Dendrimer formula

Assuming that in the course of the functionalization, each reaction between the reagent and a still free peripheral group occurs without being influenced by the number of already converted moieties,1231 the total yield A of perfectly reacted dendrimer can be calculated by means of the product formula for a stochastically independent event, if the yield of the individual reaction a is known. The yield A is given by a" where n is the number of peripheral functional groups of the dendrimer. 

Figure 1. Formulas of the ligands, abbreviations, and symbols used to represent the components of the dendrimers.

Figure 6.1 Structural formula of dendrimer 1 containing 27 ferrocene units at its periphery.20d...

Figure 6.2 Structural formula of dendrimer 2 containing 64 [FeCp(ri6-C6Me6)]+ units at its periphery.23...

Figure 6.3 Structural formula of dendrimer 3 containing an octahedral Mo6 cluster as core and 36 ferrocene units in its periphery.27...

Figure 6.4 (a) Structural formula of the 1,2,3-triazole-linked dendrimer 4 containing nine ferrocene peripheral units (b) cyclic voltammogram of 4 without (1) and in the presence of... 

Figure 6.5 Structural formula of dendrimer 5 containing 32 octamethylferrocene peripheral units.38...

Figure 6.6 (a) Structural formula of dendrimer 6 containing at its periphery 16 biferrocene... 

Figure 6.7 (a) Structural formula of the fourth-generation dendrimer 7 containing at its... 

Figure 6.8 Structural formula of dendrimer 8 carrying at its periphery 27 tetrairon [ CpFe(p3-CO) 4] clusters.44...

Figure 6.10 Structural formulas of homometallic dendrimers 10 and 11 terminated with four and eight ferrocene units, respectively, and of the related heterometallic dendrimers 12 and 13 terminated with four ferrocene and four (T 6-C6H5)Cr(CO)3 moieties, and with eight ferrocene and eight (ri6-C6H5)Cr(CO)3 moieties, respectively.50... 

Figure 6.11 Structural formulas of the fourth-generation dendrimers terminated with 64 metal complexes [Ru(bpy)3]2+ (14),54a,d [Ru(tpy)2]2+ (15),54 and [Co(tpy)212 1 (16).56...

Figure 6.12 Structural formula of dendrimer 17 containing a tris-viologen core appended with six [Ru(bpy)3]2+ complexes.57...

Figure 6.13 Structural formulas of dendrimers 18 and 19 containing four [Ru(tpy)2] + complexes in their branching points that represent the first example of dendritic constitutional isomers.58...

Figure 6.14 Structural formulas of zwitterionic dendrimers that contain four [Ru(tpy)2] complexes along the branches and eight carboxylate units either in the internal branching points (20) or at the periphery (21).58a>b...

Figure 6.17 Structural formula of the docosanuclear dendrimer 25. represent the dendrimer are those displayed in Fig. 6.15.

Figure 6.18 Structural formulas of two families of dendrimers containing a 1,3,5-trisubsti-tuted benzenoide core and 9 (A918 + and B918 + ) and 21 (B2142+ and A2142 + ) 4,4 -bipyridinium units in their branches.68 The -type dendrimers are terminated with tetraaryl-methane bulky moieties while the -type dendrimers contain in their periphery less bulky aryloxy groups. For comparison purposes the structural formulas of dendrons A24 + and B24 + and model compound DoV2 + are also reported.

Figure 6.19 Structural formula of dendrimer 26 containing a hexaphenylbenzene core and 24 C60 units.74...

Figure 6.22 Stmctural formula of dendrimer 28 consisting of a Cu(I) bis-phenanthroline complex as core, linked to four dendrons, each one containing two fullerene moieties appended at the periphery.77...

It would be beyond the scope of this textbook to dive further into the details of dendrimer nomenclature. Instead, basic rules are given to create an awareness of the problems and complexity. Nevertheless, with the aid of the literature cited (see ref. [45]) it is possible to develop names for certain formulae -and vice versa. 

Table 4.2 I ncrease of PAMAM parameters with the number of generations (dendrimer type, see Fig. 4.6) [3]. The second column lists the number of terminal groups of 1 ->3-branched aliphatic Newkome type dendrimers (see Figs. 1-5 and 4.60 for typical formulae)...

The stilbene carbon unit has also been peripherally bound to POPAM cores. Although it does not strictly belong to the hydrocarbon dendrimers, the formula of a G2 dendrimer of this type (Fig. 4.21) is depicted here as an example. It was obtained by alkylation of the corresponding eightfold mono-sulphonamide with 4-(bromomethyl)stilbene. Its fluorescence, E/Z isomerisation, photoisomerisation (see Section 5.2.2), and excimer formation were compared with those of non-dendritic stilbenes. The quantum yields of photoisomerisation (0.30) and fluorescence of the E isomer (0.014) of the dendrimer proved to be substantially lower [38]. 

Formulae of dendrimers produced for catalytic purposes have already been shown in Chapter 4 and will not be repeated here, particularly since their possible suitability has merely been tested but no specific laboratory or industrial applications presently exist. 

Bochkarev et al. [110] have recently described the anionic polymerization of HM(C6F5)3, M = Ge, Si, or Sn (Nc = 1, Nb = 3). Most noteworthy is the germanium system, where they have obtained self-limiting molecular-mass ranges of approximately 100000-170000, in spite of the mode of preparation. These workers hypothesize that deprotonation at germanium produces anions that nucleophilically displace fluorine atoms in para positions to produce a dendrimer structure of the following general formula ... 

Presently, defects of the type A and B are the only serious side-reactions encountered in the synthesis of Starburst PAMAM dendrimers (generation = 0-10) by the divergent initiator core method . Defects of the types C, D and E have been minimized to under 3-5 mole% per generation. Polydispersities (Mw/Mn) of 1.0007 have been routinely observed for Starburst PAMAM dendrimers (generation = 4 NH3 core) which has an empirical formula of C465H933N187093 and a calculated molecular weight of 10632, as verified by electrospray mass spectroscopy [169]. 

Fig. 12 Structural formula of dendrimer 10 (top) and energy transfer occurring from the peripheral dimethoxybenzene and naphthalene units to the light-emitting dansyl unit (bottom) [63]...

Fig. 14 Structural formulas of two families of dendrimers containing a 1,3,5-trisubstituted benzenoide core and 9 (A918+ and B918+) and 21 (A2142+ and B2142+) viologen units in their branches [69-71]...

Fig. 5. Schematic formula of the dendrimer and of the Re(I) guest which can complex via hydrogen bonds, at its periphery. Upon irradiation at 2=330nm, where the dendritic structure is almost selectively excited due to the different absorption profile with respect to the rhenium complex, an efficient energy transfer can occur from the dendrimer to the organometallic moiety.

Fig. 5. Formula of a dendrimer with a [RuCbpyls] " core, and the corresponding scheme (Fig. 2a).

Fig. 7. Formula of a dendrimer containing 18 amide groups in its branches and 24 chromophoric dansyl units in the periphery, capable of coordinating metal ions (Co ", Ni, or lanthanide ions), and the corresponding scheme (Fig. 2d).

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