Studying reactions that proceed from highest excited states of molecules using fluorescence quenching

2008 ◽  
Vol 105 (4) ◽  
pp. 496-510 ◽  
Author(s):  
V. I. Tomin
Keyword(s):  
Fluorescence Quenching ◽  
Excited States

An acidity scale, [H+]hv, for proton quenching of excited states

1989 ◽  
Vol 67 (2) ◽  
pp. 227-238 ◽  
Author(s):  
J. A. Pincock ◽  
P. R. Redden
Keyword(s):  
Excited State ◽  
Fluorescence Quenching ◽  
Excited States ◽  
Benzyl Alcohols ◽  
Fluorescent Indicator ◽  
Quenching Of Fluorescence ◽  
Acidity Scale

An acidity scale for excited state protonation kinetics in 20% ethanol:80% aqueous sulfuric has been developed using 1-cyano-naphthalene as a fluorescent indicator. The utility of this new scale is demonstrated using the proton quenching of fluorescence of a variety of chromophores. These include 1- and 2-cyanonaphthalenes, 1- and 2-methoxynaphthalenes, benzyl alcohols, toluenes, and 2-vinylnaphthalene. Keywords: acidity scale, fluorescence quenching, excited state basicity.

scholarly journals Photochemical processes induced by the irradiation of 4-hydroxybenzophenone in different solvents

2015 ◽  
Vol 14 (11) ◽  
pp. 2087-2096 ◽  
Author(s):  
Francesco Barsotti ◽  
Marcello Brigante ◽  
Mohamed Sarakha ◽  
Valter Maurino ◽  
Claudio Minero ◽  
...  
Keyword(s):  
Fluorescence Quenching ◽  
Excited States ◽  
Ground State ◽  
Photochemical Processes ◽  
Triplet Excited States

The singlet and triplet excited states of 4-hydroxybenzophenone (4BPOH) undergo deprotonation in the presence of water to produce the anionic ground-state, causing fluorescence quenching and photoactivity inhibition.

scholarly journals Спектры РКР и механизмы тушения флуоресценции beta-нитро-тетрафенилпорфирина

2019 ◽  
Vol 126 (3) ◽  
pp. 285
Author(s):  
Н.В. Ивашин ◽  
С.Н. Терехов
Keyword(s):  
Fluorescence Quenching ◽  
Excited States ◽  
Density Functional ◽  
Fluorescence Decay ◽  
Excitation Wavelength ◽  
Decay Kinetics ◽  
Vibrational States ◽  
The Density Functional Theory ◽  
The Matrix ◽  
Fluorescence Decay Kinetics

AbstractThe study of the excited states and photophysical characteristics of β-nitro-tetraphenylporphyrin (TPP–NO_2) has been carried out using resonance Raman scattering (RRS) spectroscopy and methods of the density functional theory. The appearance of new lines, the intensity of which depends on the composition of the matrix and excitation wavelength, has been found in the TPP–NO_2 RRS spectra in the low-temperature matrix. The calculation of the vibrational states of TPP–NO_2 allowed the linking of the additional lines with the asymmetric vibrations of the nitro group and valence C–C vibrations of the phenyl ring (Ph1) that was nearest to it. The activation of these modes is related to the specific features of the TPP–NO_2 geometry in the charge transfer (CT) state from Ph1 to the porphyrin macrocycle. It has been concluded on the basis of the analysis of the data of the study of the RRS spectra and the results of calculations that use the СAM-B3LYP and wB97XD functionals that the CT states do not play a significant role in the TPP–NO_2 fluorescence quenching, as previously assumed. The fluorescence quenching owes to strengthening channels of internal and inter-conversion by reducing the energy gaps Δ E ( S _1 – T _1) and Δ E ( S _1 – S _0) as well as increasing the spin-orbit coupling between the S _1 and T _1 states. It has been shown that TPP–NO_2 is characterized by conformational heterogeneity both in the ground and in the excited states, which explains the absence of the monoexponentiality of fluorescence decay kinetics.

Self-Amplifying Semiconducting Polymers for Chemical Sensors

MRS Bulletin ◽  
2002 ◽  
Vol 27 (6) ◽  
pp. 446-450 ◽  
Author(s):  
Timothy M. Swager ◽  
Jordan H. Wosnick
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Conjugated Polymers ◽  
Excited States ◽  
Chemical Sensors ◽  
Electronic Devices ◽  
Structural Features ◽  
Fluorescent Sensors ◽  
Semiconducting Polymers ◽  
Highly Sensitive

AbstractThe ability of excited states (excitons) to migrate rapidly and efficiently through conjugated polymers makes these materials ideal for use in sensors based on fluorescence quenching or amplification of fluorescence signals. The structural features we are able to introduce into these polymers have allowed us both to design highly sensitive fluorescent sensors for specific analytes, such as the explosive trinitrotoluene (TNT), and to create assemblies that control energy transfer along a predetermined path. The principles involved have broad utility in the design of sensory materials as well as of electronic devices and display components based on electronic polymers.

Fluorescence quenching of sterically-graded pyrene molecules by N,N-dialkylanilines. Exciplexes or locally excited states?

2018 ◽  
Vol 355 ◽  
pp. 467-478 ◽  
Author(s):  
Michael J. Bertocchi ◽  
Xian-Fu Zhang ◽  
Alankriti Bajpai ◽  
Jarugu N. Moorthy ◽  
Richard G. Weiss
Keyword(s):  
Fluorescence Quenching ◽  
Excited States ◽  
Locally Excited

scholarly journals Structure-function-dynamics relationships in the peculiar Planktothrix PCC7805 OCP1: impact of his-tagging and carotenoid type.

2022 ◽  
Author(s):  
Adjele Wilson ◽  
Elena A. Andreeva ◽  
Stanislaw Nizinski ◽  
Lea Talbot ◽  
Elisabeth Hartmann ◽  
...  
Keyword(s):  
Fluorescence Quenching ◽  
Structure Function ◽  
Excited States ◽  
Structural Changes ◽  
Structural Characteristics ◽  
Thermal Recovery ◽  
Crystal Forms ◽  
His Tag ◽  
C Terminus ◽  
Orange Carotenoid Protein

The orange carotenoid protein (OCP) is a photoactive protein involved in cyanobacterial photoprotection. Here, we report on the functional, spectral and structural characteristics of the peculiar Planktothrix PCC7805 OCP (Plankto-OCP). We show that this OCP variant is characterized by higher photoactivation and recovery rates, and a stronger energy-quenching activity, compared to other OCPs studied thus far. We characterize the effect of the functionalizing carotenoid and of his-tagging on these reactions, and the time scales on which these modifications affect photoactivation. The presence of a His-tag at the C-terminus has a large influence on photoactivation, thermal recovery and PBS-fluorescence quenching, and likewise for the nature of the carotenoid that additionally affects the yield and characteristics of excited states and the ns-s dynamics of photoactivated OCP. By solving the structures of Plankto-OCP in the ECN- and CAN-functionalized states, each in two closely-related crystal forms, we further unveil the molecular breathing motions that animate Plankto-OCP at the monomer and dimer levels. We finally discuss the structural changes that could explain the peculiar properties of Plankto-OCP.

scholarly journals A Lanthanide complex for Selective Sensing of Fe (III) Ion

2019 ◽  
Author(s):  
Putri Amanda
Keyword(s):  
Fluorescence Quenching ◽  
Excited States ◽  
Photophysical Properties ◽  
Lanthanide Complex ◽  
Lanthanide Ions ◽  
Absorption Mechanism ◽  
Fluorescence Studies ◽  
Liquid Suspension ◽  
Ft Ir ◽  
Bright Luminescence

Lanthanide complex namely [Ln(Tpy-NH2)2Cl2]Cl where Tpy-NH2 is 4-(p- aminophenyl)-2,2:6,2′′- terpyridine and Ln is Europium dan Dysprosium were synthesized. The ligan was found with reduction of 4-(p-nitrophenyl)-2,2:6,2′′- terpyridine or Tpy-NO2 and photophysical properties such as FT-IR spectra, UV-Vis absorption spectra, and luminescence properties of the complexes in the presence of various metal ions were studied. Here Tpy-NH2 acts as chromophore or light-harvesting photo sensitizing antenna for lanthanide ion in this lanthanide complex. The bright luminescence in complex suggests favorable photo-induced energy transfer happens from the Tpy-NH2 antenna to the lanthanide ions to fill long-lived emissive excited states of lanthanide ions f-f transitions. The luminescence spectral profile of complexes show characteristic sharp multiple emission bands and maximum at 5D0 →7F2 f-f transitions located at 614 nm for complekx Eu and at 4F9/2 →6H15/2 located at 578 nm for complex Dy. The Fluorescence studies revealed that this material showed a highly selective fluorescence quenching response to Fe3+ ions in liquid suspension and its fluorescence quenching response can be explained in terms of the competitive absorption mechanism.

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