Periodic Mesoporous Organosilica Functionalized Sulfonic Acids (PMO-ICS-SO₃H) as an Efficient and Recyclable NanoCatalyst for the Unsymmetric Hantzsch reaction

Hybrid mesoporous organosilica was first introduced in 1999, built from bridged organosilane precursors ((ŔO)₃Si–R–Si(OŔ)₃; R: organic bridging group, Ŕ: methyl or ethyl). Such mesoporous hybrids have been classified as periodic mesoporous organosilicas (PMOs). In these materials, the bridging organic moieties which are well distributed inside the inorganic pore wall not only increase mechanical and hydrothermal stabilities, but also higher organic loading and greater avoidance of channel blockage can be achieved in comparison with mesoporous silicas functionalized with terminal organic groups.

Polyhydroquinolines, as a family of 1,4-dihydropyridine derivatives, are one of the most important groups of nitrogen heterocycles that have attracted extensive interest because of their promising pharmacological and therapeutic activities such as calcium channel blockers, bronchodilating, antiatherosclerotic, antitumor, vasodilating, geroprotective, hepatoprotective, and antidiabetic.

The nanocatalyst were characterized by X-ray diffraction, scanning electron microscopy and thermogravimetric analysis.