Ring-opening polymerization of L-lactide efficiently triggered by an amido-indole. X-ray structure of a complex between L-lactide and the hydrogen-bonding organocatalyst

J Am Chem Soc. 2009 Oct 28;131(42):15088-9. doi: 10.1021/ja906119t.

Abstract

N-(3,5-Bis(trifluoromethyl)phenyl)-1H-indole-2-carboxamide 1e is an efficient hydrogen-bonding organocatalyst for the ring-opening polymerization of l-lactide. This new catalytic species does control the dispersity (1.08) and molecular weight (3460 g/mol vs 3064 in theory) of the poly(l-lactides) prepared in 2 h. (1)H NMR analysis showed that compound 1e complexes l-lactide in CDCl(3) through the two available NH groups (amide and indole). In particular, the catalytic species appeared to be mainly the H-bonding donor amide (1e in extended conformation, alone or dimer (1e)(2)) and, to a lesser extend, the dual H-bonding amido-indole (1e in its the pinched conformation). The first X-ray structure of the complex between a H-bonding organocatalyst and l-lactide also revealed a tight H-bonded network between the dimer (1e)(2) and l-lactide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides / chemistry*
  • Catalysis
  • Crystallography, X-Ray
  • Dioxanes / chemistry*
  • Hydrogen Bonding
  • Indoles / chemistry*
  • Models, Molecular
  • Molecular Structure

Substances

  • Amides
  • Dioxanes
  • Indoles
  • indole
  • dilactide