Selective Rb+ vs. K+ Guest Incorporation in Wheel‐Shaped 27‐Tungsto‐3‐Arsenate(III) Host, [M⊂{(β‐AsIIIW8O30)(WO(H2O))}3]14– (M = K, Rb). Issue 3 (10th October 2018) - Kandasamy, Balamurugan
Abstract : The wheel‐shaped, potassium‐templated 27‐tungsto‐3‐arsenate(III) [K⊂{(β‐As III W8 O30 )(WO(H2 O))}3 ] 14– (1 ) was synthesized by simple one‐pot condensation of the trilacunary [ B ‐α‐As III W9 O33 ] 9– precursor in aqueous, acidic KCl solution. Polyanion1 comprises three β‐{AsW8 O30 } units linked via three trans ‐{WO(H2 O)} groups, forming a cyclic assembly with a potassium ion located in the central cavity. The rubidium‐analogue [Rb⊂{(β‐As III W8 O30 )(WO(H2 O))}3 ] 14– (2 ) could also be prepared, by addition of a small amount of Rb + ions to a solution containing a large excess of K + ions. This indicates that the rigid [{(β‐As III W8 O30 )(WO(H2 O))}3 ] 15– (As3 W27 ) host exhibits high selectivity for Rb + ion guests compared to K + ions. Polyanions1 and2 were characterized in the solid state by single‐crystal XRD, FT‐IR, TGA, and elemental analysis. Abstract : We have prepared a trimeric, wheel‐shaped 27‐tungsto‐3‐arsenate(III) host, M⊂As3 W27 (M = Rb, K), which exhibits high selectivity for Rb + ions, in analogy to organic crown ethers.