TY - JOUR
T1 - Ring-opening polymerization of L-lactide by organotin(IV)alkoxides, R2Sn(OPri)(2): Estimation of the activation parameters
T2 - Estimation of the activation parameters
AU - Chisholm, Malcolm H.
AU - Gallucci, Judith C.
AU - Krempner, Clemens
N1 - Funding Information:
We thank the Department of Energy, Office of Basic Sciences, Chemistry Division for support of this work.
PY - 2007/9/20
Y1 - 2007/9/20
N2 - 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.
AB - 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.
KW - Alkoxides
KW - Catalysis
KW - Lactide polymerization
KW - Tin
UR - http://www.scopus.com/inward/record.url?scp=34548232242&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2007.06.002
DO - 10.1016/j.poly.2007.06.002
M3 - Article
SN - 0277-5387
VL - 26
SP - 4436
EP - 4444
JO - Polyhedron
JF - Polyhedron
IS - 15
ER -