Covalent conversion of cyclic onium salt end groups of poly(tetrahydrofuran) by bulky counteranions in the absence and presence of macrocyclic compounds

Citation
H. Oike et al., Covalent conversion of cyclic onium salt end groups of poly(tetrahydrofuran) by bulky counteranions in the absence and presence of macrocyclic compounds, MACROMOLEC, 32(9), 1999, pp. 2876-2882
Citations number
27
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
MACROMOLECULES
ISSN journal
00249297 → ACNP
Volume
32
Issue
9
Year of publication
1999
Pages
2876 - 2882
Database
ISI
SICI code
0024-9297(19990504)32:9<2876:CCOCOS>2.0.ZU;2-S
Abstract
A series of bulky carboxylates was introduced as a counteranion for N-methy lpyrrolidinum salt end groups of poly(tetrahydrofuran), poly(THF), having m olecular weights of ca. 5000. 4-(7,7,7-Triphenylheptoxy)benzoate was found to remain intact as a counteranion at ambient temperature but to cause the ring-opening reaction of pyrrolidinium groups at 90 degrees C to produce po ly(THF) with bulky stopper groups in a pure form in 71% yield. The relevant ring-opening reaction also took place in the presence of such macrocyclics as 30-crown-10 and cyclodextrins, but an effective entrapping of cyclic co mponents in polyrotaxanes was not achieved presumably because of the entrop ic repulsion between the two components.