[60]Fullerene-Based Pd(0) Complexes of Phosphorus Ylides as Efficient Nanocatalyst for Homo- and Heterogeneous Mizoroki–Heck Coupling Reactions

This work reports the synthesis and catalytic properties of new mono- and bidentate palladium(0)-[60]fullerene complexes, prepared by reaction of α-keto stabilized phosphorus ylides [Ph 2 P(CH 2 ) n PPh 2 =C(H)C(O)C 6 H 4 - p -R] (n = 1, R = Ph, NO 2 , (Y 1 , Y 2 ); n = 2, R = Ph, NO 2 , (Y 3 , Y 4 )), C 60 and Pd(dba) 2 (dibenzylideneacetone (dba)). Two coordination modes were observed: bidentate P,C-coordinated in the case of [(η −C 60 )Pd(κ 2 −Y 1 )] (1) and [(η 2 −C 60 )Pd(κ 2 −Y 2 )] (2) and monodentate P-coordinated for [(η 2 −C 60 )Pd(Y 3 ) 2 ] (3) and [(η 2 −C 60 )Pd(Y 4 ) 2 ] (4) complexes. All complexes have been fully characterized by 1 H, 13 C and 31 P NMR spectroscopic methods and other conventional techniques such as IR, thermogravimetry, inductively coupled plasma optical emission spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy analysis. Also, the catalytic activity of [60]fullerene-based nanocatalyst 2 in homo- and heterogeneous Mizoroki–Heck coupling reactions of various aryl chlorides with styrene was evaluated. The results implied that the both reactions exhibit their beneficial aspects such as high activity for homogeneous catalysis and facile separation and reusability for heterogeneous one. Furthermore, DFT studies of geometry-optimized monodentate and bidentate structures for 1 and 3 were calculated at the BP86/LANL2DZ and B3LYP/LANL2MB levels of theory to understand the origin of the observed coordination modes. Graphical Abstract