Investigation of protonation effects on the electronic and structural properties of halogenated sulfonated porphyrins

Influence of halogen atoms and protonation on the photophysical properties of sulfonated porphyrins

“…The results were adjusted with singleexponentials (solid lines) and the values achieved are presented in Table 1. These values present good agreement with those obtained previously [26]. However, due to the 700-ps limit detection time of our experimental setup, we were not able to obtain lifetime values for protonated and nonprotonated TDC porphyrins.…”

“…This effect also can be attributed to larger flexibility presented in protonated porphyrins [39,40]. Despite the protonation decreases the ϕ isc values, a significant increase up to 9-13.5 of the Q absorption band in the therapeutic window was observed [26]. In this way, protonation can also be a strategy to increases the photodynamic efficacy.…”

“…These choices were based on a previous study where the pK values for protonated and nonprotonated species of sulfonated halogenated porphyrins were determined [26]. It was observed that for one halogen in each phenyl outlying group (TC and TF) the pK is 3.5, while for porphyrins with two halogen atoms, reductions to 2.5 (TDF) and 2.2 (TDC).…”

“…In this context, aiming to improve its photodynamic efficiency, sulfonated porphyrins containing halogen atoms, chlorine and fluorine, in the ortho positions of phenyl rings have been synthetized, and presented an enhanced singlet oxygen generation quantum yield and photodynamic efficiency [23][24][25]. It was recently shown that these sulfonated halogenated porphyrins can be protonated in acid environments [26]. These protonated molecules presented an enhancement in the absorbance in the phototherapeutic window, suggesting that the protonation of sulfonated halogenated porphyrins can be a good strategy for the development of a drug for PDT.…”

Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil

“…Time-resolved fluorescence was acquired using an apparatus based on the time correlated single photon counting (TCSPC) method. The excitation source was a titanium-sapphire laser (Tsunami 3950-Spectra Physics), pumped by a second harmonic diode-pumped Nd:yVO 4 laser (Millenia-Spectra Physics), with frequency doubled to 465 nm in an LBO crystal (GWN-23PL-Spectra Physics); additional details can be found in (Rodrigues et al 2015, Sampaio et al 2012.…”