Photophysical properties of porphyrin derivatives: Influence of the alkyl chains in homogeneous and micro-heterogeneous systems

Abstract

This work is focused on the evaluation of the photophysical properties of protoporphyrin-IX derivatives with different alkyl chains. The goal of this work is to understand the physicochemical properties and select prototypes of photosensitizers for photodynamic therapy. Solvents with different dielectric constants were used to obtain relevant data on different physical and chemical processes, such as fluorescence quantum yield and emission level of aggregation in nonpolar media. In addition, studies were conducted in micro-heterogeneous systems through the interaction of porphyrin derivatives with different surfactants, such as cetyltrimethylammonium bromide, sodium dodecyl sulfate and octyl phenol ethoxylate. The compounds were characterized by electronic absorption spectroscopy in the ultraviolet-visible region and fluorescence emission spectroscopy. The comparative study between the different chemical environments evaluated in the present study represents a relevant contribution to the comprehension of the properties acquired by the porphyrins in different micro-heterogeneous systems, which allows us to understand various interactions that these compounds are subject in biological medium, such as the influence of the polarity of the medium in the reactivity of porphyrins with nonpolar substituents. These results show the decisive physicochemical influence of the alkyl chains on the properties of the tetraazomacrocycle porphyrin. +55 11-4996-0155 J. Porphyrins Phthalocyanines Downloaded from www.worldscientific.com by EMORY UNIVERSITY on 07/30/15. For personal use only. J. Porphyrins Phthalocyanines Downloaded from www.worldscientific.com by EMORY UNIVERSITY on 07/30/15. For personal use only.

The Red Color of Life Transformed – Synthetic Advances and Emerging Applications of Protoporphyrin IX in Chemical Biology

“…The formation of different PPIX and hemin esters is also frequently used as a method to produce derivatives with certain new functionalities ,. [33b], Examples are the incorporation of PPIX into polymeric materials, some of them with potential application in antimicrobial PDT,[68c], synthesis of porphyrins with altered physicochemical properties and the preparation of a PPIX‐cobyrinate dyad as an activator of soluble guanylyl cyclase . Ester formation on PPIX was achieved using EDC and DMAP[77a], [77b], or CDI[68c] and the respective hydroxyl‐substituted substrate to yield mono‐ and diesters 47 and 48 .…”

“…[72b], Traditional sulfuric acid‐catalyzed esterification can be carried out when the respective alcohol is used as a solvent. In this manner, de Oliveira and co‐workers obtained PPIX derivatives with long alkyl substituents showing altered photophysical properties and aggregation behavior in non‐polar solvents …”