Quaterphenylenes

Polyphenylene polymers can be prepared by this coupling. For example, the preparation of poly(/i-quaterphenylene-2,2 -dicarboxylic acid) (643) was carried out using aqueous NaHCO and a water-soluble phosphine ligand (DPMSPP)[5I I]. Branched polyphenylene was also prepared[5l2). 

Light-emitting Organic Nanoaggregates from Functionalized para-Quaterphenylenes... 

In the following the development is presented of a general approach for the synthesis of symmetrically and differently l,4" -substituted p-quaterphenylenes by application of a reliable Suzuki cross-coupling strategy. Experimental details are not given here but can be found elsewhere [51-53]. Note that organic synthesis is a key step for the bottom-up nanotechnology approach. 

Scheme 8.1 Synthesis of symmetrically 1,4 -disubstituted p-quaterphenylenes MOP4, CLP4, CNP4, NHP4, NMeP4, and NOP4 via Suzuki cross-coupling reactions (R = H or alkyl).

Scheme 8.3 Synthesis of nonsymmetrically 1,4 -idisubstituted p-quaterphenylenes MOCLP4, MOCNP4, and MONHP4 from a methoxy functionalized p-terphenylene (R = H or alkyl).

Scheme 8.4 Molecular formulas of 1-mono-functionalized p-quaterphenylenes MOHP4, CLHP4, and CNHP4.

The nonsymmetrically functionalized p-quaterphenylenes, however, behave differently [135]. 

A reliable synthesis strategy to obtain new either symmetrically or nonsymmetrically para-functionalized para-quaterphenylenes. 

Thus, it is possible to obtain tailored nanofibers from appropriately functionalized p-quaterphenylenes. A requirement for generating aligned nanofibers still seems to be muscovite mica as growth substrate, but the molecular basis is not restricted to p6P a para-phenylene molecular basis can be employed which tolerates functional groups at the para-positions. 

A. (2007) Synthesis of symmetrically and nonsymmetrically para-functionalised para-quaterphenylenes. Synthesis, 4, 613-21. 

The synthesis of a series of poly[(disilanylene)-oligophenylenes] (34, m — A) have been reported [53] and their conducting properties have been examined. Poly[(disilanylene)biphenyIenes] (34, m = 2) are synthesized by the sodium condensation of the respective bis(chlorosilyl)biphenyls, similar to the method for the synthesis of polymers 30-32, as shown in Scheme 15.3. Poly[(disilanylene)terphenylenes and quaterphenylenes] (34, m = 3 and 4) are prepared by the reaction of 1,4-dibromobenzene and 4,4 -dibromo-biphenyl with di-Grignard reagents prepared from bis(bromophenyl)disilanes in the presence of a catalytic amount of dichloro(diphenylphosphinoethane)nickel-(II) in THE at 150°C (Scheme 15.3) [51]. 

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