First molecular octahedral rhenium cluster complexes with terminal As- and Sb-donor ligands

Six new molecular octahedral cluster complexes with the general formulas trans-{Re₆(μ₃-Q)₈}(EPh₃)₄Br₂] and fac-{Re₆(μ₃-Q)₇(μ₃-Br)}(AsPh₃)₃Br₃] (Q = S or Se and E = As or Sb) were synthesized by the reactions of the cesium salts of the {Re₆(μ₃−S)₈}Br₆]⁴⁻, {Re₆(μ₃-Se)₈Br₆]³⁻, and {Re₆(μ₃-Q)₇(μ₃-Br)}Br₆]³⁻ anions with molten triphenylarsine (AsPh₃) and triphenylantimony (SbPh₃), respectively. The compositions and structures of the resulting complexes were established by single-crystal X-ray diffraction and confirmed by elemental analysis and vibrational spectroscopy. The compositions and structures of the complexes depend on the composition of the cluster core in the starting salts. The luminescence spectra were recorded for powdered samples of all these compounds and the earlier described complexes trans-{Re₆Q₈}(PPh₃)₄Br₂] and fac-{Re₆Q₇Br}(PPh₃)₃Br₃]. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1614–1619, August, 2008.