Supporting Data for “Why So Slow? Mechanistic Insights from Studies of a Poor Catalyst for Polymerization of ε-Caprolactone”

  • Chris Cramer (Creator)
  • Mukunda Mandal (Creator)
  • Lauren A Mitchell (Creator)
  • Benjamin D Neisen (Creator)
  • Daniel E Stasiw (Creator)
  • William Tolman (Creator)



These files contain data along with associated output from instrumentation supporting all results reported in Stasiw, D. E.; Mandal, M.; Neisen, B. D.; Mitchell, L. A.; Cramer, C. J.; Tolman, W. B. Why so slow? Mechanistic insights from studies of a poor catalyst for polymerization of ε-caprolactone. Inorg. Chem., 2016, 56, 725–728. Polymerization of ε-caprolactone (CL) using an aluminum alkoxide catalyst (1) designed to prevent unproductive trans binding was monitored at 110 °C in toluene-d8 by 1H NMR and the concentration versus time data fit to a first-order rate expression. A comparison of t1/2 for 1 to values for many other aluminum alkyl and alkoxide complexes shows much lower activity of 1 toward polymerization of CL. Density functional theory calculations were used to understand the basis for the slow kinetics. The optimized geometry of the ligand framework of 1 was found indeed to make CL trans binding difficult: no trans-bound intermediate could be identified as a local minimum. Nor were local minima for cis-bound precomplexes found, suggesting a concerted coordination–insertion for polymer initiation and propagation. The sluggish performance of 1 is attributed to a high-framework distortion energy required to deform the “resting” ligand geometry to that providing optimal catalysis in the corresponding transition-state structure geometry, thus suggesting a need to incorporate ligand flexibility in the design of efficient polymerization catalysts..

Corresponding author for experimental data is William B. Tolman (

Corresponding author for computational data is Christopher J. Cramer (
Date made available2017
PublisherData Repository for the University of Minnesota

Cite this

Cramer, C. (Creator), Mandal, M. (Creator), Mitchell, L. A. (Creator), Neisen, B. D. (Creator), Stasiw, D. E. (Creator), Tolman, W. (Creator) (2017). Supporting Data for “Why So Slow? Mechanistic Insights from Studies of a Poor Catalyst for Polymerization of ε-Caprolactone”. Data Repository for the University of Minnesota. 10.13020/D6F60H