New Rhenium Octahedral Cluster Sulfido-cyanide Chain Polymer: The Synthesis and Crystal Structure of Cs₄[{Re₆S₈}(CN)₄S_2/2]

Recently it was shown that reaction of ReS₂ with KCN at elevated temperature leads to formation an unique layered compound K₄Re₆S₁₀(CN)₂. In this polymer the Re₆S₈ units are linked into two-dimensional grids by sharing four apical sulphide ligands. Additionally two 'trans' rhenium atoms in cluster core are coordinated by terminal cyano-groups. Thus, crystallographic formula of this compound may be written according to Schafer notation as K₄[{Re₆Sⁱ₈}(CN)^a₂(S)^a-a_4/2]_∞∞. From formal point of view this compound could be presented as cleavage of two Re-μ₂S-Re bridges in [{Re₆Sⁱ₈}(S)^a-a_6/2] and substitution of them by terminal cyano-ligands. In present work we report the synthesis and crystal structure of new chain polymer Cs₄[{Re₆Sⁱ₈}(CN)^a₄(S)^a-a_2/2]_∞ which is the next member of a series M₄[{Re₆Sⁱ₈}(CN)^a_2x(S)^a-a_(6-2x)/2], where M is alkali metal. This compound was obtained with high yield by high temperature reaction of ReS₂ with KCN in presence of CsCl excess