Synthesis and Structural Characterization of Bis(2-oxoimidazolyl)hydroborato Complexes: A New Class of Bidentate Oxygen-Donor Ligands

A new class of bidentate ligands that feature oxygen donors, namely, the bis(2-oxo-1-tert-butylimidazolyl)hydroborato and bis(2-oxo-1-methylbenzimidazolyl)hydroborato ligands, [Bo(But)] and [Bo(MeBenz)], have been synthesized via the reactions of MBH4 with 2 equiv of the respective 2-imidazolone. Chelation of [Bo(But)] and [Bo(MeBenz)] to a metal center results in a flexible eight-membered ring that is capable of adopting a boatlike conformation that allows for secondary M center dot center dot center dot H-B interactions.