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.
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.
Universite de Bordeaux, UMR CNRS 5255, 351 Cours de la Liberation, 33405 Talence, France.
Sylvain
S
Koeller
Joji
J
Kadota
Alain
A
Deffieux
Frédéric
F
Peruch
Stéphane
S
Massip
Jean-Michel
JM
Léger
Jean-Pierre
JP
Desvergne
Brigitte
B
Bibal
D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004146:Dioxanes / Q000737:chemistry*; D006860:Hydrogen Bonding; D007211:Indoles / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure
D000577:Amides; D004146:Dioxanes; D007211:Indoles; C030374:indole; C091880:dilactide