6 ·26H 2 O (7) were obtained in high yield by reaction of cucurbituril with aqueous solutions of lanthanide(III) species. The crystal structures of the compounds show a packing of 1:1, 2:2, and 2:3 in the (cucurbituril)lanthanide [a]

A series of new zinc­(II)–thiophene-2,5-dicarboxylate (tdc) MOFs based on novel dodecanuclear wheel-shaped building blocks has been synthesized in almost quantative yields. Single-crystal X-ray diffraction analyses reveal 3D porous frameworks with a complex composition [Zn12(tdc)6(glycolate)6(dabco)3] where glycolate is a deprotonated polyatomic alcohol (ethylene glycol, EgO2, 1; 1,2-propanediol, PrO2, 2; 1,2-butanediol, BuO2, 3; 1,2-pentanediol, PeO2, 4; glycerol, GlO2, 5) and dabco is 1,4-diazo[2.2.2.]­bicyclooctane. All compounds 1–5 are isostructural except for pendant groups of the diols decorating the surface of channels. The adsorption of small gases (N2, CO2, CH4, C2H2, C2H4, C2H6) and larger hydrocarbons (benzene, cyclohexane) both in liquid and vapor phases was thoroughly investigated for all compounds. The zero-coverage adsorption enthalpies, Henry constants, and selectivity factors by various models are calculated and discussed. The versatile adsorption functionality of the title series results from the variable nature of the diol and could be tailored for a specific adsorbate system. For example, 1 shows excellent selectivity of benzene over cyclohexane (20:1 for vapors, 92:1 for liquid phase), while 4 demonstrates unprecedented adsorption preference of cyclohexane over benzene (selectivity up to 5:1). The compound 5 demonstrates great adsorption selectivity for CO2/N2 (up to 75.1), CO2/CH4 (up to 7.7), C2H2/CH4 (up to 14.2), and C2H4/CH4 (up to 9.4). Also, due to polar nature of the pores, 5 features size-selective sorption of alkaline metal cations in order Li+ > Na+ > K+ > Cs+ as well as a notable luminescent response for cesium­(I) ions and urea.

The NIIC-20 (NIIC stands for Nikolaev Institute of Inorganic Chemistry) is af amily of five isostructural metalorganic frameworks (MOFs) based on dodecanuclear wheelshaped carboxylate building blocks {Zn 12 (RCOO) 12 (glycol) 6 } (glycol is deprotonated diatomic alcohol:ethylene glycol, 1,2propanediol, 1,2-butanediol, 1,2-pentanediol or glycerol), quantitatively crystallized from readily available starting chemicals.T he crystal structures contain large mesoporous cages of 25 connected through {Zn 12 }r ings,o fwhichi nner diameter and chemical nature depend solely on the chosen glycol. The NIIC-20 compounds feature high surface area and rarely observed inversed adsorption affinity for saturated hydrocarbon (ethane) over the unsaturated ones (ethylene, acetylene). The corresponding IAST (Ideal Adsorbed Solution Theory) adsorption selectivity factors reach as muchas15.4 for C 2 H 6 /C 2 H 4 and 10.9 for C 2 H 6 /C 2 H 2 gas mixtures at ambient conditions,e xceeding those for any other porous MOF reported so far.T he remarkable combination of high adsorption uptakes and high adsorption selectivities makes the NIIC-20 series an ew benchmark of porous materials designed for ethylene separation applications.