Multinuclear beryllium amide and imide complexes: structure, properties and bonding.

The beryllium amide and imide complexes [Be(HNMes) 2 ] 3 , [(py) 2 Be(HNMes) 2 ], [Be(HNDipp) 2 ] 2 , [Be(NPh 2 )(μ 2 -HNDipp)] 2 and [Be(NCPh 2 ) 2 ] 3 have been prepared and characterised with NMR and IR spectroscopy as well as single crystal X-ray diffraction. Analysis of the localised molecular orbitals (LMOs) and intrinsic atomic orbital (IAO) atomic charges in the framework of the intrinsic bond orbital (IBO) localization method revealed a covalent bonding network consisting of 2-electron-2-centre and 2-electron-3-centre σ bonds, in which one electron pair of the anionic N-donor ligands is involved. The electron deficiency at the beryllium atoms is partially compensated through additional electron donation from the lone pair at the nitrogen atoms.