A Convenient Synthesis of a Ru(bpy)3-based Catenane-type Triad and Its Incorporation into a Protein Scaffold

A catenated heme cofactor consisting of a donor (protoheme), a sensitizer (Ru(2,2′-bipyridine)3) and an acceptor (cyclobis(paraquat-p-phenylene) was prepared by stepwise coordination, followed by iron-insersion. Reconstitution of apo-myoglobin with this cofactor afforded a protein-based, noncovalently-linked photosynthetic triad.