Redox Active Mesoporous Hybrid Materials by In situ Syntheses with Urea-linked Triethoxysilylated Phenothiazines

Triethoxysilyl functionalized phenothiazinyl ureas were synthesized and immobilized by in situ synthesis into mesoporous hybrid materials. The designed precursor molecules influence the structure of the final materials and the intermolecular distance of the phenothiazines. XRD and N-2 adsorption measurements indicate the presence of highly ordered two-dimensional hexagonally structured functional materials, while the incorporation of the organic compounds in the solid materials was proved by means of C-13 and Si-29 solid state NMR spectroscopy as well as by FT-IR spectroscopy. Upon oxidation with (NO) BF4 or SbCl5, stable phenothiazine radical cations were generated in the pores of the materials, which was detected by means of UV/Vis, emission, and EPR spectroscopies.