Efficiency of Packing the Sulfonato-calix[5]arene Bilayer Relative to the Ubiquitous Sulfonato-calix[4]arene Analogue

Ytterbium(III) forms a complex with sulfonato-calix[5]arene in water with the calixarene assembled into the common clay bilayered arrangement but having unusually dense packing of the calixarenes, which are squeezed together forming “impenetrable” bilayers. The efficiency of packing of the calixarene relates to its conformational flexibility, and it has implications in providing a protective layer in stabilizing spheroidal nanoparticles.