Precursors dendrimers

We have decorated different generations of polyphenylene dendrimers based on a biphenyl core with up to 16 perylenemonoimide chromophores at the periphery [67]. This has been achieved via the Diels-Alder reaction of a perylenemonoimide functionalized cyclopentadienone as a terminating reagent with the ethynyl precursor dendrimers. A strongly emitting nanoparticle is thus obtained. 

The properties of the various PAMAM dendrimer precursors are shown in Table 9.1. 

Precise placement of metal complexing sites within the infrastructure of a cascade molecule is of importance from a variety of perspectives. In the construction of the above noted Micellane family (cf. Sect. 3.1), we reported the construction of dendrimers with four alkyne moieties at sites equidistant from each other in the interior (17, Fig. 8) [60]. These were treated with decaborane (B10H14) to afford 1,2-dicarba-closo-dodecaboranes (o-carboranes) [71]. Rendering boron clusters soluble in water is of interest because of their use in cancer treatment by Boron Neutron Cancer Therapy. First and second generation water-soluble dendrimers containing four and twelve precisely located boron cluster sites, respectively, were synthesized (e.g., 18). These water soluble dendrimers and their precursors were characterized by 13C-, and nB-NMR spectroscopy (Fig. 8). 

Fig. 14. Chiral dendrimers 31 (prepared as racemic mixture) with a core chirality center. Compounds 32 and 34 are derived from (S)-solketal 33 as enantiopure precursor [61,64,66]...

Compound 12 is the largest photoactive dendrimer in which organic branches have been attached around a polypyridine metal core [29]. This dendrimer was obtained by reacting the metal precursor with a modified bpy carrying highly-... 

A non-covalently functionalized dendrimer was also applied in a continuous allylic amination reaction.[33] PPI dendrimers functionalized with urea adamantyl groups can act as host molecules for phosphorus ligands equipped with acetyl urea groups (Figure 4.18). The so formed supramolecular complex was reacted with a palladium precursor... 

High functionality precursors of/ > 10-20 are primary chains if they participate in crosslinking by vulcanization each monomer unit of primary chain is a potential site for crosslinking. Also, dendrimers and random hyperbranched polymers of higher molecular weight, rank among high-functionality precursors. 

Dendrimers with terminal functional groups represent mode compact precursors that are spherical and almost monodisperse, with reactive groups placed on their periphery. Their synthesis, structure and properties have been reviewed in monographs and review articles often together with hyperbranched polymers (cf., e.g. [15-20]), as well as in this book. Application of dendrimers as precursors for conventional materials is limited at this time by their relatively high cost. 

Dendrimers represent a model for compact multifunctional precursor of polymer networks. Polymer networks prepared by crosslinking of dendrimers were suggested several years ago [64]. Since then, some experimental work has been performed, but there are still many points in structural interpretation of network formation and network properties that are not well understood. 

The classic application of dendrimers terminated with functional groups as precursors of polymer networks to obtain products such as coatings, composites, or RIM materials, with advanced technological and materials properties are relatively scarce. The higher cost of dendrimers is undoubtedly one of the main reasons. 

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