Poly -containing dendrimer

Fig. 10 pH-Dependent permeability of the anions Fe(CN)6 and the cation Ru(NH3)g in nanocomposite dendrimer-poly(maleic anhydride) grafts that contain - CO2H/ - C02" and NH2/-NH3 groups in the film with a anion permeability at low pH where the... 

Cationic polymers, such as poly(L-lysine) (PEL), polyethylenimine (PEI), chitosan, polyamidoamine (PAMAM) dendrimers, poly(2-dimethylamino) ethyl methacrylate, and polyphosphoesters, condense DNA to form compacted polyplexes. ° The size and the stability of polyplexes depend on the ratio of cations vs. anions, temperature, ionic strength, and the solvent. Stability of polyplexes can be enhanced by conjugating PEG to the polycations or by using PEG-containing block or graft polymers that form micelles. Small cationic peptides are also able to condense DNA, however, six-consecutive-cations is the minimal requirement to achieve this effectively. 

A similar synthetic approach has also been used to synthesize the corresponding octaferrocenyl derivatives. A series of remarkable ferrocenyl dendritic macromolecules based on flexible poly(propylene-imine) dendrimer cores containing 4, 8, 16, 32, or 64 peripheral ferrocenyl moieties has been prepared via condensation reactions of ferrocene carbonylchloride with the first-, second-, third-, fourth-, and fifth-generation diaminobutane-based... 

Scheme 16.17 (A) Asymmetrical, bifunctional dendrimer 69 containing 16 mannose units and two coumarin chromopbores and (B) poly(methacrylate)-based glycopolymer 70 prepared by CuAAC and used for lectin binding studies with concanavalin A...

Among all types of dendrimers, phosphorus-containing dendrimers [4] that are dendrimers having one phosphorus atom at each branching point play more and more an important role. In this chapter, we will focus on their use as catalysts, for materials, and in biology. Besides our own work, a few other groups have reported the synthesis of phosphorus-containing dendrimers. We can mentioned in particular the first example of any type of phosphoms dendrimers (poly(phosphonium)... 

It has been demonstrated that dendrimers can be used also as fluorescent sensors for metal ions. Poly(propylene amine) dendrimers functionalized with dansyl units at the periphery like 34 can coordinate metal ions by the aliphatic amine units contained in the interior of the dendrimer [80]. The advantage of a dendrimer for this kind of application is related to the fact that a single analyte can interact with a great number of fluorescent units, which results in signal amplification. For example, when a Co ion enters dendrimer 34, the fluorescence of all the 32 dansyl units is quenched with a 32-fold increase in sensitivity with respect to a normal dansyl sensor. This concept is illustrated in Fig. 3. 

Other supramolecular structures such as dendrimers have also been synthesized with zinc-containing porphyrins. Sixteen free base and sixteen zinc porphyrin units were added at the fifth generation of dendritic poly(L-lysine) and intramolecular fluorescence energy transfer was observed.823 Assembly of supramolecular arrays in the solid state has been achieved with the incorporation of an amide group for hydrogen bonding. Zinc meso-tetra(4-amidophenyl)porphyrin... 

The molar ellipticity of these dendrimers was found to increase proportional to the number of chiral end groups. This is to be expected, in the absence of interactions between the terminal tryptophane moieties. No higher-generation dendrimers of this type have been reported. Other amino-acid-containing chiral dendrimers have been described by Meijer et al. who attached various amino acid derivatives to the periphery of poly(propylene imine) dendrimers (see Sect. 3) and more recently by Liskamp et al. (modification of polyamide dendra) [22] and Ritter et al. (synthesis of grafted polymerizable dendrimers containing L-aspartic acid components) [23]. 

The synthesis and structure of a dendrimer can be illustrated by the well-known poly (amidoamine) type (called PAMAM), which describes the monomers making up the complete polymer. The synthesis starts from a core diamine (or ammonia) molecule. The diamine can be of various lengths and spacer arm properties and even contain cleavable components. Typically, the core... 

Figure 1.21 Periodic properties for poly(amidoamine) (PAMAM) dendrimers as a function of generation G = 0-10 (I) flexible scaffolding (G = 0-3) (II) container properties (G = 4-6) and (III) rigid surface scaffolding (G = 7-10) various chemo/ physical dendrimer surfaces amplified according to Z = NCN where Nc = core multiplicity, Nb = branch cell multiplicity, G = generation...

Diederich and coworkers [10] synthesized so-called dendrophanes (Figure 13.6) containing a paracyclophane core embedded in dendritic poly(ether-amide) shells. X-ray crystal-structure analysis indicated that these dendrimers had an open cavity binding site in the center, suitable for the binding of aromatic guests. NMR and fluorescence titration experiments revealed a site specific binding between these dendrimers and 6-(p-toluidino)naphthalene-2-sulfonate (TNS) with a 1 1 association. Also, the fluorescence spectral shift of TNS, which is... 

Crooks et al. reported the transfer of amine-functionalized poly(amidoamine) dendrimers into toluene containing dodecanoic acid [198], The method is based on the formation of ion pairs between the fatty acids and the terminal amine-groups. These dendrimer-fatty acid complexes resemble unimolecular inverted micelles and could be used as phase transfer vehicles for the transport of Methyl Orange, an anionic dye molecule, into an organic medium. 

This chapter describes composite materials composed of dendrimers and metals or semiconductors. Three types of dendrimer/metal-ion composites are discussed dendrimers containing structural metal ions, nonstructimal exterior metal ions, and nonstructiu al interior metal ions. Nonstructural interior metal ions can be reduced to yield dendrimer-encapsulated metal and semiconductor nanoparticles. These materials are the principal focus of this chapter. Poly(amidoamine) (PAMAM) and poly(propylene imine) dendrimers, which are the two commercially available families of dendrimers, are in many cases monodisperse in size. Accordingly, they have a generation-dependent munber of interior tertiary amines. These are able to complex a range of metal ions including Pd +, and Pt +. The maximmn munber... 

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