scholarly journals Fluorescence quantum yield rationalized by the magnitude of the charge transfer in π-conjugated terpyridine derivatives

2016 ◽  
Vol 18 (42) ◽  
pp. 29387-29394 ◽  
Author(s):  
Marie Humbert-Droz ◽  
Claude Piguet ◽  
Tomasz A. Wesolowski
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Quantum Yield ◽  
Excited States ◽  
Charge Separation ◽  
Fluorescence Quantum Yield ◽  
Molecular Design ◽  
Electron Hole ◽  
Two Measures

Two measures of charge separation in ground and excited states (length of the change in dipole moment and the electron–hole distance) provide a remarkable tool for the molecular design of a fluorescent polyaromatic antenna.

scholarly journals Modulation of charge transfer by N-alkylation to control photoluminescence energy and quantum yield

2020 ◽  
Vol 11 (27) ◽  
pp. 6990-6995 ◽  
Author(s):  
Andrew T. Turley ◽  
Andrew Danos ◽  
Antonio Prlj ◽  
Andrew P. Monkman ◽  
Basile F. E. Curchod ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Yield ◽  
Excited States

A versatile N-alkylation strategy controls the presence of charge-transfer excited states and the emission colour of N-heterocyclic chromophores.

Bioconjugatable synthetic chlorins rendered water-soluble with three PEG-12 groups via click chemistry

2020 ◽  
Vol 24 (01n03) ◽  
pp. 362-378 ◽  
Author(s):  
Nobuyuki Matsumoto ◽  
Masahiko Taniguchi ◽  
Jonathan S. Lindsey
Keyword(s):  
Aqueous Solution ◽  
Quantum Yield ◽  
Click Chemistry ◽  
Fluorescence Quantum Yield ◽  
Molecular Design ◽  
Water Soluble ◽  
Propanoic Acid ◽  
Free Base ◽  
Yield Formula ◽  
Water Solubilization

Chlorins provide many ideal features for use as red-region fluorophores but require molecular tailoring for solubilization in aqueous solution. A chlorin building-block bearing 18,18-dimethyl, 15-bromo and 10-[2,4,6-tris(propargyloxy)phenyl] substituents has been transformed via click chemistry with CH3(OCH2CH[Formula: see text]-N3 followed by Suzuki coupling with 3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)propanoic acid, thereby installing a water-solubilization motif and a bioconjugatable handle, respectively. In toluene, [Formula: see text]-dimethylformamide (DMF) or water, the resulting facially encumbered free base chlorin exhibits characteristic chlorin absorption ([Formula: see text] [Formula: see text]412, 643 nm) and fluorescence ([Formula: see text] [Formula: see text]645 nm) spectra with only modest variation in fluorescence quantum yield ([Formula: see text] values (0.24, 0.25 and 0.19, respectively). The zinc chlorin derived therefrom exhibits similar spectral constancy ([Formula: see text] [Formula: see text]414 and 613 nm, [Formula: see text] [Formula: see text]616 nm) and [Formula: see text] 0.094, 0.10 and 0.086 in the three solvents. The results together indicate the viability of the molecular design and synthetic methodology to create red-region fluorophores for use in diverse applications.

Aza-substitution effect on the Q-band excitations of free-base porphin, chlorin, and bacteriochlorin: SAC-CI theoretical study

2005 ◽  
Vol 09 (05) ◽  
pp. 305-315 ◽  
Author(s):  
Jun-ya Hasegawa ◽  
Takayuki Kimura ◽  
Hiroshi Nakatsuji
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Molecular Design ◽  
Decomposition Analysis ◽  
Substitution Effect ◽  
Transition Dipole Moment ◽  
Orbital Energy ◽  
Free Base ◽  
Transition Dipole ◽  
Near Degeneracy

Electronic structure of the excited states and absorption spectra of free-base azaporphins, azachlorin, and azabacteriochlorin were systematically investigated by SAC-CI calculations. Aza-substitution at the meso position affects the orbital energy of the next-HOMO, and the transition dipole moment enlarges as the number of the substitution increases. Some of the aza-substitutions dramatically affect the direction of the transition dipole, due to reduction of the molecular symmetry, which was studied in detail by a decomposition analysis of the transition dipole moment. Tetraza-substitution in chlorin and bacteriochlorin increases the oscillator strength more than that of tetrazaporphin. The mechanism underlying these changes originates mainly from the relaxation of near-degeneracy in the main configurations. These findings would be useful for the application to the molecular design of the excited states.

Fluorescence Enhancement of a Microbial Rhodopsin via Electronic Reprogramming

2018 ◽  
Author(s):  
Maria del Carmen Marin ◽  
Damianos Agathangelou ◽  
Yoelvis Orozco-González ◽  
Alessio Valentini ◽  
Yoshitaka Kato ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Yield ◽  
Excited States ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Enhancement ◽  
Energy Surface ◽  
Wild Type ◽  
Excited State Lifetime ◽  
State Potential ◽  
Microbial Rhodopsin

The manuscript reports on two mutations of the photo-sensory protein Anabaena Sensory Rhodopsin and how these mutations modify the fluorescence quantum yield with respect to the wild-type protein. Experimental results are presented and explained theoretically on the basis of mixing of the S1 and S2 excited states. This mixing modulated by electrostatic and steric effects, tunes the excited state potential energy surface, and thereby the excited state lifetime and the fluorescence quantum yield.<br>

Intramolecular fluorescence quenching in aminocoumarines. Identification of an excited state with full charge separation

1985 ◽  
Vol 63 (7) ◽  
pp. 1649-1653 ◽  
Author(s):  
Wolfgang Rettig ◽  
André Klock
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Charge Separation ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Twisted Intramolecular Charge Transfer ◽  
Full Charge

The fluorescence of 6-aminocoumarine (A6C) is very weak and anomalously redshifted as compared to its 7-substituted analogues 4-methyl-7-aminocoumarine (A7C) and 4-methyl-7-diethylaminocoumarine (DEA7C). The solvatochromic redshift in homologous alcohols is much stronger for A6C, pointing to an increased dipole moment of the emitting state. A twisted intramolecular charge transfer (TICT) state with full charge separation is made responsible for this emission. This is rationalized by molecules-in-molecules calculations. The strong Stokes shift in n-hexane and in ethanol glass at 77 K suggests that A6C emits from a TICT state even under these conditions.

Charge Separation and Charge Transfer in the Low-Lying Excited States of Pentacene

2020 ◽  
Vol 124 (45) ◽  
pp. 24653-24666 ◽  
Author(s):  
Bushra Alam ◽  
Adrian F. Morrison ◽  
John M. Herbert
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Charge Separation

Spin-Bahn-Kopplungseffekte in nicht-ebenen Biarylen / Spin-orbit Coupling Effects in Non-planar Biaryls

1977 ◽  
Vol 32 (3-4) ◽  
pp. 339-340 ◽  
Author(s):  
M. Zander
Keyword(s):  
Charge Transfer ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Transition Probability ◽  
Heavy Atom ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Effects ◽  
Triplet Formation

Abstract The non-planar biaryls 2,2′-dimethyl-biphenyl, 1,1′-bi-naphthyl and 9,9′-biphenanthryl have higher phosphorescence/fluorescence quantum yield ratios than biphenyl, naphthalene and phenanthrene respectively. The increase of spin-orbit coupling in 1,1′-binaphthyl in comparison to naphthalene results in an increase of the phosphorescence transition probability while the triplet formation quantum yield is not enhanced. The much weaker effect of an external heavy atom pertuber on the spin-forbidden electronic tran­ sition rate probabilities in the case of 1,1′-binaphthyl in comparison to naphthalene is explained on the basis of a weaker charge-transfer interaction between luminescer and pertuber in the case of binaphthyl.

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