Professur für Makromolekulare Chemie, Department Chemie, Technische Universität Dresden

Polypeptoids from N-Substituted Glycine N-Carboxyanhydrides:

Hydrophilic, Hydrophobic, and Amphiphilic Polymers with Poisson Distribution

Corinna Fetsch, Arlett Grossmann, Lisa Holz, Jonas F. Nawroth, and Robert Luxenhofer

Ring-opening polymerization (ROP) of N-Carboxyanhydrides By ROP, a wide variety of polypeptides and polypeptoids (N-substituted polyglycines, POI) can be obtained[1]-[3]. We recently presented the preparation and characterization

of non-ionic hydrophilic, hydrophobic, and amphiphilic polypeptoids. At that point, we emphasized on the polymerization kinetics to verify the livingness of the ROP of N-

substituted N-carboxyanhydrides and prepared amphiphilic block copolymers[4]. Here, we want to summarize results, which illustrate how robust the ROP of N-substituted

NCAs is[5]. The synthetic versatility and definition with main chain degradability makes POI attractive as next generation biomimetic (bio)materials.

References

Acknowledgement

This poster is based on work supported by Award No. KUK-F1-029-32, made

by King Abdullah University of Science and Technology (KAUST).

Chain extension of Polysarcosine

Figure 5. Schematic representation of chain extension of polysarcosine

Figure 6. MALDI-ToF mass spectra of

the multiblock polysarcosine samples

(block IDs 1 through 10).

Figure 7. Gel permeation

chromatography elugrams of the

multiblock polysarcosine samples

(block IDs 1 through 10) prepared in

this study. Each elugram, starting

from P(Sar)10 represents the

macroinitiator for the polymerization

of the subsequent polymer.

Table 1. Analytical Data of the polysarcosine including all polymerization

steps.

block

ID

Mtheo.a

[kg/mol]

Mnb

[kg/mol] Ðb

Mnc

[kg/mol] Ðc

Mnd

[kg/mol]

1 0.82 0.58 1.52 0.78 1.07 -

2 1.53 1.15 1.26 1.46 1.04 -

3 2.23 1.85 1.20 1.88 1.03 -

4 2.91 2.66 1.14 2.42 1.02 -

5 3.55 3.35 1.12 2.81 1.02 -

6 4.14 4.13 1.08 3.37 1.02 -

7 4.70 4.64 1.08 3.75 1.01 -

8 5.24 5.14 1.09 4.11 1.01 -

9 5.76 5.46 1.11 4.43 1.01 -

10 6.25 5.96 1.10 4.89 1.01 5.72

aAs calculated from [M]0/[I]0. bAs determined by gel permeation chromatography. cAs

calculated from Gauss distribution fitted to MALDI-ToF mass spectra. dAs determined

by end-group analysis from 1H NMR spectroscopy in D2O (signal intensity of aromatic

protons of benzylamine-initiator vs main-chain and side-chain signal intensity).

The molar masses increase steadily

with the sequential monomer addition

with no evidence of chain transfer

events or termination of chains

throughout the entire experiment.

extraordinary robustness of ROP

Polypeptoids from N-Substituted Glycine

N-Carboxyanhydrides

Figure 1. Schematic representation of prepared homo and block

copolypeptoids.

Figure 2. MALDI-ToF

mass spectra (H+

doping, matrix

dithranol) poly(N-n-

propylglycine)25 with

an overlay of the

respective Gauss (red

curve) and Poisson

distribution (blue

curve).

(1) Kricheldorf, H. R. Angew. Chem. Int. Ed. 2006, 45, 5752.

(2) Deming, T. J. Adv. Polym. Sci. 2006, 202, 1.

(3) Hadjichristidis, N.; Iatrou, H.; Pitsikalis, M.; Sakellariou, G. Chem. Rev.

2009, 109, 5528.

(4) Fetsch, C.; Grossmann, A.; Holz, L.; Nawroth, J. F.; Luxenhofer, R.

Macromolecules 2011, 44, 6746.

(5) Fetsch, C.; Luxenhofer, R. 2012, submitted.

Kinetic Investigations of

Sarcosine-NCA

Figure 3. Linear pseudo-first order kinetic

plots of the polymerization of Sar-NCA

under different conditions.

a) Dependency of the polymerization in N-

methyl-2-pyrrolidinone (NMP) on the

pressure at 20 °C (0.5 M, [M]0/[I]0=50).

b) Comparison of polymerization of Sar-

NCA in NMP (0.5 M, 50 mbar, 20 °C) with

different initiator concentrations.

c) Comparison of different monomers in

NMP ([M]0/[M]t=50, 50 mbar, rt) and

benzonitrile (BN; ([M]0/[I]0=50, 50 mbar,

20 °C).

In all approachs linearity up to high

conversions.

Polysarcosine as

Macroinitiator

Figure 4. Gel permeation elugrams of

the polysarcosine macroinitiator (PSar)

with a second block of a) N-ethylglycine

(PSar-b-EtGly) and b) N-n-propylglycine

(PSar-b-nPrGly), respectively. The

complete shift of signal towards lower

elution times indicates high

macroinitiator efficiency.