Center for Molecular Modeling - B. Monnery

Synthesis of poly(2-oxazoline)s with side chain methyl ester functionalities: Detailed understanding of copolymerization behavior of methyl ester containing monomers with 2-alkyl-2-oxazolines

michel — Mon, 23 Mar 2015 09:25:40 +0000

P. Bouten, D. Hertsen, M. Vergaelen, B. Monnery, S. Catak, J. van Hest, V. Van Speybroeck, R. Hoogenboom

Journal of Polymer Science Part A: Polymer Chemistry

7 (17), 2711-2719

2015

Abstract

Poly(2-oxazoline)s with methyl ester functionalized side chains are interesting as they can undergo a direct amidation reaction or can be hydrolyzed to the carboxylic acid, making them versatile functional polymers for conjugation. In this work, detailed studies on the homo- and copolymerization kinetics of two methyl ester functionalized 2-oxazoline monomers with 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, and 2-n-propyl-2-oxazoline are reported. The homopolymerization of the methyl ester functionalized monomers is found to be faster compared to the alkyl monomers, while copolymerization unexpectedly reveals that the methyl ester containing monomers significantly accelerate the polymerization. A computational study confirms that methyl ester groups increase the electrophilicity of the living chain end, even if they are not directly attached to the terminal residue. Moreover, the electrophilicity of the living chain end is found to be more important than the nucleophilicity of the monomer in determining the rate of propagation. However, the monomer nucleophilicity can be correlated with the different rates of incorporation when two monomers compete for the same chain end, that is, in copolymerizations. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015

DOI

http://dx.doi.org/10.1002/pola.27733

Private attachment

15_JPolymerScienceA_xxxx_Bouten.pdf

Accelerated living cationic ring-opening polymerization of a methyl ester functionalized 2-oxazoline monomer

dietmar — Wed, 19 Nov 2014 15:41:28 +0000

P.J.M. Bouten, D. Hertsen, M. Vergaelen, B. Monnery, M.A. Boerman, H. Goossens, S. Catak, J.C.M. van Hest, V. Van Speybroeck, R. Hoogenboom

Polymer Chemistry

6, 514-518

2015

Abstract

Kinetic studies on the homo- and copolymerization of 2-methoxycarboxyethyl-2-oxazoline (MestOx) with 2-methyl-2-oxazoline (MeOx) and 2-ethyl-2-oxazoline (EtOx) were performed. For the homopolymerisation of MestOx an increased propagation rate constant was observed compared to MeOx and EtOx while the copolymerization of MestOx with MeOx or EtOx unexpectedly revealed slower incorporation of MestOx. Density functional theory (DFT) calculations show that nearby MestOx residues in the living chain can activate both the oxazolinium chain end and the attacking monomer, stabilizing the propagation transition state, leading to faster homopolymerisation of MestOx. These effects also accelerate incorporation of both monomers in the copolymerisations. However, since MeOx is shown to be more nucleophilic than MestOx, the incorporation order is reversed in the copolymerisations.

Open Access version available at UGent repository

DOI

http://dx.doi.org/10.1039/C4PY01373E

Private attachment

14_Polym-Chem_2015_6_514_Bouten.pdf

Cationic ring-opening polymerization of 2-propyl-2-oxazolines: Understanding structural effects on polymerization behavior based on molecular modeling

wim — Mon, 10 Jun 2013 13:23:46 +0000

H. Goossens, S. Catak, M. Glassner, V. De La Rosa, B. Monnery, F. De Proft, V. Van Speybroeck, R. Hoogenboom

ACS Macro Letters

2, 651-654

2013

Abstract

The surprising difference in the cationic ring-opening polymerization rate of 2-cyclopropyl-2-oxazoline versus 2-n-propyl-2-oxazoline and 2-isopropyl-2-oxazoline was investigated both experimentally and theoretically. The polymerization kinetics of all three oxazolines were experimentally measured in acetonitrile at 140 °C, and the polymerization rate constant (kp) was found to decrease in the order c-PropOx > n-PropOx > i-PropOx. Theoretical free energy calculations confirmed the trend for kp, and a set of DFT-based reactivity descriptors, electrostatics, and frontier molecular orbitals were studied to detect the factors controlling this peculiar behavior. Our results show that the observed reactivity is dictated by electrostatic effects. More in particular, the charge on the nitrogen atom of the monomer, used to measure its nucleophilicity, was the most negative for c-PropOx. Furthermore, the electrophilicity of the cations does not change substantially, and thus, the nucleophilicity of the monomers is the driving factor for kp.

DOI

http://dx.doi.org/10.1021/mz400293y

Private attachment

13_ACSMacroLetters_2,651_Goossens.pdf

Cationic ring-opening polymerization of 2-propyl-2-oxazolines: understanding structural effects on polymerization behavior based on molecular modeling

samuel — Thu, 06 Feb 2020 11:22:09 +0000

M. Glassner, H. Goossens, S. Catak, V. De La Rosa, B. Monnery, F. De Proft, V. Van Speybroeck, R. Hoogenboom

ISBN/ISSN:

Talk

Conference / event / venue

248th National Meeting of the American-Chemical-Society (ACS 2014 )

San Francisco, CA

Sunday, 10 August, 2014 to Thursday, 14 August, 2014

Theoretical Rationalization of the Propagation Rate Order of 2-Methyl-2-oxazoline and a Methyl Ester Functionalized 2-Oxazoline in Cationic Ring-opening Polymerizations

dietmar — Wed, 19 Nov 2014 15:33:29 +0000

D. Hertsen, S. Catak, H. Goossens, P.J.M. Bouten, B. Monnery, V. Van Speybroeck, R. Hoogenboom

ISBN/ISSN:

Poster

Conference / event / venue

XIth Chemical Physics Congress (CPC-XI)

Istanbul, Turkey

Friday, 17 October, 2014 to Saturday, 18 October, 2014

Abstract (private)

CPC11-Saron Catak-final.pdf

Theoretical Rationalization of the Cationic Ring-opening Polymerization of a Methyl Ester Functionalized 2-Oxazoline Monomer

dietmar — Wed, 19 Nov 2014 15:28:06 +0000

D. Hertsen, H. Goossens, S. Catak, P.J.M. Bouten, M. Vergaelen, B. Monnery, J.C.M. van Hest, R. Hoogenboom, V. Van Speybroeck

ISBN/ISSN:

Poster

Conference / event / venue

Annual IAP Meeting (P7/05)

Louvain-La-Neuve, Belgium

Friday, 19 September, 2014

Abstract (private)

poster_abstract.pdf