Intramolecular fluorescence quenching in porphyrin-bearing [2]catenates

2001 ◽  
Vol 05 (08) ◽  
pp. 633-644 ◽  
Author(s):  
GRAHAM HUNGERFORD ◽  
MARK VAN DER AUWERAER ◽  
DAVID B. AMABILINO
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Fluorescence Spectra ◽  
Model Compound ◽  
Fluorescence Decay ◽  
Critical Distance ◽  
The Core ◽  
Ligand Charge Transfer ◽  
Energy Sink ◽  
Mlct State

The fluorescence quenching of a Zn(II) porphyrin linked to Cu(I) catenates relative to a model compound without Cu(I) was attributed to energy transfer from the Zn(II) porphyrin to the metal-to-ligand charge transfer (MLCT) state of the Cu(I) (phenanthroline)2 center at the core of the molecules. The similarity of the fluorescence spectra and fluorescence decays of a Zn(II) porphyrin linked to an Au(III) porphyrin, a Zn(II) porphyrin or a benzoate moiety through the catenate framework suggested that no fluorescence quenching by electron transfer to the Au(III) porphyrin occurred and that the copper(I) (phenanthroline)2 center acts as an energy sink. The value of the critical distance for Förster type energy transfer, determined from spectral data is compatible with the observed rate constants for energy transfer and dimensions of the macrocycle. The multi-exponential nature of the fluorescence decay is attributed to the presence of different slowly interconverting conformations of the macrocycle to which the porphyrins are attached.

Fluorescence energy transfer studies in a cross-linked polyurethane network

1995 ◽  
Vol 73 (11) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jie Yang ◽  
Mitchell A. Winnik
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Fluorescence Decay ◽  
Critical Distance ◽  
Nonradiative Energy Transfer ◽  
Fluorescence Energy Transfer ◽  
Distribution Analysis ◽  
Analysis Method ◽  
Acceptor Concentration ◽  
Fluorescence Energy

A series of cross-linked polyurethane samples, labeled with dyes suitable for fluorescence energy transfer experiments, were prepared (donor, phenanthrene; acceptor, anthracene). Fluorescence decay profiles for these samples were measured as a function of acceptor concentration. These decays obey Förster nonradiative energy transfer kinetics, with an energy transfer critical distance (R0) of 26.7 Å. Fluorescence intensities, calculated from the decays by integrating the decay profiles, also fit the Perrin model, with a quenching radius (Rs) of 25.6 Å. The fluorescence decay profiles were further examined with a distribution analysis method, which also revealed uniformly distributed donors and acceptors in the polymer matrices. Keywords: fluorescence quenching, fluorescence decay, phenanthrene, anthracene, polyurethane.

scholarly journals Transition-Metal Ions in Nd-Doped Glasses: Spectra and Effects on Nd Fluorescence

1985 ◽  
Vol 61 ◽  
Author(s):  
S. E. Stokowski ◽  
D. Krashkevich
Keyword(s):  
Energy Transfer ◽  
Transition Metal ◽  
Fluorescence Quenching ◽  
Metal Ion ◽  
Impurity Content ◽  
Transition Metal Ions ◽  
Fluorescence Decay ◽  
Absorption Loss ◽  
Quenching Rate ◽  
Doped Glasses

ABSTRACTWe have measured transition-metal ion (Ti, V, Cr, Mn, Fe, Co, Ni, Cu) spectra and their effects on Nd fluorescence quenching in Nd-doped phosphate and silicate glasses. Our purpose was to determine the maximum allowable impurity content given particular limits on the absorption loss at 1053 nm and the Nd fluorescence quenching rate. To keep the absorption loss <0.1 m−1 the transition-metal impurity content should be kept below 0.5 ppmw. To keep the increase in the Nd fluorescence decay rate below 1%, the impurity content should be <3 ppmw. We have also found that the Nd quenching rates do not scale as predicted by the Forster- Dexter dipole-dipole energy transfer theory if we assume that the dominant variation with transition metal is the overlap integral of the Nd fluorescence spectrum and the transition-metal absorption. We suggest that phonon-assisted energy transfer to transition metals is effective in quenching Nd. We find that quenching rates increase 1.5 to 4 times as the Nd concentration increases from 0.5 to 10 × 1020 cm−2.

Energieübertragung zwischen gleich-und ungleichartigen Molekülen in Lösung III. Experimente über Fluoreszenzlöschung durch absorbierende Fremdstoffe/ Energy Transfer Among Like and Unlike Molecules in Solution III. Study of Fluorescence Quenching by Foreign Absorbing Substances

1975 ◽  
Vol 30 (12) ◽  
pp. 1611-1614 ◽  
Author(s):  
A. Kawski ◽  
M. Stoń
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Excitation Energy ◽  
Shell Model ◽  
Electronic Excitation ◽  
Critical Distance ◽  
Electronic Excitation Energy ◽  
Radiationless Energy Transfer ◽  
Good Agreement ◽  
Luminescent Centre

Abstract Energy Transfer Among Like and Unlike Molecules in Solution 111. Study of Fluorescence Quenching by Foreign Absorbing Substances Radiationless energy transfer between unlike molecules (heterotransfer) in fluid solutions was studied by the quenching of fluorescence by foreign absorbing substances. The quenching of electronic excitation energy of 2-aminopurine and 2-aminopyrimidine, acting as sensitizers, and by acridine or 9-methylanthracene, acting as acceptors, was investigated in ethanol and compared with the theory of "multi-shell model" of a luminescent centre. In fluid solutions the critical distance for energy transfer is little depended on the diffusion. Good agreement was found with the equation taking into account only the excitation energy migration.

scholarly journals Ultrafast Electron/Energy Transfer and Intersystem Crossing Mechanisms in BODIPY-Porphyrin Compounds

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 312
Author(s):  
Yusuf Tutel ◽  
Gökhan Sevinç ◽  
Betül Küçüköz ◽  
Elif Akhuseyin Yildiz ◽  
Ahmet Karatay ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Spectra ◽  
Visible Region ◽  
Energy Transfer Mechanism ◽  
Free Base ◽  
Pump Probe ◽  
Harvesting Efficiency ◽  
Probe Spectroscopy ◽  
Absorption Features ◽  
Transfer Mechanisms

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.

scholarly journals Graphdiyne nanosheets as a platform for accurate copper(ii) ion detection via click chemistry and fluorescence resonance energy transfer

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5320-5324
Author(s):  
Chenchen Ge ◽  
Jiaofu Li ◽  
Dou Wang ◽  
Kongpeng Lv ◽  
Quan Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Click Chemistry ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
High Specificity ◽  
Ion Detection ◽  
Fluorescence Resonance

Cu2+ detection was performed by taking advantage of the fluorescence quenching ability of graphdiyne and the high specificity of click chemistry.

Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer

2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Energy Transfer ◽  
Photophysical Properties ◽  
Fluorescence Decay ◽  
High Yield ◽  
Free Base ◽  
Time Resolved ◽  
Zinc Porphyrin ◽  
Relative Contribution ◽  
Synthetic Strategy ◽  
Decay Times

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.

Synthesis, Characterization and Photophysical Properties of Rhenium(I) Complexes Containing 4,5-Diazafluorene Ligan

2011 ◽  
Vol 239-242 ◽  
pp. 2612-2615
Author(s):  
Jie Xiu Wang ◽  
Feng Zhao
Keyword(s):  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Absorption And Fluorescence Spectra ◽  
Rhenium Complexes ◽  
H Nmr ◽  
Ligand Charge Transfer

Two related tricarbonyl rhenium complexes with the formula of [Re(CO)3(L)Cl], where L=4,5-diazafluoren-9-one (Dafo-Re) and 9-(phenylamino)-4,5-diazafluoren (PADF-Re) were successfully synthesized with the aim to explore the effect of the geometry of Dafo on Rhenium(I) coordination, and characterized by1H NMR. Photophysical behaviors are investigated by UV–vis absorption and Fluorescence spectra. The two complexes Dafo-Re and PADF-Re show metal-to-ligand charge transfer absorptions at ca.391nm, ca.394 nm and emissions at ca.492nm, ca.470nm, respectively.

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