Polybenzene

FIGURE 26.4 Simple conductive organic polymers. From top to bottom polyacetylene, polyaniline, polypyrrole, polythiophene, and polybenzene (poly-p-phenylene). (Adapted from Novak et ah, 1997, with permission of the American Chemical Society.)... 

The monodisperse polybenzene dendrimers reported by Miller and Neenan et al. are arranged symmetrically around a 1,3,5-substituted benzene core unit up to 46 benzene rings were coupled convergently (Fig. 4.15) [29]. 

Although the solubility of (unsubstituted) linear oligophenyls, starting from p-terphenyl, becomes poorer and poorer also in lipophilic solvents, polybenzene... 

Fig. 4.15 Polybenzene dendrimers (according to Miller, Nee-nan, et al.). For the sake of clarity, some of the C-C bonds are drawn with greatly exaggerated lengths to avoid overlapping in this (energetically unfavourable) planar conformation...

Polybenzene dendrimers can be peripherally functionalised, for example with peptide units, leading to a dendrimer with up to 16 terminal lysine units [36]. 

Fig, 4.18 Convergent synthetic route to polybenzene dendrimers (according to Mullen et al.). Because of the mutual ster-ic hindrance of the numerous benzene rings, the molecule shown will tend to be spherical rather than planar... 

Initial work based on the Diels-Alder reaction provided access to linear polybenzenes via copolymerisation (Fig. 4.22) [40]. Diethynylbenzene acts as dieno-phile, and bis(cyclopentadienone) as diene. 

Hyperbranched polymers of polybenzene type can be rendered water-soluble like the above-mentioned monodisperse species by introduction of carboxyl groups [62]. Starting from 3,5-dibromophenylboronic acid 1 as AB2 monomeric building block (Fig. 4.34), the polycondensate 2 was assembled in an aryl-aryl coupling analogous to Suzuki coupling in the presence of Pd(0), and subsequently reacted with carbon dioxide to form the hyperbranched compounds 3 with terminal carboxylate groups ... 

T. M. Miller, T. X. Neenan, Chem Mater. 1990, 2, 346-349. T. M. Miller, T. X. Neenan, R. Zayas, H. E. Bair, /. Am. Chem. Soc. 1992, 334, 1018-1025. We use the family name polybenzene dendrimers (generally polyarene dendrimers) instead of polyphenylene dendrimers because the rules of nomenclature restrict pheny-lene to -QHg-. 

Figure 5. The simplest decorated Z>-surface, polybenzene , found by O Keefe et at. (the stereo-pair shows 4 unit cells of space-group Pn3m, each containing 24 atoms).

At this point, it should be noted that the module of significance for the class of compounds referred to as polymantanes is adamantane. Unlike the fusion of benzene modules to form the polybenzenes, the number and variety of polymantanes increases much more rapidly. Figure 4, which illustrates the four different diamantanes is the second tier of this class of compounds. 

The polybenzene cell reported by Shacklette et al. [293] also has a LiAl negative electrode. 

Elk, S.B. (1990) A canonical ordering of polybenzenes and polymantanes using a prime number factorization technique./. Math. Chem., 4, 55-68. 

O Keefe et al. [31 [ described "polybenzene" which may be viewed as a 3D truncated octahedron lattice in which edges have been replaced by benzene rings. Only one kind of carbon atom forms the entire net. The six- and eight-membered... 

The hypothetical carbon phases that we predict to be metastable are presented in their relaxed state in Fig. l(a, b). Figures l(c, d) show polybenzene and the melano-phlogite structure. 

The polybenzene structure SC24 is more stable than the R6 and BCT8 by about... 

Poly(phenylenes) are oligomers or polymers with phenylene rings (or other related systems such as naphthaline or anthracene residues) joined together in the ortho para or meta position. They are also known as polyphenyls, oligophenyls, oligophenylenes, or polybenzenes. Higher-molar-mass poly(phenylenes) are always branched. 

Reviews on polythiophenes, polysquarines, polybenzenes, etc. have appeared elsewhere, which also discuss the tunability of the bandgap of conjugated polymers [7]. Further sections of this chapter will focus on the synthesis and characterization of the underivatized thienothiophenes (a-c) and conjugated... 

Pruss, A., and F. Beck. 1985. Polybenzene as a positive electrode in aqueous secondary batteries. 

Elk SB (1993) A Canonical Oideiing and Nomenclature for the Kekule Structures of Polybenzenes [in] Topolodcal Aspects of Benzenoid Hydrocar ns and Rdated Structures (Cyvin SJ, Bait). Max—Planck—Institut fur Strahlenchemie, Mulheim a d Ruhr Match 29 19... 

Copolymers, which are structurally different from PEO, such as polyurethane, polybenzene, and polystyrene or styrene-butadiene block copolymers, have been investigated more recently. A common feature of these components is that their is high and that they do not obviously affect the crystallinity of PEO. The most widely studied copolymers include PMMA and PAAM. 

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