Abstract: | The colored boranes closo- 1 and cyclo- 2 are obtained upon dehalogenation of sterically hindered diaminodichlorodiborane(4) 3 . The TMP groups of 1 cause the formation of a tetrahedrane, whereas in 2 the diisopropylamino substituents stabilize the bent four-membered ring. TMP=2,2,6,6-tetramethylpiperidino. |