Search

The mechanism of the chain-growth polymerization of 2-bromo-5-chloromagnesio-3-hexylthiophene (1) with Ni[(d1,3-bis-(diphenylphosphino)propane]Cl2, in which head-to-tail poly(3-hexylthiophene) (HT-P3HT) with a low polydispersity is obtained. This chain-growth polymerization involves the coupling reaction of (1) with the polymer through the Ni catalyst, which is transferred intramolecularly to the terminal C-Br bond of the elongated molecule, called 'catalyst transfer polycondensation'.

A study was done on the structure of maitotoxin which is derived from cultures of dinoflagellates treated with NaIO4 and NaBH4. Results show that the toxin is a C142 carbon chain of composition C164H256O68S2Na2 with a molecular weight of 3422. It has 32 ether rings, 28 hydroxyl groups and two sulfate esters. Most of the ether rings are trans-fused except for rings L/M and N/O which exhibits cis-fusion.

Spectroscopic measurements of the partial structure of maitotoxin (MTX) showed that 30 ether rings, 30 hydroxyls, 21 methyls and 2 sulfate esters comprise the polyether skeleton of the marine toxin. This structure was identified through extensive examination of the periodate degradation products of the extract from the dinoflagellate, Gambierdiscuc toxicus. Also, the examination reveals that the toxin molecule exhibits dual polarity due to the hydrophilic and hydrophobic properties of its segments.

The Suzuki-Miyaura coupling reaction that can be effectively used for the chain-growth polymerization to produce compounds like polyfluorene from an externally added initiator unit is described. The polycondensation is found to proceed in a chain-growth manner from the initiator unit derived from the catalyst.

The synthesis of poly-(p-phenylene) (PPP) is investigated to see whether a monomer containing no heteroatom in the aromatic ring undergoes catalyst-transfer poly-condensation. It is demonstrated that the Ni-catalyzed polycondensation of 1-bromo-4-chloromagnesio-2,5-dihexyloxybenzene proceeds by a chain-growth mechanism to afford PPP with a narrow polydispersity and that the molecular weight of PPP is controlled by the feed ratio of the monomer to the Ni catalyst.

Poly(p-benzamide)s bearing a chiral side chain on the nitrogen atom were synthesized by chain-growth polycondensation methodology. The results of X-ray crystallographic analysis of 4-(methylamino)benzoic acid oligomers substantiated that they have a helical conformation with three monomer units per turn.

The chain-growth polycondensation method for well defined aromatic polyamides has been developed for the synthesis of poly(p-benzamide) with a low polydispersity by the polycondensation of phenyl 4-(4-octyloxybenzylamino)-benzoate followed by deprotection with TFA. The self-assembly of block copolymers and star polymers containing the well-defined poly(p-benzamide) units will be versatile protocol for nanoarchitectures of aromatic polyamides.

A successful chain-growth polycondensation of meta-substituted monomers, 3-(octylamino) benzoic acid esters that yield poly(m-benzamide)s with well-defined molecular weights and low polydispersities is reported. The inductive effect of the nucleophilic site on the reactivity of the electrophilic site at the meta position of the monomer is as applicable to chain-growth polycondensation as is the resonance effect of the para-substituted monomers.