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The examination of molecular structure properties of 4,4′-oxydiphthalonitrile compound: combined spectral and computational analysis approaches
摘要： The synthesis process, X-ray diffraction analysis of its single crystal form and the structural properties of the 4,4'-oxydiphthalonitrile compound by Fourier transform infrared, nuclear magnetic resonance and ultraviolet-visible spectral methods were reported in this study. Density functional theory studies of the compound were carried out by designed modeling with the Becke three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional and 6-311G(d,p) basis set. Some molecular structure parameters obtained theoretically were compared with those obtained from the crystallographic analysis. Vibrational modes and wavenumbers with the aid of the potential energy distribution analysis, carbon and proton chemical shift values with diversified approaches and absorption wavelengths using Time-Dependent Density Functional and Conductor-Like Polarizable Continuum Model in different solvent media were examined theoretically. The compatibility of spectral and theoretical results was evaluated by examining the correlation coefficients. In addition, the frontier molecular orbitals energies, global reactivity parameters, molecular electrostatic potential map, the potential for non-linear optical material and some thermodynamic parameters at different temperature values of the 4,4'-oxydiphthalonitrile compound were investigated at the same theoretical level.
关键词： DFT,phthalonitrile,FT-IR,NMR,UV-Vis
更新于2025-09-23 15:22:29
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Enhanced Solar Conversion of CO <sub/>2</sub> to CO Using Mn-doped TiO <sub/>2</sub> Based on Photo-thermochemical Cycle
摘要： Photo-thermochemical cycle (PTC) is a promising method to converting CO2 to solar fuels. To study the mechanism of CO2 reduction based on PTC, sol-gel synthesized titanium dioxide (ST) and Mn-doped TiO2 (MT) films were produced and applied to the PTC under simulated solar light irradiation. Commercial P25 (PT) was used as a reference. Experiments show that Mn-doped TiO2 produced more CO than undoped TiO2 and P25. The average CO production of 1.0 wt% MT by the PTC was 32.19 μmol?m?2?h?1, 4.36 times than that of ST and 3.63 times that of PT. Various characterization methods were conducted to investigated the effect of Mn ions doping on the photo-response and charge transfer of samples. Density functional theory (DFT) calculations were also performed to verify the analysis and enhance the PTC mechanism. In conclusion, several key factors that Mn ions promote CO2 conversion have been clarified.
关键词： Oxygen vacancy,Mn doping,DFT calculation,CO2 reduction,Photo-thermochemical cycle
更新于2025-09-23 15:22:29
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Photoinduced electron transfer in non-covalent free-base octaethylporphyrin and 2-nitrofluorene donor-acceptor system: A combined experimental and quantum chemical study
摘要： Photosynthetic reaction center functions through non-covalent incorporation into a well-defined transmembrane proteins. In the context of exploring photoinduced electron transfer (PET) in non-covalent donor-acceptor systems, we have investigated electron transfer from free-base octaethylporphyrin (OEP) donor to 2-nitrofluorene (2NF) acceptor in acetonitrile (ACN), a polar solvent. Steady-state and time-resolved emission spectroscopic studies in conjunction with density functional theory (DFT) calculations were employed to explore the electron transfer process. Quenching of the fluorescence emission intensity as well as fluorescence lifetime of the OEP upon excitation at the Q band of OEP at 300 K, is attributed to the PET from OEP to 2NF. Our DFT [wB97XD functional and 6-31G (d,p) basis set] calculations also support the interaction between donor and acceptor and also reveals the co-facial π-π interaction energy of ?24.6 kcal/mol with intermolecular distance b4 ?. Our results are expected to shed light on PET in non-covalent donor acceptor systems.
关键词： Marcus theory,Photoinduced electron transfer,Octaethylporphyrin,Second-order bimolecular fluorescence quenching constant,2-Nitrofluorene,DFT study by wB97XD/6-31G(d,p),Time-resolved emission spectroscopy
更新于2025-09-23 15:22:29
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Synthesis of 2-methyl-5-(5-phenyl substituted-1,3,4 oxadiazole-2-yl) quinazolin-4-one fluorescent brightening agent: Computational and experimental comparison of photophysical structure
摘要： Report is about the synthesized new range of oxadiazole substituted quinazoline and studied its electronic distribution to attribute fluorescent properties. B3LYP Density Functional Theory (DFT) computational optimization was studied to observe the effect of electron donor and acceptor substituent's on photophysical properties, electronic state and energy level. DFT computational optimization was performed by Polarizable Continuum Model (PCM) of solvation strictly in the gas phase and DMF maintaining C1 symmetry in ground state geometry structure. UV-vis and fluorescence spectroscopic methods help in understanding the relationship between the electron donor and acceptor functional groups on the photophysical properties. Eventually comparing experimental spectral emission and DFT computations were envisage understanding the changes of the electronic transition, energy levels, and electronic orbital distribution in the substituted quinazoline structure. These compounds have good fluorescent brightening properties hence studied and applied as fluorescent brightening agent on polyester fiber.
关键词： TD-DFT,vertical excitation,fluorescent,oxadiazole,quinazoline
更新于2025-09-23 15:22:29
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Medium viscosity effect on fluorescent properties of Sn(IV)-tetra(4-sulfonatophenyl)porphyrin complexes in buffer solutions
摘要： Supramolecular triads consisting of hydrophilic Sn(IV)-tetra(4-sulfophenyl)-porphyrin and two axial guests such as propylphenol, tyrosine, and 2-(2-hydroxyphenyl)-benzoxazole were synthesized. The structures of synthesized complexes were identified by experimental spectroscopic and quantum-chemical simulation methods, and their fluorescent properties were studied in various viscosity media (mixed phosphate buffer-glycerin solvents of different composition). The effect of axial ligand structure on the fluorescent properties of these triads (due to the hydrogen bonding or π-π stacking between the components of ?host-guest? systems) is discussed. The potential use of synthesized complexes as environmental probes of local viscosity is proposed.
关键词： synthesis,ROESY,fluorescent properties,hydrogen bonding,DOSY,2D NMR,DFT,viscosity,Sn(IV)-porphyrins
更新于2025-09-23 15:22:29
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Azaindole-BODIPYs: Synthesis, fluorescent recognition of hydrogen sulfate anion and biological evaluation
摘要： The synthesized and sensing capability of two novel azaindole substituted mono and distyryl BODIPY dyes against bisulfate anion were reported. Structural characterizations of the targeted compounds were conducted by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 1H and 13C NMR spectroscopies. Photophysical properties of the azaindole substituted BODIPY compounds were investigated employing absorption and fluorescence spectroscopies in acetonitrile solution. It was found that the final compounds 3 and 4 exhibited exclusively selective and sensitive turn-off sensor behavior on HSO4- anion. Additionally, the stoichiometry ratio of the targeted compounds to bisulfate anion was measured 0.5 by Job’s method. Also, density function theory was performed to the optical response of the sensor for targeted compounds. Furthermore, the cytotoxicity of Azaindole-BODIPYs were examined against living human leukemia K562 cell lines.
关键词： Fluorescence,Azaindole,K562 cell lines,Borondipyrromethenes,DFT,Chemosensor,hydrogen sulfate,Anionsensor
更新于2025-09-23 15:22:29
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Bay-Linked Perylenediimides are Two Molecules in One: Insights from Ultrafast Spectroscopy, Temperature Dependence, and Time-Dependent Density Functional Theory Calculations
摘要： Bay-linked di-perylenediimide (di-PDI) molecules are finding increasing use in organic electronics due to their steric hindrance that 'twists' the two monomer units relative to one another, decreasing molecular aggregation. In this paper we explore the electronic spectroscopy and ultrafast dynamics of the singly-linked β-β-S-di-PDI (2,9'-di(undecan-5-yl)-2',9-di(undecan-6-yl)-[5,5'-bianthra[2,1,9-def:6,5,10-d'e'f']diisoquinolin]-1,1',3,3',8,8',10,10'(2H,2'H,9H,9'H)-octaone). Excitation-emission spectroscopy reveals two distinct emitting species, which are further characterized by time-dependent density functional theory (TD-DFT), demonstrating that the bay-linked PDI dimers exist in two geometrical conformations. These conformations are an 'open' geometry, where the two monomer sub-units are oriented nearly at right angles, giving them more J-like coupling, and a 'closed' geometry, in which the two monomer sub-units are nearly π-stacked, resulting in more H-like coupling. Given the extent of through-space and through-bond coupling, however, neither di-PDI conformer can be well-described simply in terms of independently-coupled monomers; instead, a full quantum chemistry description is required to understand the electronic structure of this molecule. Temperature-dependent experiments and the TD-DFT calculations indicate that the 'closed' conformer is ～70 meV more stable than the 'open' conformer, so that both conformers are important to the behavior of the molecule at room temperature and above. We use a combination of steady-state and femtosecond transient absorption and emission spectroscopies to globally fit the multiple electronic transitions underlying the spectra of both the 'closed' and 'open' conformers, which agree well with the TD-DFT calculations. The fact that di-PDI molecules are molecular species that adopt two distinct quasi-independent chemical identities has important ramifications for charge trapping and mobility in the organic electronic devices employing these materials.
关键词： TD-DFT calculations,ultrafast spectroscopy,conformational isomers,organic electronics,Bay-linked perylenediimides
更新于2025-09-23 15:22:29
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On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals
摘要： Rare earth (RE3+) doped inorganic CsPbX3 (X=Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy-conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for photoluminescence quantum yields over 100% (T. J. Milstein, et al., Nano Letters 2018, 18, 3792). In the present work, based on cubic phase of inorganic perovskite, we seek atom-level-insight into the basic mechanisms behind these observations in order to boost the further development of RE3+ doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of step-wise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with 'right-angle' Yb3+-VPb-Yb3+ couple are most likely to form in Yb3+-doped CsPbCl3. Associated with this 'right-angle' couple, the 'right-angle' Pb atom with trapped excited states would localize the photogenerated electrons and could act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.
关键词： Quantum cutting,Ytterbium-Doped inorganic perovskite,density function theory (DFT)
更新于2025-09-23 15:22:29
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Coumarin-1,2,3-triazole hybrid derivatives: Green synthesis and DFT calculations
摘要： A series of new 1,2,3-triazole-coumarin hybrid system are synthesized from the click reaction between 3-azido coumarin and different aromatic terminal alkyne derivatives in a green manner. All compounds are characterized by IR, NMR and UV–VIS spectroscopy. The experimental observations are further supported by DFT computational studies to investigate the effect of substituents at para position in these compounds.
关键词： CuAAC,1,2,3-Triazole,DFT calculation,Green synthesis,copper (I) catalyst
更新于2025-09-23 15:22:29
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Experimental and computational studies on induced thermochromic effect and re-entrant smectic phase in linear double hydrogen-bonded binary liquid crystal mixtures
摘要： Design and synthesis of the hydrogen-bonded liquid crystalline (HBLC) mixtures are accomplished from diglycolic acid and 4-n-alkoxybenzoic acid (n = 9–12). Spectroscopic characterization such as UV–Vis, FT-IR, and DSC has supported the presence of molecular geometry of HBLC mixtures. Thermochromic effect is analyzed for the polarizing filter applications. Induced new phases (Smectic X and Smectic Cr) and their transitions are confirmed through DSC along with its corresponding optical textures using polarizing microscope. Furthermore, the induced re-entrant smectic ordering due to the lone pair to π* transition is reported using density functional theory (DFT) studies. Dipole moment studies (DFT) clearly give a strong evidence of the existence of nematic and smectic phases due to the monopole–dipole interaction in the present HBLC mixtures. Band gap of the present HBLCs is 5.175 eV, which is calculated by the HOMO–LUMO analysis and is validated using experimental observations. Liquid crystal parameters such as transition temperature, enthalpy values, stability factor and tilt angles are reported.
关键词： thermal stability,Nematic,DFT,re-entrant,thermochromic
更新于2025-09-23 15:22:29