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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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GeneralInteresting ChemistryAdjacentAdjacent CarbonylConformational AnalysisCiencias QuímicasInglés
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In earlier posts, I alluded to what might make DNA wind into a left or a right-handed helix. Here I switch the magnification of our structural microscope up a notch to take a look at some more inner secrets.

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Introductory organic chemistry invariably features the mechanism of haloalkane solvolysis, and introduces both the Sn1 two-step mechanism, and the Sn2 one step mechanism to students. They are taught to balance electronic effects (the stabilization of carbocations) against steric effects in order to predict which mechanism prevails.

Chemical ITGeneralAspiring AuthorAspiring Book AuthorE-booksCiencias QuímicasInglés
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At a recent conference, I talked about what books might look like in the near future, with the focus on mobile devices such as the iPad. I ended by asserting that it is a very exciting time to be an aspiring book author, with one’s hands on (what matters), the content.

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The two previous posts have explored one of the oldest bonding rules (pre-dating quantum mechanics), which postulated that filled valence shells in atoms forming molecules follow the magic numbers 2, 8, 18 and 32. Of the 59,025,533 molecules documented at the instant I write this post, only one example is claimed for the 32-electron class.

Interesting Chemistry8-electron RuleBerylloceneCambridgeIrving LangmuirCiencias QuímicasInglés
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In discussing ferrocene in the previous post, I mentioned Irving Langmuir’s 1921 postulate that filled valence shells in what he called complete molecules would have magic numbers of 2, 8, 18 or 32 electrons (deriving from the sum of terms in 2[1+3+5+7]). The first two dominate organic chemistry of course, whilst the third is illustrated by […]

Interesting Chemistry10.112618-electron Rule54.1386.59FerroceneCiencias QuímicasInglés
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The structure of ferrocene was famously analysed by Woodward and Wilkinson in 1952,, symmetrically straddled in history by Pauling (1951) and Watson and Crick (1953). Quite a trio of Nobel-prize winning molecular structural analyses, all based on a large dose of intuition.