No abstract

No abstract

The electrophilic 14-electron alkyltitanium cations [cp2TiMe]+ (cp = 75-cyclopentadienyl) and [ind2TiMe]+ (ind = 75-indenyl), accessible via several routes, form stable complexes [cp2TiMe(L)]+ and [ind2TiMe(L)]+, L = NH3, PMe3, pyridine, MeCN, ButCN and react readily with CO and ButNC; the insertion of nitrites into titanium-carbon bonds is described.

No abstract

Perfluoroalkyl side-chain polyesters of the type -[0(CH2)2N{S02(CF2)gF}(CH2)202C(CH2)m-CO]"-, with m = 2-4,8,12, and 20, have been synthesized in high yield directly from the diacid and the diol, using a coupling agent. Molecular weights up to 40 000 were obtained. The polyesters with m > 3 showed enantiotropic mesophases, although they have no flexible spacer between the main chain and the side-group mesogen. The rigid perfluoroalkylsulfonamide group and the segregating tendency of fluorocarbons and hydrocarbons give these polyesters their liquid crystalline behavior. The mesophases were investigated by polarizing optical microscopy, DSC, and rheological DMA. They have a grainy optical texture in the POM, multiple transitions in the DSC and a low-viscosity mesophase regime in mechanical analysis.