Preparation of Functionalized Organometallic Metal–Metal Bonded Dimers Used in the Synthesis of Photodegradable Polymers

This review describes the synthesis of functional dimeric metal carbonyl complexes and their subsequent polymerization to afford polymers containing metal–metal bonds in the main chain. Such polymers are photodegradable because the metal–metal bonds are cleavable by visible light. The functionalization of the dimeric complexes and their polymerization is challenging due to the reactivity of the M–M bond, and therefore many standard synthesis and polymerization methods cannot be used. Various polymerization methods are discussed including ring-opening metathesis polymerization, acyclic diene metathesis polymerization, ring-opening polymerization, traditional step polymerization, and copper-catalyzed step polymerization using click chemistry.