{"id":25827,"date":"2023-01-03T11:34:14","date_gmt":"2023-01-03T11:34:14","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=25827"},"modified":"2023-09-21T08:09:51","modified_gmt":"2023-09-21T07:09:51","slug":"a-look-at-one-of-the-dyes-used-in-the-bayeaux-tapestry","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827","title":{"rendered":"A look at (one of) the dyes used in the  Bayeaux tapestry."},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"25827\">\n<p>I have <a href=\"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=20452\">previously looked at the pigments<\/a> used to colour the Book of Kells, which dates from around 800 AD and which contained arsenic sulfide as the yellow colourant. The Bayeaux tapestry is a later embroidery dating probably from around 1077 and here the colours are based entirely on mordanted natural dyes. These are <a href=\"https:\/\/sage-advices.com\/what-dyes-were-used-in-bayeux-tapestry\/\">generally acknowledged<\/a> to be blue woad (principle component <a href=\"https:\/\/en.wikipedia.org\/wiki\/Indigo_dye\">indigo<\/a>), red madder (principle component <a href=\"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=20333\">alizarin<\/a>) and the less well-known\u00a0yellow weld, which comes from the plant <a href=\"https:\/\/en.wikipedia.org\/wiki\/Reseda_luteola\">Reseda Luteola<\/a> and the principle component of which is luteolin.<span id=\"cite_ITEM-25827-0\" name=\"citation\"><a href=\"#ITEM-25827-0\">[1]<\/a><\/span><\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/bayeaux.svg\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-25831\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/bayeaux.svg\" alt=\"\" width=\"450\" \/><\/a><\/p>\n<p>Luteolin has an <a href=\"https:\/\/en.wikipedia.org\/wiki\/Luteolin\" target=\"_blank\" rel=\"noopener\">interesting chemical history<\/a>. It was first purified in 1829, in the dawn of organic chemistry, and its formula <span title=\"Carbon\">C<\/span><sub>15<\/sub><span title=\"Hydrogen\">H<\/span><sub>10<\/sub><span title=\"Oxygen\">O<\/span><sub>6\u00a0<\/sub>established by 1864. A. G. Perkin, the son of the William Perkin who discovered the dye mauveine, then provided the chemical structure<span id=\"cite_ITEM-25827-1\" name=\"citation\"><a href=\"#ITEM-25827-1\">[2]<\/a><\/span> in 1896. This latter article is well worth a modern read, since it beautifully illustrates how the art of structure determination was conducted in the days before crystallography and NMR.<\/p>\n<p>Perkin obtains his structure by comparing luteolin to then known quercetin, concluding that the former must also contain an aromatic hydroxy group &#8220;ortho&#8221; to the carbonyl group, as in querecetin. The\u00a0key experimental evidence was that alkylation of luteolin with iodoethane only produces a triethoxy derivative of luteolin, with &#8220;<em>one hydroxy group resisting ethylation<\/em>&#8220;. It was by then established, by four different sets of researchers, that hydroxy groups adjacent to the carbonyl in <em>e.g.<\/em> quercetin or alizarin resisted alkylation. The structure of luteolin was established (see eg <a href=\"https:\/\/doi.org\/10.5517\/cc798yq\" rel=\"noopener\" target=\"_blank\">10.5517\/cc798yq<\/a>) by combining various such observations, a method (and skill) that has largely lapsed nowadays.\u00a0<\/p>\n<p>A modern take on this selective alkylation might be to compute <em>e.g.<\/em> the wavefunction (\u03c9B97XD\/Def2-TZVPP\/SCRF=water) of luteolin to inspect the energies of the orbitals associated with alkylation of the hydroxyl group, using the energy of the nucleophilic lone pair oxygen orbital (FAIR DOI: <a href=\"https:\/\/doi.org\/10.14469\/hpc\/12185\">10.14469\/hpc\/12185<\/a>) as an indicator. The least stable such orbital (highest energy) is normally an indicator of the most nucleophilic electron pair. In this case, the highest (most reactive) such orbital is the one adjacent to the carbonyl group, which thereby reveals a mystery, since it is this very hydroxyl that resists alkylation!\u00a0A transition state approach to this might be needed to resolve the mystery, factoring in perhaps steric effects etc.<\/p>\n<table border=\"1\">\n<tbody>\n<tr>\n<th>-0.6951 au<\/th>\n<th>-0.7132 au<\/th>\n<\/tr>\n<tr>\n<td><img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951.jvxl;zoom 100;spin 3;','c1');\" class=\"aligncenter size-full wp-image-25842\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951.png\" alt=\"\" width=\"200\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951.png 600w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951-300x300.png 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo53-0.6951-150x150.png 150w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/td>\n<td> <img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205.jvxl;zoom 100;spin -3','c2');\" class=\"aligncenter size-full wp-image-25839\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132.png\" alt=\"\" width=\"200\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132.png 600w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132-300x300.png 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132-150x150.png 150w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/td>\n<\/tr>\n<tr>\n<th>-0.7169 au<\/th>\n<th>-0.7205 au<\/th>\n<\/tr>\n<tr>\n<td> <img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169.jvxl;zoom 100;spin 6;','c3');\"  class=\"aligncenter size-full wp-image-25840\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169.png\" alt=\"\" width=\"200\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169.png 600w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169-300x300.png 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo51-0.7169-150x150.png 150w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/td>\n<td><<img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin-2_mo52-0.7132.jvxl;zoom 100;spin -6;','c4');\" class=\"aligncenter size-full wp-image-25841\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205.png\" alt=\"\" width=\"200\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205.png 600w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205-300x300.png 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin-2_mo50-0.7205-150x150.png 150w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The calculated UV-Vis spectrum is shown below, showing the peak at ~300 NM responsible for the intense yellow colour (300-400 nm).<br \/>\n<a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin_uvvis.svg\"><img decoding=\"async\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin_uvvis.svg\" alt=\"\" class=\"aligncenter size-full wp-image-25853\" width=\"500\" \/><\/a><br \/>\n<img decoding=\"async\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/03\/colour-table.jpg\" alt=\"\" class=\"aligncenter size-full wp-image-25853\" width=\"500\" \/><br \/>\nThe strongest oscillator contribution to the transition is shown below.<\/p>\n<table border=\"1\">\n<tbody>\n<tr>\n<th>LUMO au<\/th>\n<th>HOMO<\/th>\n<\/tr>\n<tr>\n<td><img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin_mo75.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin_mo75.jvxl;zoom 100;','c5');\" class=\"aligncenter size-full wp-image-25842\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin_mo75.png\" alt=\"\" width=\"200\" \/><\/td>\n<td> <img decoding=\"async\" onclick=\"jmolApplet([250,250],'load wp-content\/uploads\/2023\/01\/luteolin_mo74.xyz;isosurface wp-content\/uploads\/2023\/01\/luteolin_mo74.jvxl;zoom 100;','c6');\" class=\"aligncenter size-full wp-image-25839\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/luteolin_mo74.png\" alt=\"\" width=\"200\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>So here I have cast a little more light on this relatively unknown natural yellow dye, that was used for many centuries to colour woollen materials.<\/p>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-25827-0\">C. Chavanne, A. Verney, C. Paquier-Berthelot, M. Bostal, P. Bul\u00e9on, and P. Walter, \"Bayeux Tapestry: First use of early synthetic dyes for the restoration of a masterpiece\", <i>Dyes and Pigments<\/i>, vol. 208, pp. 110798, 2023. <a href=\"https:\/\/doi.org\/10.1016\/j.dyepig.2022.110798\">https:\/\/doi.org\/10.1016\/j.dyepig.2022.110798<\/a>\n\n<\/li>\n<li id=\"ITEM-25827-1\">A.G. Perkin, \"XLIX.\u2014Luteolin. Part II\", <i>J. Chem. Soc., Trans.<\/i>, vol. 69, pp. 799-803, 1896. <a href=\"https:\/\/doi.org\/10.1039\/ct8966900799\">https:\/\/doi.org\/10.1039\/ct8966900799<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 25827 -->","protected":false},"excerpt":{"rendered":"<p>I have previously looked at the pigments used to colour the Book of Kells, which dates from around 800 AD and which contained arsenic sulfide as the yellow colourant. The Bayeaux tapestry is a later embroidery dating probably from around 1077 and here the colours are based entirely on mordanted natural dyes. These are generally [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[],"tags":[],"ppma_author":[2661],"class_list":["post-25827","post","type-post","status-publish","format-standard","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>A look at (one of) the dyes used in the Bayeaux tapestry. - Henry Rzepa&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A look at (one of) the dyes used in the Bayeaux tapestry. - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"I have previously looked at the pigments used to colour the Book of Kells, which dates from around 800 AD and which contained arsenic sulfide as the yellow colourant. The Bayeaux tapestry is a later embroidery dating probably from around 1077 and here the colours are based entirely on mordanted natural dyes. These are generally [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2023-01-03T11:34:14+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2023-09-21T07:09:51+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/bayeaux.svg\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"A look at (one of) the dyes used in the Bayeaux tapestry. - Henry Rzepa&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827","og_locale":"en_GB","og_type":"article","og_title":"A look at (one of) the dyes used in the Bayeaux tapestry. - Henry Rzepa&#039;s Blog","og_description":"I have previously looked at the pigments used to colour the Book of Kells, which dates from around 800 AD and which contained arsenic sulfide as the yellow colourant. The Bayeaux tapestry is a later embroidery dating probably from around 1077 and here the colours are based entirely on mordanted natural dyes. These are generally [&hellip;]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827","og_site_name":"Henry Rzepa&#039;s Blog","article_published_time":"2023-01-03T11:34:14+00:00","article_modified_time":"2023-09-21T07:09:51+00:00","og_image":[{"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/bayeaux.svg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"A look at (one of) the dyes used in the Bayeaux tapestry.","datePublished":"2023-01-03T11:34:14+00:00","dateModified":"2023-09-21T07:09:51+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827"},"wordCount":411,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/01\/bayeaux.svg","inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25827","name":"A look at (one of) the dyes used in the Bayeaux tapestry. - 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But when Derek Lowe took a break from his remarkable coverage of the COVID pandemic to\u2026","rel":"","context":"In &quot;General&quot;","block_context":{"text":"General","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5763,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5763","url_meta":{"origin":25827,"position":1},"title":"So near and yet so far. The story of the electrocyclic ring opening of a cyclohexadiene.","author":"Henry Rzepa","date":"December 6, 2011","format":false,"excerpt":"My previous three posts set out my take on three principle categories of pericyclic reaction. Here I tell a prequel to the understanding of these reactions. In 1965, Woodward and Hoffmann in their theoretical analysis (submitted Nov 30, 1964) for which the Nobel prize (to Hoffmann only of the pair,\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/ht.gif?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":20333,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=20333","url_meta":{"origin":25827,"position":2},"title":"The history of  Alizarin (and madder).","author":"Henry Rzepa","date":"October 18, 2018","format":false,"excerpt":"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. Here I add a little to the talk given\u2026","rel":"","context":"In &quot;Historical&quot;","block_context":{"text":"Historical","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=565"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":25726,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25726","url_meta":{"origin":25827,"position":3},"title":"Derek Lowe asks &#8220;What&#8217;s a Journal For?&#8221; &#8211; Knowledge graphs?","author":"Henry Rzepa","date":"October 21, 2022","format":false,"excerpt":"What's a Journal For? This debate has been raging ever since preprint servers were introduced as far back as 1991! Indeed, during my recent submission of a journal article, one of the questions asked was whether the article was already deposited in such a preprint server (in a positive sense,\u2026","rel":"","context":"In \"Interesting chemistry\"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?tag=interesting-chemistry"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":10825,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10825","url_meta":{"origin":25827,"position":4},"title":"150,000,000 DFT calculations on 2,300,000 compounds!","author":"Henry Rzepa","date":"July 5, 2013","format":false,"excerpt":"The title of this post summarises the contents of a new molecular database:\u00a0www.molecularspace.org and I picked up on it by following the post by Jan Jensen at\u00a0www.compchemhighlights.org (a wonderful overlay journal that tracks recent interesting articles). The molecularspace project more formally is called \"The Harvard Clean Energy Project: Large-scale computational\u2026","rel":"","context":"In &quot;Chemical IT&quot;","block_context":{"text":"Chemical IT","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":14112,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=14112","url_meta":{"origin":25827,"position":5},"title":"Natural abundance kinetic isotope effects: mechanism of the Baeyer-Villiger reaction.","author":"Henry Rzepa","date":"June 10, 2015","format":false,"excerpt":"I have blogged before about the mechanism of this classical oxidation reaction. Here I further explore computed models, and whether they match the observed kinetic isotope effects (KIE) obtained using the natural-abundance method described in the previous post. There is much previous study of this rearrangement, and the issue can\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25827","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=25827"}],"version-history":[{"count":21,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25827\/revisions"}],"predecessor-version":[{"id":26509,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25827\/revisions\/26509"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=25827"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25827"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25827"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=25827"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}