Synthesis of a chlorin with annelated lactam ring as subunit for artificial photosynthetic reaction centres

A chlorin with an annelated cyclic ketone moiety was synthesized from a tricyclic nickel complex and appropriate pyrrole building blocks. Ketone functionality of the target chlorin allows Beckmann rearrangement to yield chlorin lactams. Lactam moieties on the chlorin represent masked amino acid structures which should allow formation of peptide-like backbones, along which chlorin pigments are arranged. Due to the natural chlorin chromophores and the peptide backbone the devices should represent artificial mimetics of natural photosynthesis systems.