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Spectroscopic behavior, FMO, NLO and NBO analysis of two novel aryl boronic acid derivatives: Experimental and theoretical insights
摘要： Here we report, experimental and theoretical determination of ground and excited state dipole moments of aryl boronic acid derivatives, 2-Bromophenyl boronic acid (2BPBA) and 2-Isopropylphenyl boronic acid (2IPBA). In both the compounds, Bathochromicshift is observed with increasing solvent polarity indicating π →π* transition due to intermolecular charge transfer interactions. For both the compounds, the ground and excited sate dipole moments are parallel to each other. The excited state dipole moment (μe) is greater than ground state dipole moment (μg) for the compound 2IPBA where as for 2BPBA, excited state dipole moment (μe) is less than ground state dipole moment (μg). Further, experimentally obtained Δμ are compared with those using microscopic empirical solvent polarity (??????). In parallel, the use of Kamlet-Taft parameters to the solvent effect on spectral properties of 2BPBA and 2IPBA are also discussed. The molecular structure, Frontier Molecular Orbitals (FMO), Natural Bond Orbital (NBO) analysis, Non-Linear Optical (NLO) properties of 2BPBA and 2IPBA have been investigated using the (DFT) calculations with B3LYP/6?311++G (d, p) basis set. The chemical reactivity and kinetic stability of the compounds is shown by differences between the energy levels by analyses of Frontier molecular orbitals. The polarizability and hyperpolarizability computations determine the NLO properties, whereas Natural bond orbital (NBO) analysis showed proton transfer within the selected donor-acceptor depicting large energy of stabilization for the compounds under study.
关键词： Kamlet-Taft,FMO,MEP,ground and excited state dipole moments,Solvatochromic shift method,NBO and NLO
更新于2025-09-23 15:23:52
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Design, synthesis and structural optimization of two click modified butterfly molecules: Aggregation induced ratiometric fluorescence change and ICT associated hydrogen bonding effect in solvatochromic analysis
摘要： Two click modi?ed butter?y molecules are designed and synthesized having presence and absence of the aggregative moiety to differ between aggregation induced ratiometric emission changes via excimer formation and ICT associated hydrogen bonding effect. These two distinct phenomena can be successfully employed in solvatochromic analysis. This is also supported by the theoretical study through the structural variation of the two butter?y molecules.
关键词： Hydrogen bonding,Butter?y molecules,Ratiometric,AIE,Solvatochromic
更新于2025-09-23 15:22:29
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Exploring the spectral features and quantum chemical computations of a novel biologically active heterocyclic class of compound 2MEFPBA dye: Experimental and theoretical approach
摘要： Here we report, experimental and theoretical determination of ground and excited state dipole moments of the class of heterocyclic compound namely 2-Methoxy-5-fluoro phenyl boronic acid (2MEFPBA) dye. Bathochromic shift with increasing solvent polarity is observed indicating π →π* transition due to intermolecular charge transfer interactions. The ground and excited state dipole moments are found to be parallel to each other. The molecular structure, Frontier molecular orbital (FMO), Natural bond orbital (NBO) analysis and Nonlinear optical (NLO) properties of 2MEFPBA have been investigated using the Density Functional Theory with B3LYP/6?31 ++ g(d, p) basis set. Chemical reactivity and kinetic stability of 2MEFPBA are analyzed using F M O energy. Polarizability and hyperpolarizability computations are used to determine the NLO properties, whereas Natural bond orbital (NBO) analysis showed the proton transfer within the selected donor-acceptor depicting large energy of stabilization for the compound under study.
关键词： MEP,NBO,FMO,Solvatochromic ground and excited state dipole moments,and NLO.
更新于2025-09-23 15:22:29
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Solvent effects on the absorption and fluorescence spectra of Zaleplon: Determination of ground and excited state dipole moments
摘要： Solvent effects on the absorption and fluorescence spectra of Zaleplon, a nonbenzodiazepine sedative/hypnotic drug that is mainly used for the short term treatment of insomnia, were investigated in 18 different solvents with diverse polarities. Dipole moments of the ground and excited state (μg and μe) were determined by Lippert–Mataga, Bakhshiev, Reichardt, McRae and Suppan solvatochromic methods. The dipole moment of Zaleplon ground state in the gas phase has been calculated as μg = 10.95 D (TD-DFT) with B3LYP/cc-pVTZ functional. There is a good agreement of theoretical data with Reichardt, McRae, and Suppan correlations, while some dissidence with Lippert–Mataga and Bakhshiev equations is suggesting the occurrence of specific solute–solvent interactions. Additionally, multiple linear regression analyses with Kamlet–Taft and Catalan solvatochromic models was applied to solute–solvent interactions. Dominant property of the solvent that affects the absorption band and Stokes shifts of Zaleplon is polarity of the solvent while the emission band is influenced mainly by solvent basicity.
关键词： Solvatochromic methods,Dipole moment,Stokes shift,MLR analysis,Zaleplon
更新于2025-09-23 15:22:29
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Theoretical design, synthesis and studies on the solvatochromic behaviour of low band gap phenylenevinylene based copolymers
摘要： A new series of low band gap phenylenevinylene based copolymers was designed by employing density functional theory in the periodic boundary condition using HSE06 exchange correlation functional using 6-31G basis set and synthesized via the Gilch polymerization. The theoretical band gap of the copolymers MD-CA-PPV, MD-FL-PPV, MD-PT-PPV and MD-AN-PPV were found to be 1.98, 2.07, 2.31 and 1.99 eV respectively using the DFT/HSE06/6-31G calculation and the optical band gap of 1.96, 2.03, 2.01 and 1.98 eV respectively, according to the onset edge of lower energy peak of the polymers in solution. The experimental results supported the theoretical prediction. Solvatochromic behaviour of the synthesized copolymers was studied thoroughly in toluene/acetonitrile mixtures of varying polarity at room temperature. The absorption spectrum of the PPV polymers was sensitive to solvent effects which showed bathochromic and hypsochromic shifts with increasing solvent polarity indicating that the transitions involved were π-π* and n-π*. The ground and excited state dipole moments were calculated using solvatochromic correlations. Onsager radius determined from ab initio calculation was used in the determination of dipole moments. The change in the dipole moment (Δμ) was calculated both from solvatochromic shift method and on the basis of microscopic empirical solvent polarity parameter (ET(30)) and values are compared. It was observed that the excited state dipole moment (μe) was larger than its ground state (μg) counterpart. This indicated that a substantial redistribution of the π-electron densities occurred in the more polar excited state for the selected phenylenevinylene polymers. The third-order nonlinear optical (NLO) properties of the copolymers, evaluated by Z-scan method with nanosecond laser beam at 532 nm, are reported. The nonlinear absorption coefficient of the copolymers were calculated to be 0.17×10-10, 2.06 × 10-10, 0.63 × 10-10 and 2.83 × 10-10 esu, respectively for MD-CA-PPV, MD-FL-PPV, MD-PT-PPV and MD-AN-PPV which certified that the polymers showed semiconductor properties.
关键词： Nonlinear optical properties,Solvatochromic properties,Gilch polymerisation,Density functional theory,Poly(p-phenylenevinylene) derivatives
更新于2025-09-19 17:15:36
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Study on Solvent Effect and Estimation of Dipole Moments of Laser Dye 3ADHC
摘要： In this paper solvent effect of 3-acetyl-7-(diethylamino)-2H-chromen-2-one (3ADHC) dye molecule have been studied by solvatochromic shift method. The electronic absorption and emission spectra of the dye molecule were recorded in a variety of polar protic and polar aprotic solvents at room temperature (298K). Solvatochromic shifts, specifically bathochromic (red) shifts were observed in the absorption and emission spectra as a result of solvent polarity, it signifies the π→π* transition involved. The ground state dipole moment and excited state dipole moment of 3AHDC is calculated using solvent correlation methods. Obtained results are in good agreement with the ground state dipole moment calculated by Gaussion computational methods. The ground and excited state dipole moment of the 3ADHC have also been computed from ab initio calculations and compared with those determined experimentally. It has been found that excited-state dipole moment (μe) is greater than ground-state dipole moment (μg) for the title molecule. The increase in dipole moment in the excited singlet states ranges between 3.93 to 8.60D for 3ADHC. This demonstrates that test molecule is more polar in excited states than in ground states for all the solvents used. The spectral changes were analyzed by Kamlet-Taft parameters.
关键词： Stokes shift,Solvatochromic,Molecular Structure of 3-acetyl-7-(diethylamino)-2H-chromen-2-one (3ADHC),Ground state and excited state dipole moment
更新于2025-09-12 10:27:22
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Pyrene Based NLOphoric D‐π‐A‐π‐D Coumarin‐Chalcone and Their Red Emitting OBO Difluoride Complex: Synthesis, Solvatochromism, Z‐scan, and Detailed TD‐DFT Studies
摘要： NLOphoric D-π-A-π-D coumarin chalcone 5 and their BF2 complex 6 were designed, synthesized and characterized through Mass,13C-NMR, and 1H-NMR analysis. Their Photophysical properties are extensively studied in solvents of different polarity. On BF2 complexation of coumarin chalcone shows highly red shift in absorption and emission spectra compared to uncomplexed coumarin chalcone. Positive solvatochromism observed which is well supported by linear and multilinear regression analysis. For BF2 complexed coumarin-chalcone 6 the solvent dipolarity (CSdP) is the main factor responsible for slightly red shift in absorption spectra, and also for the highly red-shift in emission spectra. Frontier molecular orbital, molecular electrostatic potential and Generalized Mulliken-Hush analysis revealed intramolecular charge transfer in these compounds. Nonlinear optical (NLO) properties for compounds 5 and 6 were studied by solvatochromic and computational method. The linear polarizability (α), first-order hyperpolarizability (β) and second-order hyperpolarizability (γ) of compounds were studied by the time dependent density functional theory using three different functionals namely B3LYP, BHHLYP and CAM(cid:0) B3LYP with the 6–31 G (d) basis set. BF2 complexed compound 6, show higher values for αe + αv as well as βe+βv compared to compound 5. Third order nonlinear optical susceptibility (χ(3)) of these compounds obtained by Z-scan analysis. Third-order (χ(3)) non-linear optical properties of BF2 complexed coumarin-chalcone 6 were observed to be several times higher than those of the uncomplexed coumarin-chalcone 5 these justify the design approach.
关键词： NLOphoric,Z-Scan,positive solvatochromism,pyrene-chalcones,TD-DFT,solvatochromic NLO
更新于2025-09-11 14:15:04
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MCM-SO3H catalyzed synthesis of environment-sensitive fluorophores incorporating pyrene moiety: Optimization, fluorescence emission and theoretical studies
摘要： Six new highly fluorescent 5-(aryl)-1-phenyl-3-(pyren-1yl)-2-pyrazolines were synthesized by reaction of various (E)-3-aryl-1-(pyren-1-yl)prop-2-en-1-ones with phenyl hydrazine in the presence of sulfonated mesoporous silica (MCM-SO3H) as efficient and eco-friendly acidic catalyst. The chemical structures of all synthesized compounds were illustrated on the basis of spectral data (IR, 1H NMR and 13C NMR). This was followed by photophysical properties-based absorption and emission studies of the target compounds in solutions of different solvent polarities. The microenvironment-sensitive fluorescent pyrazolines labeled with pyrene exhibited valuable fluorescence properties with emission in the range of 600–700 nm with a marked response to change in the environmental polarities. A significant and pronounced red shift was observed in the emission spectrum of 5-(aryl)-1-phenyl-3-(pyren-1yl)-2-pyrazolines Δλ ～ 50 nm compared to the absorption spectrum Δλ ～ 10 nm upon increasing the solvent polarity. This indicated the presence of higher dipole moment in the excited state than in the ground state and the transition involved are π-π* transition through the charge transfer phenomena. The fundamental understanding of solvatochromic properties were analyzed through Lippert-Mataga and Reichardts correlations in order to estimate the change in dipole moments (Δμ) which suggested the emissive state of designed fluorescent 2-pyrazoline derivatives is of strong ICT character.
关键词： Pyrene,Solvatochromic properties,Eco-friendly,2-Pyrazolines,Fluorophores,MCM-SO3H
更新于2025-09-10 09:29:36
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Synthesis, optical characterization, and TD-DFT studies of novel mero/bis-mero cyanine dyes based on N-Bridgehead heterocycles
摘要： Novel mero/bis-mero cyanine dyes based on N-Bridgehead imidazo[1,2-g]quinolino[2,1-a][2,6]naphthyridine have been synthesized and characterized to evaluate intramolecular charge transfer (ICT) effect on the energy gap (E0-0). The UV–Vis/emission spectral studies revealed that, dyes are absorbed in the region of λmax (485-577) nm and emitted at (567-673) nm. Their solvatochromic behavior in solvents of various polarities, viz. (CCl4, C6H6, H2O, CHCl3, acetone, and DMF) was studied to emphasize the effect of solvent polarity on the absorption maxima, molar extinction coefficients of the dyes, and excitation energy of the dyes. Their electron cloud delocalization in HOMO/LUMO levels were studied by DFT using Gaussian 09 software. Time-dependent density functional theory (TD-DFT) was applied to theoretically explore the first excitation energy (E0-0) of these dyes which in well agreement with experimental results.
关键词： TD-DFT calculations,Photo-physical properties,Solvatochromic behavior,Mero cyanine
更新于2025-09-09 09:28:46
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Conformational change due to intramolecular hydrophobic interaction leads to large blue-shifted emission from single molecular cage solutions
摘要： We demonstrate a unique negative solvatochromic emission (NSE) process from a conformational change of a coordination cage in response to solvent composition. The cationic cage contains two tetra-(4-pyridylphenyl)ethylene (TPPE) luminogens on two opposite faces, linked by Pt(PEt3)2 and isophthalate. When the solvent changes from acetone/acetonitrile/methanol to water, the emission of single cages gradually shifts to short wavelength (NSE) with a drastic value of B60 nm. Small angle X-ray scattering (SAXS) measurements indicate a molecular conformational change during the process and intramolecular p–p stacking and hydrophobic interaction between the TPPE planes could be the driving forces. As a comparison, a cage with a longer inter-fluorophore distance does not have such strong intramolecular interactions and only shows regular positive solvatochromic emission (PSE) under the same conditions.
关键词： coordination cage,intramolecular hydrophobic interaction,small angle X-ray scattering,TPPE luminogens,negative solvatochromic emission
更新于2025-09-04 15:30:14