Henry, so you are saying you think something is wrong with that pathway. >From what I can see, there are two possible pathways from the chair -- one with a twist to the "left"; one with a twist to the "right." The enatiomeric twist is not depicted. (Although I think you could invert the configuration of all models and see it!) So from the get-go, symmetry is broken. Nothing wrong with that.... The entire sequence is chiral!
Bob On Wed, Feb 23, 2011 at 1:29 PM, Rzepa, Henry <[email protected]>wrote: > >Hens! Good to hear from you. I hope you don't mind my co-opting your model > -- reminds me that I need to put a link to WeTChe there. > > > >I'd love a little discusson of this, because I'd like to get this out > there. My understanding is that both are "correct" -- the boat transition > state is lower than the twist chair (though I don't see exactly why) > > > Because the angles are opened up beyond 109 in the half chair > > >, and so statistically the molecule will find itself more often in a boat > than a twist chair anyway, I think the "synthetic organic chemist" should > realize that what is > >shown is not a potential surface, but one degree of freedom singled out. > > > Surely a molecular dynamics trajectory is more accurate, since a degree of > freedom can only be harmonic and you cannot have harmonic modes connecting > the entire surface? The MD trajectory seems to show a boat transition state > being involved at the half way point, not a twist boat minimum? > > My concern is that a single degree of freedom singled out does not marry > with group theory! > > > -- > > +44 (020) 7594 5774 (Voice); Blog: http://www.ch.ic.ac.uk/rzepa/blog/ > Dept. Chemistry, Imperial College London, SW7 2AZ, UK. > > (Voracious anti-spam filter in operation for received email. > If expected reply not received, please phone/fax). > > > > ------------------------------------------------------------------------------ > Free Software Download: Index, Search & Analyze Logs and other IT data in > Real-Time with Splunk. Collect, index and harness all the fast moving IT > data > generated by your applications, servers and devices whether physical, > virtual > or in the cloud. Deliver compliance at lower cost and gain new business > insights. http://p.sf.net/sfu/splunk-dev2dev > _______________________________________________ > Jmol-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/jmol-users > -- Robert M. Hanson Professor of Chemistry St. Olaf College 1520 St. Olaf Ave. Northfield, MN 55057 http://www.stolaf.edu/people/hansonr phone: 507-786-3107 If nature does not answer first what we want, it is better to take what answer we get. -- Josiah Willard Gibbs, Lecture XXX, Monday, February 5, 1900
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