Dendrons, metal-containing

Figure 7.26 Dendrimers made with a disulfide-containing core can be reduced to produce dendrons having free thiol groups for surface modification. Dative binding of these thiol-dendrons to gold or metallic surfaces can provide a high density of amine groups for coupling proteins or other molecules.

The chemical composition of particles can be just as varied as their shape. Commercial particles can consist of polymers or copolymers, inorganic constructs, metals and semiconductors, superparamagnetic composites, biodegradable constructs, and synthetic dendrimers and dendrons. Often, both the composition of a particle and its shape govern its suitability for a particular purpose. For instance, composite particles containing superparamagnetic iron oxide typically are used for small-scale affinity separations, especially for cell separations followed by flow cytometry analysis or fluorescence-activated cell sorting (FACS). Core-shell semiconductor particles, by... 

For this purpose, a series of Frechet-type polyether dendrons of zeroth-to third-generation containing an NCN-pincer metal complex (M = Pt, Ni) at the focal point of the wedge were prepared [69]. Their synthesis was either... 

Star-shaped multi-porphyrin arrays have been constructed to mimic energy funneUng in photosynthesis. These dendrimers contain free-base porphyrin cores (Pfb) connected to four dendrons consisting of 1,3, or 7 zinc-metallated porphyrins (Pzn) embedded in an organic matrix coimected by ether linkages (Scheme 21) [70,71]. The periphery consists of methoxy-terminated poly(aryl ether) dendrons. For comparison, cone-shaped arrays consisting of Pfb cores monosubstituted with Pz dendrons were also synthesized. 

A variety of metal acetylide-containing stars and dendrimers have been synthesized.329-332 Dendrimer 280 was prepared via reaction of a chloro-substituted platinum complex 278 with ethynyl functionalized dendron 279 in the presence of Cul (Scheme 2.73).329 This method generated dendrimers with up to 45 platinum units. 

In the early 1990 s, Balzani and coworkers began to synthesize decanuclear homo- and heterometallic dendrimers which contain Ru(II) and Os(II) surrounded by nitrogen-containing ligands (bpy derivatives). The metals occupied sites in both the dendrons and at the core of the... 

Several reactions could be carried out in ILs solvents examples are transition-metal-catalyzed hydrogenation, hydroformylation, isomerization, dimerization, and coupling reactions (Holbrey and Seddon, 1999b). Carborane derivatives could also be synthesized successfully in ILs such as l-n-butyl-3-methylimidazolium chloride (Li et al., 2008) the same IL was used for the preparation of functional carboranyl-containing dendrons (Galie et al., 2006 Mollard and Zharov, 2006). 

A number of metal acetylide-containing dendrimers and stars have also been prepared." Scheme 25 shows the synthesis of a first-generation platinum acetylide dendrimer (87) containing 9 platimun complexes in its structure. Dendrimer 87 was made by the reaction of a chloro-substituted platinum complex (85) with an ethynyl functionalized dendron (86) in the presence of Cul." Dendrimers with up to 45 platinum emits were synthesized using this methodology. 

Achar and Puddephat [29], on the other hand, investigated the synthesis of dendrimers containing a metal atom at each layer (Scheme 7). Their synthetic scheme was based on the oxidative addition of the C-Br bonds of aromatic bromomethyl to the platinum complexes. The first-generation dendrons consisting of two platinum centers were the result of the reaction between... 

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