Trianionic Organoborate Triangles
Scientists at the University of Melbourne in Australia are currently doing research on Trianionic Organoborate triangles (Abrahams, B.F.; Boughton, B.A.; Choy, H.; Clarke, O.; Grannas, M.J.; Price, D.J.; Robson, R, Inorg. Chem. 2008, 47, 10.1021). Specifically, supramolecular systems containing the ligand 3,3,3?,3?-tetramethyl-1,1?spirobisindane-5,5?,6,6?-tetrol, or LH4.
Prior studies have been done on the anion L4-, resulting in boron derivatives with a square arrangement. Continued research has resulted in the Molecule of the Week, which is the new boron derivative, [B3L3]3- ligand. Although studies have been performed using the cations, C3H5N2+, and Et4N+, dabcoH+, I focused on the Et3NH+ cation. When solvated, the [B3L3](Et3NH)2? form stacks of alternating chirality. The overall effect of the overlap results in a Rhombus-like cross section when stacks are viewed from above.
What interested me in particular about this molecule was that the cations were actually located within the ligand, rather than the ligand attaching next to the cation. Also, there is something intrinsically aesthetically pleasing about the organization of the anions. Unfortunately the scientists do not offer any particular use for the development of these molecules beyond simply analyzing their organization.