Ary-Branched and Connectivity

When diphenyl ether or 1-methylnaphthalene was used as solvent, the polyphenylenes were determined to possess higher Mn values with xylene. No molecular weight increase was obtained by the addition of added monomer at or toward the end of the polymerization. The highest molecular weight was obtained using nitrobenzene as the solvent. 

In order to investigate the unimolecular micellar behavior of the water-soluble, lithium salt of polycarboxylic acid 4, the NMR spectrum of 4 in the presence of an NaOAc/ H20 solution of p-toluidine was recorded. Absorptions associated with the guest molecule ) shifted upfield and were dramatically broadened. 

Webster et al. l4a expanded on the preparation of the polyphenylenes to develop the one-pot synthesis of hyper-crosslinked poly(triphenylcarbinol). Thus, reaction of 4,4 -dilithiobiphenyl with (CH3)2C03 (— 80 °C — 25 °C, THF) afforded trityl alcohol-based polymer. The absence of carbonyl or methoxycarbonyl NMR resonances led to the speculation that the polymer grows via a branched convergent process. 

Repetitive Diels-Alder reactions utilizing bis-ort/io-quinodimethane units have been employed[14bl for the construction of polymeric and oligomeric [60]-fullerenes with molecular weights up to 80,000 amu. The potential of using this method for dendrimer construction was suggested. 

Frechet et al. 15 reported the high yield, one-step, reproducible preparation of the hyperbranched aromatic polyester (5) with controllable molecular weights via the selfcondensation of 3,5-bis(trimethylsiloxy)benzoyl chloride (6), which was synthesized from 3,5-dihydroxybenzoic acid by silylation (Me3SiCl, Et3N), followed by treatment with thionyl chloride and a catalytic amount of tetramethylammonium chloride. 

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