(5,10,15,20-Tetraphenylporphyrinato)manganese acetate as a novel initiator for the ring-opening polymerization of 1,2-epoxypropane

(5,10,15,20-Tetraphenylporphyrinat o)manganese acetate (2) was found to bring about the ring-opening polymerization of 1,2-epoxypropane (3) (R² = CH₃) under mild conditions to give the polymer with a bimodal molecular weight distribution consisting of a sharp main peak and a small shoulder on the higher molecular weight side. The polymerization was found to proceed even in the presence of a protic compound such as an alcohol or a carboxylic acid to give the polymer with a unimodal very narrow molecular weight distribution. The number of the polymer molecules is in good agreement with the sum of those of 2 and the protic compound, demonstrating the “immortal” nature of polymerization.