Talk:Cahn-Ingold-Prelog priority rule
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how to assign R,S configuration to a chiral centre which is the more correct method- by performing even no. of exchanges (converting wedge formula into 2D) or in a 3D formula—Preceding unsigned comment added by 61.17.123.146 (talk • contribs)
any illustrations that could be added would greatly enhance the effectiveness of this explanation. R- and S- configurations are a highly spacial/visual concept, and in this case, I believe a picture is worth more like 5,000 words.—Preceding unsigned comment added by 129.237.40.188 (talk • contribs)
The current explanation of the priority rule indicates that one exhausts the highest priority branch completely before considering any of the others. This appears to be at odds with Cahn, Ingold, and Prelog's original paper, which I read this morning and for which I added a reference. The authors' explanation uses a series of "sets" (really passes), each of which considers atoms one unit farther from the stereocenter than the previous pass. Any difference found in a pass breaks a tie, regardless of whether it is on the highest-priority branch. For example, consider the groups -CH(NH-CH2-Cl)(CH3) and -CH(NH-CH3)(CH2-Br). The Wikipedia procedure declares the first group higher priority because of the Cl, but the authors' procedure declares the second higher priority because of the Br (it is closer to the attachment point than the Cl). Unless I hear an objection, I think I will replace the current explanation with my own based on the original paper. Hashproduct 17:45, 5 October 2007 (UTC)
- I went ahead and rewrote the explanation of priorities from my understanding of the original papers, making it much more thorough. It's possible that I am mistaken about some points or have made careless errors in the examples. If you believe I am wrong about a major point, go ahead and redo the explanation if you like, but please discuss the issue with me so we can make sure the article ends up saying the correct thing according to the official definition of the system. I took the opportunity to improve the article in some other ways at the same time. Hashproduct 05:21, 13 October 2007 (UTC)
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- Good job. The rules seem correct and readable enough to me, but I then I knew them already. ;-) I think that the article could be made much easier to understand if it had some figures, especially about the use of ghost atoms. --Itub 09:46, 13 October 2007 (UTC)
[edit] Use in Inorganic chemistry
The CIP rules are also used in inorganic coordination complex naming to prioritise the ligands as part of assigning the configuration index. Can this be added?--Axiosaurus (talk) 16:45, 21 March 2008 (UTC)
