Reductive depolymerization of plastics catalyzed with transition metal complexes

Herein we summarize the recent efforts of plastic waste management using homogenous transition metal catalysis. Pioneering studies involve the use of pincer type noble metal catalysis, in particular ruthenium and iridium complexes. Recent studies show more sustainable alternatives, including Earth-abundant transition metal catalysis, reusable catalysts, as well as supported single-atom catalysis. So far, organometallic chemists could depolymerize carbonyl-containing polymers such as polyesters, polylactic acids, polycarbonates, and polyamides with hydrogen gas which could be obtained from renewable resources. However, nonhydrolyzable polymers that resist enzymatic hydrolysis seem to be the real challenge of synthetic chemists.