Hexasulfonated Calix[6]arene Derivatives: A New Class of Catalysts, Surfactants, and Host Molecules

Seiji Shinkai, Seiichi Mori, Hiroshi Koreishi, Takayuki Tsubaki, Osamu Manabe

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463 Citations (Scopus)

Abstract

Water-soluble hexasulfonated calix[6]arenes with various substituents (1-R) have been synthesized for the first time and applied as host molecules in an aqueous system. Dynamic 1H NMR studies established that calix[6]arene-p-hexasulfonate (1-H) adopts a “winged” or “hinged” conformation in D2O-Me2SO-d6 (2:1 v/v) owing to hydrogen bonding among the OH groups, while 5,11,17,23,29,35-hexasulfonato-37,38,39,40,41,42-hexakis(hexyloxy)calix[6]arene (1-C6) adopts a similar conformation in D20 owing to hydrophobic bonding among the hexyl groups. The aggregation behavior in water was examined about 1-C6 and 1-C12. Physical (light-scattering, surface tension, and conductance) and spectral (fluorescence and absorption spectroscopies) studies established that 1-C6 has a cmc at ca. 6 X 10-4 M, as does sodium dodecyl sulfate (SDS), while 1-C12 has no detectable cmc and rather acts as a “unimolecular” micelle. In fact, 1-C6 associated with small molecules (pyrene, 2-anilinonaphthalene, and Orange OT) according to the micelle-like biphasic concentration dependence, while 1-C12 formed host-guest-type 1:1 complexes with these molecules. It was found that these calix[6]arene derivatives efficiently accelerate acid-catalyzed hydration of 1-benzyl-1,4-dihydronicotinamide and the reaction proceeds according to the Michaelis-Menten kinetics. In particular, the rate constants for 1-H and l-CH2COOH, which both have acidic protons to catalyze the reaction and anionic sulfonates to stabilize the cationic intermediate at the two edges of the cavity, were greater by 426-1220-fold than those for noncyclic analogues. These findings indicate that hexasulfonated calix[6]arenes serve as a new class of catalysts, surfactants, and host molecules. This is the first example for the host-guest-type behavior of calixarenes observed in an aqueous system.

Original languageEnglish
Pages (from-to)2409-2416
Number of pages8
JournalJournal of the American Chemical Society
Volume108
Issue number9
DOIs
Publication statusPublished - 1986
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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