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BIGUANIDE METAL COMPLEXES AS EFFICIENT ROP CATALYSTS FOR SUSTAINABLE (CO-)POLYMERS
Autoři: Vlk Lukáš | Chlupatý Tomáš | Théron Benjamin | Breilly Damien | Růžičková Zdeňka | Malacea-Kabbara Raluca | Le Gendre Pierre | Růžička Aleš
Rok: 2025
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng BIGUANIDE METAL COMPLEXES AS EFFICIENT ROP CATALYSTS FOR SUSTAINABLE (CO-)POLYMERS One of the biggest drawbacks in modern polymer chemistry is the heavy impact of current petrol-based plastics on the environment both in terms of origin and the after-use waste processing. Hence, efforts to replace these materials with bio-degradable polymers are underway, with the family of cyclic esters – most prominently lactide available from renewable natural sources – emerging as a viable alternative.1 However, by far the most common industrial catalyst for ring-opening polymerization (ROP) of lactide to polylactic acid (PLA) is tin octoate, which has been determined as toxic. A suitable replacement has not been yet introduced, although several transition or main group metal compounds (oxides, alkoxides and a plethora of complexes) were used for ROP of lactide in recent years. One of the most active systems employed an N-donor multidentate ligands stabilizing metal amides.2 Our research in recent years has developed a capable ligand platform for controlled structural arrangement of multimetallic guanidinate/biguanide complexes. The first trial tests showed promising activity and control of some compounds in ROP of lactide. After pursuing this route, we were able to tailor exceptional Mg and Zn-based catalysts for ROP of cyclic esters, demonstrated on monomers like lactide, ε-caprolactone, β-butyrolactone and trimethylenecarbonate. The highly active and robust species were able to polymerize several thousand equivalents of the monomer in minutes at room temperature. The most efficient catalysts surpassed turn-over frequencies of 60 000 h-1 in lactide ROP. Moreover, di- and triblock co-polymers of some combinations of rac-, L-, D-lactide, ε-caprolactone and β-butyrolactone were obtained in immortal catalytic conditions, showcasing the power of a truly universal, active and immortal catalyst. biguanide metal complexes; ROP catalysis; sustainable (co-)polymers; main group metal catalysis; tunable metal-metal cooperation