Effect of protonation on the photophysical properties of meso-tetra(sulfonatophenyl) porphyrin

Excited-state absorption investigation of a cationic porphyrin derivative

“…4 shows that the fluorescence evolution of the investigated porphyrin clearly follows a mono-exponential behavior whose fitting provide a value of 15 (±0.2) ns for the relaxation time. Although slower, this fluorescence lifetime is of the same order of magnitude of the data reported in literature [30,36,37] for other free-base porphyrins. In order to investigate the singlet excited-state absorption (S 1 → S n transition), we employed the WLC Z-scan technique, which provides Z-scan signatures for each wavelength of the complete WLC range, captured simultaneously.…”

Studying the intersystem crossing rate and triplet quantum yield of meso-substituted porphyrins by means of pulse train fluorescence technique

“…This behavior is opposite to that of porphyrins with Ru(II) inserted in macrocycle core. Sulfonated free-base porphyrins possessing halogenated substituents [23] exhibited increased intersystem crossing quantum yields ( isc ) [21]. For example, ϕ T increased from 0.77 to 0.84 upon introduction of two fluorine atoms and to 0.85 and 0.91 for one and two chlorine atoms, respectively.…”

“…For example, Gonçalves et al [20] demonstrated that the insertion of zinc in sulfonated porphyrin free-bases drastically reduced the ISC rate from 13 ns [21] to 2.2 ns [20]. Sampaio et al [22] have shown that free-base 5,10,15,20-tetra(4-pyridyl)porphyrin (H 2 TP y P) with ruthenium(II) ions bound at the peripheral groups of the macrocycle increases the ISC time about twofolds compared to porphyrins without Ru(II) (from 14 ns to 25 ns).…”

Nonlinear absorption properties of 5,10-A2B2porphyrins—correlation of molecular structure with the nonlinear responses

“…The highest ratio of the excited to the ground state absorption cross-section reached values in the range of 45-48. Moreover, other reports explored other means of OL response tuning through incorporation of different axial ligands, 16 protonation of free base compounds, 17 oligomerization of porphyrins, 18 or binding of porphyrins to other OL materials such as graphene or fullerene. 19 Generally speaking NLA is very susceptible to structural modifications of the basic dyes potentially allowing further progress in the OL field.…”