scholarly journals Photophysical Properties and Electronic Structure of Symmetrical Curcumin Analogues and Their BF2 Complexes, Including a Phenothiazine Substituted Derivative

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2299
Author(s):  
Emese Gál ◽  
Levente Csaba Nagy
Keyword(s):  
Theoretical Study ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Molecular Structures ◽  
Excitation Energies ◽  
Dft Methods ◽  
Conjugated Systems ◽  
Vertical Excitation ◽  
Td Dft ◽  
The One

Symmetrically substituted curcumin analogue compounds possess electron donor moieties at both ends of the conjugated systems; their difluoroboron complexes were synthesized, and their structures were fully characterized. A novel compound with enhanced photophysical properties bearing phenothiazine moieties is reported. The introduction of BF2 into the molecular structures resulted in bathochromic shifts both in the absorption and emission spectra, indicating that the π-conjugation was more extended than the one in the initial compounds. The solvatochromic effects were studied, which in case of the phenothiazinyl-curcumin BF2 complex was the most notable. Theoretical study of the investigated compounds was carried out using DFT and TD-DFT methods to evaluate the ground state geometries and vertical excitation energies.

XAS of tetrakis(phenyl)- and tetrakis(pentafluorophenyl)-porphyrin: an experimental and theoretical study

2015 ◽  
Vol 17 (3) ◽  
pp. 2001-2011 ◽  
Author(s):  
Marco Vittorio Nardi ◽  
Roberto Verucchi ◽  
Luca Pasquali ◽  
Angelo Giglia ◽  
Giovanna Fronzoni ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Oscillator Strength ◽  
Theoretical Study ◽  
Excitation Energies ◽  
Porphyrin Macrocycle ◽  
Td Dft

NEXAFS outcomes and TD-DFT calculations pertaining to H2TPP and H2TPP(F) demonstrate the electronic inertness of b1u porphyrin macrocycle 1s → π* excitations. In fact, corresponding excitation energies, but not their oscillator strength values, are substantially unaffected upon fluorination of Ph rings.

An experimental and TD-DFT theoretical study on the photophysical properties of Methylene Violet Bernthsen

2015 ◽  
Vol 112 ◽  
pp. 341-351 ◽  
Author(s):  
Gabriel E. Jara ◽  
Claudia A. Solis ◽  
Natalia S. Gsponer ◽  
Juan J. Torres ◽  
Carlos A. Glusko ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Photophysical Properties ◽  
Td Dft ◽  
Methylene Violet

scholarly journals Cross-conjugation controls the stabilities and photophysical properties of heteroazoarene photoswitches

2021 ◽  
Author(s):  
Daniel Adrion ◽  
Steven Lopez
Keyword(s):  
High Throughput Screening ◽  
Density Functional ◽  
Photophysical Properties ◽  
Photochemical Reactions ◽  
Free Energies ◽  
Excitation Energies ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Screening Study

Azoarene photoswitches are versatile molecules that interconvert from their E-isomer to their Z-isomer with light. Azobenzene is a prototypical photoswitch but its derivatives can be poorly suited for in vivo applications such as photopharmacology due to undesired photochemical reactions promoted by ultraviolet light and its relatively short half-life (t1/2) of the Z-isomer (2 days). Experimental and computational studies suggest that these properties (λmax of the E isomer and t1/2 of the Z-isomer) are inversely related. We identified isomeric azobisthiophenes and azobisfurans from a high-throughput screening study of 1700 azoarenes as photoswitch candidates with improved λmax and t1/2 values relative to azobenzene. We used density functional theory to predict the activation free energies, reaction free energies, and vertical excitation energies of the E- and Z-isomers of 2,2- and 3,3-substituted azobisthiophenes and azobisfurans. The half-lives depend on whether the heterocycles are 𝜋-conjugated or cross-conjugated with the diazo 𝜋-bond. The 2,2-substituted azoarenes both have t1/2 values on the scale of 1 hour, while the 3,3-analogues have computed half-lives of 40 (thiophene) and 230 (furan) years. The 2,2-substituted heteroazoarenes have significantly higher λmax absorptions than their 3,3-substituted analogs: 76 nm for azofuran and 77 nm for azothiophene.

Predicting Carbonyl Excitation Energies Efficiently Using EOM-CC Trends

2020 ◽  
Author(s):  
Keiran Rowell ◽  
Scott Kable ◽  
Meredith J. T. Jordan
Keyword(s):  
Single Point ◽  
Zero Point ◽  
Tropospheric Chemistry ◽  
Excitation Energies ◽  
Relaxation Energy ◽  
Point Energy ◽  
Vertical Excitation ◽  
Td Dft ◽  
Vertical Excitation Energy ◽  
Carbonyl Species

We approach the problem of predicting excitation energies of diverse, larger (5–6 carbons) carbonyl species central to earth’s tropospheric chemistry. Triples contributions are needed for the vertical excitation energy (E<sup>vert</sup>), while EOM-CCSD//TD-DFT calculations provide acceptable estimates for the S<sub>1</sub> relaxation energy (E<sup>relax</sup>), and (TD-)DFT suffices for the S<sub>0</sub> → S<sub>1</sub> zero-point vibration energy correction (∆E<sup>ZPVE</sup>). <div><br></div><div>Perturbative triples corrections deliver E<sup>vert</sup> values close in accuracy to full iterative triples EOM-CC calculations. The error between EOM-CCSD and triples-corrected E vert values appears to be systematic and can be accounted for with scaling factors. However, saturated and α,β-unsaturated carbonyls must be treated separately. Double-hybrid S<sub>0</sub> minima can be used to calculate E<sup>vert</sup> with negligible loss in accuracy, relegating the O(N<sup>5</sup>) expense of CCSD to only single-point energy and excitation calculations. </div><div><br></div><div>This affordable protocol can be applied to all volatile carbonyl species. E<sup>0−0</sup> predictions do overestimate measured values by ∼8 kJ/mol due to a lack of triples contribution in E relax, but this overestimation is systematic and the mean unsigned error is within 4 kJ/mol once this is accounted for.</div>

Photophysical and electrochemical properties of two trans-A2B-corroles: differences between phenyl or pyrenyl groups at the meso-10 position

2020 ◽  
Vol 22 (29) ◽  
pp. 16965-16977 ◽  
Author(s):  
Thiago V. Acunha ◽  
Henrique F. V. Victória ◽  
Klaus Krambrock ◽  
Amanda C. Marques ◽  
Luiz Antônio S. Costa ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Electrochemical Properties ◽  
Photophysical Properties ◽  
Electrochemical Analysis ◽  
Molecular Structures ◽  
Td Dft

The photophysical properties of two meso–trans-A2B-type corroles containing phenyl or pyrenyl units were reported in this study. TD-DFT calculations and electrochemical analysis were conducted to better understand the corrole molecular structures.

scholarly journals Structural Dependence of Electronic Properties in A-A-D-A-A-Type Organic Solar Cell Material

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ram S. Bhatta ◽  
Mesfin Tsige
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Industrial Development ◽  
Density Functional ◽  
Frontier Molecular Orbital ◽  
Excitation Energies ◽  
Dft Methods ◽  
Potential Surfaces ◽  
Vertical Excitation ◽  
Structural Dependence

Small conjugated molecules (SCMs) are promising candidates for organic photovoltaic (OPV) devices because of their structural simplicity, well control over synthetic reproducibility, and low purification cost. However, industrial development of SCM-based OPV devices requires improving their performance, which in turn relies on the fundamental understanding of structural dependence of electronic properties of SCMs. Herein, we report the structural and electronic properties of the BCNDTS molecule as a model system for acceptor-acceptor-donor-acceptor-acceptor (A-A-D-A-A) type SCMs, using density functional theory (DFT) and time-dependent DFT methods. Systematic calculations of two-dimensional potential energy surfaces, molecular electrostatic potential surfaces, ground state frontier molecular orbital energies, and the vertical excitation energies are performed. We found that the lowest energy conformation of the BCNDTS molecule is planar. The planar conformation favors the lowest ground state and the excited state energies as well as the strongest oscillator strength. The present results suggest that SCMs containing central dithienosilole cores connected with 2,1,3-benzothiadiazole groups have potential to be an efficient electron donor for OPV devices.

scholarly journals Computer aided chemical design: using quantum chemical calculations to predict properties of a series of halochromic guaiazulene derivatives

2016 ◽  
Vol 3 (11) ◽  
pp. 160373 ◽  
Author(s):  
Adam W. Woodward ◽  
Ebrahim H. Ghazvini Zadeh ◽  
Mykhailo V. Bondar ◽  
Kevin D. Belfield
Keyword(s):  
Data Storage ◽  
Density Functional ◽  
Computational Study ◽  
Photophysical Properties ◽  
Photon Absorption ◽  
Optoelectronic System ◽  
Dft Methods ◽  
Two Photon Absorption ◽  
Td Dft ◽  
Calculation Results

With the scientific community becoming increasingly aware of the need for greener products and methodologies, the optimization of synthetic design is of greater importance. Building on experimental data collected from a synthesized guaiazulene derivative, a series of analogous structures were investigated with time-dependent density functional theory (TD-DFT) methods in an effort to identify a compound with desirable photophysical properties. This in silico analysis may eliminate the need to synthesize numerous materials that, when investigated, do not possess viable characteristics. The synthesis of several computationally investigated structures revealed discrepancies in the calculation results. Further refined computational study of the molecules yielded results closer to those observed experimentally and helps set the stage for computationally guided design of organic photonic materials. Three novel derivatives were synthesized from guaiazulene, a naturally occurring chromophore, exhibiting distinct halochromic behaviour, which may have potential in a switchable optoelectronic system or combined with a photoacid generator for data storage. The protonated forms were readily excitable via two-photon absorption.

A theoretical study on the electronic structures and photophysical properties of phosphorescent Iridium(iii) complexes with –CH3/H and t-Bu substituents

2016 ◽  
Vol 45 (31) ◽  
pp. 12587-12593 ◽  
Author(s):  
Yanling Si ◽  
Nan Qu ◽  
Liying Cui ◽  
Bo Gao ◽  
Zhijian Wu
Keyword(s):  
Electronic Structures ◽  
Theoretical Study ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Absorption And Emission ◽  
Absorption And Emission Spectra ◽  
Shed Light

We present the electronic structures, absorption and emission spectra of a series of Ir(iii) complexes to shed light on the effect of different substituents on the photophysical properties.

scholarly journals Benchmarking Density Functional Approximations for Excited-State Properties of Fluorescent Dyes

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7434
Author(s):  
Anna M. Grabarz ◽  
Borys Ośmiałowski
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Fluorescent Dyes ◽  
Dipole Moments ◽  
Photophysical Properties ◽  
Excitation Energies ◽  
Data Set ◽  
Vertical Excitation ◽  
A Minor ◽  
Vertical Excitation Energies

This study presents an extensive analysis of the predictive power of time-dependent density functional theory in determining the excited-state properties of two groups of important fluorescent dyes, difluoroboranes and hydroxyphenylimidazo[1,2-a]pyridine derivatives. To ensure statistically meaningful results, the data set is comprised of 85 molecules manifesting diverse photophysical properties. The vertical excitation energies and dipole moments (in the electronic ground and excited states) of the aforementioned dyes were determined using the RI-CC2 method (reference) and with 18 density functional approximations (DFA). The set encompasses DFAs with varying amounts of exact exchange energy (EEX): from 0% (e.g., SVWN, BLYP), through a medium (e.g., TPSSh, B3LYP), up to a major contribution of EEX (e.g., BMK, MN15). It also includes range-separated hybrids (CAM-B3LYP, LC-BLYP). Similar error profiles of vertical energy were obtained for both dye groups, although the errors related to hydroxyphenylimidazopiridines are significantly larger. Overall, functionals including 40–55% of EEX (SOGGA11-X, BMK, M06-2X) ensure satisfactory agreement with the reference vertical excitation energies obtained using the RI-CC2 method; however, MN15 significantly outperforms them, providing a mean absolute error of merely 0.04 eV together with a very high correlation coefficient (R2 = 0.98). Within the investigated set of functionals, there is no single functional that would equally accurately determine ground- and excited-state dipole moments of difluoroboranes and hydroxyphenylimidazopiridine derivatives. Depending on the chosen set of dyes, the most accurate μGS predictions were delivered by MN15 incorporating a major EEX contribution (difluoroboranes) and by PBE0 containing a minor EEX fraction (hydroxyphenylimidazopiridines). Reverse trends are observed for μES, i.e., for difluoroboranes the best results were obtained with functionals including a minor fraction of EEX, specifically PBE0, while in the case of hydroxyphenylimidazopiridines, much more accurate predictions were provided by functionals incorporating a major EEX contribution (BMK, MN15).

scholarly journals Predicting Carbonyl Excitation Energies Efficiently Using EOM-CC Trends

2020 ◽  
Author(s):  
Keiran Rowell ◽  
Scott Kable ◽  
Meredith J. T. Jordan
Keyword(s):  
Single Point ◽  
Zero Point ◽  
Tropospheric Chemistry ◽  
Excitation Energies ◽  
Relaxation Energy ◽  
Point Energy ◽  
Vertical Excitation ◽  
Td Dft ◽  
Vertical Excitation Energy ◽  
Carbonyl Species

We approach the problem of predicting excitation energies of diverse, larger (5–6 carbons) carbonyl species central to earth’s tropospheric chemistry. Triples contributions are needed for the vertical excitation energy (E<sup>vert</sup>), while EOM-CCSD//TD-DFT calculations provide acceptable estimates for the S<sub>1</sub> relaxation energy (E<sup>relax</sup>), and (TD-)DFT suffices for the S<sub>0</sub> → S<sub>1</sub> zero-point vibration energy correction (∆E<sup>ZPVE</sup>). <div><br></div><div>Perturbative triples corrections deliver E<sup>vert</sup> values close in accuracy to full iterative triples EOM-CC calculations. The error between EOM-CCSD and triples-corrected E vert values appears to be systematic and can be accounted for with scaling factors. However, saturated and α,β-unsaturated carbonyls must be treated separately. Double-hybrid S<sub>0</sub> minima can be used to calculate E<sup>vert</sup> with negligible loss in accuracy, relegating the O(N<sup>5</sup>) expense of CCSD to only single-point energy and excitation calculations. </div><div><br></div><div>This affordable protocol can be applied to all volatile carbonyl species. E<sup>0−0</sup> predictions do overestimate measured values by ∼8 kJ/mol due to a lack of triples contribution in E relax, but this overestimation is systematic and the mean unsigned error is within 4 kJ/mol once this is accounted for.</div>

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