Metal sulfonatocalix[4,5]arene complexes: Bi-layers, capsules, spheres, tubular arrays and beyond

Jerry L. Atwood, Leonard J. Barbour, Michaele J. Hardie, Colin L. Raston

Research output: Contribution to journalReview articlepeer-review

377 Citations (Scopus)

Abstract

The main focus of this review is the self-assembly in aqueous solutions of bowl-shaped sodium p-sulfonatocalix[4,5]arenes with main group, transition metal and lanthanoid species, and with various organic molecules as additional supramolecular building components, for example 18-crown-6, and other macrocycles, pyridine N-oxide, amino-acids, and more. The versatility of building up new materials based on these components is demonstrated by the formation of a diverse range of complex inclusion structures assembled through π-stacking, hydrogen bonding and coordination interactions. There are up-down arrangements of calix[4]arenes in hydrophobic-hydrophobic bi-layer structures with the positively charged species and included molecules between the layers. A variant of this is prevalent in structures incorporating 18-crown-6 which, in essence, are built up of globular superanions or ionic capsules, for example {Na+ ⊂ (18-crown-6)(H2O)n} ⊂ {(p-sulfonatocalix[4]arene4-)2}7-, n = 0 or 2. These can crystallize, often selectively, polynuclear hydrolytic M(III) cations [M2(OH)2(H2O)8]4+, [M3(OH)4(H2O)10]5+, [M4(OH)6(H2O)12]6+, M = Cr or Rh, or [Al13O4(OH)24(H2O) 12]7+, depending on the pH and other synthetic parameters. Lanthanide(III) ions form a range of complexes at specific pH in the presence of the calixarene and crown ether, including complexes containing the capsule [{18-crown-6} ⊂ ((M(H2O)7 3+ )1.33(p-sulfonatocalix[4]arene4-)}2], for the smaller lanthanides, or the Ferris-wheel type structure [{La3+ ⊂ (18-crown-6)(OH2)3} ∩ {(p-sulfonatocalix[4]arene4- + 2H+)}]+, for the larger lanthanide. In the presence of pyridine N-oxide, at pH 4 where the calixarenes take on 5 - charge, an up-up arrangement of sulfonated calixarenes results, either assembled in icosahedral spheres, or infinite chiral, helical nano-tubes.

Original languageEnglish
Pages (from-to)3-32
Number of pages30
JournalCoordination Chemistry Reviews
Volume222
Issue number1
DOIs
Publication statusPublished - 1 Jan 2001
Externally publishedYes

Keywords

  • Sodium p-sulfonatocalix[4,5]arenes
  • Supramolecular building components

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