Synthesis and Reactivity of Paramagnetic Nickel Polypyridyl Complexes Relevant to C(sp2 )-C(sp3 )Coupling Reactions.

A number of new transition metal catalyzed methods for the formation of C(sp2 )-C(sp3 ) bonds have recently been described. These reactions often utilize bidentate polypyridyl-ligated Ni catalysts, and paramagnetic NiI halide or aryl species are proposed in the catalytic cycles. However, there is little knowledge about complexes of this type. Here, we report the synthesis of paramagnetic bidentate polypyridyl-ligated Ni halide and aryl complexes through elementary reactions proposed in catalytic cycles for C(sp2 )-C(sp3 ) bond formation. We investigate the ability of these complexes to undergo organometallic reactions that are relevant to C(sp2 )-C(sp3 ) coupling through stoichiometric studies and also explore their catalytic activity.