2,3,5,6-tetrakis[3,5-bis(trifluoromethyl) phenoxy]-2,5-bis(dimethylamino) 2,3,5,6-tetrabora-1,4-dioxane diethyl ether 0.667-solvate

The title compound, C36H26B4F24N2O6 center dot 0.667C(4)H(10)O, has centrosymmetric tetraboradioxane molecules, half each of three of these comprising the asymmetric unit together with a molecule of diethyl ether. Disorder affects most of the CF3 groups and one ethyl group of the solvent molecule. The B4O2 rings are approximately planar and contain two B atoms with trigonal geometry and two with distorted tetrahedral geometry, the B - O bonds for the four- coordinate B atoms being longer than those for the three- coordinate B atoms. N H center dot center dot center dot O hydrogen bonds link two of the crystallographically independent molecules together in chains, while the third molecule forms discrete trimolecular clusters with two solvent molecules via N - H center dot center dot center dot O hydrogen bonds. This is the first crystallographically characterized example of a tetraboradioxane molecule containing both four- and three- coordinate B atoms.