Self-assembled NiO-ZrO2 nanocrystals with mesoscopic void space: an efficient and green catalyst for C-S cross-coupling reaction in water.

New NiO-ZrO(2) nanocrystals (MNZ-1) with mesoscopic self-assembly have been synthesized by using a non-ionic surfactant as the structure directing agent (SDA) via evaporation induced self-assembly (EISA) method. Powder X-ray diffraction (PXRD), N(2) sorption study and transmission electron microscopic (TEM) image analyses revealed the cubic structure, mesoporosity and mesoscopic self-assembly of ca. 7.0 nm sized tiny nanocrystals in the material. MNZ-1 catalyzes the aerobic aryl-sulfur cross-coupling reactions for a series of aryl-iodides with 4-chlorothiophenol in environment friendly water medium at elevated as well as room temperature. Pure ZrO(2) mesoporous nanocrystals are inactive, whereas pure NiO nanocrystals showed much lower catalytic activity under similar reaction conditions. The MNZ-1 nanocatalyst is completely non-air sensitive, inexpensive and effective for the synthesis of a series of essential biomolecules derived from diaryl sulfides.