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

• Published in: Chemistry, an Asian journal an Asian journal, 2010-09, Vol.5 (9), p.2001-2015
• Main Authors: Zhou, Zhou, Franz, Adam W., Bay, Sarah, Sarkar, Biprajit, Seifert, Andreas, Yang, Piaoping, Wagener, Alex, Ernst, Stefan, Pagels, Markus, Müller, Thomas J. J., Thiel, Werner R.
• Format: Article
• Language: English
• Subjects: electron transfer; mesoporous materials; optical materials; organic-inorganic hybrid composites; phenothiazine
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201000098

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 N2 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 13C and 29Si 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. Making hybrids: Mesoporous hybrid materials containing covalently grafted phenothiazines have been synthesized by the direct condensation of TEOS and appropriate silicon derivatives. Upon oxidation with (NO)BF4 or SbCl5, stable phenothiazine radical cations are generated in the pores of the materials, which can be detected by means of UV/Vis, emission, and EPR spectroscopies. The electron transfer into and out of these materials has been investigated by cyclic voltammetry.