Neutron Diffraction Study of [Nd(AlMe4)3]⋅0.5 Al2Me6 at 100 K: The First Detailed Look at a Bridging Methyl Group with a Trigonal-Bipyramidal Carbon Atom

Weak agostic Nd⋅⋅⋅H interactions and Nd−C bonds are involved in the bonding of the bridging methyl groups in the title compound (see sketch on the right): Two of the three H atoms of the methyl group are directed at the Nd center. The C atoms have distorted trigonal-bipyramidal geometry with the Nd atom and one of the H atoms (H_A) as axial ligands, and the Al atom and the other two H atoms (H_B and H_C) in equatorial positions. The Al₂Me₆ “solvate” molecule is disordered.