Dendrimer schematization

Fig.1. Non-activated and activated PAMAM-dendrimers. Schematic diagram of a non-acti-vated (left) and activated dendrimer (middle). The right panel shows a magnification of the dendrimer branches...

Fig. 2.14 Supramolecular self-construction of dendrimers (schematic according to Hirsch et at.)...

Dendrimers are complex but well-defined chemical compounds, with a treelike structure, a high degree of order, and the possibility of containing selected chemical units in predetermined sites of their structure [4]. Dendrimer chemistry is a rapidly expanding field for both basic and applicative reasons [5]. From a topological viewpoint, dendrimers contain three different regions core, branches, and surface. Luminescent units can be incorporated in different regions of a dendritic structure and can also be noncovalently hosted in the cavities of a dendrimer or associated at the dendrimer surface as schematically shown in Fig. 1 [6]. 

Fig. la-i. Schematic illustration of the possible location of photoactive imits, represented by circles, covalently hnked (types a-g) or associated (types h-i) to a dendrimer... 

Fig. 6. Laser emission spectrum from DCM/dendrimer solution in cuvette. Inset schematically illustrates experimental setup...

Figure 8.9 Schematic representation of a conical monodendron self-assembled into a supramolecular spherical micellar dendrimer, and then into an fm3m cubic mesophase.

Fig. 2. Schematic representation of the supramolecular cylinders of the dendrimer derived from macromonomer 9 (R=OC12H25,n=3) in the Qh mesophase atop view of a cylinder containing six repeat units in a stratum with the alkyl tails melted to match the average column radius determined by X-ray scattering experiments b side view of a cylinder containing 30 repeat units of the polymer assembled with melted alkyl tails. Reproduced with permission from references 5 a...

Fig. 7. a Cross sectional profile of an ultrathin film of dendrimer 23 on HOPG along x-x as indicated in (b). The height difference between adjacent terraces has the dimension of a monolayer [Ah = 4.3 ( 0.2) nm]. Large scale (2.4 x2.4 pm2) SFM image of monomolecular terraces, c Schematic model of closely packed molecular cylinders in thin films of 23 on HOPG... 

Scheme 9.4 Schematic of metal nanoparticles synthesis within dendrimer templates. (Reprinted from [54] copyright 2002, Marcel Dekker.)...

Since the properties of the modular components are known and different modules can be located in the desired positions of the dendrimer array, synthetic control of the various properties can be obtained. It is therefore possible, as schematically shown in Figure 2, to construct arrays where the electronic energy migration pattern can be predetermined, so as to channel the energy created by light absorption on the various components towards a selected module (antenna effect). 

Figure 10.2 Schematic illustration of synthesis of (EDA) core PAMAM dendrimers (E 0-2). Higher generations can be obtained by successive reiterations.

Figure 12.20 Schematic representation of a core-shell tecto-(dendrimer) molecule in solution...

Figure 16.3 Schematic representation of the compression of alkyl modified dendrimers at the air-water interface, the dendrimers assume a flattened, disklike conformation...

Figure 16.6 Schematic representation of the energy transfer process between OPV-poly(propylene imine) dendrimer and a dye guest molecule [84]...

Figure 16.7 TEM picture (uranyl acetate staining) of vesicles reported by Schenning etal. [44] (A) schematic representation of the bilayer, (B) palmitoyl-and (C) azobenzene-modified poly(propylene imine) dendrimers used in the construction of the aggregates...

Scheme 3 Schematic representations of electrostatic assemblies of dendrimer porphyrins 6a, 7a with MV2+...

Figure 5 Schematics of dendrimer growth by the divergent and the convergent methods...

Fig. 5 Schematic representation of the [Zn(2)2]2+ species in which the dendrimer branches are extending outward...

Figure 28 A schematic representation of the possible composition of ferrocene-based dendrimers. (a) Dendrimers containing a single ferrocene unit (b) dendrimers containing multiple ferrocene units...

Fig.1. Schematic description of dendritic polymers comprising dendrimers and hyper-branched polymers...

FIGURE 1.1. Schematic drawing of the dendrimer-assisted preparation of uniform-sized metal particles. Metal ions (Mn+) are first complexed to a 4th generation OH-terminated poly(amidoamine) dendrimer. Then the metal ions are reduced to a metal particle, isolated from other metal particles. 

Fig. 3. Schematic illustration of the synthesis of metal nanoparticles within dendrimer templates. The composites are prepared by mixing of the dendrimer and metal ion, and subsequent chemical reduction. These materials can be immobilized on electrode surfaces where they serve as electrocatalysts or dissolved in essentially any solvent (after appropriate end-group functionalization) as homogeneous catalysts for hydrogenation and other reactions...

Fig. 15. Schematic illustration of the method used to prepare dendrimer-encapsulated Ag,Au, Pd, and Pt nanoclusters by primary and secondary displacement reactions using G6-OH(Cu ) or G6-OH(Ag2n) as starting materials...

Fig. 17. Schematic illustration of the preparation of dendrimer-encapsulated bimetallic clusters by three different methods. Displacement reaction, co-complexation, and sequential loading...

Fig. 21. Schematic illustration of phase-transfer catalysis using an amine-terminated den-drimer-encapsulated nanoparticle complexed with a fatty acid (present in the organic phase). The fatty acid surrounds the dendrimer, yielding a monodisperse inverted micelle which is soluble in the organic phase. After catalysis, the catalyst can be reclaimed by changing the pH of the aqueous phase...

Fig. 22. Schematic illustration of the approach used to carry out fluorous biphasic catalysis using dendrimer-encapsulated metal nanoparticles modified on their exterior with perfluoroether ponytails. Note that the ponytails can be attached by either electrostatic or covalent means. Reprinted with permission from Ref. 103 Copyright 2000 American Chemical Society...

Fig. 13a,b. a Surface pressure - film area isotherms of (1) dendrimer 1, (2) dendrimer 2, and (3) hyperbranched polymer with OH end groups [74]. b Schematic interpretation of the phase transitions from a dense monolayer (I) via a reoriented monolayer (II) to a thick liquid film (III)... 

Fig. 7.1 Schematic representation of linear versus dendritic polymers linear (left) and hyperbranched (middle) polymers, perfect dendrimer (right). The amount of terminal groups is indicated below each structure. These architectures can also be attached to a cross-linked polymer bead to obtain a high-loading hybrid material.

Fig. 7. Schematic representation of the non-covalent immobilization of ligands to a dendrimer support and the actual supramolecular dendritic complex containing 32 phosphine ligands 21).

Fig. 13. Schematic representation of a scandium triflate cross-linked fourth generation poly(propyl-ene imine) dendrimer (DAB).

Fig. 14. Schematic representation of four types water-soluble PAMAM dendrimers containing phosphine ligands.

Fig. 15. Schematic representation of the formation of an inverse micelle from a PAMAM dendrimer-encapsulated palladium nanoparticle.

The divergent method is illustrated in Fig. 2-22 for the synthesis of polyamidoamine (PAMAM) dendrimers [Tomalia et al., 1990]. A repetitive sequence of two reactions are used—the Michael addition of an amine to an a,P-unsaturated ester followed by nucleophilic substitution of ester by amine. Ammonia is the starting core molecule. The first step involves reaction of ammonia with excess methyl acrylate (MA) to form LXIII followed by reaction with excess ethylenediamine (EDA) to yield LXIV. LXV is a schematic representation of the dendrimer formed after four more repetitive sequences of MA and EDA. 

Figure 11.9 (Top) A typical structure of Tha)oimanavan s amphiphilic dendrimers. (Bottom) Schematic representation of micelle-type and inverse miceUe-type structural organization.

Figure 11.11 Schematic representation of the stmctural impact of counterion screening on the size of the dendrimer.

Figure 11.13 Schematic representation of dynamic conformational change from diskhke to spherical morphologies in dendrimers.

Schematic representation of the monolayer organization of amphiphilic dendrimers on the water surface.

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