There is currently much interest in avoiding precious metals in Catalysis. The devel-opment of nickel catalysts to replace palladium in the Mizoroki-Heck reaction is a relevant case in this line of research since both elements share many chemical features. This contri-bution focuses on -Phenyl elimination in alkylnickel complexes. This is the microscopic reverse of olefin insertion (or carbometallation), a fundamental step of the Heck cycle that is usually considered irreversible and selectivity-determining. However, the potential reversibil-ity of carbometallation is generally concealed by the facile beta-hydrogen elimination that follows. Where -hydrogen elimination is hindered, beta-aryl elimination may ensue. We have previously shown that cationic 2-methyl-2-phenylpropyl (neophyl) palladium com-plexes supported by bidentate ligands experience -Ph elimination, which can be seen as an example of olefin de-insertion. In this contribution, we report that -phenyl elimination can also occur in their nickel analogs, in which case fast hydrolyses of the resulting phenyl product can follow the reaction. We investigated the mechanism of these processes and compared their feasibility for nickel and palladium catalysts using DFT calculations. These results are relevant information for the design of nickel-based catalysts for the Heck reac-tion.

Carbon nanotubes (CNTs) are effective supports for nano metals and together they represent hybrids that combine unique properties of both. A microwave induced reaction was used to deposit nano palladium on carboxylated and octadecylamine functionalized multiwall CNTs, which were used to carry out C-C coupling reactions in DMF and toluene. These hybrids showed excellent catalytic activity with yield as high as 99.8% while its enhancement with respect to commercially available Pd/C catalyst reached as high as 109%, and the reactions times were significantly lower. Polarity of the functionalized form was found to be a significant factor with the polar carboxylated CNT showing better activity in DMF while the relatively nonpolar octadecyl amine was better in toluene. The results suggest the possibility of tailor making functionalized CNT when used as catalyst supports

Bimetallic PdCu nanoparticles with different Pd:Cu ratios and morphologies can be synthesized and immobilized on a variety of support materials. Accordingly, PdCu nanoparticles can be efficiently applied as heterogeneous catalysts in a large number of organic transformations including C-C coupling and cross-coupling reactions. As related to their favorable electronic and structural interactions, the catalytic performance of PdCu bimetallic nanoparticles may be superior to the monometallic species. The heterogeneous catalysts can be recovered and reused and the presence of copper tends to reduce the cost of the expensive Pd catalyst, which would be beneficial for industrial applications.

The construction of carbon-carbon bonds by direct involvement of two unactivated carbon-hydrogen bonds, without any directing group, ensures an high atom economy of the entire process. Here it is described a simple protocol for the Pd(II)/Cu(II)-promoted intermolecular cross-dehydrogenative coupling (CDC) of 5-arylimidazoles, benzimidazoles, benzoxazole and 4,5-diphenylimidazole at their C-2 position with functionalized styrenes. This specific CDC, known as Fujiwara-Moritani reaction or oxidative Heck coupling, allowed also the C-4 alkenylation of the imidazole nucleus when both 2 and 5 positions are occupied.