Variably Isotactic Poly(hydroxybutyrate) from Racemic β‐Butyrolactone: Microstructure Control by Achiral Chromium(III) Salophen Complexes

ROP artists: The ROP of racemic β-butyrolactone (BL) catalyzed by highly active chromium(III) salophen complexes 1 gives poly(hydroxybutyrate) (PHB) with high molecular weight and with isotacticities of 60–70 %. The product is a biodegradable polymer material with mechanical properties that can be varied from crystalline to thermoplastic. DFT calculations indicate that the induction of stereochemical information occurs through the formation of dimeric cagelike structures.