Structural study of compounds modelling elementary polymer units, 3.† Molecular and crystal structure of 1,3,5-tris[4′-(C-o-carboranyl)biphenyl-4-yl]benzene

Following the studies on elucidating the main structural features of elementary units of polyphenylene‐type polymers prepared by condensation of di‐ and monoacetylaromatic compounds, an X‐ray structural analysis of 1,3,5‐tris[4′‐(C‐o‐carboranyl)biphenyl‐4‐yl]benzene (2) (systematic name: 1,3,5‐tris[)1,2‐dicarba‐closo‐dodecarborane(12)‐1‐yl(biphenyl‐4‐yl]benzene), which is the low‐molecular‐weight analog of one of the polymers in the given series, was performed. Compound 2 crystallizes as unstable solvate 1:1:1 with chloroform and benzene. The crystals are monoclinic, a = 17,060 Å, b = 20,220 Å, c = 18,448 Å, β = 102,79°, space group P21/n, Z = 4. Molecule 2 exhibits asymmetric conformation with substantial distortions of the linear geometry of polyphenylene units. The crystal is built of layers of molecules 2, the solvate molecules being situated between these molecules in the channels and cavities with a population of 2/3. The benzene molecules participate in stacking‐interaction with one of the carboranyl‐substituted (i.e., the strongest electron‐acceptor) benzene rings of the host molecule 2; chloroform molecules pack the channels without a specific interaction with the host molecules