Synthesis of 9-borafluorene analogues featuring a three-dimensional 1,10-bis(o-carborane) backbone

The synthesis of [1,10-bis(o-carboranyl)] boranes was achieved through the deprotonation of 1,10-bis(o-carborane) reagents followed by salt metathesis with (iPr) 2NBCl2. X-ray crystallography confirms planar central BC4 rings and Gutmann-Beckett studies reveal an increase in Lewis acidity at the boron center in comparison to their biphenyl congener, 9-borafluorene.