Ein neuer Zugang zum ikosaedrischen closo ‐NB 11 ‐Gerüst

A Novel Access to the Icosahedral closo NB 11 Skeleton At 200°C, the open skeleton of NB 9 H 12 is closed to the icosahedral skeleton of NB 11 H 10 Y ( 3 ) by the action of three equivalents of Et 3 N · BH 3 , whereby one equivalent forms a bridge Y = BH 2 NEt 2 CH 2 CH 2 between the adjacent cluster atoms N1 and B2; the product 3 crystallizes in the space group P ¯. With L · BH 3 (L = NMe 3 , SMe 2 ) instead of Et 3 N · BH 3 , the nido ‐borane NB 9 H 12 is transformed into the closo ‐borane (LBH 2 )NB 11 H 11 ( 4a, b ) at 140°C. By allowing t BuNH 2 to react with 4b , the N ‐bonded ligand Me 2 SBH 2 is removed with formation of the aza‐ closo ‐dodecaborate [ t BuNH 3 ] [NB 11 H 11 ], thus opening a new route to closo ‐NB 11 H 12 .