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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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Chemical ITAcademic PublishingAcrobatArticlesChemical DiscoveriesCiencias QuímicasInglés
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The traditional structure of the research article has been honed and perfected for over 350 years by its custodians, the publishers of scientific journals. Nowadays, for some journals at least, it might be viewed as much as a profit centre as the perfected mechanism for scientific communication.

Interesting ChemistryChemical KineticsChemical ReactionChemistryDeuteriumCiencias QuímicasInglés
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Five years back, I speculated about the mechanism of the epoxidation of ethene by a peracid, concluding that kinetic isotope effects provided interesting evidence that this mechanism is highly asynchronous and involves a so-called “hidden intermediate”. Here I revisit this reaction in which a small change is applied to the atoms involved.

Chemical ITAcademiaAcademic PublishingAmerican Chemical SocietyAngewandte ChemieCiencias QuímicasInglés
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For perhaps ten years now, the future of scientific publishing has been hotly debated. The traditional models are often thought to be badly broken, although convergence to a consensus of what a better model should be is not apparently close.

HistoricalAlan DronsfieldAlizarinAnthraquinone DyesArt MaterialsCiencias QuímicasInglés
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The Royal Society of Chemistry historical group (of which I am a member) organises two or three one day meetings a year. Yesterday the October meeting covered (amongst other themes) the fascinating history of madder and its approximately synthetic equivalent alizarin.

Interesting ChemistryCiencias QuímicasInglés
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Here is the concluding part of my exploration of a recently published laboratory experiment for undergraduate students. I had previously outlined a possible mechanistic route, identifying TS3 (below) as the first transition state in which C-C bond formation creates two chiral centres.

Interesting ChemistryAbsolute ConfigurationBiochemistryBulk SolutionsChemical TransformationsCiencias QuímicasInglés
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I am exploring the fascinating diverse facets of a recently published laboratory experiment for undergraduate students. Previously I looked at a possible mechanistic route for the reaction between an enal (a conjugated aldehyde-alkene) and benzyl chloride catalysed by base and a chiral amine, followed by the use of NMR coupling constants to assign relative stereochemistries.

Interesting ChemistryBenzyl GroupChemistryCyclopropanationCyclopropane ProductsCiencias QuímicasInglés
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In the previous post, I investigated the mechanism of cyclopropanation of an enal using a benzylic chloride using a quantum chemistry based procedure. Here I take a look at the NMR spectra of the resulting cyclopropane products, with an evaluation of the original stereochemical assignments.

Interesting ChemistryAmmoniumBenzyl GroupCationsChemical DiagramsCiencias QuímicasInglés
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Symbiosis between computation and experiment is increasingly evident in pedagogic journals such as J. Chemical Education. Thus an example of original laboratory experiments, that later became twinned with a computational counterpart. So when I spotted this recent lab experiment I felt another twinning approaching.

Interesting ChemistryCarbonChairChemistryConformationCiencias QuímicasInglés
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Following the general recognition of carbon as being tetrahedrally tetravalent in 1869 (Paterno) and 1874 (Van’t Hoff and Le Bell), an early seminal exploitation of this to the conformation of cyclohexane was by Hermann Sachse in 1890.

Interesting ChemistryArrow PushingChemical ReactionChemical SocietyChemistCiencias QuímicasInglés
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In 2012, I wrote a story of the first ever reaction curly arrows, attributed to Robert Robinson in 1924. At the time there was a great rivalry between him and another UK chemist, Christopher Ingold, with the latter also asserting his claim for their use.