It does to me in the sense that I am think of assigning R and S - not other labels - in a correct manner according to the CIP rules. Why do I want to do that and not @/@@? Well because that how we do it. @/@@ it is useful for database search etc but we don’t use it in the classroom or in the seminars, in no place at all!
Clearly I made a mistake in trying to help Dimitri with the chemistry. Good luck! On 4 December 2013 00:00, Craig James <cja...@emolecules.com> wrote: > Hi Yoel, > > On Tue, Dec 3, 2013 at 7:44 PM, Yoel <yoe...@gmail.com> wrote: >> >> Hum! I’m pretty confident with what I know but the issue here is that >> you answer isn’t contributing to clarifying the question. The question >> is how to we determine the chirality of a centre regardless of how you >> may choose to represent it at a later point. And this problem >> inevitable will come down to applying the CIP rules. Do you disagree >> with that? > > > In addition to what Geoff said, I'll add this. You're distinguishing the > chirality from the representation, but in fact CIF rules are only useful for > the purpose of a representation. CIF allows you to say "R" or "S". SMILES > rules allow you to say "@" or "@@". A 3D file format doesn't need concepts > like R/S or @/@@ because the stereo configuration is specified by the > coordinates. > > The concept of "chiral" is separate from representation. A chiral > molecule's mirror image is different from the molecule. But the concept of > "chirality" only applies to representations -- usually lexical or > mathematical (graph) representations. So to ask, "how do we determine the > chirality of a centre regardless of the representation?" doesn't even make > sense. > > Cheers, > Craig -- View this message in context: http://forums.openbabel.org/stereo-config-question-tp4656879p4657006.html Sent from the General discussion mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Sponsored by Intel(R) XDK Develop, test and display web and hybrid apps with a single code base. Download it for free now! http://pubads.g.doubleclick.net/gampad/clk?id=111408631&iu=/4140/ostg.clktrk _______________________________________________ OpenBabel-discuss mailing list OpenBabel-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openbabel-discuss
