scholarly journals Solvent effect on the absorption and emission spectra of carbon dots: evaluation of ground and excited state dipole moment

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Parisa Mohammad-Jafarieh ◽  
Abolfazl Akbarzadeh ◽  
Rahman Salamat-Ahangari ◽  
Mohammad Pourhassan-Moghaddam ◽  
Kazem Jamshidi-Ghaleh
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Carbon Dots ◽  
Dipole Moments ◽  
Emission Spectra ◽  
Aprotic Solvents ◽  
One Step ◽  
The Difference ◽  
Excited State Dipole Moment

Abstract Background Carbon dots (C-dots) are photoluminescent nanoparticles with less than 10 nm in size. Today, many studies are performed to exploit the photoluminescence (PL) property of carbon dots, and our focus in this study is to estimate the dipole moment of carbon dots. For reaching our aims, C-dots were synthesized and dissolved in the different solvents. Results Carbon dots with intense photoluminescence properties have been synthesized by a one-step hydrothermal method from a carbon bio-source. In this research, we report on the effect of aprotic solvents on absorption and fluorescence spectra and dipole moments of C-dots dispersed in a range of many aprotic solvents with various polarity and dielectric constant at room temperature. The change in the value of dipole moment was estimated by using the Stokes shifts. The difference between the dipole moment of the excited state and the ground state was shown using an extended form of Lippert equations by Kawski and co-workers. Conclusions The values found for μg = 1.077 D, and μe = 3.157 D, as well as the change in the dipole moments. The results showed that the dipole moment of the excited state is more than the ground state, indicating a high density and redistribution of electrons in the excited state. Finally, the quantum yield of C-dots in the eclectic aprotic solvents was communicated and discussed.

scholarly journals Solvatochromic Study of Supramolecular Amphiphile Based on Calix[4]arene Connected to a Fluorescent Benzofurazan Moiety at Lower Rim: Evaluation of Ground and Excited State Dipole Moments-=SUP=-*-=/SUP=-

2020 ◽  
Vol 128 (12) ◽  
pp. 1864
Author(s):  
S. Joshi
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Fluorescence Spectra ◽  
Dipole Moments ◽  
Photophysical Properties ◽  
Bathochromic Shift ◽  
Fluorescence Emission ◽  
Wide Range ◽  
Excited State Dipole Moment

Photophysical properties of a supramolecular amphiphile of calix[4]arene having benzofurazan moiety at the lower rim, L has been studied. Electronic absorption and fluorescence spectra of L have been recorded in wide range of solvents of different polarities and data were used to study solvatochromic properties. The ground state and the excited state dipole moment of L were estimated from the Bakhshiev's and Bilot-Kawaski's equations. High value of dipole moment is observed for excited state as compared to ground state value and this is attributed to more polar excited state of molecule. Also, fluorescence emission peak undergoes a bathochromic shift with increase in the polarity of the solvent, confirming π-> π* transition. Scanning electron microscopy reveals that the aggregation of L is increased on going from the polar to non polar solvents. Keywords: solvatochromism, benzofurazan, dipole moment, quantum yield, absorption, fluoresence.

Theoretical and Experimental Investigation on Dipole Moment of Synthetized yt-Base in the Ground and Excited States

1979 ◽  
Vol 34 (2) ◽  
pp. 172-175 ◽  
Author(s):  
I. Gryczyński ◽  
Ch. Jung ◽  
A. Kawski ◽  
S. Paszyc ◽  
B. Skalski
Keyword(s):  
Experimental Investigation ◽  
Dipole Moment ◽  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Fluorescence Spectra ◽  
Dipole Moments ◽  
Aprotic Solvents ◽  
Absorption And Fluorescence Spectra ◽  
First Excited State

Abstract The electric dipole moment of yt-Base calculated by the CNDO/S and JNDO/S method is μg = 3.42 D and μg = 3.74 D in the ground state and μe = 4.41 D and μe = 5.67 D in the first excited ππ*-state, respectively, μg and μe being nearly antiparallel. Measurements of absorption and fluorescence spectra of yt-Base in aprotic solvents of different polarity yielded μg = 3.8 D and μe = 4.3 D and the directions of dipole moments were found to be nearly antiparallel.This comparison may be considered as an indication for the ππ* character of the observable first excited state, although the CNDO/S-and JNDO/S-calculations predict a nπ*-state as the lowest lying excited state

scholarly journals Study of Solvent Effect in 2, 5-DPAPMC Dye Using Different Solvent Polarity Parameters and Estimation of Dipole Moments

2017 ◽  
Vol 13 (1) ◽  
pp. 101-117
Author(s):  
Thipperudrappa J
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Linear Regression ◽  
Ground State ◽  
Dipole Moments ◽  
Solvent Polarity ◽  
Ground State Dipole Moment ◽  
Regression Approach ◽  
Polarity Parameter ◽  
Excited State Dipole Moment

The solvent effect on absorption and fluorescence spectra of      a ketocyanine      dye 2,5-di[(E)-1-(4- dipropylaminophenyl)     methylidine]-1-cyclopentanone (2,5-DPAPMC) is analysed using Lippert-Mataga bulk polarity function, Reichardt’s microscopic solvent polarity parameter and Kamlet’s multipl e linear regression approach. The spectral properties better follows Reichardt’s microscopic solvent polarity parameter than Lippert-Mataga bulk polarity parameter. This indicates the presence of both general solute – solvent interactions and specific   interactions.   Kamlet’s multiple linear regression   approach indicates the major role of polarizability/dipolarity solvent influence than HBD and HBA. The spectral data in different solvents is used to estimate excited state dipole moment using theoretically determined ground state dipole moment. The excited state dipole moment of dye is found to be larger than its corresponding ground state dipole moment and, ground and excited state dipole moments are not parallel, but subtends an angle of 29 o .

Molecular and structural characterization of New Red and Erythrosine by fluorescence polarization spectroscopy

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740062
Author(s):  
Chun Zhu ◽  
Jia-Meng Du ◽  
Jin-Chen Zhao ◽  
Tuo Zhu ◽  
Guo-Qing Chen
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Dipole Moments ◽  
Linear Structure ◽  
Polarization Spectroscopy ◽  
Angle Shift ◽  
Ground State Structures ◽  
Average Angle

The fundamental and the fluorescence anisotropies of New Red and Erythrosine were measured. The intersection angles between the absorption and the emission dipole moments for New Red and Erythrosine are 4.44[Formula: see text] and 23.26[Formula: see text], respectively. The average angle shift of the emission dipole moment of New Red is 3.91[Formula: see text] during the lifetime of the excited state. This indicates that it has a bifurcated linear structure with weak rotational capacity. The average angle shift of the emission dipole moment of Erythrosine is 9.25[Formula: see text], indicating that it has a partial planar structure and is easier to rotate. The spatial ground state structures were simulated with Gaussian 09.

scholarly journals Computational and Spectral Means for Characterizing the Intermolecular Interactions in Solutions and for Estimating Excited State Dipole Moment of Solute

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1299
Author(s):  
Dana Ortansa Dorohoi ◽  
Dorina Emilia Creanga ◽  
Dan Gheorghe Dimitriu ◽  
Ana Cezarina Morosanu ◽  
Antonina Gritco-Todirascu ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Solvation Shell ◽  
Spectral Shift ◽  
Binary Solvents ◽  
Ternary Solutions ◽  
Chemical Computation ◽  
The Difference ◽  
Excited State Dipole Moment ◽  
Active Solvent

The results obtained both in quantum chemical computation and in solvatochromic study of pyridinium di-carbethoxy methylid (PCCM) are correlated in order to estimate the electric dipole moment in the excited state of this molecule. This estimation is made by a variational method in the hypothesis that the molecular polarizability does not change in time of the absorption process. Ternary solutions of PCCM in protic binary solvents are used here, both establishing the contribution of each type of interaction to the spectral shift and to characterize the composition of the first solvation shell of PCCM. Results are compared with those obtained before for other binary solvents. The difference between the interaction energies in molecular pairs of PCCM-active solvent and PCCM-less active solvent was also estimated based on the cell statistical model of the ternary solutions.

scholarly journals Estimating the Ground and Excited State Dipole Moments of Levofloxacin and Norfloxacin Drugs Using Solvatochromic Effects and Computational Work

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Kinfe Woldegiorges ◽  
Abebe Belay ◽  
Alemu Kebede ◽  
Tamirat Abebe
Keyword(s):  
Excited State ◽  
Ground State ◽  
Dipole Moments ◽  
Bacterial Species ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Electron Charge Density ◽  
Nonpolar Solvents ◽  
Computational Work ◽  
Excited State Dipole Moments

Levofloxacin (LVF) and norfloxacin (NRF) are a group of fluoroquinolone antibiotics, broad spectrum used to treat various infections caused by many bacterial species. The drugs contain functional groups which control the type and degree of interaction with different solvents. In this research, the ground and excited state dipole moments of LVF and NRF drugs were estimated using solvatochromic effects and computational work. The dipole moments were estimated from absorption and emission spectra in polar and nonpolar solvents using Bakhshiev’s, Kawski–Chamma–Viallet, Lippert–Mataga, and Reichardt models. The results indicated the emission spectra are more strongly affected by solvent polarity than the absorption spectra. The calculated excited state dipole moment is larger than that of the ground state, indicating that the probe compounds are significantly more polarized in the excited state than in the ground state. From computational work, the HOMO-LUMO energy band gap, the dipole moments, electron charge density distribution, and oscillator strength were determined using the semiempirical MP6 method, DFT-B3LYP-6-31G, and DFT-B3LYP-3-21G employing Gaussian 09 software. In general, larger dipole moments were obtained by computation rather than from experiments due to the absence of solvent effects.

Ground-and Excited-State Dipole Moments of 6-Propionyl-2-(dimethylamino)naphthalene Determined from Solvatochromic Shifts

1999 ◽  
Vol 54 (6-7) ◽  
pp. 379-381 ◽  
Author(s):  
A. Kawski
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Singlet State ◽  
Fluorescence Probe ◽  
Dipole Moments ◽  
Free Molecule ◽  
Excited Singlet ◽  
Solvatochromic Shifts ◽  
Excited State Dipole Moments

Abstract The dipole moments in the ground-and excited-state of the fluorescence probe 6-propionyl-2-(dim-ethylamino)naphthalene (PRODAN) are determined from solvatochromic shifts to μe = 2.1 D and μg = 6.4 D. These values concern the free molecule. In the first excited singlet state the dipole moment is only 3 times greater than in the ground state.

scholarly journals Photophysical Approach of Biological Active Benzofuran Derivatized Pyrrole with Green Synthesized Silver NPs Using C. Roseus Leaves: Computational and Spectroscopic Study

2021 ◽  
Author(s):  
Shivaprasadagouda Patil ◽  
Mahanthesh M. Basanagouda ◽  
Sudhir M. Hiremath ◽  
Aishwarya Nadgir ◽  
Malatesh S Pujar ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Molecular Orbital ◽  
Ground State ◽  
Solvent Polarity ◽  
Ag Nps ◽  
Ground State Dipole Moment ◽  
Computational Calculations ◽  
Silver Nps ◽  
Excited State Dipole Moment

Abstract The electronic absorption and fluorescence emission spectra of N-(2,5-dimethyl-pyrrol-1-yl)-2-(5-methoxybenzofuran-3-yl)acetamide (DPMA) molecule were recorded in various solvents at room temperature with the aim of estimation of ground state (\({\mu }_{g}\)) and excited states (\({\mu }_{e}\)) dipole moments using Lippert’s, Bakshiev’s and Kawski-Chamma-Viallete’s equations. The results were signified that, the excited state dipole moment is greater than the ground state dipole moment, which indicates the excited state dipole moment is more polar than the ground state dipole moment. Ecofriendly green synthesis of silver nanoparticles (Ag NPs) were synthesized using catharanthus roseus (C.R) leaf extract was done. These synthesized Ag NPs were used as fluorescence quenchers. Fluorescence lifetime measurement is carried out using time correlated single photon counting technique of DPMA molecule with various concentrations of Ag NPs. A linear Stern-Volmer (S-V) plot was obtained in steady state and transient state method. Furthermore we have estimated computational calculations such as ground state optimized geometry, molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), experimental and theoretical energy band gap, solvent polarity and normalized solvent polarity values. Morphology and sizes of green synthesized silver NPs were characterized by transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDX) and also characterized by UV-Visible absorption.

Thermochromic Shifts of Absorption and Fluorescence Spectra and Excited State Dipole Moment of PRODAN

2000 ◽  
Vol 55 (5) ◽  
pp. 550-554 ◽  
Author(s):  
A. Kawski ◽  
B. Kukliński ◽  
P. Bojarski
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ethyl Acetate ◽  
Satisfactory Agreement ◽  
Fluorescence Spectra ◽  
Dipole Moments ◽  
Absorption And Fluorescence Spectra ◽  
Shift Method ◽  
Solvatochromic Method ◽  
Excited State Dipole Moment

Abstract Using the thermochromic shift method of absorption and fluorescence spectra, the dipole moments in the ground, µg, and excited. µe , state are simultaneously determined for PRODAN in ethyl acetate. The obtained values for µg and µe are compared with those previously determined by the solvatochromic method for two different Onsager radii, and a satisfactory agreement has been obtained

Photophysical characteristics of two novel coumarin derivatives: Experimental and theoretical estimation of dipole moments using the solvatochromic shift method

2014 ◽  
Vol 92 (11) ◽  
pp. 1330-1336 ◽  
Author(s):  
Shivaram N. Patil ◽  
F.M. Sanningannavar ◽  
B.S. Navati ◽  
N.R. Patil ◽  
R.A. Kusanur ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Dipole Moments ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Spectral Shift ◽  
Coumarin Derivatives ◽  
Solvatochromic Shift ◽  
Shift Method ◽  
Solvatochromic Shift Method

The exited state (μe) dipole moment of a molecule is an important parameter, which gives information about electronic and geometrical structure of the molecule in the short-lived state. We have experimentally estimated the exited state (μe) dipole moment of two novel coumarin derivatives, namely, diethyl 2-acetamido-2-((6-methyl-2-oxo-2H-chromen-4-yl) methyl) malamute (DAM) and 5,6-Benzo-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)] coumarin (5BDTC) by three methods, namely, Lippert’s, Bakhshiev’s, and Kawski–Chamma–Viallet’s. In the Solvatochromic shift method, spectral shift is due to internal excitation of the molecule. We have recorded absorption and emission spectra of the above two novel coumarin derivatives at room temperature using solvents of different polarities. The geometry of the molecules were fully optimized and the ground state dipole moment (μg) were also calculated theoretically by Gaussian 03 software using B3LYP/6-31g* level of theory. The excited state dipole moment was calculated using CIS/6-31G* level of theory. The μg and μe were calculated using the solvatochromic shift method and μe was also determined in combination with μg. It was observed that μe were greater than those of μg, indicating a substantial redistribution of the π-electron densities in a more polar excited state for this coumarin. Further, the changes in dipole moment (Δμ) were calculated both from the solvatochromic shift method and on the basis of microscopic empirical solvent polarity ([Formula: see text]) and the values are compared.

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