Primary ammonium/tertiary amine-mediated controlled ring opening polymerisation of amino acid N-carboxyanhydrides.

TLDR: Stable commercial primary ammonium chlorides were combined with tertiary amines to initiate the controlled ring opening polymerisation of amino acid N-carboxyanhydrides to yield polypeptides with defined end group structure, predetermined molar mass and narrow molarmass distribution.

About: This article is published in Chemical Communications.The article was published on 2015-10-15 and is currently open access. It has received 43 citations till now. The article focuses on the topics: Tertiary amine & Molar mass distribution.

Figures

Fig. 4 Time-conversion plots for the polymerisations of (a) BLG–NCA (100 equiv.) and (b) LLeu–NCA (100 equiv.) in DMF initiated by BnA HCl (1 equiv.), BnA HCl/TEA (1 : 0.5 equiv.), BnA (1 equiv.), and TEA (0.5 equiv.). Monomer conversions were determined by FT-IR spectroscopy (see ESI†); numbers in (a) are the polymer dispersities determined by SEC.

Fig. 3 Polymerisation of BLG–NCA (150 equiv.) in DMF initiated by PyA HCl/TEA (1 : 0.5 equiv.), paused at 24 h by adding HCl and resumed at 81 h by adding TEA. (a) time-conversion plot, (b) number-average molar mass and dispersities (at 24 h, 81 h, 120 h, and 168 h) determined by SEC.

Fig. 2 SEC traces (RI in black, UV340nm in purple) of polymerisations of BLG–NCA (150 equiv.) in DMF initiated by (a) PyA HCl/TEA (1 : 1.1) at (top to bottom) 2 h, 6 h, 10 h, 24 h; (b) PyA HCl/TEA (1 : 1.5) at (top to bottom) 2 h, 6 h, 8 h, 24 h; the peak (*) is a high molar mass polystyrene (PS2M, 2 MDa) used as internal standard for calculating the monomer conversion (ESI†).

Fig. 1 SEC traces of PBLGs obtained during the polymerisations of BLG–NCA (150 equiv.) in DMF initiated by (a) TAB 3HCl (1 equiv.), r.t.; (b) TAB 3HCl (1 equiv.), 50 1C; (c) TAB 3HCl/TEA (1 : 0.5 equiv.), r.t.; and (d) TEA (0.5 equiv.), r.t.; the peak (*) is a high molar mass polystyrene (PS2M; 2 MDa) used as internal standard for calculating the monomer conversion (ESI†).