Molecular octahedral sulfido-bromide rhenium clusters: Synthesis and crystal structure of (PPh(4))(2)[Re6S6Br8]center dot CH3C6H5 and (PPh(4))(3)[Re6S7Br7]

Two high-temperature (550 degrees C) methods were used to prepare sulfide-bromide cluster complexes of rhenium; namely the reaction of Re3Br9 with PbS in the presence of KBr, and the reaction of Re6S4Br10 with KNCS. From the former reaction, a salt of [Re6S6Br8](2-) has been obtained while the latter reaction gave a [Re6S7Br7](3-) salt. X-ray structure determinations have shown both (PPh(4))(2)[Re6S6Br8]. CH3C6H5 and (PPh(4))(3) [Re6S7Br7] have Re-6 clusters with bromine atoms at terminal positions. The face-capping positions are randomly occupied by sulfur and bromine atoms.