A Promising New Dearomatization Agent: Crystal Structure, Synthesis, and Exchange Reactions of the Versatile Complex TpRe(CO)(1-methylimidazole)(η2-benzene) (Tp = Hydridotris(pyrazolyl)borate)

The π-basic metal fragment {TpRe(CO)(MeIm)} (MeIm = 1-methylimidazole; Tp = hydridotris(pyrazolyl)borate) binds a variety of aromatic molecules, including benzene, 2,6-lutidine, and 1 - methylpyrrole, in an η 2 fashion. Although TpRe(CO)(MeIm)(η 2 -benzene) as a solid shows no decomposition over several months at 25 °C under a nitrogen atmosphere, the complex has proven to be a valuable precursor to a variety of other aromatic complexes through ligand exchange reactions in solution.