scholarly journals Theoretical Study of 8-hydroxyquinoline Derivatives as Potential Antennas in Lanthanide complexes: Photophysical Properties and Elucidation of Energy Transfer Pathways.

2021 ◽  
Author(s):  
Juan Julian Santoyo-Flores ◽  
Dayan Paez-Hernandez
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Lanthanide Complexes ◽  
Significant Contribution ◽  
Theoretical Study ◽  
Energy Transfer Process ◽  
Photophysical Properties ◽  
Intersystem Crossing ◽  
Antenna Effect ◽  
Multiconfigurational Methods

A series of 8-hydroxyquinoline derivatives were characterized and tested as potential antennas in a set of designed lanthanide complexes. The molecular structure and ligand localized nature of the excited states were studied in the framework of the multiconfigurational methods CASSCF/NEVPT2 combined with TDDFT- based approaches, which allows applying a fragmentation scheme in the analysis of the most probable sensitization pathway via antenna effect. The photophysical properties of all the complexes and antennas were carefully analyzed, and the most probable energy transfer pathways were elucidated. Rate constants for photophysical processes involved in the mechanism were calculated, showing a significant contribution of the vibronic coupling in all cases and the predominant intersystem-crossing between S1 and T1 states was demonstrated from the analysis of the nature of the wave function of those states. The energy transfer process described herein demonstrates the possibility of Eu(III) and Nd(III) sensitization by the studied ligands. The proposed methodology gives a complete picture of the antenna excited state dynamics.

The radiation-induced formation of excited states of aromatic hydrocarbons in alicyclic hydrocarbons I. Yields of excited singlet and triplet state solute molecules

1975 ◽  
Vol 347 (1648) ◽  
pp. 61-73 ◽  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Pulse Radiolysis ◽  
Minor Role ◽  
Intersystem Crossing ◽  
Excited Singlet ◽  
Excited Triplet ◽  
Upper Limit ◽  
Radiation Induced ◽  
A Minor

The dependences on concentration of the yield of excited triplet naphthalene, G ( 3 Naph٭), and of the radiation-induced fluorescence obtained on pulse radiolysis of solutions of naphthalene in cyclopentane, cyclooctane and decalin are reported. The yields of singlet excited naphthalene, G( 1 Naph٭), formed on pulse radiolysis of these solutions have been determined by comparing the intensity of the radiation-induced fluorescence with that obtained on photo excitation and the extent of formation of 3 Naph٭ by intersystem crossing, G ( 3 Naph٭) i. s. c., is assessed. Upper limit yields of solvent excited states, G ( 1 RH٭), were determined by measuring the extent of singlet energy transfer to toluene. It is concluded that energy transfer from solvent excited states plays a minor role in the formation of excited states of aromatic solutes.

Intramolecular energy transfer and photoisomerization in stilbene dendrimers

2017 ◽  
Vol 95 (9) ◽  
pp. 1013-1023 ◽  
Author(s):  
Masahiro Taima ◽  
Yuka Ishida ◽  
Tatsuo Arai
Keyword(s):  
Energy Transfer ◽  
Energy Harvesting ◽  
Photophysical Properties ◽  
Intersystem Crossing ◽  
Intramolecular Energy Transfer ◽  
The Core ◽  
Transfer Processes ◽  
Trans Isomerization ◽  
Photophysical Processes ◽  
In Cis

Stilbene dendrimers with energy harvesting chromophores, such as naphthalene and benzophenone, have been prepared and their photochemical and photophysical properties have been examined. These dendrimers underwent trans–cis mutual photoisomerization on excitation of the core stilbene or the peripheral naphthalene and benzophenone chromophores through several energy transfer processes, and photophysical processes such as intersystem crossing finally resulted in cis-trans isomerization of the core stilbene.

scholarly journals Photophysical Challenges and Antenna Effect Between Click Reaction-based Bodipy Derivatives Manufactured From Knorr Pyrrole

2021 ◽  
Author(s):  
ahmed nuri kursunlu ◽  
Akif Kagan Yilmaz ◽  
Elif Bastug ◽  
Ersin Guler
Keyword(s):  
Energy Transfer ◽  
Quantum Yield ◽  
Absorption Coefficient ◽  
Organic Solvents ◽  
Click Reaction ◽  
Photophysical Properties ◽  
Molar Absorption Coefficient ◽  
Antenna Effect ◽  
Preliminary Study

Abstract In this paper, a series of click reaction-based Bodipy derivatives have been synthesized as part of a preliminary study. Following the characterization of the four challenger molecules, the photophysical properties (absorption, emission, excitation, molar absorption coefficient, quantum yield, etc.) were examined in various organic solvents. The results showed that the energy transfer from the Bodipy cores to other moieties was calculated between 71% and 93% depending on different π-electron configurations and chromophore groups.

scholarly journals Photophysical Properties of Nitrated and Halogenated Phosphorus Tritolylcorrole Complexes: Insights from Theory

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2779 ◽  
Author(s):  
Marta Alberto ◽  
Bruna De Simone ◽  
Gloria Mazzone ◽  
Nino Russo ◽  
Marirosa Toscano
Keyword(s):  
Excited States ◽  
Density Functional ◽  
Energy Gap ◽  
Photophysical Properties ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Excited Singlet ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Singlet And Triplet States

The photophysical properties of a series of nitrated and halogenated phosphorus tritolylcorrole complexes were studied in dichloromethane solvent by using the density functional theory. Particular emphasis was given to the absorption spectra, the energy gap between the excited singlet and triplet states, and the magnitude of the spin-orbit couplings for a series of possible intersystem crossing channels between those excited states. The proposed study provides a better description of the photophysical properties of these systems while giving insights into their possible use as photosensitizers in photodynamic therapy.

Bis- and trisporphyrin bio-inspired models for bacterial antennas and photosystems

2011 ◽  
Vol 15 (11n12) ◽  
pp. 1150-1171 ◽  
Author(s):  
Pierre D. Harvey ◽  
Mikhail A. Filatov ◽  
Roger Guilard
Keyword(s):  
Energy Transfer ◽  
Photosynthetic Bacteria ◽  
Photophysical Properties ◽  
Antenna Effect ◽  
Purple Photosynthetic Bacteria ◽  
Special Pair ◽  
Energy Transfers ◽  
Donor Acceptor ◽  
Individual Contributions ◽  
Cascade Processes

This review presents the synthetic aspects and photophysical properties of trimeric systems constructed with a first unit consisting of a cofacial porphyrin and then of another porphyrin attached as a side arm. Two scenarios are dealt with. The first one is the case where the three chromophores are different, called donor 1–donor 2–acceptor, specifically where the cofacial fragment is composed of donor 1 and donor 2, and the side arm is the acceptor. They are considered as models for the apo-proteins used in the LH II (light harvesting device) in the purple photosynthetic bacteria. The second one is the case where the chromophores of the cofacial bisporphyrin residue are identical and are closely placed to each other for inter-ring π-interactions. The side arm is simply a mono-porphyrin, and therefore it is different. The cofacial bisporphyrin unit exhibits then similar characteristics to the special pairs located within the reaction center protein, and are designated as artificial special pairs. On the synthetic standpoint, the various pathways to access such models are presented fully exploiting the Suzuki methodology. On the photophysical side, a large emphasis will be placed on the singlet energy transfers. Cascade processes in the trimers donor 1–donor 2–acceptor are presented and each individual contributions donor 1 → donor 2; donor 2 → acceptor; donor → acceptor are addressed qualitatively and quantitatively. For the artificial special pairs flanked with an antenna, the effect of the spacer between the artificial special pair and the antenna will be discussed as well as the choice of substituents and metal demonstrating that one can reverse the orientation of the singlet energy transfer: artificial special pair → side arm or side arm → artificial special pair. Finally, the antenna effect are presented for one example of artificial special pair equipped with 6 semi-flexible dendritic antennas.

scholarly journals The Synthesis and Photophysical Properties of Weakly Coupled Diketopyrrolopyrroles

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4744
Author(s):  
Michał Pieczykolan ◽  
James B. Derr ◽  
Amara Chrayteh ◽  
Beata Koszarna ◽  
John A. Clark ◽  
...  
Keyword(s):  
Excited States ◽  
Density Functional ◽  
Transient Absorption ◽  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Electronic Transitions ◽  
Intersystem Crossing ◽  
Straightforward Manner ◽  
Functional Theory ◽  
Weakly Coupled

Three centrosymmetric diketopyrrolopyrroles possessing either two 2-(2′-methoxyphenyl)benzothiazole or two 2-(2′-methoxyphenyl)benzoxazolo-thiophene scaffolds were synthesized in a straightforward manner, and their photophysical properties were investigated. Their emission was significantly bathochromically shifted as compared with that of simple DPPs reaching 650 nm. Judging from theoretical calculations performed with time-dependent density functional theory, in all three cases the excited state was localized on the DPP core and there was no significant CT character. Consequently, emission was almost independent of solvents’ polarity. DPPs possessing 2,5-thiophene units vicinal to DPP core play a role in electronic transitions, resulting in bathochromically shifted absorption and emission. Interestingly, as judged from transient absorption dynamics, intersystem crossing was responsible for the deactivation of the excited states of DPPs possessing para linkers but not in the case of dye bearing meta linker.

scholarly journals Ферстеровский резонансный перенос энергии с участием светлых и темных экситонов в массивах эпитаксиальных квантовых точек CdSe/ZnSe

2018 ◽  
Vol 60 (8) ◽  
pp. 1575
Author(s):  
Т.Н. Михайлов ◽  
Е.А. Европейцев ◽  
К.Г. Беляев ◽  
A.A. Торопов ◽  
A.В. Родина ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Energy Transfer Process ◽  
Dipole Interaction ◽  
Energy Transfer Mechanism ◽  
Time Resolved ◽  
Decay Times ◽  
Förster Energy Transfer ◽  
Excitonic States ◽  
Time Resolved Photoluminescence

AbstractUsing time-resolved photoluminescence (PL) spectroscopy, we establish the presence of the Förster energy transfer mechanism between two arrays of epitaxial CdSe/ZnSe quantum dots (QDs) of different sizes. The mechanism operates through dipole–dipole interaction between ground excitonic states of the smaller QDs and excited states of the larger QDs. The dependence of energy transfer efficiency on the width of barrier separating the QD insets is shown to be in line with the Förster mechanism. The temperature dependence of the PL decay times and PL intensity suggests the involvement of dark excitons in the energy transfer process.

Effects of ligand and guest solvent molecules on the luminescence properties of Tb : Eu-codoped indium-based MOFs

2016 ◽  
Vol 45 (11) ◽  
pp. 4518-4521 ◽  
Author(s):  
Wenbo Yan ◽  
Le Wang ◽  
Kete Yangxiao ◽  
Zhixing Fu ◽  
Tao Wu
Keyword(s):  
Energy Transfer ◽  
Triplet State ◽  
Excited States ◽  
Transfer Process ◽  
Energy Transfer Process ◽  
Luminescence Properties ◽  
Solvent Molecules

A ligand with its triplet state located between the excited states of the Tb and Eu ions shows effective facilitation in the energy transfer process between them, and the energy transfer process in this case is also influenced by polar guest solvent molecules.

scholarly journals Photophysical Properties of The DCM and DFSBO Styryl Dyes Consequence for Their Laser Properties

1990 ◽  
Vol 10 (5-6) ◽  
pp. 277-296 ◽  
Author(s):  
Jean-Claude Mialocq ◽  
Martine Meyer
Keyword(s):  
Excited States ◽  
Intramolecular Charge Transfer ◽  
Dipole Moments ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Emission Spectra ◽  
Intersystem Crossing ◽  
Laser Dye ◽  
Styryl Dyes ◽  
Polar Solvents

The two styryl dyes, 4-dicyanomethylene-2-methyl-6-P-dimethylaminostyryl-4H-pyran (DCM) and 7- dimethylamino-3-(p-formylstyryl)-l, 4-benzoxazin-2-one (DFSBO) exhibit similar solvent-induced shifts of their absorption and emission spectra related to a large intramolecular charge transfer (ICT) in the first singlet excited state. From the Stokes shift values (vA−vF) and a vectorial analysis of their ground state dipole moment (μg= 6.1 D for DCM and 5.8 D for DFSBO), and using the Lippert-Mataga theory, we have estimated the dipole moments of their fluorescent excited states S1 (μe = 26.3 D for DCM and 27.6 D for DFSBO). Intersystem crossing to the triplet state is totally inefficient in DCM but significant in DFSBO. Moreover the absorption of the DFSBO triplet is quite large in the emission band (600–650 nm), which makes of DFSBO a poor laser dye. Although DCM trans-cis photoisomerization can be quite efficient in non polar solvents (chloroform, tetrahydrofuran), DFSBO does not photoisomerize probably due to steric hindrance and to the S1 character which should be more "benzoxazinone" than ethylenic. DFSBO is also shown to exhibit rotamerism.

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