Synthesis and properties of a fifteen-coordinate complex: The thorium aminodiboranate [Th(H₃BNMe₂BH₃)₄]

(Figure Presented) Playing with a full deck: Single-crystal X-ray and neutron diffraction data show that the Th center in the title complex 1 (see structure; Th orange, B beige, N purple, C black, H blue) forms bonds with 15 H atoms, thus making 1 the first crystallographically characterized example of a complex with a Werner coordination number of fifteen. DFT calculations suggest that 1 adopts the fully symmetric 16-coordinate structure in the gas phase.