Phenylene-based periodic mesoporous organosilica supported melamine: An efficient, durable and reusable organocatalyst

A novel melamine functionalized phenylene-based periodic mesoporous organosilica (PH-PMO@Melamine) is synthesized, characterized and its catalytic performance is investigated in the coupling of aldehydes with malononitrile. The PH-PMO@Melamine was prepared through grafting of 3-chloropropyltrimethoxysilane on a phenylene-based PMO followed by treatment with melamine. Several techniques such as Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption analysis and transmission electron microscopy (TEM) were used to characterize this nanomaterial. The PH-PMO@Melamine was catalytically applied in the condensation of a variety of different aldehydes with malononitrile under solvent free conditions and delivered corresponding products in high to excellent yields. The catalyst was recovered and reused several times without a significant decrease in activity or product selectivity.