Polymer poly dendrime

The poly(imine) dendrimers form a special type of polymer. The dendrimers have different physical properties from linear polymers, and some have been used for biomedical applications. Dendrimers typically start with a core molecule. Ammonia can be used for this purpose. In the presence of methanol, ammonia reacts with methyl acrylate forming N(CH2CH2COOCH3)3. The resulting molecule can react further with ethylenediamine or other diamines forming N(CH2CH2CONHCH2CH2NH2)3- At the end of each branch is a free amino group that can react with two methyl acrylate monomers and further with two ethylenediamine molecules. The continuation of the process leads to a dendrimer (polyamidoamine or PAMAM) [2]. A different dendrimer is poly(propylene imine), which has butylenediamine as a core molecule. 

Tomalia-type poly(amidoamine) (PAMAM) dendrimers and their use as precise, fundamental building blocks to form poly(dendrimers) or so-called starburst polymers. These poly(dendrimers) are now referred to as megamers [35,36] and are described in more detail later. Other pioneers in the dendritic polymer field include Vogtle, New-kome, Frechet, and others. These historical contributions have been reviewed recently [33],... 

Some attention has arisen to consider dendrimers as building blocks for the construction of nanoarchitectures possessing higher complexity and dimensions beyond the dendrimer. In an early paper, Tomalia et al referred to their starburst polymers as a class of macromolecules obtained from the chemical bridging of starburst dendrimers. These macromolecules have been termed megamers, which have been defined as architectures derived from the combination of two or more dendritic macromolecules or poly(dendrimers). Many examples of randomly assembled as well as structure-controlled megamers have been reported, such as oligomeric covalent assemblies of dendrimers (i.e., dimers, trimers) referred... 

More recently, non-traditional polymerization strategies have evolved to produce a fourth new major polymer architecmral class, now referred to as dendritic polymers [43]. This new architectural polymer class consists of four major subsets (1) random hyperbranched, (2) dendrigrafts, (3) dendrons and (4) dendrimers. Dendrimers, the most extensively studied subset were discovered by the Tomalia group while in The Dow Chemical Company laboratories (1979) and represent the first example of synthetic, macromolecular dendritic architecture [43,44]. First use of the term dendrimer appeared in preprints for the first SPSJ International Polymer Conference, held in Kyoto, Japan in 1984 [45]. The following year, a full article in Polymer Journal [46] (Fig. 8) described the first preparation of a complete family of Tomalia-type poly(amidoamine) (PAMAM) dendrimers (G = 1-7) and their use as precise, fundamental building blocks to form poly (dendrimers) or so-called starburst polymers. These poly(dendrimers) are now referred to as megamers [47, 48] and are described in more detail later in Sect. 6.4.3. Other pioneers in the dendritic polymer field include Vogtle, Newkome, Frechet, Majoral, and others. These historical contributions have been reviewed recently [52]. ... 

Thousands of polymers have been developed for the delivery of nucleic acid drugs. Although some polymer-based carriers have introduced totally different concepts into the design of their backbones, most of the polymer-based carriers rely on a few basic polymers. In this section, we will describe three basic polymers, poly (L-lysine) (PLL), poly(ethylenimine) (PEI), and poly(amidoamine) (PAMAM) dendrimer in order to survey the standard concepts of polymer-based carriers. 

DILLON R A and SHRivER D F (2001), lon transport and vibrational spectra of branched polymer and dendrimer electrolytes , Chem Mater, 13 1369-1373 FENTON D E, PARK J M and WRIGHT p V (1973), Complexes of alkali metal ions with poly (ethylene oxide) . Polymer, 14 589-589 FEUILLADE G and PERCHE p (1975), lon-condnctivc macromolecular gels and membrane for solid lithium cells , J Appl Electrochem, 5 63-69 FONTENELLA J J, WINTERGILL M C, CALAME J P and ANDEEN C G (1983), Electrical relaxation in pure and alkah metal thiocyanate complexed poly(ethylene oxide) . Solid State Ionics, 8 333—339... 

Brief definitions of starburst polymers, dendrimers, and dendrons are as follows, and the reader is referred for detailed descriptions to Tomalia s excellent reviews [1]. Starburst is a the trademark name of poly(amide-amine)s, as shown in Scheme 1, and was presented by Tomalia. Recently, dendrimers and dendrons have been defined in general terms for a class of hyperbranched polymers. Dendrimers are systematically constructed to form regularly branched treelike structures. Under ideal conditions, the molecular architecture is very uniform, as shown in Figure 1. A dendron is one of the major subdivisions of a dendrimer. For example. Figure 1 shows the division of a dendrimer into three separate dendrons, labeled A, B, and C. Further subdivisions are also possible, with each of the three dendrons dividing into two subdendrons, each of which then divides into two subdendrons, etc. Thus, one of the major differences between linear polymers and dendrimers is this branched architecture. 

Dendrimers have structures similar to that of hyperbranched polymer and can be taken as the perfectly branched polymer with monodispersity. However, they need to be prepared by a multistep procedure. Therefore, very little work has been done on dendritic polyfarylcnc ether)s. Morikawa et al. prepared a series of monomers with a various number of phenylene units.164,165 These monomer were used to prepare poly(ether ketone) dendrons with graded structures (Scheme 6.24). 

Metal-acetylide complexes have been used as a unit of organometallic polymers that have metallic species in the main chain [20]. Representative examples are metal-poly(yne) polymers (19) of group 10 metals depicted in Scheme 5. These polymers are easily prepared from M(PR3)2Cl2 (M=Pt, Pd) and dialkynyl compounds catalyzed by Cu(I) salts in amine. Recently, this synthetic method was successfully applied to the construction of metal-acetylide dendrimers. 

Metal-acetylide complexes including metal-poly(yne) polymers often show unique properties [21-23]. Thus, metal-acetylide dendrimers are of interest because amplification of the functionality due to metal-acetylide units based on three-dimensional assembly with a regular dendritic structure is expected. 

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