The remarkable ability of B3LYP/3-21G(*) calculations to describe geometry, spectral and electrochemical properties of molecular and supramolecular porphyrin–fullerene conjugates

Zandler, Melvin E.; D’Souza, Francis

doi:10.1016/j.crci.2005.12.008

Cited by 133 publications

(48 citation statements)

References 58 publications

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“…Such electronic structure would accelerate the electron transfer process. 62 Predictably, the LUMO of the dyad was fully localized on the fullerene entity. Further, using the redox, optimized structural and excited singlet energy data, the free-energies of charge-separation (GCS) and charge recombination (radical-ion pair formation) (GCR) were calculated using Rehm-Weller's approach according to equations 1 and 2.…”

Section: Resultsmentioning

confidence: 99%

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

et al. 2015

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A donor-acceptor dyad comprised of BF2-chelated dipyrromethene (BDP or BODIPY) and fullerene connected with a pyrrole ring spacer, 1 has been newly synthesized and characterized. Due to -carbon substitution and extended conjugation offered by the pyrrole ring, the optical absorbance and emission spectra of BDP macrocycle was found to be red-shifted significantly.Electrochemical studies provided information on the redox potentials while computational studies performed at the B3LYP/6-31G* level yielded an optimized geometry of the dyad that was close to that reported earlier for a BDP-C60 dyad covalently connected through the central boron atom, 2. The HOMO of the dyad was found to be on the BDP macrocycle, extended over the pyrrole bridging group, a property that is expected to facilitate electronic communication between the BDP and fullerene entities. The established energy level diagram using spectral, redox and optimized structural results predicted possibility of photoinduced electron transfer in both benzonitrile and toluene, representing polar and nonpolar solvents. However, such energy diagram suggested different routes for the charge recombination processes, that is, direct relaxation of the radical ion-pair in polar solvent while populating the triplet level of the sensitizer ( 3 BDP* or 3 C60*) in nonpolar solvent. Proof for charge separation and solvent dependent charge recombination processes were established from studies involving femto-and nanosecond pump-probe spectroscopy. The measured rate of charge separation, kCS for 1 was higher in both solvents compared to the earlier reported values for 2 due to electronically well-communicating pyrrole spacer. The charge recombination in toluene populated 3 BDP* as an intermediate step while in benzonitrile it yielded directly ground state of the dyad. The present findings reveal the significance of pyrrole spacer between the donor and acceptor to facilitate charge separation and solvent polarity dependent charge recombination processes.

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Section: Resultsmentioning

confidence: 99%

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

et al. 2015

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“…This probably arises from a large basis set superposition error (BSSE) or basis set incompleteness error (BSIE), which is inherent in the 3-21G* basis set. 54 This suggests that at least the TD-B3LYP/6-31G* level of theory should be used in calculations of the solvent effect on the excited states to replicate the experimental data efficiently. The use of solvent in the calculation of the excited states is needed in depicting the real environment of the analogues which can give a much better agreement with the experimental values; on the other hand, calculating the analogues in the gas phase, could give reversed oscillator strengths on its transition energies giving an error in its simulated spectra as observed with some porphyrins with fused benzoheterocycles.…”

Section: Resultsmentioning

confidence: 99%

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

Balanay

Kim

2008

Phys. Chem. Chem. Phys.

137

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Density functional theory (DFT) and time-dependent DFT calculations have been employed to model Zn meso-tetraphenylporphyrin (ZnTPP) complexes having different b-substituents, in order to design an efficient sensitizer for dye-sensitized solar cells. To calculate the excited states of the porphyrin analogues, at least the TD-B3LYP/6-31G* level of theory is needed to replicate the experimental absorption spectra. Solvation results were found to be invariant with respect to the type of model used (PCM vs. C-PCM). Most of the electronic transitions based on Gouterman's four-orbital model of ZnTPP-A and ZnTPP-B are p -p* transitions, so that cell efficiency can be enhanced by increasing the p-conjugation and electron-withdrawing capability of the bsubstituent. This proposition was tested by inserting thiophene into the b-substituent of ZnTPP-A to form a new analogue, ZnTPP-C. Compared with ZnTPP-A and ZnTPP-B, ZnTPP-C has a smaller band gap, which brings LUMO closer to the conduction band of TiO 2 , and a red-shifted absorption spectrum with higher extinction coefficients, especially in the Q-band position.

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“…To explore these possibilities with dispatch, numerous preliminary sequential H 2 O addition runs were carried out with HF/3-21G * . Although HF/3-21G * gives inflated attraction energies as a result of basis set superposition error [8][9][10], we have observed on many occasions (for example see ref. [3]) that it gives the same hydrate structures as higher level calculations.…”

Section: Ea + Hydrate Structuresmentioning

confidence: 93%

Hydrogen bonding. Part 87: DFT MO study of hydration of tetramethyl- and tetraethylammonium ions – Correlation of hydrate symmetry with 14N to CH NMR coupling

Harmon

2009

Journal of Molecular Structure

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The remarkable ability of B3LYP/3-21G(*) calculations to describe geometry, spectral and electrochemical properties of molecular and supramolecular porphyrin–fullerene conjugates

Cited by 133 publications

References 58 publications

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

Hydrogen bonding. Part 87: DFT MO study of hydration of tetramethyl- and tetraethylammonium ions – Correlation of hydrate symmetry with 14N to CH NMR coupling

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