Summary

w88 slot online Interests

Mechanism of the Scholl w88 slot online

The development of the Scholl reaction, which is the acid-catalyzed oxidation of aryl CH vertices to generate new aryl-aryl bonds, has been a major project in the BTK group. Although this reaction holds enormous potential for the synthesis of new PAHs, as demonstrated by its use by Müllen to prepare large graphitic disks, its scope and mechanism had been unexplored. We study its mechanism using computational and experimental w88 slot online. Our calculations suggest that the mechanism involves an arenium cation intermediate that engages in electrophilic aromatic substitution with another aryl moiety. A radical cation mechanism was also investigated but exhibits much higher activation barriers. The possibility of inner-sphere electron transfer has not yet been addressed.

w88 slot online coordinate diagram for the arenium cation, cascade Scholl w88 slot online.
The Smallest Known w88 slot online: Quadrannulene

We recently reported the preparation w88 slot online first [4]circulene, for which we proposed the name quadrannulene. Our product, tetrabenzo[4]circulene, is deeply bowl shaped and contains the most distorted double bonded C atom that has been structurally characterized. Our unoptimized, five-step synthesis provides tetrabenzo[4]circulene in low yield.

Organometallic Methodology for w88 slot online: Zirconium-Mediated Biphenylation

We have developed new methodologies for preparing PAHs. The serendipitous discovery of the square antiprismatic complex Zr(2,2'-biphenyldiyl)4-4, from the w88 slot online of 2,2'-dilithiobiphenyl with zirconocene dichloride, led to a novel family of organozirconium compounds. The zirconate bearing three biphenyldiyl ligands, Zr(biphe)3-2 exhibits interesting reactivity - it reacts with o-dihalobenzenes to give triphenylenes. w88 slot online is a fundamentally new disconnection for PAH syntheses and is capable of introducing significant molecular strain, as evidenced by the one-step preparation of 9,18-dimethyltetrabenzoanthracene.

We then applied this Zr-based methodology to the synthesis of two unusual molecules. This is first a dimer of tetrabenzanthracene linked through the gulf positions. The bond that constitutes the linkage is perhaps the most hindered single C-C bonds in w88 slot online. Interestingly, while this bond is highly strained, having a homolytic bond dissociation energy only 55% of that in similar compounds, it has a perfectly normal length of 1.49Å. The leads to perhaps the most important conclusions of the paper: forces, not energies, determine bond lengths.

We also used w88 slot online to prepare triphenylene-based triptycenes. The development of a convenient preparation of hexabromotriptycene followed by its treatment with the Zr biphenylation reagent afforded the extended triptycene. This molecule possesses an enormous free volume, defined as the unfilled volume of a prism containing the molecule, of 700 Å3, which is about ten times greater than that of the parent triptycene. Its tripodal structure and large free volume suggest applications as a stator for molecular motors.

Theory of w88 slot online

Our interests include the electronic nature of polycyclic aromatic hydrocarbons (PAHs). We have developed rules for valence-bond (VB) descriptions of π-bonding in carbon nanotubes (CNTs). A particularly interesting finding was that conductive CNTs require only aromatic sextets for their complete valence representation. We have applied w88 slot online VB model to understand patterns of addition reactions to CNTs. Simple models, based on sterics, had been proposed but failed to predict long-range patterns. Our model predicts reactivity.

About the Reynold Clayton Fuson Endowed w88 slot online Professorship

Reynold Clayton Fuson was an American chemist who spent 14 years at the end of his career as a distinguished visiting professor at the University. Fuson considered his students and colleagues his family and divided his substantial estate between several universities to support students, lecturers and professorships. Established: 1984. (College of w88 slot online)

Education

• Postdoctoral Research Associate (2000-2002), w88 slot online of California, Berkeley (Robert G. Bergman)
• Ph.D. (2000), w88 slot online of Colorado (Josef Michl)
• B.S. (1992), Northeastern w88 slot online