Polyphenylenes dendritic

In contrast to dendrimers built up from aliphatic chains, polyphenylene dendrimer micelles possess shape and size persistent cavities due to their rigid scaffold which strongly depends on the type of dendrimer. In this case a selective incorporation of guest molecules, e.g., fluorescent dyes, should be possible, dependent on the size of the guest molecule and the cavity of the host. The non-covalent uptake of dyes with an appropriate size thus allows the investigation of their interactions within the dendritic micelle. In our case we made the second-generation polyphenylene dendrimer 48, which bears 16 carboxy-functions at the periphery, by starting from a tetrahedral core and an appropriately... 

Recently, Kimura et al. have reported the encapsulation of electro chemically and photo chemically active groups such as a porphyrin unit (51) or a ruthe-nium(II) bis(terpyridyl) (52) unit in the interior of a 1,3,5-polyphenylene-based dendritic structure (Scheme 21). The dendritic porphyrins have been synthesiz-... 

A wide range of other monomer units have been employed in the synthesis of hyperbranched macromolecules and the range of structures obtained is nearly as diverse as those for dendritic macromolecules. For example, hyperbranched polyphenylenes [93], polyesters [104, 107-109], polyethers [110-112], polyamides [113], polysilanes [114], polyetherketones [100], polycarbazoles [115], etc. [116-118] have been prepared. Interestingly, a number of groups have also used growth processes other than condensation chemistry to prepare hyper-... 

ENSEMBLE PHOTOPHYSICS OF RIGID POLYPHENYLENE BASED DENDRITIC STRUCTURES... 

Ensemble Photophysics of Rigid Polyphenylene Based Dendritic Structures... 

Large polybenzenoids have been extensively studied by Mullen et al. [ 143 -145]. Among various sizes and shapes of these superacenes , as he named them, are 107,108, and the 50-benzene-unit PAH (109). These compounds are generally constructed from their dendritic polyphenylene precursors in good yields, albeit difficult to characterize conclusively. Even larger sheets have been proposed and where the limits lie is still unknown. 

A. Adedeji. High flow polyphenylene ether formulations with dendritic polymers. US Patent 6 809 159, assigned to General Electric Company (Pittsfield, MA), October 26, 2004. 

In the synthesis of graphene-type molecules, dendritic or hyperbranched polyphenylene precursors are transformed into the target molecules through intramolecular cyciodehydrogenation, with concurrent planarization. In this chapter, the various cyciodehydrogenation protocols employed to achieve C-C bond formation will be discussed with respect to their chemistry and applicability towards the construction of graphene-type systems. These transformations include (i) Lewis acid-catalyzed oxidative cyciodehydrogenation (Scholl reaction)... 

Following an initial report by Kim etal. [20, 54] of a branching factor for a hb polyphenylene, Frechet et al. [55] later deflned for the first time the DB for describing hb polymers. By adopting the structure of an ideally branched dendrimer possessing only dendritic and terminal units, it was possible to relate the sum of dendritic and terminal units to the total sum of all repeating units, by considering linear units as units which decreased the DB (Equation 24.1) ... 

Complex formation of polycationic core-shell macromolecules with natural polyanions such as DNA has been investigated. Three generations of core-shell polymers consisting of a dendritic polyphenylene core and an outer shell containing a defined number of primary amino groups have been synthesized via ATRP (Fig. 2a shows structures 3a and 3b, generations 1 and 2, respectively) [23]. All polymers... 

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