Synthesis, characterization, and X-ray crystal structure of the octabromodiosmate(III) salt [(C5Me4H)2OsBr]2[Os2Br8] and its conversion to [(C5Me4H)2OsBr][Os2HBr4(cod)2]

The salt [(C5Me4H)2OsBr]2[Os2Br8] has been synthesized and the Os2Br82- anion shown to adopt an eclipsed (D4h) conformation. Treatment of [(C5Me4H)2OsBr]2[Os2Br8] with 1,5-cyclooctadiene in ethanol affords octamethylosmocene, (C5Me4H)2Os, and the salt [(C5Me4H)2OsBr][Os2HBr4(cod)2], which is a rare example of a diosmium complex containing a bridging hydride.