Tetraphenylporphyrin (Chlorin free)

Typical Procedure:
The flask containing tetraphenylporphine ((TPP)H₂)(1.0 mmol) is purged with dry N₂, and then CH₂Cl₂ (20 mL) is introduced to dissolve (TPP)H₂. To this solution is added Et₂AlCl (1.2 mmol, 20% excess to (TPP)H₂) by syringe under a N₂ atmosphere at room temperature with stirring. After a definite time, the volatile materials are removed from this reaction mixture under reduced pressure to give a purple solid (TPP)AlCl) with metallic luster. CH₂Cl₂ (20 mL) is introduced to this flask to dissolve the product, to obtain the catalyst solution.
To the catalyst solution ((TPP)AlCl 20.4 mM) with stirring is added β-propiolactone (6.12 mol) by syringe at room temperature in a N₂ atmosphere. After a definite time, a large excess of methanol is added to the reaction mixture to stop the polymerization, and then volatile materials are removed under reduced pressure to leave the product. The polymer is isolated as a slightly yellow-green powder by precipitation of the product from chloroform/methanol after shaking the chloroform solution with dilute hydrochloric acid.
The gel permeation chromatogram (GPC) of the resulting polymer shows the weight average molecular weight to the number average molecular weight (Mw/Mn) : 1.26 and the number average molecular weight (Mn) : 3500.