Charged dendrimers, structural

In general, dendrimers show sharp M+ signals at the expected values. This confirms the overall dendrimer structure. Mass spectra may be complicated by the presence of small peaks corresponding to two- or three-molecule aggregates bearing a single charge and this phenomenon is... 

The addition of charge to a dendrimer structure could be expected to cause a structural expansion that minimizes the ensuing coulombic repulsions, similar to the... 

Poly(amidoamine) dendrimers such as 91, which differ only in the presence of an ethylenediamine (instead of ammonia) core, were used to host the electron transfer reaetion between photoexcited polycyelic aromatic hydrocarbons (PAHs) and ni-tromethane [169]. Quenching studies in aqueous solution indicate that the PAHs associate with the dendrimer, residing in the interior region, far from the charged surface. It was also found that within the dendrimer structure, nitromethane quenches alternant PAHs, while nonalternant PAHs are not quenched. This selective behavior of nitromethane parallels that commonly observed in solution, while in the presence of traditional micelles both classes of PAHs are quenched by nitromethane. 

Depending on the type of charges, polycationic PEG-P(Lys) and polyanionic PEG-P(Asp) are used for the preparation of such PIC micelles (Fig. 6). Based on recent research, core-shell type PIC micelles with a 52 nm diameter were prepared from a Zn-porphyrin-dendrimer with 32 carboxylate groups on the periphery, 32(-)DPZn, and PEG-P(Lys) block copolymers (56,57). On the contrary, when the dendrimer structure is cationic, a third-generation porph3rrin-dendrimer with 32 primary amine groups on the periphery, 32(+)DPZn, and PEG-P(Asp) were used to prepare a PIC micelle, and had a spherical structure with a 55 nm-sized diameter (58). Both... 

This review of the electroactive metal-containing dendrimers, not exhaustive for space reasons, clearly indicates that several interesting dendrimers have been synthesized, but in most cases their electrochemical properties have not been investigated in detail. A few carefully performed studies have shown that electrochemistry is a powerful technique (i) to elucidate the structure (and purity) of the dendrimers, a task not at all easy in the case of highly charged compounds,... 

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