Hexagonal supramolecular assemblies based on a Ru^II(DMSO) ₃- or Os^II(DMSO)₃-Capped {HW₉O ₃₃} isopolyanion with potassium cations as linkers

Crystallization of the {HW₉O₃₃} isopolyanion in the presence of M^II(DMSO)₄Cl₂ (where M = Ru, Os) and Na and K cations yielded one-dimensional chains, {K[HW₉O ₃₃M₂(C₂H₆SO)₆] ^6-}_n. The {HW₉O₃₃} isopolyanion is capped by M^II(DMSO)₃ moieties, which are, in turn, linked by potassium cations. The chains for the Ru^II-based compound show a prismatic coordination around the K⁺ linker and {HW₉O ₃₃} moieties that are eclipsed relative to each other along the chain, while the Os^II-based compound has an octahedral coordination around the K⁺ linker and {HW₉O₃₃} moieties that are staggered relative to each other along the chain. The three-dimensional arrangement of the two compounds is quite different. For the Ru^II compound, channels are obtained by the arrangement of six {K[HW ₉O₃₃Ru₂(C₂H₆SO) ₆]^6-}_n chains along the c axis. The channel is stabilized by the binding of sodium cations, which interlock the chains through coordination of different oxygen atoms and leads to a tight staggered arrangement between the chains of {K[HW₉O₃₃Ru ₂(C₂H₆SO)₆]^6-} _n. The channels have an approximate diameter of 8 Å and are occupied by layers of six sodium cations that form chair-like hexagons with Na-Na interatomic distances of 2.807 Å. There are five water molecules that separate the layers of the Na⁺ cations. For the osmium compound, two different types of channels, defined by the arrangement three {K[HW ₉O₃₃Os₂(C₂H₆SO) ₆]^6-}_n chains, are formed. The channels are formed through interchain bonding through a bridge formed by connecting sodium atoms to the terminal atoms of the {HW₉O₃₃} unit. Here, the {K[HW₉O₃₃Os₂(C₂H ₆SO)₆]^6-}_n chains are eclipsed relative to one another. Water molecules occupy one channel, while the other channel is occupied by K⁺ cations hexacoordinated to aqua ligands. The approximate diameter of the channels is 5.5 Å.