Polyhedral azaborane chemistry. The establishment of members of the hypho-type family [(RH2N)B8H11NHR], where groups R are now other than ethyl

The reaction of [B 9 H 13 (SMe 2 )] with primary amines NH 2 R to give eight-boron cluster species [(RH 2 N)B 8 H 11 NHR] is not limited to the case where R = ethyl. We find that the n-butyl, isopropyl and tert-butyl analogues are also readily formed. The structural type is illustrated by a single-crystal X-ray diffraction analysis on the isopropyl member of the family. The reaction proceeds stepwise, via an initial ligand exchange on [B 9 H 13 (SMe 2 )] to give [B 9 H 13 (NH 2 R)], as confirmed by treatment of [B 9 H 13 (SMe 2 )] with NH 2 Bu t to give [B 9 H 13 (NH 2 Bu t )] followed by treatment with Pr i H 2 N to give the mixed species [(Pr i H 2 N)B 8 H 11 NHBu t ], also confirmed by single-crystal X-ray work, and showing that the amine on the starting arachno-{B 9 H 13 } residue is the one that finishes in the more intimately bound bridging position.