Abstract-From steric considerations as well as from an analysis of CD spectra a (P)-screw configuration could be attributed to the (-)-rotating molecules of poly(t-butyl isocyanide).

Each of nine chiral isocyanides, R*-N=C, in enantiomerically pure or almost pure form, is polymerized to the corresponding poly(iminomethylene), [R*-N=C<]n. The group R* either contains at least one substituent (carboxylic ester, phenyl, phosphinyl) or is unsaturated (C=C, C=C). The polymers are of the rigid-rod type with a helical main chain of carbon atoms. Because of the chirality of R*-N=C either the P or the M helix is preferentially formed. CD spectra and optical rotation at 578 nm are determined and compared with those of the model compounds R*-N=CH(i-C4H9) and the monomers. This comparison and earlier calculations on [i-C4H9-N=C<]n allowed the assignment to each polymer of the excess screw sense. The screw sense is also theoretically predicted by two approaches, a thermodynamic and a kinetic one. The latter approach gives an appreciably better fit with the experimental results.

No abstract

A polymer of an isocyanide (R–N=C<)n has been synthesized in which R contains a benzo‐18‐crown‐6 group. The crown ether rings are on top of each other and form channels which bind metal ions. The channel compound can be incorporated in vesicles and is able to transport ions across the bilayer membrane.

Please be advised that this information was generated on 2018-05-10 and may be subject to change. Pays-Bas, 105/9, september 1986 255 ether extracts of the aqueous phase. Most of the diol mixture (1.09 g, 84 %) was found in the precipitate. After drying (M g S 0 4) and removal of solvent, the crude diol mixture (1.22 g, 93%) was obtained. Recueil des Travaux Chimiques des Separation of diolsThis was effected (700 mg product per column) using silica (150 g; Woelm, 100-200, aktiv) in a 42 cm x 39 mm column. A slurry of silica in hexane was poured into the column. Eluents were hexane/EtOAc: 9/1 (200 ml), 4/1 800 ml), 7/3 (3000 ml), 3/7 (1000 ml). More polar eluents cause exothermic reaction with silica, moderated by external cooling to 5 -1 0°C using a wet ice-cold cloth.The order of elution was diol 2 (235 mg, 34%) followed by diol 3 (310 mg, 44%, both after purification). Total yield from the column was 86%; of pure diols 78%. Each diol showed only one TLC spot. Department of Organic Chemistry, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands (Received February 10th, 1986) Abstract.The synthesis of polymers of isocyanides having stacks of donor and acceptor functions in their side-chains is described. These side-chains are based on the betaine compounds used by Dimroth et al. for the construction of their ET scale of solvent polarity. The UV-VIS spectra of the polymers together with those of the low-molecular-weight model compounds are discussed. Svn,svn-D'\o\