Day: November 4, 2010

Electromechanical Molecular Actuators Based Quantum Mechanical Mechanisms

Thursday, November 4, 2010 11:00 am – 12:00 pm
Room 610, M&M Building

Prof. Miklos Kertesz
Department of Chemistry
Georgetown University
Washington DC

Abstract

Charged or neutral radicals often display π-stacking geometries that show signs ofintermolecular covalent bonding based on the partial occupancy of π-orbitals. This interaction issensitive to the number of π-electrons available for this bonding and goes beyond van derWaals interactions. We analyze known cases of intermolecular π-bonding in various radicaldimers and chains and connect the intermolecular bonding properties to observed properties.The simulations involve molecular and periodic first principles density functional theorycalculations. Various stacked chains are analyzed for their suitability as electrochemically drivenactuating molecules and compared with other mechanisms of electrochemical actuationincluding those based on polyacetylene and carbon nanotubes as well as those based onlocalized 2 center/3 electron bonds.

Relevant references

“Dimensional Changes as a Function of Charge Injection in Single Walled Carbon Nanotubes”Sun, G.Y.; Kürti, J.; Kertesz, M.; R. H. Baughman,  J. Am. Chem. Soc. 2002, 124, 15076-15080.

“Electronic Structure of Helicenes, C2S Helicenes, and Thiaheterohelicenes”Yong-Hui Tian, Gyoosoon Park, Miklos Kertesz, Chem Mater. 2008, 20, 3266-3277.

“Molecular Actuators Designed with S…N(sp(2)) Hemibonds Attached to a ConformationallyFlexible Pivot“ Tian, Y.-H.; Kertesz, M. Chem. Mater. 2009, 21, 2149-2157.

“Is There a Lower Limit to the CC Bonding Distances in Neutral Radical ?-Dimers? The Case ofPhenalenyl Derivatives”, Tian, Y.-H.; Kertesz, M. J. Am. Chem. Soc. 2010. 132, 10648-10649.