{"id":123,"date":"2009-09-30T13:23:47","date_gmt":"2009-09-30T20:23:47","guid":{"rendered":"http:\/\/wordpress.reed.edu\/chem201202\/2009\/09\/carbocation-stability-hyperconjugation.html"},"modified":"2014-03-18T10:13:04","modified_gmt":"2014-03-18T17:13:04","slug":"carbocation-stability-hyperconjugation","status":"publish","type":"post","link":"https:\/\/blogs.reed.edu\/chem201202\/2009\/09\/carbocation-stability-hyperconjugation\/","title":{"rendered":"Carbocation stability &amp; Hyperconjugation"},"content":{"rendered":"<p>The slides I showed in lecture today are available <a href=\"https:\/\/blogs.reed.edu\/chem201202\/files\/L12%20093009%203%20Carbocations.pdf\"><b>here<\/b><\/a>.<\/p>\n<p>I have three short comments to go with these:<br \/><!--more--><\/p>\n<ol>\n<li>Check out the material on <b>hyperconjugation <\/b>in the Chapter 4 section of your Solutions Manual\/Study Guide. I have only recently begun looking at this text and I&#8217;m impressed by the material inside it. I was going to lecture on MO models of hyperconjugation, but maybe I don&#8217;t have to.<\/li>\n<li>I drew two resonance structures for CH3CH2+ to show how hyperconjugation changes bond and charge patterns. <u>Chemists do not normally draw these resonance structures<\/u>. So when I ask you to &#8220;draw resonance structures&#8221; for some random carbocation, don&#8217;t include hyperconjugation. Instead, look for pi bonds and lone pairs that are poised for electron-sharing.<\/li>\n<li>My slides don&#8217;t say anything about the relative energies of these carbocations, but the ChemActivity that I handed out in lecture captures this point. Three weakly electron-donating methyl groups greatly stabilize a carbocation. Likewise, a single strongly electron-donating vinyl group. CH3CH2+, by comparison, is highly unstable and is never observed in routine chemical processes.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>The slides I showed in lecture today are available here.I have three short comments to go with these:&#8230;<\/p>\n","protected":false},"author":55,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-123","post","type-post","status-publish","format-standard","hentry","category-post-lecture"],"_links":{"self":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/123","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/users\/55"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/comments?post=123"}],"version-history":[{"count":2,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/123\/revisions"}],"predecessor-version":[{"id":5172,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/123\/revisions\/5172"}],"wp:attachment":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/media?parent=123"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/categories?post=123"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/tags?post=123"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}