Highly efficient catalysts‐acetylacetonato complexes of transition metals in the 4th period for ring‐opening polymerization of 1,3‐benzoxazine

Abstract Acetylacetonato (acac) complexes of transition metals in the 4th period were examined as catalysts for the ring‐opening polymerization of benzoxazine. This examination revealed that acac complexes of manganese, iron, and cobalt exhibited the highest activity, which was comparable or slightly higher than that exhibited by p ‐toluenesulfonic acid. By replacing acac ligand by hexafluoroacetylacetonato (F 6 ‐acac) ligand, the activity of manganese and iron complexes was remarkably enhanced. These metal F 6 ‐acac complexes were tolerant to moisture to allow their use under air without special caution. Another advantage was their negligible effect to promote unfavorable weight loss during the polymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 479–484, 2010