architectural control of isosorbide-based polyethers via

O

OO

O

OO

O

OO1

2

O

OO3

4

O[Sc]

O [Sc]

O

[Sc]

δ+O

[Sc]

O

OOδ+

b

a ΔG‡1 = 29.7 kcal mol–1

ΔG‡2 = 27.5 kcal mol–1

b

a

ΔG‡3 = 24.2 kcal mol–1

ΔG‡4 = 23.0 kcal mol–1

Architectural control of isosorbide-based polyethers via ring-opening polymerizationDerek J. Saxon, Mohammadreza Nasiri, Mukunda Mandal, Saurabh Maduskar, Paul J. Dauenhauer, Christopher J. Cramer, Anne M. LaPointe, and Theresa M. Reineke

We thank the NSF Center for Sustainable Polymers (CHE-1413862) for financial support.

References: (1) Saxon, D. J.; Nasiri, M.; Mandal, M.; Maduskar, S.; Dauenhauer, P. J.; Cramer, C.J.; LaPointe, A. M.; Reineke, T. M. J. Am. Chem. Soc. 2019, 141, 5107. (2) Fenouillot, F.;Rousseau, A.; Colomines, G.; Saint-Loup, R.; Pascault, J.-P. Prog. Polym. Sci. 2010, 35, 578. (3)Cope, A. C.; Shen, T. Y. J. Am. Chem. Soc. 1956, 78, 5912. (4) You, L.; Hogen-Esch, T. E.; Zhu, Y.;Ling, J.; Shen, Z. Polymer 2012, 53, 4112.

Monomer Synthesis + Initial Screening

Conclusions + Future Directions

Ring-Opening Polymerization + Architectural Control

Note: SGP = step-growth polymerization; RP = radical polymerization; ROP = ring-opening polymerization

Motivation + Goals

Computational Selectivity of Bridgehead vs Terminal Ether

Acknowledgements

ROP

O

OO

O

OO

H

H

O = bridgehead; O = terminal

5

• mild, catalytic conditions » architectual control

This work

O

OHO

OH

H

H

RP

SGP

O

OO

O

H

HR

OO

O

OR

O

H

H

ROP

• energy intensive• limited control

• oligomers only (DP ~ 5)• undesirable crosslinking

• non-degradable backbone

Previous work

OO O

O O

O

OHO

OHO

OAcO

OH

H

H

P. fluorescens

acetonert, 24 h

H

H

OAcK2CO3

MeOHrt, 10 min

O

OAcO

OTsTsCl, py

rt, 24 h

H

H

99% 70%

High-throughput screening• ~ 250 polymerizations• Identified cationic ROP • Mn up to 10 kg mol–1

O

OOR1

H

H

O

OO OR2

O

OO

Me

O

OO

Me

O

OO1

2

O

OO3

4

TfOMeOTf

ΔG‡1 = 30.4 kcal mol–1

ΔG‡2 = 32.1 kcal mol–1

O

OO MeOTf

ΔG‡3 = 29.1 kcal mol–1

ΔG‡4 = 28.7 kcal mol–1

TfO

We aim to exploit the structureand functionality of isosorbide toemploy controlled polymerizationunder mild conditions to designrenewable materials.Project Goals:

1. Prepare annulated derivative2. Exploit computation + high-

throughput screening3. Control polymer architecture

ü Renewable / non-toxicü Versatile functionalityü High Tg polymers with

good optical clarity

O

OO

OH

H

Classical initiatorLewis acid + epoxide

Theory: M06-2X/6-311+G(d,p)//M06-L/6-31+G(d,p) at 298.15 K

Quasi-zwitterionic control (MeOTf + PO):

Developed a platform for tailored polymer architectures from isosorbide via ring-opening polymerizationü High-yielding monomer synthesis requiring minimal purificationü High-throughput screening + computation informed follow-up workü Control over macromolecular architectureü Recycle unreacted monomer via sublimationOngoing and future work: (i) target high Mn polymers, (ii) access statistical/block copolymers, and (iii) study thermal + mechanical properties

70% cyclicpolymers 100% linear

polymers

85% linearpolymers!

Ring-opening selectivity (1H NMR):

isosorbide

PO-initiated polyether

–15.2 kcal mol–1 –9.1 kcal mol–1∆H =

bridgeheadfavored

O

OHO

OTs

H

H O

OOKOtBu

THFrt, 3 h

KOH

300 ºC

97% 89% (KOtBu)≥95% selectivity (KOH)

ROP