A switch from carbanions to aza-anions is performed by the addition of N-tosylaziridine (TAz) to living poly(styryl) (PS) chains. This is the first example of carbanionic aziridine ring-opening which was previously activated by amidation with a tosyl group to enable nucleophilic ring-opening by the living chain end. Poly(styrene)-tosylaziridines (PS-TAz) with narrow molecular weight distributions and variable molecular weights are synthesized. The removal of the tosyl group and subsequent functionalization is shown, evidencing quantitative transfer to azaanionic species. All polymers are characterized in detail by (1) H NMR spectroscopy, DOSY (1) H NMR spectroscopy, and size exclusion chromatography (SEC). This strategy allows the introduction of amine groups via anionic polymerization in analogy to the well-established epoxide termination.
Vinyl ferrocenyl glycidyl ether (VfcGE) is the first ferrocene-based, orthogonal monomer for both anionic and radical polymerization to generate polyvalent and redox-active materials.
Summary: 2-(Oct-7-en-1-yl)-N-mesylaziridine was used as a novel monomer for the anionic ring-opening polymerization. This is the first functional aziridine-derivative that can be polymerized via an anionic mechanism. Homo-and copolymers with (2-n-decyl-N-mesylaziridine) were synthesized and characterized via NMR spectroscopy and SEC. Molecular weight distributions were all monomodal and very narrow (M w /M n < 1.1). The pendant double bonds were functionalized with a protected cysteine derivative as a model for potential bioconjugation.
Redox-responsive poly(ferrocenylsilane) (PFS) is used to construct nanocontainers that can be loaded with hydrophobic cargo by a miniemulsion approach. The resulting structures comprise a solid shell surrounding a liquid oil core and have diameters of approximately 470 nm with a shell thickness of ca. 29 nm. The electrochemical behavior of the ferrocene group is investigated using cyclic voltammetry. Electrochemical oxidation and the thereby caused change of container morphology are shown. Hydrophobic molecules (Nile Red and 2-propylpyiridine) are loaded into the nanocontainers and can be released upon oxidation of the shell material. The oxidation is achieved chemically by the addition of hydrogen peroxide or by the enzymatic oxidation of glucose to release 2-propylpyridine over a period of time.
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