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 [B9H13(SMe2)] with primary amines NH2R to give eight-boron cluster species [(RH2N)B8H11NHR] 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 [B9H13(SMe2)] to give [B9H13(NH2R)], as confirmed by treatment of [B9H13(SMe2)] with NH2But to give [B9H13(NH2But)] followed by treatment with (PrH2N)-H-i to give the mixed species [((PrH2N)-H-i)B8H11NHBut], also confirmed by single-crystal X-ray work, and showing that the amine on the starting arachno-{B9H13} residue is the one that finishes in the more intimately bound bridging position.