Inorganic Chemistry, Vol.47, No.21, 9797-9803, 2008
Trianionic Organoborate Triangles
The rigid, angular ligand 3,3,3', 3'-tetramethyl- 1, 1'spirobisindane-5,5',6,6'-tetrol, LH4, in the form of its tetra-anion, L4-, affords crystalline compounds containing the triangular macrocyclic boron derivative [B3L3](3-) with the counter cations, triethylammonium, imidazolium, tetraethylammonium, and protonated dabco (dabco = 1,4-diazabicyclo[2,2,2]octane). Within a triangular unit all three chiral L4- ligands have the same hand although the crystal does contain a racemic mixture of macrocycles. In all four compounds, one out of the three counter-cations per macrocycle is bound inside the macrocycle.