Facile construction & modeling of a highly active thiacalixphenyl[4]arene-protected nano-palladium catalyst for various C–C cross-coupling reactions

The design and creation of thiacalixphenyl[4]arene tetraacetohydrazide (TPTAH) has been utilized for the construction of palladium nanoparticles (PdNps). The molecular modelling studies give an insight into the surface properties of TPTAH capped PdNps. The plausible reduction mechanism of Pd(II) to Pd(0) is due to the presence of hydrazide group on the periphery. The charge transfer for this reduction was initiated by the carbonyl group and N-atom. TPTAH behaves as a reducing and stabilizing agent for the formation of catalytically active TPTAH-PdNps that were characterized by UV-Vis spectroscopy, selected area electron diffraction (SAED), transmission electron microscopy (TEM), and powder X-ray diffraction. The TPTAH-PdNps with size 4 ± 2 nm were found to be catalytically active for C–C cross-coupling reactions such as the Suzuki–Miyaura, Heck, and Stille reactions. TPTAH-PdNps are superior to the conventional Pd catalyst in terms of yield, catalyst loading, reaction time, and recyclability.