Synthesis and Characterization of 5,10,15,20‐Tetrakis(4‐ethylphenyl)porphyrin and (Zn²⁺, Mn²⁺, Sn²⁺, Ni²⁺, Al³⁺, V³⁺)‐Derivatives: Photophysical and DFT study

Abstract

A novel family of porphyrins based on 5,10,15,20‐Tetrakis(4‐ethylphenyl)porphyrin (1) and six metallo‐derivatives (Zn2+(2), Sn2+(3), Mn2+ (4), Ni2+ (5), Al3+ (6) and V3+ (7)) were synthesized via the Alder‐cols method (synthesis yield between 59%‐75%) and characterized through 1H‐ and 13C‐ NMR, MALDI‐TOF mass spectrometry and FT‐IR assay. Photophysical study was carried out by UV‐Vis and fluorescence spectrophotometry with the aim of assessing their potential as dye sensitizers for photodynamic therapy (PDT). In this regard, fluorescence quantum yield values are between 0.002‐0.38, being the macrocycle 3, the porphyrin with the highest fluorescence quantum yield while the derivative 7 showed the lowest value. Quantum chemical calculations were carried out to study the molecular structure of the porphyrins and to get insight of the luminescent process for 1, which is the free metal system and 3 which includes Sn2+ as metal center. Results indicated that the emissive states involve the transitions with LLCT character for 1, while for 3 it is ML–LCT. This fact evidenced the metal effects on their photophysical properties. Finally, optical and spectroscopic properties and besides, DFT study suggest that 3 could be used as sensitizer in photodynamic therapy applications.

In Vitro Anti-Leishmanial Effect of Metallic Meso-Substituted Porphyrin Derivatives against Leishmania braziliensis and Leishmania panamensis Promastigotes Properties

“…In a recent publication, our group reported in detail the photophysical and DFT results for (1-7). In that study, we proposed that (1-7) could be tested as sensitizers for photodynamic therapy [39]. In view of that, in the present study, our aim is to demonstrate the cytotoxic activity of (1-7) against L. braziliensis and L. panamensis.…”

“…All reagents were supplied by Aldrich. We synthesized porphyrin according to Alder and Cols method [55], which relies on stirring aldehyde and pyrrole in propionic acid for 6 h at room temperature and an oxygen atmosphere (see Scheme 1) [39]:…”

“…All reagents were supplied by Aldrich. We synthesized porphyrin according to Alder and Cols method [55], which relies on stirring aldehyde and pyrrole in propionic acid for 6 h at room temperature and an oxygen atmosphere (see Scheme 1) [39]: Scheme 1. Chemical synthesis of: (1) 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin and metalderivatives, (2) Zn (II), ( 3) Sn (IV), ( 4) Mn (III), ( 5) Ni (II), ( 6) Al (III), ( 7) V (III).…”