The influence of the support on the singlet oxygen quantum yields of porphyrin supported photosensitizers

Marta Pineiro,Sónia M Ribeiro,Arménio C Serra

doi:10.3998/ark.5550190.0011.506

Marta Pineiro, Sónia M Ribeiro + Show 1 more

Open Access

https://doi.org/10.3998/ark.5550190.0011.506

Copy DOI

Abstract

A halogenated porphyrin was covalently supported on aminoalkylated silica and aminoalkylated Merrifield polymer through a chlorosulfonation reaction. The supported porphyrin was tested for the photoxidation of α-terpinene. The kinetics of photocatalysis were evaluated using 9,10-dimethylanthracene as target and singlet oxygen formation quantum yield was calculated. The influence of the support, silica, Merrifield and other polymers, on the quenching of singlet oxygen were also evaluated.

Highlights

Singlet oxygen mediated oxidations are very attractive reactions which make use of clean, accessible and economical reaction conditions.[1,2] They can give products which can hardly be obtained by other methods, for example endoperoxides[3,4] and allylic hydroperoxides.[5,6] The need for a photosensitizer molecule to transfer energy through oxygen to organic molecules, which sometimes have low stability and that must be separated from the products, can be viewed as a limitation of the process
We studied the ability of these supported photosensitizers (SPS) in generating singlet oxygen relative to free chlorinated porphyrins, highlighting the quenching effects caused by the support that can influence the efficiency of these supported catalysts
We developed a straightforward method for supporting chlorinated porphyrins on a modified Merrifield polymer using different lengths of spacers between porphyrin and polymer backbone.[10]

Summary

Introduction

Singlet oxygen mediated oxidations are very attractive reactions which make use of clean, accessible and economical reaction conditions.[1,2] They can give products which can hardly be obtained by other methods, for example endoperoxides[3,4] and allylic hydroperoxides.[5,6] The need for a photosensitizer molecule to transfer energy through oxygen to organic molecules, which sometimes have low stability and that must be separated from the products, can be viewed as a limitation of the process. We studied the ability of these SPS in generating singlet oxygen relative to free chlorinated porphyrins, highlighting the quenching effects caused by the support that can influence the efficiency of these supported catalysts.

Results

Conclusion