Electronic structures and spectra of symmetric meso‐substituted porphyrin: DFT and TDDFT—PCM investigations

Venkataramanan, Natarajan Sathiyamoorthy; Suvitha, Ambigapathy; Nejo, H.; Mizuseki, Hiroshi

doi:10.1002/qua.22519

Cited by 30 publications

(19 citation statements)

References 37 publications

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“…They are shown in Fig. 2 (as well as those of the nearly-degenerate LUMO and LUMO+1) and are similar to those found previously for the same system [22] and for the parent TPP molecule [16,17,19,20,[45][46][47]. For the rest of the spectrum each spectroscopic feature (peak) results from several MOs and there is no simple trend to attribute its origin to specific atoms in the 2 Such procedure, also used in other studies [42] is necessary since the UPS spectrum was taken on a solid surface, a fact that is not taken into account in the calculations.…”

Section: Resultssupporting

confidence: 88%

“…A redistribution of the frontier MO is known to have important consequences for the optical properties of substituted porphyrins [13,17,46,47,56]. In the following the evolution of the UV-Vis spectra of TPP upon amino substitution will be analyzed in the light of the UPS/IPES results and compared with TD-DFT calculations of the first singlet excitations ( Table 2).…”

Section: Resultsmentioning

confidence: 99%

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Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

Giovanelli

Lee

Lacaze‐Dufaure

et al. 2017

Journal of Electron Spectroscopy and Related Phenomena

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao. b s t r a c tThe valence and conduction bands of a thin film of tetra(4-aminophenyl)porphyrin (TAPP) are investigated by direct and inverse photoemission as well as by comparison to density functional theory (DFT) calculations. By projecting the electronic eigenfunctions onto the molecular framework it was possible to interpret the origin of each spectroscopic feature. Although the majority of the photoemission spectrum is attributed to the unsubstituted tetraphenylporphyrin (TPP) parent molecule, several features are clearly due to the amino substitution. Substitution also has important consequences for the energy positions of the frontier orbitals and therefore on the low-energy electronic excitations. The measured electronic transport energy gap (E g = 1.85 eV) between the highest occupied molecular orbital (HOMO) and lowest unoccupied (LUMO) in TAPP is found to be significantly reduced with respect to TPP. Moreover, an increased energy separation between the two highest occupied states (HOMO and HOMO−1) is found both experimentally and by DFT calculations. Such evidence is attributed to an increased HOMO orbital destabilization due to an enhanced electron-donor character of the phenyl substituents upon amino functionalization. Finally, the above findings together with further time-dependent DFT calculations are used to interpret the effect of the amino groups on the UV-Vis absorption spectrum, namely an overall red-shift of the spectrum and remarkable intensity changes within the Q band.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

Giovanelli

Lee

Lacaze‐Dufaure

et al. 2017

Journal of Electron Spectroscopy and Related Phenomena

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“…It has already been reported that this type of modification is typical when the TD-DFT methods are applied to predict the excitation energy of the S 0 → S 1 transition with respect to both porphyrins and chlorins. 7,[19][20][21] On the other hand, no shift-correction to the Q y -band is required. In addition, other small deviations from the experimental data may be due to the neglect of anharmonicity.…”

Section: Discussionmentioning

confidence: 99%

“…The effect of solvent has been introduced by the polarizable continuum model (PCM) with a dielectric constant (ε) of 1.9406 for n-octane, 20 DMSO. The excited electronic states in solution have been modeled using the external iteration (EI) approach.…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical reproduction of the Q-band absorption spectrum of free-base chlorin

Wójcik

Ratuszna

Peszke

et al. 2015

The Journal of Chemical Physics

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The computational results of the features observed in the room-temperature Q-band absorption spectrum of free-base chlorin (H2Ch) are presented. The vibrational structures of the first and second excited singlet states were calculated based on a harmonic approximation using density functional theory and its time dependent extension within the Franck-Condon and Herzberg-Teller approaches. The outcome allowed to identify the experimental bands and to assign them to the specific vibrational transitions. A very good agreement between the simulated and measured wavelengths and their relative intensities provided the opportunity to predict the origin of the S0 → S2 transition which could not be determined experimentally.

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“…In general, the optical properties are governed by the frontier molecular orbital (FMO) components, the HOMO and LUMO energy levels, and energy gaps. 58 The FMO compositions and energy levels for FPR5, 7, and 14 are shown in Fig. 6.…”

Section: Optical Property Of Fpr Polymersmentioning

confidence: 99%

Polymerization of cyanoacetylene under pressure: Formation of carbon nitride polymers and bulk structures

2012

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High-pressure phase transitions of polar and nonpolar molecular structures of cyanoacetylene (HC 3 N) are studied by using first-principles simulations at constant pressure. In both polar and nonpolar crystals, at pressure ∼20 GPa, the cyanoacetylene molecules are interconnected together and form polyacrylonitrile (PA) polymers. At pressure ∼30 GPa, PA polymers are transformed to polymers with fused pyridine rings (FPR's). The individual geometrical structures of PA and FPR polymers obtained from polar and nonpolar molecular crystals of cyanoacetylene are identical, but their stacking is different. At pressures above 40 GPa, the FPR polymers are interconnected together and new three-dimensional (3D) carbon nitride systems are formed. At ambient pressure, the long-length PA and FPR polymers are metallic, and the created 3D structures are an insulator with energy band gaps around 2.85 eV. The electron transport characteristics of FPR polymers with different lengths are investigated at finite biases by using the nonequilibrium Green's function technique combined with density functional theory (DFT) by connecting the polymers to gold electrodes. The results show that FPR polymers have negative differential resistance behavior. Our time-dependent DFT calculations reveal that FPR polymers can absorb light in the visible region. From our results, it is expected that the FPR polymers will be a good material for optoelectronic applications.

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Electronic structures and spectra of symmetric meso‐substituted porphyrin: DFT and TDDFT—PCM investigations

Cited by 30 publications

References 37 publications

Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

Theoretical reproduction of the Q-band absorption spectrum of free-base chlorin

Polymerization of cyanoacetylene under pressure: Formation of carbon nitride polymers and bulk structures

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