Amine-terminated polystyrene

Another interesting example belonging to the same general principle was described by Graham (56). On one hand he prepared an amine terminated polystyrene (sodium amide initiation in liquid ammonia) and showed that it contained only one terminal primary amine group per polymer chain. On the other hand copolymers were prepared by free-radical initiated solution copolymerization of small amounts of /S-iso-cyanatoethyl methacrylate with several other monomers as methyl, butyl and lauryl methacrylates, acrylonitrile and styrene. 

Graham, R. K. Preparation of graft copolymers by the reaction of primary amine-terminated polystyrene with copolymers containing /3-isocyanatoethyl methacrylate. J. Polymer Sci. 24, 367 (1957). 

Although benzyllithium has been aminated to 97% yield using these reagents- attempted amination of poly(styryl)lithium (IVI = 2 x 10 ) was achieved with only 5 % efficiency using literature procedures After extensive modification of those procedures, poly(styryl)Iithium has been aminated with 92% efficiency using a twofold excess of methoxyamine/methyllithium . In addition, pure 1 ° amine-terminated polystyrene can be isolated by silica gel chromatography since it is easily separated from the unaminated polymer. 

Gallot et al. published one of the earliest reports on the preparation of PLL-based hybrid block copolymers. The synthetic segments in these copolymers were primary amine-terminated polystyrene or polybutadiene that were used to initiate the ROP of ZLL-NCA. The authors intended to use the hybrid conjugates as a model for biological membranes. In the following years, several reports emerged on the synthesis of PLL hybrid block copolymers based on macroinitiators prepared by vinyl monomer polymer-ization. ° The pH and temperature dependence of the copolymer vesicles formed in solution was investigated. ... 

The facile addition of primary and secondary amines to Cjq has been used to synthesize polymer-bound Cjq [126-133]. Solutions of precursor polymers containing primary amino groups in the side chain or secondary amino groups in the main chain [132] were allowed to react with CgQ in a "buckybalT fishing process. Fullerene end capped polymers (type V) are accessible by reaction of amino-terminated polystyrene [128], poly(ethylene glycol) or poly(propylene glycol) [129] with Cgo. 

These results indicate that if polydienes and similar polymers can be prepared quantitatively with tertiary amine terminal groups, then they can be combined with other halogen functional polymers using established techniques to create interesting new block copolymer systems. For example, consider the reaction between telechelic pyridine terminated polybutadiene and monofunctional bromine terminated polystyrene (equation 4) -the latter has been prepared in 95% yield. >it The product would be an ABA... 

Polypropylene imine) dendrimers (see Scheme 1 for structure) have been constructed step by step onto an amine functionalized polystyrene [38, 130, 131]. The challenge in this synthesis is finding conditions for the polypropylene imine) synthesis under which the low MW polystyrene (MW=3200) is soluble [38]. Similar poly(imine) dendrimers with carboxylic acid end groups have also been prepared [130]. The polypropylene imine) dendrimer has also been synthesized on an amino-terminated poly(2-methyl-2-oxazoline) [132]. 

Reynhout et al. [52] recently published a completely solid phase method for the synthesis of peptide-based triblock copolymers. Amine-functionalized polystyrene was first coupled to an aldehyde-modified resin to give a polystyrene functionalized secondary amine on the resin, which could then be coupled to the next amino acid (Fig. 11). Then the sequence Gly - Ala - Asn -Pro - Asn - Ala - Ala - Gly (GANPNAAG)—a known -hairpin folding peptide found in the CS protein of the Malaria parasite plasmodium falciparum— was synthesized, using standard Fmoc peptide chemistry. After removing the final Fmoc group from the peptide, a carboxylic acid-functionalized polystyrene was coupled to the terminal amine. 

Telechelic a,CD-bis(dimethylamino)-terminated polystyrene was prepared by first reacting s c-butyllithium with 24 to form an amine-functionalized initiator, 25 a-dimethylaminopoly (styryl)lithium, 26, was prepared by initiating styrene polymerization with 25 as shown in Scheme The living,... 

Bidentate ligands were used by Alper and coworkers. The bis(diphenylphospino-methyl)amine ligands were prepared on primary amine-terminated PAMAM dendrons on silica as well as polyamido dendrons on polystyrene via the double Mannich-like reaction with formaldehyde and diphenylphosphine (Scheme 15.36a). " Subsequently, Alper and coworkers subjected the dendronized ligand-decorated supports to complexation with rhodium and palladium precursors in order to prepare active catalysts for a number of important chemical transformations (Scheme 15.36b). Initially, the dendronized rhodium catalysts were tested in the hydroformylation reaction and carbonylative ring expansion of... 

Low molecular weight reactants such as phthalic anhydride and dimethylsuccinic anhydride were used as model compounds for trimellitic anhydride terminated polystyrene and styrene-maleic anhydride (SMA) copolymer. As amine functional species, benzyl-amine and 1,2 diphenylethylamine, were employed, the transposal of the knowledge gained from model compounds to a real polymer blend system reacted in the melt under shear was only slightly instmctive. The low reactivity observed in the case of the reactive polymers has been ascribed to a chemically different environment and not to a diffusion-controlled process as is generally considered. 

Aside from encapsulation of proteins, much work has been done on the surface functionalization of microparticles for cellular interaction and proliferative effects. Surface modification of PLGA micro-spheres with an amine-terminated dendrimer improved long-term proliferation of chondrocytes without observed changes in the cell phenotype, as compared to monolayer culture systems (Thissen et al. 2006). Additionally, surface functionalization of polystyrene magnetic microbeads with the DLL4 notch ligand used in coculture has been shown to efficiently generate T cells from mouse bone marrow hematopoietic stem cells (Taqvi et al. 2006). 

Amines can add to C50. An early paper showed that up to 15 amine molecules may be added to the fullerene, but the hexa-adduct with the chains attached to the central double bond of the six pyracyclene unit constituting the Qo seems favored [32]. This addition has been used to graft Qo on poly(ethylene imine) and poly(4- [(2-aminoethyl)imino]methyl styrene) [33] or amine functionalized ethylene propylene terpolymer [34] to obtain sidefullerene polymers. Amino-terminated polystyrene with very narrow molar mass distributions, synthesized using amonic polymerization followed by end functionalization, can add to Coo to form multiarm stars (Scheme 5.7). Even, if a ratio C60/PS-NH2 of 2 1 is used in order to favor the mono-adduct, about 20% of di-adducts as well as small amounts of higher adducts are obtained [35]. 

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