Visible light singlet oxygen production with tetra(4-carboxyphenyl)porphyrin/SiO2

•Tetra(4-carboxypenyl)porphyrin adsorbed on SiO2 with visible light generate singlet oxygen.•The absence of the EPR DMPO-O2− signal evidenced that superoxide anion was not present.•Anthraquinone and oxanthrone produced by the decomposition of the endoperoxide intermediary were identified as the only oxidation products of anthracene.

The production of singlet oxygen with tetra(4-carboxyphenyl)porphyrin adsorbed on SiO2 irradiated with visible light (λ > 500 nm) was evidenced by EPR spectra of TEMPO formed by oxidation of 2,2,6,6-tetramethyl-4-piperidone(TEMP) with 1O2. The formation of singlet oxygen was also evidenced by the formation of anthraquinone and oxanthrone as oxidation products of anthracene with 1O2. The absence of the EPR DMPO-O2− signal evidenced that superoxide anion was not present. No other oxygen radicals were detected. TCPP and TCPP/SiO2 were characterized with UV–vis, UV–vis diffuse reflectance and FT-IR spectroscopy.