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.