Synthesis, Functionlization, Structures And Properties Research On Trichalcogenasumanene

The discovery of fullerene has stimulated much interest in many fields for its unique properties. Corannulene and Sumanene are two representative units of C60 fullerene. Corannulene was firstly synthesized via 17 steps by Lawton and Barth in 1966, and a practical synthetic route was established by Scott group using flash vacuum pyrolysis(FVP) as a key step. Compared with Corannulene, Sumanene is a more strained buckybowl, and its chemical synthesis is thus more challenging due to higher strain energy for the ring cyclization. The first successful synthesis was accomplished by Sakurai et al in 2003, they also demonstrated it had unique physicochemical properties. Heterasumanenes can be achieved by replacement of sp2 carbons on the rim benzene ring by heteroatoms, this have attacted intensive attention recently.We herein start our research from replacing the sp2 carbons on the sumanene by Sulfur, Selenium and Tellurium. We successfully disclose a non-pyrolytic two-step synthesis of triselenasumanene, trithiasumanene and tritelluasumanene from triphenylene derivatives. The photophysical properties and crystal structures of these new heterasumanes and their precursors are elucidated.In Chapter 1, we firstly made a brief introduction about the background of the bowl-shaped molecules, and summarized the development of Corannulene. Then we outlined the two different strategies to synthesize Corannulene by FVP and solution. Besides, we introduced the history of Sumanene, and further elucidate the photophysical properties and crystal structures. Then the structures and charactors of these three kinds of twisted PAHs were introduced. Finally, we showed the current research status on the heterasumanenes.In Chapter 2, we designed our strategy for synthesis by(i) ring cyclization, fusion of multiple chalcogenole and 1,2-dichalcogenin rings at the bay regions of triphenlyene skeleton, and(ii) ring contraction, dechalcogenation of 1,2-dichalcogenin to form the desired trichalcogenasumanene. This present synthesis can be easily conducted and the desired products can be obtained in multigram-scale. By the same way, the bowl-shaped hetetrasumanenes cotains one sulfur, two seleniums and one selenium, two sulfurs were prepared. In the end, we successfully prepared tritellesumanene via ultra-assisted reaction by one step.In Chapter 3, on the basis of a lot of heterasumanenes and their precursors which have been prepared successfully, we further discussed the structural and physicochemical features of these new compounds.In Chapter 4, One of the flank benzene rings of trithiasumanene and triselesumanene was opened when we tried to oxidate it by using potassium peroxymonosulfate(Oxone) or tert-butyl hydroperoxide(TBHP) as an oxidant. Then we report a facile and highly efficient synthetic approach toward trithiasumanene derivatives. On the basis of this ring-opening reaction, a series of unprecedented donor-acceptor type [5-6-7]-fused polyheterocycles were created with a “molecular surgery” type functionalization, and their structural and physicochemical features were elucidated later.In chapter 5, we report a huge crystal deformation whose shape reversibly responds to temperature changes. This phase-transition phenomenon induced by temperature was confirmed by DSC. Then we further discussed the intrinsic structures caused by changing temperatures.In chapter 6, we studied the oxidation of heterasumanenes under trifluoroacetic acid and sodium nitrite. The heterasumanenes were found to be coverted into dark ketones in trifluoroacetic acid and sodium nitrite. A series of “scoop-shaped” π-conjugated molecules were prepared by reacting with 1,2-diaminobenzene, then we further discussed the shortage of these work.