ITbM-RCMS Seminar (Prof. Roald Hoffmann)
Date: 2016/11/4, Fri. 13:30〜15:30
Venue: Lecture Room, Noyori Materials Science Laboratory 2nd floor
Speaker: Prof. Roald Hoffmann (Cornell University, USA)
Title: "Two new games for carbon, we hope"
Professor Hoffmann is a famous theoretical chemist who has received the 1981 Nobel Prize in Chemistry with Kenichi Fukui, and he is now the Frank H. T. Rhodes Professor of Humane Letters Emeritus at Cornell University. He likes to characterize his contribution to chemistry as "applied theoretical chemistry", his own blend of computations stimulated by experiment and coupled to the construction of generalized models, or frameworks for understanding. He is also a poet and playwright, sharing his understanding of science with the public at large through literature, educational television, and the stage.
Clathrate structures, large polyhedral networks, can be built from any node that favors tetrahedral four-coordination - be it water, SiO2 or group 14 elements. Those constructed of C alone have never been made, even as they are pretty close to diamond in stability. Tao Zeng's work suggests a strategy for making these, incorporating lithiums into the cavities, and substituting B in the carbon cages around. Recently CH nanothreads, one-dimensional, probably disordered, completely saturated polymers of benzene have been made and visualized in the slow decompression of benzene at 20 GPa by John Badding's group at Penn State. Bo Chen in our group has explored the building up of these, through stepwise polymerization of benzene into one-dimensional chain with varying degrees of unsaturation. And benzene is not the global energy minimum for composition CH. Graphanes, not one, but several, are. They are still waiting to be made, reproducibly. For that matter, what are the most stable structures of stoichiometry CHn? Or N, or CO?