Reports: UR351716-UR3: Ligands for the Cobalt-Catalyzed Dimerization of Alpha Olefins
Richard D. Broene, Bowdoin College
Isonitrile Ligands
We optimized the synthesis Cp*Co(ethene)(isocyanide) complexes 1 using 4- methoxyphenylisonitrile. Isolation of the mono isocaynide, mono ethene complexes were highly dependent upon the reaction conditions and cobalt catalyst purity: even trace amounts of the Cp*Co(ethene)2 precursor, Cp*Co(CO)I2, resulted in the polymerization of the isonitrile. Optimal conditions included hydrocarbon solvents at short reaction times, wherein the poorly soluble product precipitated from solution. Solvent removal under vacuum was strongly associated with the formation of a green colored product tentatively assigned as dimer 2. Addition of HBArF to 1 resulted in a cationic complex, which will be tested for terminal alkene dimerization.
Figure 1. Crystal Structure of 1 and proposed structure of 2.