Aerogel Photocatalyst Composed of Transparent Mesoporous Polymethylsilsesquioxane Softly Post‐Modified with a Visible‐Light‐Absorbing Metal Complex

Abstract Physical adsorption of various metal complexes including multinuclear heterometallic species onto polymethylsilsesquioxane (PMSQ) aerogel afforded their highly transparent mesoporous hybrids. One of the fabricated materials containing Ru(II) tris‐phenanthroline complex RuPhen₃−OH (RuPhen₃−OH@PMSQ) exhibited a photocatalytic activity for the dehydrogenation of the Hantzsch 1,4‐dihydropyridine 1_H2, which was close to that observed for the corresponding homogeneous system. The photocatalytic activity of RuPhen₃−OH@PMSQ was superior than that of RuPhen₃−OH on other silica gels having larger or smaller pores, suggesting that the pore size of the PMSQ aerogel plays an important role for the high photocatalytic activity by allowing both the light and substrates to easily access the catalysts located at the inner space of the material.