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Keywords:

  • Polyoxometalates;
  • Tungsten;
  • Ruthenium;
  • Osmium;
  • X-ray diffraction

Abstract

Crystallization of the {HW9O33} isopolyanion in the presence of MII(DMSO)4Cl2 (where M = Ru, Os) and Na and K cations yielded one-dimensional chains, {K[HW9O33M2(C2H6SO)6]6–}n. The {HW9O33} isopolyanion is capped by MII(DMSO)3 moieties, which are, in turn, linked by potassium cations. The chains for the RuII-based compound show a prismatic coordination around the K+ linker and {HW9O33} moieties that are eclipsed relative to each other along the chain, while the OsII-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 RuII compound, channels are obtained by the arrangement of six {K[HW9O33Ru2(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[HW9O33Ru2(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[HW9O33Os2(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(C2H6SO)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.