Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C-S cross-coupling reaction

Highly active reduced graphene oxide supported Ni nanoparticles for C-S coupling reactions

Air-stable Ni nanoparticles (with particle size ∼ 11 nm) supported on reduced graphene oxide [Ni(0)@RGO] was prepared by a simple and easy procedure. We previously described the Kumada-Corriu C-C cross-coupling reaction between iodo-arenes and Grignard reagents with Ni(0)RGO as a stable and efficient catalyst. This Ni(0)RGO catalyst gave an excellent yield (92%) and good recyclability (up to the 5th cycle). This communication confirms that the catalyst shows superior efficacy for the C-S coupling reaction, similar to that for the Kumada-Corriu C-C cross-coupling reaction. A catalytic experiment with the Ni(0)@RGO recycled material was also performed. HRTEM study of the reused material after the C-S coupling reaction confirmed the retention of the original (fresh) catalyst structure. It is reusable up to the 7th cycle without any activity loss.

Aryldithiocarbamates as thiol alternatives in Cu-catalyzed C(aryl)-S coupling reactions using aryldiazonium tetrafluoroborate salts

An efficient method for the synthesis of unsymmetrical diaryl sulfides has been developed by the C-S cross coupling of aryldithiocarbamates and aryldiazonium salts in the presence of CuI-2,2'-bipyridine and Zn. Aryldithiocarbamate compounds have been used here as thiol substitutes. The protocol shows wide substrate scope and good yields of the products.

Ni nanoparticle supported reduced graphene oxide as a highly active and durable heterogeneous material for coupling reactions

We report the loading of highly air stable Ni(0) nanoparticles (average particle size = 11 nm) on the surface of a reduced graphene oxide (RGO) material. The material was characterized using different techniques, including Raman spectroscopy, XRD, TEM, SEM, and HRTEM analysis. The Ni(0)@RGO catalyst showed superb efficiency towards Kumada-Corriu C-C cross-coupling reactions, with 92% yield of 4-methoxybiphenyl at 60 °C. The recycled material can be reused up to the 5^th cycle after regeneration by calcination, without loss of activity.