The supramolecular binding exclusively by H-bonds of SeO42–, MoO42– and WO42– ions to form nanojars of the formula [EO42–⊂{cis-CuII(μ-OH)(μ-pz)}n]2– (CunEO4; E = Se, Mo, W; n = 28–34; pz = pyrazolate) was studied in solution by electrospray ionization mass spectrometry, variable temperature, paramagnetic 1H NMR and UV–vis spectroscopy, and in the solid state by single-crystal X-ray crystallography. These large anions allow for the observation of a record nanojar size, Cu34EO4 (E = Mo, W). Six crystal structures are described of nanojars of varying sizes with either SeO42–, MoO42– or WO42– entrapped ions, including the first example of a cocrystal of two different nanojars in crystallographically unique positions, Cu31MoO4 and Cu32MoO4. The latter provides unprecedented structural information about the Cu8+Cu14+Cu10 ring combination of a nanojar with an entrapped tetrahedral anion. Also, the first crystal structure of a supramolecular host–guest complex with an entrapped WO42– ion, Cu31WO4 is reported in this work. The relative strength of binding of SeO42–, MoO42– and WO42– ions by nanojars of different sizes was assessed by reactivity studies toward Ba2+ ions and NH3. Thermal stability studies of the various CunEO4 nanojars were conducted in DMSO-d6 solutions over a 22–150 °C range. Furthermore, liquid–liquid extraction of SeO42–, MoO42– and WO42– ions from water into an organic solvent by nanojars was investigated.

Supramolecular Entrapping and Extraction of Selenate, Molybdate and Tungstate Ions from Water by Nanojars