Yttrium phosphasalen initiators for rac-lactide polymerization: Excellent rates and high iso-selectivities

Clare Blakewell (1) , Thi-Phuong-Anh Cao (2) , Nicholas Long (1) , X. F Le Goff (2) , Audrey Auffrant (2) , Charlotte K Williams (1)

1 Department of Chemistry [Imperial College London]
2 DCPH - Laboratoire Hétéroéléments et Coordination

Highly active yttrium phosphasalen initiators for the stereocontrolled ring-opening polymerization of rac-lactide are reported. The initiators are coordinated by a new class of ancillary ligand: an iminophosphorane derivative of the popular "salen" ligand, termed "phosphasalen". Changing the phosphasalen structure enables access to high iso-selectivities (Pi = 0.84) or hetero-selectivities (Ps = 0.87). The initiators also show very high rates, excellent polymerization control, and tolerance to low loadings; furthermore, no chiral auxiliaries/ligands are needed for the stereocontrol. The combination of such high rates with high iso-selectivities is very unusual.

Keywords: catalyse.; Iminophosphorane; ligand; métal; chimie de coordination; complexes organométalliques; catalyse

Domains: Chemical Sciences; Coordination chemistry

Clare Blakewell, Thi-Phuong-Anh Cao, Nicholas Long, X. F Le Goff, Audrey Auffrant, et al.. Yttrium phosphasalen initiators for rac-lactide polymerization: Excellent rates and high iso-selectivities. Journal of the American Chemical Society, 2012, 134 (51), pp.20577-20580. ⟨10.1021/ja310003v⟩. ⟨hal-00906007⟩