural, spectroscopic, quantum chemical, and molecular docking study towards cartilage protein of (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one)

This article presents the results of the structural and spectroscopic analysis of (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one) by the means of IR, Raman, NMR, and Density functional theory methods. The structure of the compound was optimized at the B3LYP/6-311++G(d,p) level of theory. The NMR spectra were predicted using the Gauge Independent Atomic Orbital approach. The mean absolute differences between experimental and theoretical chemical shifts were 0.44 and 2.3 ppm for 1H and 13C NMR spectra thus proving the applicability of the chosen level of theory. The vibrational (IR and Raman) spectra were assigned based on the optimized structure following the Potential Energy Distribution (PED) analysis. The intermolecular interactions governing the stability of the compound were investigated by the Natural Bond Orbital and Quantum Theory of Atoms in Molecules analyses. The active positions in the compound were assessed by the Fukui functions calculation and Molecular electrostatic potential map. The inhibitory activity of the compound was analyzed by molecular docking toward cartilage proteins. This activity, along with the groups included in interactions, proved the activity of various parts of the molecule. The inhibitory activity was higher than that of a native ligand. The ecotoxicity assessment proved low toxicity towards aquatic organisms. These results show the high potential of enaminone derivatives obtained under mild conditions.

DFT and Molecular Docking Study of 1-(2´-Thiophen)-2-propen-1-one-3-(2,3,5-trichlorophenyl) (TTCP) Molecule as Antiviral to Covid-19 Main Protease.

Thiophene-containing compounds have antiviral properties and may be among the drugs tested for the treatment of COVID-19 diseases. In order to better understand the molecular definition of the 1-(2´-Thiophen)-2-propen-1-one-3-(2,3,5-trichlorophenyl) molecule from thiophene-containing compounds, the physico-chemical (molecular structure analysis, spectroscopic properties, boundary orbital analysis) mechanisms underlying the protein–ligand interaction should be examined in detail. For this reason, geometric parameters, IR and UV–vis spectra, conformational analysis, electronic, NBO and NLO properties, molecular electrostatic potential map and Mulliken charge distributions of the TTCP molecule were investigated theoretically using DFT theory in the Gaussian program. Accordingly, molecular docking calculations with COVID-19 main protease (PDB 5R7Y) were performed to determine the pharmaceutical activities of the TTCP molecule against coronavirus diseases.

Bromine Substitution Effect on Structure, Reactivity, and Linear and Third-Order Nonlinear Optical Properties of 2,3-Dimethoxybenzaldehyde.

The structural and electronic properties of 2,3-dimethoxybenzaldehyde (2,3-DMB), 5-bromo-2,3-dimethoxybenzaldehyde (5-BRB), and 6-bromo-2,3-dimethoxybenzaldehyde (6-BRB) were extensively discussed with emphasis on linear and nonlinear optical responses. The intermolecular interactions were comparatively studied by Hirshfeld surfaces, quantum theory of atoms in molecules (QTAIM), and natural bond orbitals (NBOs), indicating that bromine substitution decreases the H···H and C···H contacts and increases H···Br and Br···Br closed-shell interactions on crystalline arrangements. The frontier molecular orbitals and molecular electrostatic potential map, carried out at the CAM-B3LYP/6-311++G(d,p) level of theory, showed that the kinetic stability occurs in the increasing order 6-BRB < 5-BRB < 2.3-DMB. The bromine atom has a beneficial effect on the nonlinear third-order susceptibility of 2,3-DMB, with theoretical predictions of 89.54 ×10-22 and 83.15 ×10-22 (m/V)2 for 6-BRB and 5-BRB, respectively. These findings were favorably compared with available theoretical and experimental data of other organic crystals that may be promising as NLO materials.

A series of phenanthroline-imine compounds: Computational, OLED properties and fluorimetric sensing of nitroaromatic compounds

In this study, Schiff base compounds (1–5) were synthesized by the reaction of 5-amino-1,10-phenanthroline with various aldehydes. The molecular structures of the synthesized compounds were characterized by FT-IR, 1H/13C NMR and mass spectroscopic methods. Single crystals of 1 were obtained and their molecular structures in crystalline form were determined by single crystal X-ray diffraction study. The sensor properties of the synthesized compounds against nitroaromatic compounds [nitrobenzene (NB), 4-nitrophenol (NP), 2,4-dintrophenol (DNP) and 1,3,5-trinitrophenol (TNP)] were investigated by fluorescence spectroscopy. Compound 3 have highest sensitivity for the sensing of 1,3,5-trinitrophenol (TNP) (Ksv: 4.63 × 104 M−1) with LOD of 4.01 µM while compound 5 showed the highest sensitivity for 2,4-dinitrophenol (DNP) (Ksv: 5.71 × 104 M−1) with LOD of 4.75 µM. In addition, the structural parameters (bond angles/lengths), contour diagrams of HOMO/LUMO molecular orbitals, molecular electrostatic potential (MEP) maps, non-linear optical (NLO) and OLED properties were investigated by computational studies. According to the HOMO and LUMO energies, the NLO property of the molecule (5) is higher than both other molecules and the reference substance urea.