The Origin of Time-Resolved Emission Spectra (TRES) Changes of 4-Aminophthalimide (4-AP) in SDS Micelles. The Role of the Hydrogen Bond between 4-AP and Water Present in Micelles

Steady state and time-resolved spectroscopic measurements of fluorenone and 4-hydroxyfluorenone dissolved in binary nonpolar, polar and polar protic mixed solvents have been performed at room temperature. The absorption and emission spectra show that, apart from the free molecules, hydrogen bond complexes exist in the ground and excited states in the mixed solvents used. The data obtained were used to determine the stoichiometric equilibrium constants. The fluorescence decay data point that in the binary used solutions the radiation appears from an assembly of luminescence centers emitting fluorescence light of different wavelengths and decay times. Molecules forming simple hydrogen bond complexes (with fluorenone) show different photophysical properties from those where a proton-relay complex (with 4-hydroxyfluorenone) is established.

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Role of hydrogen bond alternation and charge transfer states in photoactivation of the Orange Carotenoid Protein

Communications Biology ◽

10.1038/s42003-021-02022-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Igor A. Yaroshevich ◽

Eugene G. Maksimov ◽

Nikolai N. Sluchanko ◽

Dmitry V. Zlenko ◽

Alexey V. Stepanov ◽

...

Keyword(s):

Crystal Structure ◽

Hydrogen Bond ◽

Charge Transfer ◽

Electric Field ◽

Quantum Chemical ◽

Time Resolved ◽

Bond Alternation ◽

Orange Carotenoid Protein ◽

The Impact

AbstractHere, we propose a possible photoactivation mechanism of a 35-kDa blue light-triggered photoreceptor, the Orange Carotenoid Protein (OCP), suggesting that the reaction involves the transient formation of a protonated ketocarotenoid (oxocarbenium cation) state. Taking advantage of engineering an OCP variant carrying the Y201W mutation, which shows superior spectroscopic and structural properties, it is shown that the presence of Trp201 augments the impact of one critical H-bond between the ketocarotenoid and the protein. This confers an unprecedented homogeneity of the dark-adapted OCP state and substantially increases the yield of the excited photoproduct S*, which is important for the productive photocycle to proceed. A 1.37 Å crystal structure of OCP Y201W combined with femtosecond time-resolved absorption spectroscopy, kinetic analysis, and deconvolution of the spectral intermediates, as well as extensive quantum chemical calculations incorporating the effect of the local electric field, highlighted the role of charge-transfer states during OCP photoconversion.

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ROLE OF THE CONSERVATIVE INTERHELICAL HYDROGEN BOND SER74-TRP158 AT THE CHOLESTEROL BINDING SITE IN THE CONFORMATIONAL STABILITY OF THE b2-ADRENERGIC RECEPTOR: MOLECULAR DYNAMICS SIMULATION

Журнал структурной химии ◽

10.15372/jsc20170224 ◽

2017 ◽

Keyword(s):

Molecular Dynamics ◽

Hydrogen Bond ◽

Molecular Dynamics Simulation ◽

Binding Site ◽

Adrenergic Receptor ◽

Conformational Stability ◽

Dynamics Simulation ◽

Cholesterol Binding

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Time-resolved detection of SDS-induced conformational changes in α-synuclein by a micro-stopped-flow system

RSC Advances ◽

10.1039/d0ra09614h ◽

2021 ◽

Vol 11 (2) ◽

pp. 1086-1097

Author(s):

Shunki Takaramoto ◽

Yusuke Nakasone ◽

Kei Sadakane ◽

Shinsaku Maruta ◽

Masahide Terazima

Keyword(s):

Conformational Changes ◽

Flow System ◽

Stopped Flow ◽

Time Resolved ◽

Sds Micelles ◽

Conformation Changes ◽

System P

Dynamics of conformation changes of α-synuclein induced by the presence of SDS micelles are revealed using time-resolved diffusion, CD, and FRET measurements combined with a micro-stopped flow system.

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Role of the hydrogen bond donor component for a proper development of novel hydrophobic deep eutectic solvents

Journal of Molecular Liquids ◽

10.1016/j.molliq.2019.02.107 ◽

2019 ◽

Vol 281 ◽

pp. 423-430 ◽

Cited By ~ 11

Author(s):

Matteo Tiecco ◽

Federico Cappellini ◽

Francesco Nicoletti ◽

Tiziana Del Giacco ◽

Raimondo Germani ◽

...

Keyword(s):

Hydrogen Bond ◽

Deep Eutectic Solvents ◽

Hydrogen Bond Donor

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On the role of hydrogen-bond exchanges in the spectral diffusion of water

The Journal of Chemical Physics ◽

10.1063/5.0041270 ◽

2021 ◽

Vol 154 (6) ◽

pp. 064501

Author(s):

Zeke A. Piskulich ◽

Damien Laage ◽

Ward H. Thompson

Keyword(s):

Hydrogen Bond ◽

Spectral Diffusion

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The role of spin in the degradation of organic photovoltaics

Nature Communications ◽

10.1038/s41467-020-20601-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ivan Ramirez ◽

Alberto Privitera ◽

Safakath Karuthedath ◽

Anna Jungbluth ◽

Johannes Benduhn ◽

...

Keyword(s):

Transient Absorption ◽

Bulk Heterojunction ◽

Critical Factor ◽

Model Systems ◽

Transient Absorption Spectroscopy ◽

Triplet States ◽

Paramagnetic Resonance ◽

Time Resolved ◽

A Charge

AbstractStability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C60 via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C60 excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.

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Optical, electrochemical and third-order nonlinear optical studies of triphenylamine substituted zinc phthalocyanine

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424616500838 ◽

2016 ◽

Vol 20 (08n11) ◽

pp. 1173-1181 ◽

Cited By ~ 5

Author(s):

Narra Vamsi Krishna ◽

Puliparambil Thilakan Anusha ◽

S. Venugopal Rao ◽

L. Giribabu

Keyword(s):

Nonlinear Optical ◽

Emission Spectra ◽

Optical Emission ◽

Soret Band ◽

Laser Pulses ◽

Zinc Phthalocyanine ◽

Third Order ◽

Time Resolved ◽

Nlo Properties ◽

Scan Data

Zinc phthalocyanine possessing triphenylamine at its peripheral position has been synthesized and its optical, emission, electrochemical and third-order nonlinear optical (NLO) properties were investigated. Soret band was broadened due to the presence of triphenylamine moiety. Electrochemical properties indicated that both oxidation and reduction processes were ring centered. Emission spectra were recorded in different solvents and the fluorescence yields obtained were in the range of 0.02–0.17 while the time-resolved fluorescence data revealed radiative lifetimes of typically few ns. Third-order NLO properties of this molecule have been examined using the Z-scan technique with picosecond (ps) and femtoseocnd (fs) pulses. Closed and open aperture Z-scan data were recorded with 2 ps/1 50 fs laser pulses at a wavelength of 800 nm and NLO coefficients were extracted from both the data. Our data clearly suggests the potential of this molecule for photonics applications.

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