952516-06-2Relevant academic research and scientific papers
Ring-opening polymerization of l-lactide by organotin(IV)alkoxides, R2Sn(OPri)2: Estimation of the activation parameters
Chisholm, Malcolm H.,Gallucci, Judith C.,Krempner, Clemens
, p. 4436 - 4444 (2008/10/09)
The ring-opening polymerization of l-lactide, l-LA, to give poly-l-lactide by R2Sn(OPri)2 compounds, where R = Bun and p-XC6H4 (X = CF3, F, H, Me and OMe) has been studied in benzene over a temperature range. There is a relatively small variation in ΔH≠ as a function of R with all the values falling within the range 11 ± 2 kcal mol-1. The entropy of activation, ΔS≠, is consistently large and negative, -50 ± 5 eu, supporting the view that the ring-opening event, the enchainment step involves a highly ordered transition state. The crystal and molecular structures of the compounds Ph2Sn(OPri)2, (p-FC6H4)2Sn(OPri)2 and (p-Me2NC6H4)3SnOPri are also reported. While the latter compound is monomeric in the solid state the former are both dimeric with a pair of bridging OPri ligands.
