聚氨基酸的活性聚合方法.ppt

Several methods for living polymerization of α-amino acid-N-carboxyanhydrides Traditional initiators of NCAs Primary amines more nucleophilic than basic, are good general initiators for the polymerization of NCA monomers. i.e. CH3(CH2)6N H2 Tertiary amines, alkoxides and other initiators more basic than nucleophilic, can prepare polymers of very high weight where primary amine initiators cannot i.e. (CH3CH2)3N CH3CH2ONa . Mechanisms of NCAs polymerizationinitiated by primary amine Method 1:using zerovalent nickel and cobalt initiators Method 2:high vacuum technique (HVT) Method 2:high vacuum technique (HVT) Method 3: Decreasingthe Reaction Temperature Method 3: Decreasingthe Reaction Temperature NACE nonaqueous capillary electrophoresis (非水相毛细管电泳） Method 4:Primary amine hydrochlorides initiator Method 4:Primary amine hydrochlorides initiator Method 4:Primary amine hydrochlorides initiator Comparison of these methods Method 1:only one group use it in the world Method 2:need very complicated apparatus Method 3:polymerization time too long ( a week) Method 4:commendable Thank you very much! * * Hermann Leuchs First man discovered NCAs Origin of NCAs Syntheses and polymerizations of α-amino acid N-carboxyanhydrides(NCAs) were reported for the first time by Hermann Leuchs in1906. Since that time, these cyclic and highly reactive amino acid derivatives were used for stepwise peptide syntheses but mainly for the formation of polypeptides by ring-opening polymerizations. Application of NCAs in different fields. According to the definition given by the IUPAC Commission on Macromolecular Nomenclature, a living polymerization is a chain polymerization from which chain transfer and chain termination are absent Produce polypeptides with narrow molecular-weight distribut