Effect of substituents on the absorption properties of three pyridylindolizine derivatives: A DFT and TDDFT study

Aittala, Pekka J.; Cramariuc, Oana; Vasilescu, Marilena; Bandula, Rodica; Hukka, Terttu I.

doi:10.1016/j.chemphys.2009.04.020

Cited by 8 publications

(9 citation statements)

References 30 publications

(44 reference statements)

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“…In effect, among the selected functionals, B3LYP and PBE0 yield the best estimates of transition energies. Similar consideration regarding the performances of the two functionals also results from LR-PCM TD-DFT investigations of several related pyrrolopyridazines and pyridil-indolizines . The particular behavior of the M06-HF functional in predicting a different ordering of the second and third excited states ( n π* < ππ*) may also be noted.…”

Section: Resultssupporting

confidence: 56%

Conformational Effects on the Lowest Excited States of Benzoyl-Pyrrolopyridazine: Insights from PCM Time-Dependent DFT

et al. 2013

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Time-dependent density functional theory (TD-DFT) computations and steady-state electronic spectroscopy measurements are performed on two recently synthesized pyrrolopyridazines to account for the detrimental effect of benzoyl substitution on the blue fluorescence emission. In the case of the highly fluorescent ester derivative, planar in ground state, we show that TD-DFT using the PBE0 and B3LYP hybrid functionals in the state-specific solvation approach provides an accurate description of absorption and emission properties. In benzoyl-pyrrolopyridazine, the (pretwisted) orientations of the benzoyl group and the solvent polarity are both found to modulate the nature of the lowest excited states. The first excited state has nπ* character at ground-state geometry of the main conformer (carbonyl group facing the diazine ring) in nonpolar solvents and become nearly degenerate with a ππ* state in polar solvents. The latter, lower than the nπ* state at the ground state geometry of a minor conformer, relaxes into a twisted intramolecular charge transfer. Experimental absorption and excitation spectra are consistent with the conformational-dependent picture of the lowest excited state (as derived from TD-DFT). A rather qualitative agreement in predicting the fluorescence emission wavelength is achieved in computations employing the CAM-B3LYP and BH&HLYP functionals, whereas global hybrids with low or moderate amounts of exact exchange exhibit the expected TD-DFT failure with up to 1 eV underestimated transition energies.

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Section: Resultssupporting

confidence: 56%

Conformational Effects on the Lowest Excited States of Benzoyl-Pyrrolopyridazine: Insights from PCM Time-Dependent DFT

et al. 2013

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“…The design of these new structures needs accurate knowledge of the effects induced by the substituents on the electronic properties of the pyrene moiety. Quantum chemical studies − can give a powerful test bench for an a priori correlation between the structural and electronic properties, thus helping to address the synthesis of new molecules for photovoltaic applications. In this field, the investigation of new hybrid systems based on organic dyes and noble metal (Ag, Au) or semiconductor (TiO 2 ) nanoparticles, seen in Scheme , can be of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Tuning the Photophysical Properties of Pyrene-Based Systems: A Theoretical Study

et al. 2011

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Recently new molecular systems based on the pyrene moiety were developed for photovoltaic applications. Here we present the results of a quantum chemical study focused on the effects induced by some different substituents on the electronic properties of pyrene, to obtain general hints for the molecular design of new pyrene-based systems. In particular, a series of electron-donating (hydroxy, amino, acetylamino) and electron-withdrawing (cyano, carbamoyl, formyl, ethynyl, ethenyl) groups were considered. Furthermore, in addition to the single pyrene molecule, two pyrene units linked by ethenylene, ethynylene, 2,5-thienylene, and ethynylene-p-phenylene containing chains of different lengths were taken into account. For all of the model structures presented, the ground state geometries have been optimized using the density functional approach, while the vertical transition energies were calculated using the time-dependent density functional theory. We will show that the tuning of the lowest electronic excitation energy (i.e., the HOMO-LUMO energy gap) as well as the localization of the spatial distributions of the frontier molecular orbitals (i.e., the nature of the electron-hole pair, generated by photon absorption) can be obtained through the analysis of the pyrene frontier molecular orbitals. This approach allows to evaluate the most suitable position of the substituents on the pyrene moiety giving rise to enhanced electronic effects also in function of their electronic nature. In this way, pyrene-structures with tailored electronic properties could be modeled. Our screening shows that promising candidates for photovoltaic applications could be molecular structures formed by two pyrene units joined/linked by a short conjugated bridge containing double or triple bonds (henceforth pyrene-linked dimers). As far as the single pyrene units are considered, the most significant reduction of the transition energy of the lowest optical electronic excitation is obtained with disubstituted pyrenes with push-pull character.

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“…TDDFT formalism has been applied for calculation of the structural and electronic properties of the ground and excited states of organic dyes. Aittala et al studied the structural and electronic properties of the ground states and the UV-vis absorption spectral characteristics of indolizine derivatives 18 and fluorescence properties of pyridylindolizine derivatives 19 by applying DFT and TDDFT. The performance of the two hybrid-type functionals (BH&HLYP and B3LYP) and one generalized gradient approximation (GGA) functional (PBE) with different basis sets has been assessed.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study on the absorption and fluorescence properties of substituted aryl hydrazones of 1,8-naphthalimide

Cheshmedzhieva

Ivanova

Stoyanov

et al. 2011

Phys. Chem. Chem. Phys.

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Absorption and fluorescence spectra in acetonitrile for a series of substituted aryl hydrazones of N-hexyl-1,8-naphthalimide are studied with the aim of potential application of the compounds for enzyme activity localization. The influence of the substituents on the spectral characteristics has been evaluated. The absorption and fluorescence energies of substituted aryl-1,8-naphthalimide hydrazones have been calculated with the PCM TDDFT formalism. The M06 and PBE0 functionals, combined with the 6-31+G(d) atomic basis set, have been found to accurately model the excited state properties of the present set of solvated fluorophores. Absorption and fluorescence spectral characteristics have been rationalized in terms of experimental and theoretical electronic indices in order to assess their predictive abilities for application in designing analogues with good emitting properties. An excellent linear dependence is established between the experimental fluorescence and Hammett σ(p)(+) substituent constants and on the other hand σ(p)(+) constants correlate with the theoretically calculated values for the electrostatic potential at nuclei (EPN). A model for predicting the fluorescence properties of substituted hydrazones by means of EPN is drawn, including the polysubstituted derivatives, where Hammett constants are not applicable.

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Effect of substituents on the absorption properties of three pyridylindolizine derivatives: A DFT and TDDFT study

Cited by 8 publications

References 30 publications

Conformational Effects on the Lowest Excited States of Benzoyl-Pyrrolopyridazine: Insights from PCM Time-Dependent DFT

Conformational Effects on the Lowest Excited States of Benzoyl-Pyrrolopyridazine: Insights from PCM Time-Dependent DFT

Tuning the Photophysical Properties of Pyrene-Based Systems: A Theoretical Study

Experimental and theoretical study on the absorption and fluorescence properties of substituted aryl hydrazones of 1,8-naphthalimide

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