Abstract
A series of bis- and tris(oxobenzimidazolyl)hydroborato compounds, namely, [Bo
]Na and [To
]-Na (R = Me, Bu
, Ad), which feature uncommon sterically demanding LX [O
] and L
X [O
] donor ligands, have been obtained via the reactions of NaBH
with 1-R-1,3-dihydro-2H-benzimidazol-2-ones. Evidence that the alkyl substituents are suitably located to have a significant impact on the coordination environment is provided by the observation that the methyl derivative [To
]Na(κ
-diglyme) exhibits κ
-coordination of the diglyme, whereas the t-butyl and adamantyl derivatives, [To
]Na(κ
-diglyme) and [To
]Na(κ
-diglyme), exhibit κ
-coordination. The [Bo
] and [To
] ligands also allow for isolation of discrete mononuclear thallium compounds, [Bo
]Tl and [To
]Tl, for which the steric demands of the ligands have been quantified in terms of both cone angle and buried volume concepts.