scholarly journals Intrareticular charge transfer regulated electrochemiluminescence of donor–acceptor covalent organic frameworks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rengan Luo ◽  
Haifeng Lv ◽  
Qiaobo Liao ◽  
Ningning Wang ◽  
Jiarui Yang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Oxidation Mechanism ◽  
Emission Mechanism ◽  
Direct Oxidation ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Anions And Cations ◽  
Mediated Oxidation

AbstractThe control of charge transfer between radical anions and cations is a promising way for decoding the emission mechanism in electrochemiluminescence (ECL) systems. Herein, a type of donor-acceptor (D-A) covalent organic framework (COF) with triphenylamine and triazine units is designed as a highly efficient ECL emitter with tunable intrareticular charge transfer (IRCT). The D-A COF demonstrates 123 folds enhancement in ECL intensity compared with its benzene-based COF with small D-A contrast. Further, the COF’s crystallinity- and protonation-modulated ECL behaviors confirm ECL dependence on intrareticular charge transfer between donor and acceptor units, which is rationalized by density functional theory. Significantly, dual-peaked ECL patterns of COFs are achieved through an IRCT mediated competitive oxidation mechanism: the coreactant-mediated oxidation at lower potential and the direct oxidation at higher potential. This work provides a new fundamental and approach to improve the ECL efficiency for designing next-generation ECL devices.

Binding Energies of Organic Charge-Transfer Complexes Calculated by First-Principles Methods

1998 ◽  
Vol 63 (8) ◽  
pp. 1223-1244 ◽  
Author(s):  
Cordula Rauwolf ◽  
Achim Mehlhorn ◽  
Jürgen Fabian
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Ground State ◽  
Density Functional ◽  
Binding Energies ◽  
Basis Set ◽  
Dispersion Energy ◽  
Functional Theory ◽  
Basis Set Superposition Error ◽  
Donor And Acceptor

Weak interactions between organic donor and acceptor molecules resulting in cofacially-stacked aggregates ("CT complexes") were studied by second-order many-body perturbation theory (MP2) and by gradient-corrected hybrid Hartree-Fock/density functional theory (B3LYP exchange-correlation functional). The complexes consist of tetrathiafulvalene (TTF) and related compounds and tetracyanoethylene (TCNE). Density functional theory (DFT) and MP2 molecular equilibrium geometries of the component structures are calculated by means of 6-31G*, 6-31G*(0.25), 6-31++G**, 6-31++G(3df,2p) and 6-311G** basis sets. Reliable molecular geometries are obtained for the donor and acceptor compounds considered. The geometries of the compounds were kept frozen in optimizing aggregate structures with respect to the intermolecular distance. The basis set superposition error (BSSE) was considered (counterpoise correction). According to the DFT and MP2 calculations laterally-displaced stacks are more stable than vertical stacks. The charge transfer from the donor to the acceptor is small in the ground state of the isolated complexes. The cp-corrected binding energies of TTF/TCNE amount to -1.7 and -6.3 kcal/mol at the DFT(B3LYP) and MP2(frozen) level of theory, respectively (6-31G* basis set). Larger binding energies were obtained by Hobza's 6-31G*(0.25) basis set. The larger MP2 binding energies suggest that the dispersion energy is underestimated or not considered by the B3LYP functional. The energy increases when S in TTF/TCNE is replaced by O or NH but decreases with substitution by Se. The charge-transferred complexes in the triplet state are favored in the vertical arrangement. Self-consistent-reaction-field (SCRF) calculations predicted a gain in binding energy with solvation for the ground-state complex. The ground-state charge transfer between the components is increased up to 0.8 e in polar solvents.

scholarly journals INVITED PAPER

2007 ◽  
Vol 3 (1) ◽  
pp. 1-12 ◽  
Author(s):  
María Moreno Oliva ◽  
Mari Carmen Ruiz Delgado ◽  
Juan Casado ◽  
M. Manuela M. Raposo ◽  
A. Maurício C. Fonseca ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Charge Transfer ◽  
Dft Calculations ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Molecular Properties ◽  
Functional Theory ◽  
End Groups ◽  
Donor Acceptor

series of push-pull chromophores built around thiophene-based . π-conjugating spacers and bearing various types of amino-donors and cyanovinyl-acceptors have been analyzed by means of UV-Vis- NIR spectroscopic measurements. Density functional theory (DFT) calculations have also been performed to help the assignment of the most relevant electronic features and to derive useful information about the molecular structure of these NLO-phores. The effects of the donor/acceptor substitution in the electronic and molecular properties of the .π -conjugated spacer have been addressed. The effectiveness of the intramolecular charge transfer (ICT) has also been tested as a function of the nature of the end groups (i.e., electron-donating or electron-withdrawing capabilities).

Accurate description of hybridized local and charge-transfer excited-state in donor–acceptor molecules using density functional theory

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 108404-108410 ◽  
Author(s):  
Y. Y. Pan ◽  
J. Huang ◽  
Z. M. Wang ◽  
S. T. Zhang ◽  
D. W. Yu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Ground State ◽  
Density Functional ◽  
Accurate Description ◽  
Functional Theory ◽  
Donor Acceptor ◽  
Acceptor Molecules

The ωB97X was the most reliable functional for the accurate description of HLCT state at ground state and excited state.

Electronic Transport Properties of the Azobenzene-Based Optical Molecular Switch with Different Substituents

2011 ◽  
Vol 284-286 ◽  
pp. 816-819
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Jing Wang
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Density Functional ◽  
Molecular Switch ◽  
Functional Theory ◽  
Electronic Transport Properties ◽  
Switching Performance ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Theoretical Results

By applying nonequilibrium Green’s function formalism combined first-principles density functional theory, we investigate the electronic transport properties of the azobenzene -based optical molecular switch with different substituents. Theoretical results show that the donor/acceptor substituent plays an important role in the electronic transport of molecular devices. The switching performance can be improved to some extent through suitable donor and acceptor substituents.

scholarly journals Density Functional Theory Study of Substitution Effects on the Second-Order Nonlinear Optical Properties of Lindquist-Type Organo-Imido Polyoxometalates

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1636
Author(s):  
Emna Rtibi ◽  
Benoit Champagne
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Density Functional ◽  
Energy Charge ◽  
Substitution Effects ◽  
First Hyperpolarizability ◽  
Functional Theory ◽  
State Approximation ◽  
Donor And Acceptor

Density functional theory and time-dependent density functional theory have been enacted to investigate the effects of donor and acceptor on the first hyperpolarizability of Lindquist-type organo-imido polyoxometalates (POMs). These calculations employ a range-separated hybrid exchange-correlation functional (ωB97X-D), account for solvent effects using the implicit polarizable continuum model, and analyze the first hyperpolarizabilities by using the two-state approximation. They highlight the beneficial role of strong donors as well as of π-conjugated spacers (CH=CH rather than C≡C) on the first hyperpolarizabilities. Analysis based on the unit sphere representation confirms the one-dimensional push-pull π-conjugated character of the POMs substituted by donor groups and the corresponding value of the depolarization ratios close to 5. Furthermore, the use of the two-state approximation is demonstrated to be suitable for explaining the origin of the variations of the first hyperpolarizabilities as a function of the characteristics of a unique low-energy charge-transfer excited state and to attribute most of the first hyperpolarizability changes to the difference of dipole moment between the ground and that charge-transfer excited state.

scholarly journals Predicting Excitation Energies of Twisted Intramolecular Charge-Transfer States with Time-Dependent Density Functional Theory: Comparison with Experimental Measurements in the Gas-Phase and Solvents Ranging from Hexanes to Acetonitrile

2020 ◽  
Author(s):  
James Shee ◽  
Martin Head-Gordon
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Excited States ◽  
Linear Response ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Experimental Measurements ◽  
Excitation Energies ◽  
Donor And Acceptor ◽  
Donor Acceptor

Electronically-excited states characterized by intramolecular charge-transfer play an essential role in many biological processes and optical devices. The ability to make quantitative ab initio predictions of the relative energetics involved is a challenging yet desirable goal, especially for large molecules in solution. In this work we present a data set of 61 experimental measurements of absorption and emission processes, both in the gas phase and solvents representing a broad range of polarities, which involve intramolecular charge-transfer mediated by a non-zero, “twisted” dihedral angle between one or more donor and acceptor subunits. Among a variety of density functionals investigated within the framework of linear-response theory, the “optimally tuned” LRC-ωPBE functional, which utilizes a system-specific yet non-empirical procedure to specify the range-separation parameter, emerges as the preferred choice. For the entire set of excitation energies, involving changes in dipole moment ranging from 4 to >20 Debye, the mean signed and absolute errors are 0.02 and 0.18 eV, respectively (compared, e.g., to -0.30 and 0.30 for PBE0, 0.44 and 0.47 for LRC-ωPBEh, 0.83 and 0.83 for ωB97X-V). The performance of polarizable continuum solvation models for these charge-transfer excited states is closely examined, and clear trends emerge when measurements corresponding to the four small DMABN-like molecules and a charged species are excluded. We make the case that the large errors found only for small molecules in the gas phase and weak solvents cannot be expected to improve via the optimal tuning procedure, which enforces a condition that is exact only in the wellseparated donor-acceptor limit, and present empirical evidence implicating the outsized importance for small donor-acceptor systems of relaxation effects that cannot be accounted for by linear-response TDDFT within the adiabatic approximation. Finally, we demonstrate the utility of the optimally tuned density functional approach by targeting the charge-transfer states of a large biomimetic model system for light-harvesting structures in Photosystem II.

scholarly journals Charge Transfer Complexes of 1,3,6-Trinitro-9,10-phenanthrenequinone with Polycyclic Aromatic Compounds

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6391
Author(s):  
Roman Linko ◽  
Michael Ryabov ◽  
Pavel Strashnov ◽  
Pavel Dorovatovskii ◽  
Victor Khrustalev ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Energy Levels ◽  
Orbital Energy ◽  
Charge Transfer Complexes ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Polycyclic Aromatic ◽  
And Control

Understanding the interactions of organic donor and acceptor molecules in binary associates is crucial for design and control of their functions. Herein, we carried out a theoretical study on the properties of charge transfer complexes of 1,3,6-trinitro-9,10-phenanthrenequinone (PQ) with 23 aromatic π-electron donors. Density functional theory (DFT) was employed to obtain geometries, frontier orbital energy levels and amounts of charge transfer in the ground and first excited states. For the most effective donors, namely, dibenzotetrathiafulvalene, pentacene, tetrathiafulvalene, 5,10-dimethylphenazine, and tetramethyl-p-phenylenediamine, the amount of charge transfer in the ground state was shown to be 0.134−0.240 e−. Further, a novel charge transfer complex of PQ with anthracene was isolated in crystalline form and its molecular and crystal structure elucidated by single-crystal synchrotron X-ray diffraction.

scholarly journals Predicting Excitation Energies of Twisted Intramolecular Charge-Transfer States with Time-Dependent Density Functional Theory: Comparison with Experimental Measurements in the Gas-Phase and Solvents Ranging from Hexanes to Acetonitrile

2020 ◽  
Author(s):  
James Shee ◽  
Martin Head-Gordon
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Excited States ◽  
Linear Response ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Experimental Measurements ◽  
Excitation Energies ◽  
Donor And Acceptor ◽  
Donor Acceptor

Electronically-excited states characterized by intramolecular charge-transfer play an essential role in many biological processes and optical devices. The ability to make quantitative ab initio predictions of the relative energetics involved is a challenging yet desirable goal, especially for large molecules in solution. In this work we present a data set of 61 experimental measurements of absorption and emission processes, both in the gas phase and solvents representing a broad range of polarities, which involve intramolecular charge-transfer mediated by a non-zero, “twisted” dihedral angle between one or more donor and acceptor subunits. Among a variety of density functionals investigated within the framework of linear-response theory, the “optimally tuned” LRC-ωPBE functional, which utilizes a system-specific yet non-empirical procedure to specify the range-separation parameter, emerges as the preferred choice. For the entire set of excitation energies, involving changes in dipole moment ranging from 4 to >20 Debye, the mean signed and absolute errors are 0.02 and 0.18 eV, respectively (compared, e.g., to -0.30 and 0.30 for PBE0, 0.44 and 0.47 for LRC-ωPBEh, 0.83 and 0.83 for ωB97X-V). The performance of polarizable continuum solvation models for these charge-transfer excited states is closely examined, and clear trends emerge when measurements corresponding to the four small DMABN-like molecules and a charged species are excluded. We make the case that the large errors found only for small molecules in the gas phase and weak solvents cannot be expected to improve via the optimal tuning procedure, which enforces a condition that is exact only in the wellseparated donor-acceptor limit, and present empirical evidence implicating the outsized importance for small donor-acceptor systems of relaxation effects that cannot be accounted for by linear-response TDDFT within the adiabatic approximation. Finally, we demonstrate the utility of the optimally tuned density functional approach by targeting the charge-transfer states of a large biomimetic model system for light-harvesting structures in Photosystem II.

Enhanced electronic communication through a conjugated bridge in a porphyrin-fullerene donor-acceptor couple

2021 ◽  
Author(s):  
Ruben Caballero ◽  
Joaquin Calbo ◽  
Juan Aragó ◽  
Pilar de la Cruz ◽  
Enrique Orti ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electronic Communication ◽  
Density Functional Theory Calculations ◽  
Electrochemical Measurements ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Donor Acceptor

A ZnP-2EDOTV-C60 triad, with enhanced electronic communication between terminus donor and acceptor moieties, was synthesized and studied both experimentally and theoretically. Electrochemical measurements and density functional theory calculations support that...

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