Hr. Webb et al., Scandium(III) coordination polymers containing capsules based on two p-sulfonatocalix[4]arenes, CHEM-EUR J, 7(16), 2001, pp. 3616-3620
fReactions of sodium p-sulfonatocalix[4]arene and scandium(III) tristriflat
e in the presence, and absence, of [18]crown-6 give the crystalline complex
es [Sc-2 (mu -OH)(2)(H2O)(10)]{Na-4(H2O)(8)-[calix[4]arene(SO3)(4)](2)} . 1
3H(2)O and {[Sc-2(mu -OH)(2)(H2O)(8)] [Sc(H2O)(4)](2)[calix[4]arene(SO3)(4)
-H+](2)([18]crown-6)} . 16H(2)O. Both complexes involve novel coordination
polymers with calixarene units linked through sodium or scandium centers an
d also feature capsule assemblies through to the head-to-head association o
f calixarenes. A linear array of capsules associated with an infinite chain
of aquo-bridged sodium ions, and an aquated hydroxy-bridged scandium(III)
dimer, [Sc-2(mu -OH)(2)(H2O)(10)](4+), are found in the absence of the crow
n ether. In the presence of [18]crown-6 both hydrated scandium monomers and
dimers bridge between calixarenes in a two-dimensional coordination networ
k. The crown ethers reside in cavities created by two calixarenes from adja
cent polymeric sheets via a variety of supramolecular interactions(hydrogen
-bonding, shape complementarity), and effectively add a third dimension to
the network. The extended structure of both of these polymers is highly por
ous, and resembles a bilayer.