scholarly journals Intramolecular Photo-Oxidation as a Potential Source to Probe Biological Electron Damage: A Carboxylated Adenosine Analogue as Case Study

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2877
Author(s):  
Maria Elena Castellani ◽  
Jan R. R. Verlet
Keyword(s):  
Charge Transfer ◽  
Carboxylic Acid ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Adenosine Monophosphate ◽  
Time Resolved ◽  
Starting Point ◽  
Molecular Charge ◽  
Intra Molecular Charge Transfer

A carboxylated adenosine analog (C-Ado−) has been synthesized and probed via time-resolved photoelectron spectroscopy in order to induce intra-molecular charge transfer from the carboxylic acid moiety to the nucleobase. Intra-molecular charge transfer can be exploited as starting point to probe low-energy electron (LEE) damage in DNA and its derivatives. Time-dependent density functional theory (TD-DFT) calculations at the B3LYP-6311G level of theory have been performed to verify that the highest occupied molecular orbital (HOMO) was located on carboxylic acid and that the lowest occupied molecular orbital (LUMO) was on the nucleobase. Hence, the carboxylic acid could work as electron source, whilst the nucleobase could serve the purpose of electron acceptor. The dynamics following excitation at 4.66 eV (266 nm) were probed using time-resolved photoelectron spectroscopy using probes at 1.55 eV (800 nm) and 3.10 eV (400 nm). The data show rapid decay of the excited state population and, based on the similarity of the overall dynamics to deoxy-adenosine monophosphate (dAMP–), it appears that the dominant decay mechanism is internal conversion following 1ππ* excitation of the nucleobase, rather than charge-transfer from the carboxylic acid to the nucleobase.

Theoretical study on photo-induced processes of 1-methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium halide species: an application of constrained density functional theory

2018 ◽  
Vol 20 (6) ◽  
pp. 3911-3917 ◽  
Author(s):  
Takao Otsuka ◽  
Masato Sumita ◽  
Hironori Izawa ◽  
Kenji Morihashi
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Excited States ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
Molecular Charge ◽  
Intra Molecular Charge Transfer

Inter-molecular charge transfer (SET) and intra-molecular charge transfer (SM1) excited states are involved in the photo-induced processes of 1-methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium halide.

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

A fluorogenic and chromogenic dual sensor for the detection of cyanide and copper(ii) in water samples and living cells

2016 ◽  
Vol 8 (38) ◽  
pp. 6909-6915 ◽  
Author(s):  
T. M. Ebaston ◽  
G. Balamurugan ◽  
S. Velmathi
Keyword(s):  
Charge Transfer ◽  
Detection Limit ◽  
Fluorescent Sensor ◽  
Aqueous Media ◽  
Living Cells ◽  
Dual Sensor ◽  
Molecular Charge ◽  
Intra Molecular Charge Transfer ◽  
Good Detection Limit ◽  
Good Detection

Here we describe a simple fluorescent sensor based on intra molecular charge transfer to detect cyanide in aqueous media selectively with a very good detection limit and cascade recognition of aq. copper(ii) ions.

Anthracene Based AIE Active Probe for Colorimetric and Fluorimetric Detection of Cu2+ Ions

2019 ◽  
Vol 233 (7) ◽  
pp. 895-911 ◽  
Author(s):  
Abdullah G. Al-Sehemi ◽  
Ahmad Irfan ◽  
Mehboobali Pannipara ◽  
Mohammed A. Assiri ◽  
Abul Kalam
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Photophysical Properties ◽  
Functional Theory ◽  
Water Fraction ◽  
Cu Complex ◽  
Active Probe ◽  
And Function ◽  
Intra Molecular Charge Transfer ◽  
Metal Charge Transfer

Abstract A novel aggregation induced emission (AIE) active anthracene based dihydroquinazolinone derivative (probe 1) has been synthesized and characterized by means of spectroscopic methods. The photophysical properties of this probe have been investigated in solvents of different polarity display that fluorescence states are of intramolecular charge transfer (ICT) character. Probe 1 show clear AIE behavior in water/THF mixture on reaching water fraction 95%. The AIE behavior of probe 1 have been exploited for the detection of metal ions in aqueous solution which reveals high selectivity and sensitivity towards Cu2+ ions by colorimetrically and function as a chemosensor in a remarkable turn-off fluorescence manner. Further, the experimental results were investigated by computational means by optimizing the ground state geometries of probe 1 and probe 1-Cu complex using density functional theory (DFT) at B3LYP/6-31G∗∗ and B3LYP/6-31G∗∗(LANL2DZ) levels of theory. Intra-molecular charge transfer was observed in probe 1 while ligand to metal charge transfer (LMCT) for probe 1-Cu complex.

THEORETICAL STUDY ON PHOTOINDUCED INTRAMOLECULAR CHARGE TRANSFER IN A NOVEL ORGANIC SENSITIZER C201

2011 ◽  
Vol 10 (05) ◽  
pp. 641-649 ◽  
Author(s):  
FENGJIE ZHOU ◽  
YAPING ZHANG ◽  
SHUO CAO ◽  
YONG DING ◽  
SHASHA LIU
Keyword(s):  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Transition Density ◽  
Dft Method ◽  
Transition Dipole Moment ◽  
Transition Dipole ◽  
Level Densities ◽  
Charge Difference Density

A new organic dye (C201) composed of triarylamine unit as electron donor and anchoring unit as electron acceptor, was theoretically investigated by quantum chemical methods. We optimized the geometry of C201 with density functional theory (DFT) at B3LYP/6-311G (d) level. Densities of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), as well as the energies are listed. The excited states of the dye molecules C201 were calculated by time dependent-DFT (TD-DFT) method. Two main visible bands at 572 nm and 407 nm were mainly attributed to the electronic transition from HOMO→LUMO and HOMO-1→LUMO, respectively. 3D cube representations including transition density (TD) and charge difference density (CDD) directly visualized the character of intramolecular charge transfer of C201. The orientation and strength of transition dipole moment were showed visually using TD. Furthermore, we illustrate the orientation and results of the intramolecular charge transfer by CDD.

scholarly journals Real-time probing of charge-transfer induced interfacial fields in a dye-semiconductor system using time-resolved XPS

2019 ◽  
Vol 205 ◽  
pp. 05021
Author(s):  
Johannes Mahl ◽  
Stefan Neppl ◽  
Friedrich Roth ◽  
Andrey Shavorskiy ◽  
Nils Huse ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Carrier ◽  
Photoelectron Spectroscopy ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
X Ray ◽  
Charge Carrier Dynamics ◽  
Semiconductor System ◽  
Induced Charge ◽  
Polypyridine Complexes

Photo-induced charge carrier dynamics and transient interfacial fields at the interface between N3 polypyridine complexes and films of nanocrystalline ZnO are probed by picosecond time-resolved X-ray photoelectron spectroscopy.

Studying the influence of triplet deactivation on the singlet–triplet inter-conversion in intra-molecular charge-transfer fluorescence-based OLEDs by magneto-electroluminescence

2014 ◽  
Vol 2 (31) ◽  
pp. 6264-6268 ◽  
Author(s):  
Qiming Peng ◽  
Aiwu Li ◽  
Yunxia Fan ◽  
Ping Chen ◽  
Feng Li
Keyword(s):  
Charge Transfer ◽  
Dynamic Process ◽  
Fluorescent Materials ◽  
Molecular Charge ◽  
Intra Molecular Charge Transfer

The singlet–triplet inter-conversion in CT fluorescent materials is a dynamic process, and the deactivation rates of singlet and triplet determine the direction of the conversion.

scholarly journals The Role of Structural Flexibility in Plasmon-Driven Coupling Reactions: Kinetic Limitations in the Dimerization of Nitro-Benzenes

2021 ◽  
Author(s):  
Wouter Koopman ◽  
Evgenii Titov ◽  
Radwan Mohamed Sarhan ◽  
Tina Gaebel ◽  
Robin Schürmann ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Bond Activation ◽  
Density Functional Theory Calculations ◽  
Surface Enhanced Raman Spectroscopy ◽  
Bimolecular Reaction ◽  
Structural Flexibility ◽  
Coupling Reactions ◽  
Time Resolved

<div>The plasmon-driven dimerization of 4-nitrothiophenol (4NTP) to 4-4’-dimercaptoazobenzene (DMAB) has become a testbed for understanding bimolecular photoreactions enhanced by nanoscale metals, in particular, regarding the relevance of electron transfer and heat transfer from the metal to the molecule. By adding a methylene group between the thiol bond and the nitrophenyl, we add structural flexibility to the reactant molecule. Time-resolved surface-enhanced Raman-spectroscopy proves that this (4-nitrobenzyl)mercaptan (4NBM) molecule has a larger dimerization rate and dimerization yield than 4NTP and higher selectivity towards dimerization. X-ray photoelectron spectroscopy and density functional theory calculations show that the electron transfer would prefer activation of 4NTP over 4NBM. We conclude that the rate limiting step of this plasmonic reaction is the dimerization step, which is dramatically enhanced by the additional flexibility of the reactant. This study may serve as an example for using nanoscale metals to simultaneously provide charge carriers for bond activation and localized heat for driving bimolecular reaction steps. The molecular structure of reactants can be tuned to control the reaction kinetics.<br></div>

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