Lanthanide-induced helical arrays of [{Co(iii) sepulchrate} ∩ {p-sulfonatocalix[4]arene}] supermolecules

Abstract

In the presence of lanthanide ions, a Co(III) sepulchrate cation [Co(diHOsar)]3+ and sodium p-sulfonatocalix[4]arene form a 1:1 host-guest complex which is self-assembled into a zeolite-like lattice network comprised of parallel, single stranded helices.

From Simple Rings to One‐Dimensional Channels with Calix[8]arenes, Water Clusters, and Alkali Metal Ions.

“…Here, however, as with all the other alkali metals, the formation of a crystalline complex was the result of using the interfacial crystallization method. Thus, reaction of 4-tert-butylcalix [8] 27 Here, the square is stabilized by two hydrogen bond interactions (O16-O9; 2.715(2) Å ) with two THF molecules, each water molecule in fact being oriented in such a way that one hydrogen atom bridges to the neighboring water molecule whereas the second hydrogen atom points outward from the square. 27,28 Further water molecules (O17 and symmetry equivalents) are linked to oxygen atoms of the calixarene ligand and are shielded by H bonding to THF ligands (O12) arranged around the sandwich structure.…”

“…11 This is certainly due to different reasons such as limited solubility, poor control over stereoselective substitution reactions at the two rims, and finally the high flexibility of the molecules itself, which allow a large variety of structural conformations and hence hinder long-range order in the solid state. While calix [4]arenes can be observed in four conformations (cone, partial cone, 1,2-alternate or 1,3-alternate) in solution, calix [8]arenes can adopt in principle more conformations, although the 'pleated loop' conformation is favored even in solution because of intramolecular hydrogen bonding by the OH groups. 12 This hydrogen bond stabilization may be weakened upon metallation of the hydroxide groups, leading to more flexible conformations.…”

“…[7][8][9] In addition to the large choice of ring sizes, calixarenes can adopt different conformations, which can be tuned by substituents at the upper and/or lower rims. In the calixarene family, calix [4]arenes have been the most intensively studied, 10 while calix [8]arenes remain comparatively little investigated in the solid state. 11 This is certainly due to different reasons such as limited solubility, poor control over stereoselective substitution reactions at the two rims, and finally the high flexibility of the molecules itself, which allow a large variety of structural conformations and hence hinder long-range order in the solid state.…”

Solid‐state Supramolecular Architectures by p‐Sulfonatocalix[4]arene with Bispyridinium Derivatives

“…In the broad area of supramolecular chemistry and crystal engineering, p-sulfonatocalix [n]arenes (CnAS,n＝4,5,6,8), with high water-solubility, multicharged rims, and flexible frameworks, are demonstrated to be a well-known kind of versatile building blocks. 1 Several kinds of spectacular architectures besides the conventional bilayer array 2 have been fabricated by CnAS upon complexation with various types of guest molecules and/or metal ions, such as molecular capsules, 3 the "ferris wheel", 4 the "Russian doll", 5 the helical array, 6 water-filled channels, 7 coordination and hydrogen-bonding polymers, honeycomb aggregates, 8 spheroidal 9 and tubular arrays, 10 and others.…”

“…1 Several kinds of spectacular architectures besides the conventional bilayer array 2 have been fabricated by CnAS upon complexation with various types of guest molecules and/or metal ions, such as molecular capsules, 3 the "ferris wheel", 4 the "Russian doll", 5 the helical array, 6 water-filled channels, 7 coordination and hydrogen-bonding polymers, honeycomb aggregates, 8 spheroidal 9 and tubular arrays, 10 and others. 11 Among the family of these water-soluble calixarenes, p-sulfonatocalix [4]arene (C4AS), as the smallest conformation-constrained analogue, emerges to be the most popular subunit that is convenient for studying the influences of different guests upon the formation of supramolecular assemblies from host-guest complexes.…”