Formation of PCP pincer cobalt complexes with cobaltacyclopropane moieties via double C sub(sp) super(3)-H bond activation

The introduction and changes of the substituents at the middle carbon atom of the preligand dipyrrolmethane have a significant impact on the reaction results. When the substituent at the C sub(sp) super(3) atom is a methyl group, the reaction of the preligand with CoMe(PMe sub(3)) sub(4) delivered cobalt(i) complex 2 as a C sub(sp) super(3)-H bond activation product. In the case of ethyl, propyl and pentyl groups, PCP pincer cobalt complexes 3-5 with cobaltacyclopropane moieties were formed via double C sub(sp) super(3)-H bond activation. With iso-propyl as the substituent, cobalt(i) complex 6 as C sub(sp) super(2)-H activation product was obtained.