A New Phase of the Octahedral Tellurium-Iodine Cluster Complex of Rhenium

A cluster complex of the composition [{Re₆Te₈}(TeI₂)₆]I₂·[{Re₆Te₈}(TeI₂)₄(TeI₃)₂]·I₂ is obtained by a reaction between [{Re₆Te₈}Te₇] and I₂ in a sealed quartz ampoule at 400 °C. More than three times increase in the volume of the ampoule in which the reaction is performed with maintaining the other conditions is shown to lead to the formation of the previously described cluster complex [{Re₆Te₈}(TeI₂)₆]I₂. An increase in the synthesis temperature to 450 °C leads to the formation of X-ray amorphous products of the unknown composition. The [{Re₆Te₈}(TeI₂)₆]I₂·[{Re₆Te₈}(TeI₂)₄(TeI₃)₂]·I₂ compound obtained at 400 °C crystallizes in the triclinic crystal system, space group \(P\bar{1}\) , and unit cell parameters a = 11.0859(3) Å, b = 11.9021(4) Å, c = 21.1308(7) Å, α = 79.259(2)°, β = 85.533(2)°, γ = 66.220(2)°, V = 2506.55(14) Å³, Z = 1. The crystal structure consists of four layers of two types that alternate along the c parameter: 1) the layer formed by iodine anions and [{Re₆Te₈}(TeI₂)₆]²⁺ cluster cations and 2) the layer formed by neutral cluster complexes [{Re₆Te₈}(TeI₂)₄(TeI₃)₂] and crystallization I₂ molecules. Weak interactions between the adjacent cluster complexes are observed in both layers along with I⋯I halogen bonds. The layers are linked with each other via I⋯I and Te⋯I interactions.