Ultrafast dynamics and solvent-dependent deactivation kinetics of BODIPY molecular rotors

2017 ◽  
Vol 19 (30) ◽  
pp. 19998-20007 ◽  
Author(s):  
Tomislav Suhina ◽  
Saeed Amirjalayer ◽  
Sander Woutersen ◽  
Daniel Bonn ◽  
Albert M. Brouwer
Keyword(s):  
Excited State ◽  
Ground State ◽  
Solvent Polarity ◽  
Molecular Rotors ◽  
Conical Intersection ◽  
Ultrafast Dynamics ◽  
Molecular Rotor ◽  
Deactivation Kinetics ◽  
Viscous Solvents ◽  
Kinetics Of

The fluorescent excited state of a molecular rotor based on the meso-substituted boron-dipyrromethane (BODIPY) core decays rapidly to the ground state via a conical intersection. The fluorescence is strongly increased in viscous solvents, but solvent polarity has only a small effect.

scholarly journals Studies on Photophysical Properties of Mono-carbonyl Curcumin Analogues: Experimental and Theoretical approach

2018 ◽  
Vol 34 (4) ◽  
pp. 2170-2179
Author(s):  
Manjula Rayanal ◽  
Prasad Pralhad Pujar ◽  
Sridhar D
Keyword(s):  
Excited State ◽  
Ground State ◽  
Dipole Moments ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Solvent Polarity ◽  
Frontier Molecular Orbital ◽  
Curcumin Analogues ◽  
Td Dft ◽  
Ground State Dipole Moments

The solvatochromic fluorescence behaviour of mono-carbonyl curcumin analogues has been studied in ten different solvents ranging from non-polar to polar. The solvent effect on the spectral properties of analogues has been discussed. The ground state dipole moments were estimated experimentally by Bilot-Kawski equation which is a function of Stokes shift with the solvent polarity parameters and Guggenheim method and theoretically by TD-DFT studies. The excited state dipole moment was determined using Bilot-Kawski equations. The excited state dipole moments for the two molecules were found to be higher than their corresponding ground state dipole moments. Theoretically Frontier molecular orbital (HOMO/ LUMO) energies were determined by Gaussian 09 W software using TD-DFT.

scholarly journals A semi-empirical estimation of ground and excited state dipole moments of zinc phthalocyanine from solvatochromic shift data

2018 ◽  
Vol 6 (2) ◽  
pp. 190
Author(s):  
Abimbola Ogunsipe
Keyword(s):  
Excited State ◽  
Ground State ◽  
Dipole Moments ◽  
Solvent Polarity ◽  
Zinc Phthalocyanine ◽  
Empirical Estimation ◽  
Solvatochromic Shift ◽  
Excited State Dipole Moments ◽  
Semi Empirical ◽  
Ground State Dipole Moments

A semi-empirical determination of ground and excited state dipole moments of zinc phthalocyanine (ZnPc) from solvatochromic shifts is hereby presented. The ratio of the excited- and ground-state dipole moments of ZnPc ( ) was estimated by a combination of the Bakshiev and the Kawski-Chamma-Viallet’s equations, while the difference in the excited- and ground-state dipole moments (Dm) was estimated usingthe molecular-microscopic solvent polarity parameters ( ), alongside the Stokes’ shifts (Dῡ) in the various solvents. The dipole moment of ZnPc is significantly higher in the excited singlet state (me = 3.12 D) than in the ground state (mg = 1.50 D). Obviously charge separation is greater in the excited state of ZnPc than in its ground state.  

scholarly journals Conical intersection dynamics of pyrimidine nucleosides tracked with sub-20-fs UV pulses

2019 ◽  
Vol 205 ◽  
pp. 10007
Author(s):  
Rocío Borrego-Varillas ◽  
Artur Nenov ◽  
Lucia Ganzer ◽  
Aurelio Oriana ◽  
Irene Conti ◽  
...  
Keyword(s):  
Excited State ◽  
Numerical Simulations ◽  
Ab Initio ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Conical Intersection ◽  
Ultrafast Dynamics ◽  
Conical Intersections ◽  
Pyrimidine Nucleosides

By combining transient absorption spectroscopy with sub-20-fs UV pulses and ab initio numerical simulations we follow the ultrafast dynamics in pyrimidine nucleosides and visualize the passage through conical intersections presiding excited state deactivation.

Dipole moments and quenching of fluorescence of a new coumarin dye

2020 ◽  
Vol 98 (8) ◽  
pp. 761-769
Author(s):  
Omnath Patil ◽  
P.K. Ingalagondi ◽  
Shivaraj Gounhalli ◽  
S.M. Hanagodimath
Keyword(s):  
Activation Energy ◽  
Excited State ◽  
Ground State ◽  
Density Functional ◽  
Dipole Moments ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Chemical Hardness ◽  
Fluorescence Emission Spectra ◽  
Coumarin Dye

The absorption and fluorescence emission spectra of a newly synthesized laser grade coumarin dye, 1-((4-methoxyphenoxy) methyl)-3H-benzo[f]chromen-3-one (4-MPMBC), have been recorded in various solvents having different polarities. The spectrum peak was found to shift toward a higher wavelength with an increase in the solvent polarity. The dipole moments of the ground state (μg) and excited state (μe) were estimated using the Lippert, Bakshiev, and Kawski–Chamma–Viallet equations. The μe values were found to be greater than the μg values in all solvents, indicating that the dye is more polar in the excited state than in the ground state. The absorption maximum and emission maximum energies, ground- and excited-state dipole moments, and HOMO–LUMO energy gaps were estimated using Gaussian 16W. These have been compared with the experimental results. The estimated chemical hardness of the dye molecule indicates the soft nature in all of the solvents. The reactive centers such as nucleophilic and electrophilic sites were identified along with contour action using electrostatic potential three-dimensional map density functional theory analysis. The fluorescence quenching has been studied in solvents of varying polarities using aniline as a quencher. The quenching process was found to follow the Stern–Volmer equation and was studied by considering the role of diffusion. In all solvents, the probability of quenching per encounter (p) was found to be less than unity. The activation energy for diffusion and activation energy for quenching were estimated using the values of p.

scholarly journals Effect of solvent polarity on the photophysical properties of chalcone derivatives

RSC Advances ◽  
2017 ◽  
Vol 7 (39) ◽  
pp. 24204-24214 ◽  
Author(s):  
Rekha Kumari ◽  
Anitha Varghese ◽  
Louis George ◽  
Sudhakar Y. N.
Keyword(s):  
Excited State ◽  
Organic Solvents ◽  
Ground State ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Chalcone Derivatives ◽  
Effect Of Solvent

The photophysical properties were studied for FNPO, AFPO and FHPO in different organic solvents. The excited state of the molecules were found to be more polar than the ground state.

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.

scholarly journals Excited-State Decay Pathways of Molecular Rotors: Twisted Intermediate or Conical Intersection?

2016 ◽  
Vol 7 (21) ◽  
pp. 4285-4290 ◽  
Author(s):  
Tomislav Suhina ◽  
Saeed Amirjalayer ◽  
Benedetta Mennucci ◽  
Sander Woutersen ◽  
Michiel Hilbers ◽  
...  
Keyword(s):  
Excited State ◽  
Molecular Rotors ◽  
Conical Intersection ◽  
State Decay

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.

scholarly journals Illuminating the photoisomerization of a modified azobenzene single crystal by femtosecond absorption spectroscopy

2019 ◽  
Vol 97 (6) ◽  
pp. 488-495
Author(s):  
Kamil M. Krawczyk ◽  
Ryan L. Field ◽  
Lai Chung Liu ◽  
Mingxin Dong ◽  
G. Andrew Woolley ◽  
...  
Keyword(s):  
Excited State ◽  
Single Crystal ◽  
Ground State ◽  
Transient Absorption ◽  
Ultrafast Dynamics ◽  
Femtosecond Transient Absorption ◽  
Spectral Components ◽  
Long Time ◽  
And Inversion ◽  
Insight Into

The mechanism of isomerization for azobenzene is a topic still to be completely elucidated. Here, we describe the ultrafast dynamics of a brominated dioxane-methoxy-azobenzene under single crystal conditions by means of femtosecond transient absorption (TA) spectroscopy. Upon excitation with 400 nm light, spectral components with decays of 0.72, 2.9, and >10 ps are observed. The fast components of the system correspond to vibrational cooling of the population on the S1 excited state, with a decay to a local minimum in the reaction coordinate, followed by a longer evolution to a dark intermediate state prior to relaxing to the ground state, S0. The long time constant can be used to describe the isomerization process, returning excited population to the ground state. Spectral frequencies observed at 33 and 82 cm−1 suggest that both rotation and inversion occur in the system, with a stronger contribution coming from the latter due to a weakened N–N double bond in the excited state. This information provides insight into the structural nature of modified azobenzene systems and sets the stage for future structural studies of the molecule’s isomerization dynamics.

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