Polyethers of low and medium molecular weight containing at both ends
stable ionic groups (phosphonium ions) were obtained by living cationi
c polymerization of tetrahydrofuran initiated by difunctional initiato
r: trifluoromethanesulfonic anhydride, followed by termination with tr
iphenylphosphine. It was shown, that products contain significant quan
tities of low molecular weight diphosphonium salt; a plausible explana
tion is presented. Alternative approach to the synthesis of diionicall
y terminated polyethers was based on the conversion of hydroxyl end-gr
oups of polyether diols, which can be obtained by cationic Activated M
onomer (AM) polymerization of e.g. oxiranes, into phosphonium ion end-
groups. Using this approach, poly(ethylene oxide)'s with M(n) ranging
from 300 to 3400, terminated at both ends with stable ionic groups, we
re prepared and characterized. Measurements of NMR relaxation times an
d viscosity measurements provide the evidence for the aggregation of i
onic end-groups. The potential applications of inter- and intramolecul
ar aggregation are discussed. It is shown, that intramolecular aggrega
tion of ionic terminal groups in low molecular weight poly(ethylene ox
ide) leads to cyclic structures resembling crown ethers and showing co
mparable efficiency for complexing cations.