Synthesis of hybrid silicates containing porphyrins incorporated by a sol-gel process and their properties

Porphyrin was incorporated in a silicate network, via a covalent bond, by g rafting a functional group with 3-aminopropyltriethoxysilane, using a sol-g el process. We have carried out the synthesis and measured the absorption s pectra, nuclear magnetic resonance spectra, infrared (IR) spectra, luminesc ence spectra and lifetime of these hybrid silicates, porphyrinosilicas. The se samples contained the following free-base porphyrins: meso-tetrakis-p-ch lorobenzoylporphyrin, meso-tetrakis-2,6-dichloro-3-chlorosulfonylphenylporp hyrin. The obtained porphyrinosilicas have similar absorption and luminesce nce spectra to the free base porphyrins in solution. IR spectra confirm the formation of monomeric species. Lifetime measurement for porphyrinosilica reveals that 32% +/- 2% of porphyrin is covalently bonded to the silica net work. (C) 1999 Elsevier Science B.V. All rights reserved.