Crowned polyacetylene. I. Synthesis and characterization of poly(4′‐ethynylbenzo‐15‐crown‐5)

Abstract

Abstract 4′‐Ethynylbenzo‐15‐crown‐5 ( EB15C5 ) polymerized with high yields in the presence of (bicyclo[2.2.1] hepta‐2,5‐diene) rhodium(I) chloride dimer and triethylamine as a cocatalyst in chloroform at 30°C. Common catalysts for the polymerization of substituted acetylenes, WCl 6 and MoCl 5 , did not produce any polymer from EB15C5 . The structure of the main chain for poly(4′‐ethynylbenzo‐15‐crown‐5) ( PEB15C5 ) was determined to be predomi‐nantly cis form, based upon the relatively sharp signals attributed to the main chain atoms that was observed in the 1 H and 13 C NMR spectra. The cation‐binding properties of PEB15C5 are very similar to that of poly(4′‐vinylbenzo‐15‐crown‐5), and the selectivity is in the order of K + > Rb + ≫ Cs + ⋙ Na + , Li + . The electrical conductivity of PEB15C5 increased from 1.3 × 10 −10 to 1.3 × 10 −6 S. cm −1 , when the polymer was doped with iodine. © 1995 John Wiley & Sons, Inc.