Crystalline Hybrid Polyphenylene Macromolecules from Octaalkynylsilsesquioxanes, Crystal Structures, and a Potential Route to 3-D Graphenes

We report here the Diels-Alder reaction of octa(diphenylacetylene)silsesquioxane [DPA(8)OS] with tetraphenyl cyclopentadienone or tetra(p-tolyl)cyclopentadienone to form octa(hexaphenylbenzene)octasilsesquioxane, (Ph6C6)(8)OS, or octa(tetratolyldiphenylbenzene) octasilsesquioxane, (p-Tolyl(4)Ph(2)C(6))(8)OS. Likewise, tetra(p-tolyl)cyclopentadienone reacts with octa(p-tolylethynylphenyl)OS to form octa(pentatolylphenylbenzene)octasilsesquioxane (p-Tolyl(3)PhC(6))(8)OS. These compounds, with molecular weights of 4685-5245 Da, were isolated and characterized using a variety of analytical methods. The crystal structure of DPA(8)OS offers a 3 nm(3) unit cell with Z = 1. The crystal structure of (Ph6C6)(8)OS was determined to have a triclinic unit cell of 11 nm(3) with Z = 1. The latter structure is believed to be the largest discrete molecular structure reported with 330 carbons. Efforts to dehydrogenatively cyclize (Scholl reaction) the hexaarylbenzene groups to form 3-D octgraphene compounds are described.