New methodologies for construction of hyperbranched organic and organometallic polymers

A series of completely soluble hyperbranched polymers were synthesized by polycyclotrimerization of diynes for the first time. TaCl5-Ph 4Sn was found to be the effective catalyst and toluene to be the efficient solvent. A possible polycyclotrimerization mechanism via tantalacyclopentadiene intermediates is proposed. The polymerization processes including initiation, propagation and termination are analyzed.The unique backbiting reaction was found to be a plausible way to terminate the propagation chain. Conformations of the diynes greatly affect the occurrence of backbiting reaction and affect the solubility of resultant polymers to certain extent. Diynes with short spacers such as 1,5-hexadiyne (21 ) 1,6-heptadiyne (22) 1,7-octadiyne (23) and 1,8-nonadiyne (17) possess a conformation in which the two triple bonds locate closely. Such a conformation makes the backbiting termination to occur easily. Thus, soluble polymers are readily formed from these diynes.For the diynes of long spacers, a conformation with two far-separating triple bonds dramatically reduces the chance of backbiting reaction. Consequently, only partially soluble or insoluble polymers could be prepared.In the polycyclotrimerization of internal diynes, hexasubstituted benzene rings were formed. The steric effect of the terminal substituents plays an important role in the polymerization reaction. Internal diynes with bulky substituents such as 1,9-bis(trimethylsilyl)-1,8-nonadiyne (74), 1,6-bis(dimethylphenylsilyl)-1,5-hexadiyne (75), 1,8-bis(dimethylphenylsilyl)-1,7-octadiyne (76) gave little amount of polymers. Internal diynes with less bulky substituents and short spacers [e.g. 3,9-dodecadiyne (78) and 2,9-undecadiyne (79)] offered soluble polymers.In the study on hyperbranched organometallic polymers, a new methodology for the preparation of hyperbranched polysilynes was developed. Ceramization of the hyperbranched polymers produced mesoporous magnetoceramic materials. The compositions of the ceramic products 125--133 change with the pyrolytic conditions.Transition metal carbonyl complexes M(CO)3(mes) (M = Mo, W) and Mo(CO)3(nbd) (mes = mesitylene, nbd = norbornadiene) were found to be the effective, are-stable, and single-component catalysts for the polymerizations of acetylenes with both nonpolar and polar functional groups. (Abstract shortened by UMI.)...