Functionalized pendant group

This article summarizes and analyzes the results obtained for the anionic copolymerization of cyclic ethers with cyclic anhydrides. This reaction is of great practical importance, especially as curing reaction of epoxy resins and is also used for the preparation of linear polyesters with special functional pendant groups. 

An important advantage of the use of such added nucleophiles is that it allows controlled/living cationic polymerization of alkyl vinyl ethers to proceed at +50 to +70°C [101,103], relatively high temperatures at which conventional cationic polymerizations fail to produce polymers but result in ill-defined oligomers only, due to frequent chain transfer and other side reactions. Recently, initiators with functionalized pendant groups [137] and multifunctional initiators [ 138—140] have been developed for the living cationic polymerizations with added nucleophiles. 

Almost all of the initiating systems discussed in this section can be applied to the living cationic polymerizations of vinyl ethers that carry a variety of functional pendant groups, in a general form [42,43,65,66,180] ... 

This method involves the use of functional initiators with a protected or unprotected functional group. When the functional group is unreactive under the polymerization conditions, protection is not necessary. Functional vinyl ethers have extensively been used in the Bving cationic polymerizations of vinyl ethers and these functional poly(vinyl ethers) can be derivatized to the desired functionahty by simple organic reactions. Vinyl ethers carrying a variety of functional pendant groups, in a general form (Scheme 26.1) ... 

Similar ligands involving a diphosphine ligand on a ferrocene framework with various functionalized pendant groups have been designed. Additionally, other ligands have been... 

Ouchi T, Nozaki T, Ishikawa A, Pujimoto I and Ohya Y (1997) Synthesis and enzymatic hydrolysis of lactic acid-depsipeptide copolymers with functionalized pendant groups, J Polym Sci A Polym Chem 35 377-383. 

Ouchi T, Shiratani M, Jinno M, Hirao M, Ohya Y (1993), Synthesis and enzymatic hydrolysis of polydepsipeptides with functionalized pendant groups , Macromol. Rapid Commun., 14 (12), 825-831. 

The living polymerization process offers enormous flexibiUty in the design of polymers (40). It is possible to control terminal functional groups, pendant groups, monomer sequencing along the main chain (including the order of addition and blockiness), steric stmcture, and spatial shape. 

The synthetic methods of macromolecules having an active pendant group include (1) the transformation reactions of polymer and copolymers, and (2) polymerization and copolymerization of functional monomers having active pendant groups. The macromolecules, either in the shape of film or microbeads, can be used as the substrate. As we have mentioned previously, the rate of polymerization initiated with the Ce(IV) ion redox system is much faster than that initiated by Ce(l V) ion alone, as expressed in / r 1. Therefore, the graft... 

Two compounds of this type, T8[c-C5H9]8 and Tslc-CeHnls (Table 31, entries 1 ) are of particular interest not because of the nature of their pendant groups which are difficult to functionalize (a few examples of the use of such compounds as polymer nanofillers have been reported), but because they are the precursors to compounds with TsRyR structures (R = C-C5H9 or c-CeHu) as described at the end of this section. 

The polyphosphazenes are high molecular weight polymers with a wide range of novel and potentially useful properties. The large number of different pendant groups with widely varied functionality which can be attached to the P-N backbone demonstrate the unusual molecular design potential of this class of polymers. Undoubtedly, some of these will hold promise for future research and development. 

The large number of different pendant groups with widely varied chemical functionality which can be attached to the... 

NHC ligands with a pendant group that enforces chelation have also been coordinated to copper centers. The reaction of Cu20 with pyridine fV-functionalized carbene ligand led to the formation of several compounds.91 In the case of mesityl derivatives, a dinuclear complex with a weak metal-metal interaction was isolated 60,91 whereas for the bulkier 2,6-diisopropylphenyl group, a monomeric complex was formed and characterized 61 (Figure 25).91... 

The sulfimide group R2S = NR is isoelectronic with R2S = O, and recent studies have revealed the first examples of macrocyclic derivatives from reaction of the thia crown with MSFI.155,156 These compounds are of interest as ligands in their own right, and also because they provide a means of functionalizing the thiacrown at the S atom and hence the possibility of introducing pendant groups. 

Hiller and Funke extensively investigated the change of the polymer structure as a function of the monomer and the initiator concentration in various solvents [231]. The content of pendant vinyl groups in the polymer was about 100% for n-BuLi concentrations below 2 mol % and for the whole range of the monomer concentration studied (20-100 g/1). The content of pendant groups decreased when the n-BuLi concentration increased and approached 80% in the transition region of a soluble polymer to a macrogel. As seen in Fig. 45, the decrease of pen-... 

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