Synthesis, Characterization and Evaluating Photochemical Properties of Porphyrin-substituted Azobenzene Structure

Herein a new azobenzene-substituted porphyrin molecule was synthesized, characterized and its optoelectronic properties were investigated by combining the high optoelectronic properties of porphyrin with the photosensitive properties of azobenzene. The carboxylic acid of azobenzene was covalently connected to -OH group of the porphyrin ring by using Steglich esterification. Molecular structure of the obtained azobenzene-porphyrin (8), was elucidated, by FTIR, 1 H and 13 C NMR and HRMS. After structural characterization absorption and emission, characteristics were determined in solvents that have different. And also, optical and fluorescence behaviors in the range of different acid pH with trans-cis photoisomerization behaviors were investigated in aqueous-THF solution in acid media.

Theoretical and experimental analysis of porphyrin derivatives with suitable anchoring groups for DSSC applications

In this contribution, different porphyrin derivatives were experimentally synthesized and theoretically analyzed using several electronic structure methods to study the geometrical and electronic properties of A4, trans-A2B[Formula: see text]and A3B porphyrins bearing several functional groups (–OH, –COOH, -3,5-di-[Formula: see text]Bu, –OCH2CH2CH2COOEt and –OMe) suitable to be employed as dyes in Dye Sensitized Solar Cells (DSSC). A4 (R [Formula: see text] -H, -OMe, -OH, -3,5-di-tert-butyl, –OCH2CH2CH2COOEt) and A3B (R[Formula: see text][Formula: see text]R[Formula: see text][Formula: see text]R[Formula: see text][Formula: see text]–H; R[Formula: see text][Formula: see text]–OH and R[Formula: see text][Formula: see text]-3,5-di-[Formula: see text]Bu) porphyrins were synthesized and characterized by UV-vis and 1H NMR spectroscopies for comparison. The geometrical parameters were analyzed in the ground state and gas phase using the semiempirical method PM6 and the DFT functionals M06-2X and B3LYP, in combination with the 6-31G(d), DZVP and TZVP basis set. For calculations of the electronic and excited state properties, CAM-B3LYP, M06-2X and HSE06, using SMD as solvation model, were applied. This study revealed that HSE06/DZVP protocol is the best methodology to simulate electronic spectra in these porphyrin derivatives. Indeed, whereas substituent groups did not significantly affect the geometrical structure of the porphyrin derivatives studied, they do influence their electronic structures, mainly in the LUMO (lowest unoccupied molecular orbital) energy levels.

Theoretical study of novel azo-tetraphenylporphyrins: potential photovoltaic materials

A density functional theory study was performed to analyze the electron donor-acceptor properties of the cis and trans isomers of a novel azobenzene-containing tetraphenylporphyrin (TPPN2PhC14H29) with different substituents (Br or TMS). In general, the trans isomers are better electron acceptors than the correspondent cis homologues. Their UV-vis spectra were also obtained and a comparison with available experimental results is included. According to these results, the azo compounds reported here are promising materials for the elaboration of dye-sensitized solar cells because their HOMO-LUMO gaps are close to 2 eV. Moreover, the energy of the high intensity absorption bands also fulfills the requirements needed for the operation of a solar cell built with TiO2 and the I(-)/I3(-) pair.