Synthesis and structural characterization of tris(2-oxo-1-tert-butylimidazolyl) and tris(2-oxo-1-methylbenzimidazolyl)hydroborato complexes: a new class of tripodal oxygen donor ligand

A new class of tripodal L2X ligands that feature three oxygen donors, namely the tris(2-oxo-1-tert-butylimidazolyl) and tris(2-oxo-1-methylbenzimidazolyl) hydroborato ligands, [To(But)] and [To(MeBenz)], has been synthesized via the reactions of NaBH4 with the respective imidazolone. Structural and spectroscopic studies indicate that both [To(But)] and [To(MeBenz)] are significantly more sterically demanding but less electron donating than the related [O-3] donor ligand, [CpCo{P(O)(OEt)(2)}(3)].