Cobalt nanospheres

Scheme 10.23 Cobalt nanospheres in Mizoroki-Heck-type reactions.

Coupling reactions. Hollow nanospheres of cobalt can substitute for Pd species in Sonogashira coupling. The catalyst system still contains Cul, Ph3P, and K2C03. ... 

Different nanocrystals shapes are obtained by variation of the organic stabilizer type and its concentration. For instance, if organometallic compounds such as nickel bis-cyclooctene-l,5-diene(Ni(COD)2) are subjected to the heat treatment and decomposition in the presence of hexadecylamine (GDA) or trioctylphosphenoxide, the nanorods or nanospheres can be obtained [311]. The particles of bracelet shape and 27 nm size have been synthesized in Ref. [312]. The tetrahedral structures [313] have been obtained when the cobalt nanoclusters react with NaAOT/toluene at 130 °C. 

Recently, cobalt hollow nanospheres were successfully used in stereoselective Mizoroki-Heck-type reactions of acrylates with aryl bromides and iodides [49]. The recyclable catalyst was most efficient when using NMP and K2CO3 as solvent and base respectively (Scheme 10.23). 

Wang, G.H., Hilgert, J., Richter, F.H., Wang, F., Bongard, H.J., Spliethoff, B., Weidenthaler, C., Schuth, F., 2014. Platinum—cobalt bimetallic nanoparticles in hollow carbon nanospheres for hydrogenolysis of 5-hydroxymethylfurfural. Nature Materials 13, 293—300. 

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