A theoretical study on anion sensing mechanism of multi-phosphonium triarylboranes: intramolecular charge transfer and configurational changes

2017 ◽  
Vol 19 (22) ◽  
pp. 14811-14820 ◽  
Author(s):  
Haamid R. Bhat ◽  
Prakash C. Jha
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Density Functional ◽  
Theoretical Study ◽  
Intramolecular Charge Transfer ◽  
Functional Level ◽  
Anion Sensing ◽  
Absorption And Emission ◽  
Sensing Mechanism ◽  
Emission Studies

A theoretical study of the fluorescence quenching of multiphosphonium TABs in anion sensing involving intramolecular charge transfer and developing a new density functional level of theory for their absorption and emission studies.

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 Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

2019 ◽  
Author(s):  
Pralok K. Samanta ◽  
Md Mehboob Alam ◽  
Ramprasad Misra ◽  
Swapan K. Pati
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
First Hyperpolarizability ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Nlo Response ◽  
Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (β<sub>total</sub>) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (β<sub>vec</sub>) to β<sub>total</sub> also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.<br>

scholarly journals Ingenious modification of molecular structure effectively regulates excited-state intramolecular proton and charge transfer: a theoretical study based on 3-hydroxyflavone

RSC Advances ◽  
2018 ◽  
Vol 8 (52) ◽  
pp. 29589-29597 ◽  
Author(s):  
Jianhui Han ◽  
Xiaochun Liu ◽  
Chaofan Sun ◽  
You Li ◽  
Hang Yin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Excited State ◽  
Charge Transfer ◽  
Proton Transfer ◽  
Theoretical Study ◽  
Intramolecular Charge Transfer ◽  
Intramolecular Proton Transfer ◽  
Great Promise ◽  
Fluorescence Sensing

Harnessing ingenious modification of molecular structure to regulate excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) characteristics holds great promise in fluorescence sensing and imaging.

A THEORETICAL STUDY ON DUAL FLUORESCENCE OF 4-DIMETHYLAMINOPYRIDINE BY POLARIZABLE CONTINUUM MODEL

2008 ◽  
Vol 07 (04) ◽  
pp. 821-832 ◽  
Author(s):  
JUAN-QIN LI ◽  
XIANG-YUAN LI ◽  
FENG WANG
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Emission Spectra ◽  
Polarizable Continuum Model ◽  
Transfer Model ◽  
Dual Fluorescence ◽  
Field Methods ◽  
Complete Active Space ◽  
Self Consistent Field

Dual fluorescence spectra of 4-dimethylaminopyridine (DMAP) is investigated using time-dependent density functional theory and complete active space self-consistent field methods. Electronic absorption and emission spectra of DMAP have been investigated in three solvents, that is, cyclohexane, chloroform, and acetonitrile. The present study reveals that the dual fluorescence phenomena of DMAP appear in the cases of acetonitrile and chloroform, but not in cyclohexane. The electronic structures of the ground state and the intramolecular charge transfer states are, therefore, studied in order to reveal the insight of dual fluorescence. Our theoretical results suggest that the twisting of dimethylamino moiety in DMAP is necessary for the intramolecular charge transfer. The mechanism of the dual fluorescence of DMAP is discussed based on the twisted intramolecular charge transfer model and the dual fluorescence phenomenon is explained theoretically.

scholarly journals Synergistic Approach of Ultrafast Spectroscopy and Molecular Simulations in the Characterization of Intramolecular Charge Transfer in Push-Pull Molecules

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 430 ◽  
Author(s):  
Barbara Patrizi ◽  
Concetta Cozza ◽  
Adriana Pietropaolo ◽  
Paolo Foggi ◽  
Mario Siciliani de Cumis
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Ultrafast Spectroscopy ◽  
Intramolecular Charge Transfer ◽  
Molecular Simulations ◽  
System Size ◽  
Significant Information ◽  
Electronic Density ◽  
Complex Molecules

The comprehensive characterization of Intramolecular Charge Transfer (ICT) stemming in push-pull molecules with a delocalized π-system of electrons is noteworthy for a bespoke design of organic materials, spanning widespread applications from photovoltaics to nanomedicine imaging devices. Photo-induced ICT is characterized by structural reorganizations, which allows the molecule to adapt to the new electronic density distribution. Herein, we discuss recent photophysical advances combined with recent progresses in the computational chemistry of photoactive molecular ensembles. We focus the discussion on femtosecond Transient Absorption Spectroscopy (TAS) enabling us to follow the transition from a Locally Excited (LE) state to the ICT and to understand how the environment polarity influences radiative and non-radiative decay mechanisms. In many cases, the charge transfer transition is accompanied by structural rearrangements, such as the twisting or molecule planarization. The possibility of an accurate prediction of the charge-transfer occurring in complex molecules and molecular materials represents an enormous advantage in guiding new molecular and materials design. We briefly report on recent advances in ultrafast multidimensional spectroscopy, in particular, Two-Dimensional Electronic Spectroscopy (2DES), in unraveling the ICT nature of push-pull molecular systems. A theoretical description at the atomistic level of photo-induced molecular transitions can predict with reasonable accuracy the properties of photoactive molecules. In this framework, the review includes a discussion on the advances from simulation and modeling, which have provided, over the years, significant information on photoexcitation, emission, charge-transport, and decay pathways. Density Functional Theory (DFT) coupled with the Time-Dependent (TD) framework can describe electronic properties and dynamics for a limited system size. More recently, Machine Learning (ML) or deep learning approaches, as well as free-energy simulations containing excited state potentials, can speed up the calculations with transferable accuracy to more complex molecules with extended system size. A perspective on combining ultrafast spectroscopy with molecular simulations is foreseen for optimizing the design of photoactive compounds with tunable properties.

Sign in / Sign up

Export Citation Format

Share Document