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Herein, we report the quantum chemical results based on density functional theory for the polarizability ( α ) and first hyperpolarizability ( β ) values of diacetylene-functionalized organic molecules (DFOM) containing an electron acceptor (A) unit in the form of nitro group and electron donor (D) unit in the form of amino group. Six DFOM 1 - 6 have been designed by structural tailoring of the synthesized chromophore 4,4'-(buta-1,3-diyne-1,4-diyl) dianiline ( R ) and the influence of the D and A moieties on α and β was explored. Ground state geometries, HOMO-LUMO energies, and natural bond orbital (NBO) analysis of all DFOM ( R and 1 - 6 ) were explored through B3LYP level of DFT and 6-31G(d,p) basis set. The polarizability ( α ), first hyperpolarizability ( β ) values were computed using B3LYP (gas phase), CAM-B3LYP (gas phase), CAM-B3LYP (solvent DMSO) methods and 6-31G(d,p) basis set combination. UV-Visible analysis was performed at CAM-B3LYP/6-31G(d,p) level of theory. Results illustrated that much reduced energy gap in the range of 2.212-2.809 eV was observed in designed DFOM 1 - 6 as compared to parent molecule R (4.405 eV). Designed DFOM (except for 2 and 4 ) were found red shifted compared to parent molecule R . An absorption at longer wavelength was observed for 6 with 371.46 nm. NBO analysis confirmed the involvement of extended conjugation and as well as charge transfer character towards the promising NLO response and red shift of molecules under study. Overall, compound 6 displayed large α and β tot , computed to be 333.40 (a.u) (B3LYP gas), 302.38 (a.u.) (CAM-B3LYP gas), 380.46 (a.u.) (CAM-B3LYP solvent) and 24708.79 (a.u), 11841.93 (a.u.), 25053.32 (a.u) measured from B3LYP (gas), CAM-B3LYP (gas) and CAM-B3LYP (DMSO) methods respectively. This investigation provides a theoretical framework for conversion of centrosymmetric molecules into non-centrosymmetric architectures to discover NLO candidates for modern hi-tech applications.

New 2,6-bis(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone (2Tris@PMDA) and its polymeric hybrids with Anderson polyoxometalates (DiTA@PMDA) and with Lindquist polyoxometalates (DiTL@PMDA) have been synthesized and thoroughly characterized. Using dr. Blade's approach, TiO2 based thin films of 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA have been designed to explore the adsorption study, optical activity, and photocurrent generation. The calculated electrical conductivity values for 2Tris@PMDA, DiTA@PMDA and DiTL@PMDA were 2.8 × 103 S/m−1.90 × 103 S/m, 2.7 × 103 S/m−1.7 × 103 S/m, and 2 × 103 S/m−1.65 ×103 S/m, respectively. Furthermore, computational analysis for 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA has been studied at B3LYP using 6-31 G (d, p) and LanL2DZ level of density functional theory. It indicates that the conjugation of 2Tris@PMDA with polyoxometalates makes them a suitable candidate for dye sensitized solar cell due to the charge transfer process in DiTA@PMDA and DiTL@PMDA. [ABSTRACT FROM AUTHOR]

For the binary mixture of water and N, N-dimethylacetamide (DMA), observations have been done of the ultrasonic velocity (u), density (ρ), viscosity (η) and refractive index (n) in excess of the whole composition range at various temperature. Deviation in ultrasonic velocity (Δu), excess intermolecular free length (LfE), excess acoustic impedance (ZE), excess molar volume (VmE), deviation in molar refraction (ΔRm), deviation in viscosity (Δη) and excess Gibbs' free energy of activation for viscous flow (ΔG*E) were used to investigate the intermolecular interactions present in the mixture. Derived parameters such as isoentropic compressibility (Ks), the specific heat ratio (γ), and the effective Debye temperature (qD) at varying concentrations of DMA have also been computed using experimental data. Various semi-empirical mixing rules have also been applied to the binary mixture. Density functional theory is utilised to optimise the geometry of DMA, DMA with water, and calculation of H-bonded intermolecular interactions. [ABSTRACT FROM AUTHOR]

In this study, five new asymmetrical fullerene-free acceptor molecules (N1 to N5) have been designed for organic solar cell applications. Density functional theory and time dependent density functional theory has been employed for exploring the opto-electronic, photovoltaic and geometric properties of the designed molecules. A narrow energy band gap with high red-shifting in the absorption spectrum has been noted. High open circuit voltage with good values of reorganizational energy of electron suggested that designed molecules are effective contributor for solar cell applications. Transition density matrix and frontier molecular orbitals analysis also expressed the presence of charge density within a molecule with different types of transitions. Finally, blend study also performed for exploring the charge transfer between donor polymer and acceptor molecule. [ABSTRACT FROM AUTHOR]

Ten coumarin class of compounds, including new fused coumarinolignoids namely, mucronin-C (1) were isolated from the methanol extract from whole plant of Daphne mucronata Royle. The structures of mucronin-C (1) and its configurations were determined by chemical and spectroscopic methods including 1DNMR, 2D-NMR and HR-FAB-MS. The isolated compounds 1-10 were evaluated for in-vitro biological activities. The anti-inflammatory (lipoxygenase) activities of compound 1, 4, 8, 9 and 10 (IC50 = 21.7, 23.7, 25.1, 27.3 and 26.0 µg/mL, respectively) were higher compared with standard Quercetin (IC50 = 22.5 µg/mL). The antioxidant property of coumarin as evaluated by DPPH scavenging bioassay was significantly greater in compounds 1-5, 9 and 10 (IC50 = 0.7, 0.8, 1.9, 2.3, 2.8, 0.5 and 2.1 µg/mL respectively) as standard Trolox (IC50 = 0.3 µg/mL). The density functional descriptors in the progress of quantitative structure-activity relationship (QSAR) are significant to analyze the reactive sites and antioxidant ability of compounds. We have explored the reactive sites and radical scavenging activity of studied coumarin derivatives by shedding light on electron affinity, ionization potential, molecular electrostatic potential, frontier molecular orbitals and molecular descriptors analysis. First-principles calculations about one-electron transfer mechanism revealed that smaller ionization potential value of Compounds 1-5, 9 and 10 are leading to superior antioxidant activity, which is in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Herein, we report linear polarizibilty (α) and hyperpolarizibility (β) of anthracyl-based organic materials containing electron acceptor (NO 2) and electron donor (NH 2) moieties. Six compounds (a – f) were designed by structural modification of a reported chromophore 9,10-bis(phenylethynyl)anthracene (R). Ground state geometries, HOMO-LUMO energies polarizability, first hyperpolarizability and natural bond orbital (NBO) analyses of all compounds (R and a – f) were studied through density functional theory. FMO's results showed that the energy gaps of designed molecules a – f (1.791–2.215eV) were much lower than parent molecule R (2.606 eV). UV Visible analysis of designed compounds showed a red shift in the absorption spectrum as compared with reference molecule (R). The highest λ max was observed for compound c (816.7 nm). NLO analysis and hyper polarizibility values computed for compounds a - f were much higher than reference compound R (0.023 a.u.). The observed red shifts in the absorption spectra indicated the decrease in excitation energy, an important factor in enhancing NLO response. Overall, compound c showed larger α total and β total values of 575.9 a.u. (LC-BLYP/6–31++G(d,p) , and 58156.8 a.u. (LC-BLYP/6–31++G(d,p) , respectively. The findings of our study provide a theoretical platform for useful conversion of centrosymmetric compounds to non-centrosymmetric materials for enhancing the NLO behavior through structural modifications for modern technological applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Organic materials development, especially in terms of nonlinear optical (NLO) performance, has become progressively more significant owing to their rising and promising applications in potential photonic devices. Organic moieties such as carbazole and quinoline play a vital role in charge transfer applications in optoelectronics. This study reports and characterizes the donor–acceptor–donor–π–acceptor (D–A–D–π–A) configured novel designed compounds, namely, Q3D1–Q3D3, Q4D1–Q1D2, and Q5D1. We further analyze the structure–property relationship between the quinoline–carbazole compounds for which density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed at the B3LYP/6-311G(d,p) level to obtain the optimized geometries, natural bonding orbital (NBO), NLO analysis, electronic properties, and absorption spectra of all mentioned compounds. The computed values of λmax, 364, 360, and 361 nm for Q3, Q4, and Q5 show good agreement of their experimental values: 349, 347, and 323 nm, respectively. The designed compounds (Q3D1–Q5D1) exhibited a smaller energy gap with a maximum redshift than the reference molecules (Q3–Q5), which govern their promising NLO behavior. The NBO evaluation revealed that the extended hyperconjugation stabilizes these systems and caused a promising NLO response. The dipole polarizabilities and hyperpolarizability (β) values of Q3D1–Q3D3, Q4D1-Q1D2, and Q5D1 exceed those of the reference Q3, Q4, and Q5 molecules. These data suggest that the NLO active compounds, Q3D1–Q3D3, Q4D1–Q1D2, and Q5D1, may find their place in future hi-tech optical devices. [ABSTRACT FROM AUTHOR]

The pyrimidine ring is significantly distributed in nature due to its existence in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) as nitrogenous bases. The heterocyclic aromatic compounds have become an important pharmacophore due to promising applications in medicine and nonlinear optics (NLO) fields. Keeping in view of the significance of 4-thiopyrimidines derivatives, we selected phenyl pyrimidine derivatives namely: ethyl 4-((3-chlorobenzyl)thio)-6-methyl-2-phenylpyrimidine-5-carboxylate (1), (4-((4-chlorobenzyl)thio)-6-methyl-2-phenyl-pyrimidin-5-yl)methanol (2) and 4-((4-chlorobenzyl)thio)-5,6-dimethyl-2-phenylpyrimidine (3) for NLO study and comparative analysis. Overall, density functional theory (DFT) findings of structural parameters at B3LYP/6-311G(d,p) level show excellent concurrence with the experimental data which confirms the purity of 1 , 2 and 3. The vibrational analysis of 1 , 2 and 3 have been carried out by DFT calculations based on B3LYP/6-311G(d,p) level of theory. The natural bonding orbital (NBO) analysis has been used to get insight into non-covalent interactions. From DFT calculations, various parameters such as natural population analysis (NPA) atomic charges, HOMO–LUMO energies and global reactivity parameters have been obtained. The molecular electronic potential (MEP) and parametric molecular electrostatic potential (PMEP) have also been derived for 1 , 2 and 3. The photophysical properties of investigated molecules were estimated using time dependent DFT (TDDFT) at B3LYP/6-311G(d,p) level of theory. Nonlinear optical (NLO) analysis has also been carried out by DFT calculations with B3LYP/6-311G(d,p) functional. The NLO properties of 1 , 2 and 3 were observed larger as compared to the standard molecule indicating the considerable NLO character of all molecules especially recommended the NLO activity of 1 for optoelectronic associated hi-tech applications. Image 1 • Three novel phenyl pyrimidine derivatives 1 , 2 and 3 were studied. • Computational study was done at B3LYP/6-311G(d,p) level for comparative study. • Comparative study reveals a good agreement between XRD and DFT results. • FMO, NBO, global reactivity parameter, NPA, MEP, PMEP and NLO analysis were performed. • All studied compounds hold considerable NLO character and recommended for optoelectronic associated hi-tech applications. [ABSTRACT FROM AUTHOR]

A novel C 9 N 4 nanosheet has been investigated for its potential use as an electrochemical sensor for gaseous pollutants including CO, NO, CO 2 , HF, and COCl 2. The sensing ability of C 9 N 4 is explored theoretically at the ωB97XD/6-311G (d, p) level of theory. The results showed the physisorption of all analytes on the C 9 N 4 surface. The highest interaction energy of −21.96 kcal/mol was observed in COCl 2 @C 9 N 4. The order of interaction energy was COCl 2 @C 9 N 4 > NO@C 9 N 4 > HF@C 9 N 4 > CO 2 @C 9 N 4 > CO@C 9 N 4. The Electronic properties of the complexes were examined using EDD (Electron Density Difference), NBO (natural bond orbital), FMO (frontier molecular orbital), and DOS (density of state) analysis. According to NBO analysis, CO 2 @C 9 N 4 exhibited the maximum amount of charge transfer (−0.026 e−), whereas COCl 2 @C 9 N 4 exhibited the minimum amount of charge transfer. The adsorption of COCl 2 onto the surface of C 9 N 4 resulted in change in the energy gap with a value of −3.12 eV compared to −3.15 eV for C 9 N 4. These findings highlighted the potential of C 9 N 4 as a promising electrochemical sensor for COCl 2. The transfer of charges takes place from the analytes to the C 9 N 4, except in HF, where no charge transfer took place. This divergence could be attributed to the strongly bonded electrons between the fluorine and hydrogen atoms of HF. QTAIM and NCI analysis were performed to determine the nature of non-covalent interactions. At 298K, a recovery time of 1.25 × 104 s was calculated for the desorption of COCl 2 from the surfaces of C 9 N 4. It was observed that C 9 N 4 shows the highest sensitivity toward COCl 2 among all selected analytes. [ABSTRACT FROM AUTHOR]

In this work, we reported the synthesis of hydrazide derivatives namely; N' -(4-(prop-2-ynyloxy)benzylidene)isonicotinohydrazide (1) and 4-methyl- N '-(4(prop-2-ynyloxy)benzylidene)- benzenesulfonohydrazide (2), their characterization through spectroscopic techniques as EIMS, 1H NMR, FT-IR, UV–Visible and single crystal X-ray diffraction (SC-XRD). Quantum chemical methods were performed for both compounds (1) and (2) to explore the structural, spectral and electronic properties for comparative analysis with experimental data. The theoretical vibrational spectra (FT-IR), frontier molecular orbitals (FMOs) and nonlinear optical (NLO) analysis were performed at DFT/B3LYP/6-311 + G(d,p) level. Natural bond orbitals (NBOs) analysis was carried out at M06-2X/6-311G(d,p)level of theory. However, the time dependent density functional theory (TDDFT) was used for the calculations of vertical electronic transition states at B3LYP level with 6-311 + G(d,p) basis set. The NBO analysis revealed that both compounds (1) and (2) have high molecular stability due to hyperconjugative interactions. Moreover, the global reactivity descriptors were calculated using the energies of FMOs. NLO analysis showed that both compounds (1) and (2) have significant NLO properties as compared to prototype compound (urea) which disclosed their potential for technology related applications. Overall, a well synchroneity is found between the experimental dataand DFT based results of both compounds. Image 1 • Two novel hydrazide derivatives were synthesized. • XRD, 1H NMR, FT-IR and UV–Vis were performed for the characterization. • Computational study was done for comparative analysis. • Comparative study reveals a good agreement between experimental and DFT results. • FMOs, NBO analysis and nonlinear optical (NLO) properties were calculated. [ABSTRACT FROM AUTHOR]