{"id":24348,"date":"2021-10-14T09:21:53","date_gmt":"2021-10-14T08:21:53","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=24348"},"modified":"2021-10-14T10:06:20","modified_gmt":"2021-10-14T09:06:20","slug":"herapathite-an-example-of-double-serendipity","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=24348","title":{"rendered":"Herapathite: an example of (double?) serendipity."},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"24348\">\n<p>On October 13, 2021, the historical group of the Royal Society of Chemistry organised a symposium celebrating ~150 years of the history of (molecular) chirality. We met for the first time in person for more than 18 months and were treated to a splendid and diverse program about the subject. The first speaker was Professor John Steeds from Bristol, talking about the early history of light and the discovery of its polarisation. When a slide was shown about herapathite<span id=\"cite_ITEM-24348-0\" name=\"citation\"><a href=\"#ITEM-24348-0\">[1]<\/a><\/span> my &#8220;antennae&#8221; started vibrating. This is a crystalline substance made by combining elemental iodine with quinine in acidic conditions and was first discovered by William Herapath as long ago as 1852<span id=\"cite_ITEM-24348-1\" name=\"citation\"><a href=\"#ITEM-24348-1\">[2]<\/a><\/span> in unusual circumstances. Now to the serendipity!<\/p>\n<p>Herapath was able to get small crystals of this substance and discovered that when he placed one crystal upon another at &#8220;right angles&#8221;, the combination went &#8220;black as midnight&#8221;. He recognised that it was functioning as an excellent linear light polarizer, absorbing virtually all the light polarized along the shorter axis of the best-developed facet of the crystal. A number of well known scientists investigated this substance at the time, but by about 1951 it had largely been forgotten. The person to rediscover it was Edwin Land, of Polaroid camera fame.<span id=\"cite_ITEM-24348-2\" name=\"citation\"><a href=\"#ITEM-24348-2\">[3]<\/a><\/span> He oriented the microcrystals into an extruded polymer to stabilize them and hence produce the first large-aperture light polarizer, which enabled him to manufacture his first camera. The serendipity resulted from him spotting the by then forgotten properties of Herapathite (I wonder if he recorded how this actually came about) and recognising how to exploit it.<\/p>\n<p>In 2009 Bart Kahr had noticed that the crystal structure of this material had never been reported. It was a challenging structure to solve<span id=\"cite_ITEM-24348-0\" name=\"citation\"><a href=\"#ITEM-24348-0\">[1]<\/a><\/span> but established that the polarizing property of the crystals was in large measure due to the presence of infinite chains of I<sub>3<\/sub><sup>&#8211;<\/sup> units aligned in an almost linear channel in the crystal structure. And so it was that in October 2021, John Steeds showed the structure containing these iodine chains in his slide on the topic. The crystal structure is in the CCDC database as <strong>WEYDOV<\/strong> and can be seen here at DOI: <a href=\"https:\/\/dx.doi.org\/10.5517\/ccsdg7v\" target=\"_blank\" rel=\"noopener\">10.5517\/ccsdg7v<\/a>\u00a0I show below part of the extended lattice, showing that chain of iodines.<\/p>\n<div id=\"attachment_24350\" style=\"width: 460px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" aria-describedby=\"caption-attachment-24350\" class=\"size-medium wp-image-24350\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/10\/WEYDOV.mol2;spin 3;','c1');\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/herapathite.jpg\" alt=\"\" width=\"450\" \/><p id=\"caption-attachment-24350\" class=\"wp-caption-text\">Click to view 3D model of WEYDOV<\/p><\/div>\n<p>So the next (possible) instance of serendipity. From the audience, I immediately recognised this structural motif as being related to the crystal structure of both Na<sup>+<\/sup>I<sup>&#8211;<\/sup>\u00a0(NAIACE) and Na<sup>+<\/sup>I<sub>2<\/sub><sup>&#8211;<\/sup> (GADMOO)<span id=\"cite_ITEM-24348-3\" name=\"citation\"><a href=\"#ITEM-24348-3\">[4]<\/a><\/span> which I discussed in one of the very first posts on this blog in 2009 as part of <a href=\"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=439\">a story about the Finkelstein reaction<\/a>. Both these structures were obtained from acetone solution, and this solvent very much forms part of the crystal structures, serving to coordinate the sodium cations and playing the role of the quinine in herapathite. The iodine chains, comprising in GADMOO units of I<sub>3<\/sub><sup>&#8211;<\/sup> and I<sup>&#8211;<\/sup>,\u00a0are almost exactly linear!<\/p>\n<p><div id=\"attachment_24354\" style=\"width: 460px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24354\" class=\"size-large wp-image-24354\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/10\/NAIACE.mol;spin 3;','c2');\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/NAIACE.jpg\" alt=\"\" width=\"450\" height=\"339\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/NAIACE.jpg 1456w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/NAIACE-300x226.jpg 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/NAIACE-1024x771.jpg 1024w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/NAIACE-768x578.jpg 768w\" sizes=\"auto, (max-width: 450px) 100vw, 450px\" \/><p id=\"caption-attachment-24354\" class=\"wp-caption-text\">Click to view 3D model of NAICE<\/p><\/div> <div id=\"attachment_24353\" style=\"width: 460px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" aria-describedby=\"caption-attachment-24353\" class=\"size-medium wp-image-24353\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/10\/GADMOO.mol2;spin -3;','c3');\"  src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/GADMOO.jpg\" alt=\"\" width=\"450\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/GADMOO.jpg 1106w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/GADMOO-300x289.jpg 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/GADMOO-1024x985.jpg 1024w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/GADMOO-768x739.jpg 768w\" sizes=\"(max-width: 1106px) 100vw, 1106px\" \/><p id=\"caption-attachment-24353\" class=\"wp-caption-text\">Click to view 3D model of GADMOO<\/p><\/div><\/p>\n<p>So, the question arises as to whether crystals of Na<sup>+<\/sup>I<sub>2<\/sub><sup>&#8211;<\/sup> have ever been examined for light polarisation? One might also ask whether eg the chiral quinine imparts a critical property to the herapathite crystal, or could the achiral acetone also serve the purpose? What would happen if substituted versions of acetone were used (halo, methyl etc)? Would they destroy those linear chains, or would they survive? Are repeating chains of I<sub>3<\/sub><sup>&#8211;<\/sup> units essential, or can chains of alternating units of I<sub>3<\/sub><sup>&#8211;<\/sup> and I<sup>&#8211;<\/sup> also serve the purpose? All questions that can only be answered by experiments! Anyone up for trying?<\/p>\n<hr \/>\n<p>This post has DOI: 10.14469\/hpc\/9537<\/p>\n<hr \/>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-24348-0\">B. Kahr, J. Freudenthal, S. Phillips, and W. Kaminsky, \"Herapathite\", <i>Science<\/i>, vol. 324, pp. 1407-1407, 2009. <a href=\"https:\/\/doi.org\/10.1126\/science.1173605\">https:\/\/doi.org\/10.1126\/science.1173605<\/a>\n\n<\/li>\n<li id=\"ITEM-24348-1\">W.B. Herapath, \"XXVI. &lt;i&gt;On the optical properties of a newly-discovered salt of quinine, which crystalline substance possesses the power of polarizing a ray of light, like tourmaline, and at certain angles of rotation of depolarizing it, like selenite&lt;\/i&gt;\", <i>The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science<\/i>, vol. 3, pp. 161-173, 1852. <a href=\"https:\/\/doi.org\/10.1080\/14786445208646983\">https:\/\/doi.org\/10.1080\/14786445208646983<\/a>\n\n<\/li>\n<li id=\"ITEM-24348-2\">E.H. Land, \"Some Aspects of the Development of Sheet Polarizers*\", <i>Journal of the Optical Society of America<\/i>, vol. 41, pp. 957, 1951. <a href=\"https:\/\/doi.org\/10.1364\/josa.41.000957\">https:\/\/doi.org\/10.1364\/josa.41.000957<\/a>\n\n<\/li>\n<li id=\"ITEM-24348-3\">R.A. Howie, and J.L. Wardell, \"Polymeric tris(\u03bc&lt;sub&gt;2&lt;\/sub&gt;-acetone-\u03ba&lt;sup&gt;2&lt;\/sup&gt;&lt;i&gt;O&lt;\/i&gt;:&lt;i&gt;O&lt;\/i&gt;)sodium polyiodide at 120\u2005K\", <i>Acta Crystallographica Section C Crystal Structure Communications<\/i>, vol. 59, pp. m184-m186, 2003. <a href=\"https:\/\/doi.org\/10.1107\/s0108270103006395\">https:\/\/doi.org\/10.1107\/s0108270103006395<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 24348 -->","protected":false},"excerpt":{"rendered":"<p>On October 13, 2021, the historical group of the Royal Society of Chemistry organised a symposium celebrating ~150 years of the history of (molecular) chirality. We met for the first time in person for more than 18 months and were treated to a splendid and diverse program about the subject. The first speaker was Professor [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_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},"jetpack_post_was_ever_published":false},"categories":[2644,1745,565,4],"tags":[],"ppma_author":[2661],"class_list":["post-24348","post","type-post","status-publish","format-standard","hentry","category-chiroptics","category-crystal_structure_mining","category-historical","category-interesting-chemistry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Herapathite: an example of (double?) serendipity. - 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=24348\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Herapathite: an example of (double?) serendipity. - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"On October 13, 2021, the historical group of the Royal Society of Chemistry organised a symposium celebrating ~150 years of the history of (molecular) chirality. We met for the first time in person for more than 18 months and were treated to a splendid and diverse program about the subject. The first speaker was Professor [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=24348\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2021-10-14T08:21:53+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2021-10-14T09:06:20+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/10\/herapathite.jpg\" \/>\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=\"3 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Herapathite: an example of (double?) serendipity. - 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=24348","og_locale":"en_GB","og_type":"article","og_title":"Herapathite: an example of (double?) serendipity. - Henry Rzepa&#039;s Blog","og_description":"On October 13, 2021, the historical group of the Royal Society of Chemistry organised a symposium celebrating ~150 years of the history of (molecular) chirality. 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Quite a trio of Nobel-prize winning molecular structural analyses, all based on a large dose of intuition. The structures of both proteins and DNA succumbed\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\/04\/ferrocene-aim.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":17311,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17311","url_meta":{"origin":24348,"position":1},"title":"The &#8220;hydrogen bond&#8221;; its early history.","author":"Henry Rzepa","date":"December 31, 2016","format":false,"excerpt":"My holiday reading has been Derek Lowe's excellent\u00a0Chemistry Book setting out 250 milestones in chemistry, organised by year. An\u00a0entry for 1920 entitled hydrogen bonding\u00a0seemed worth exploring in more detail here. As with many historical concepts, it can often take a few years to coalesce into something we would readily recognise\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":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/12\/066-1024x91.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":2423,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=2423","url_meta":{"origin":24348,"position":2},"title":"The oldest reaction mechanism: updated!","author":"Henry Rzepa","date":"September 14, 2010","format":false,"excerpt":"Unravelling reaction mechanisms is thought to be a 20th century phenomenon, coincident more or less with the development of electronic theories of chemistry. Hence electronic\u00a0arrow pushing as a term. But here I argue that the true origin of this immensely powerful technique in chemistry goes back to the 19th century.\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.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/09\/wheland.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":20333,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=20333","url_meta":{"origin":24348,"position":3},"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":6438,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=6438","url_meta":{"origin":24348,"position":4},"title":"Confirming the Fischer convention as a structurally correct representation of absolute configuration.","author":"Henry Rzepa","date":"March 13, 2012","format":false,"excerpt":"I wrote in an earlier post\u00a0how Pauling's\u00a0Nobel prize-winning suggestion in February 1951 of a (left-handed)\u00a0\u03b1-helical structure for proteins was based on the wrong absolute configuration of the amino acids (hence his helix should really have been the right-handed enantiomer). This was most famously established a few months later by Bijvoet's\u2026","rel":"","context":"In &quot;Chiroptics&quot;","block_context":{"text":"Chiroptics","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2644"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5411,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5411","url_meta":{"origin":24348,"position":5},"title":"Henry Armstrong: almost an electronic theory of chemistry!","author":"Henry Rzepa","date":"November 7, 2011","format":false,"excerpt":"Henry Armstrong studied at the Royal College of Chemistry from 1865-7 and spent his subsequent career as an organic chemist at the Central College of the Imperial college of Science and technology until he retired in 1912. He spent the rest of his long life railing against the state of\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":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/11\/affinity%2Bresultant.jpg?resize=350%2C200","width":350,"height":200},"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\/24348","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=24348"}],"version-history":[{"count":22,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/24348\/revisions"}],"predecessor-version":[{"id":24378,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/24348\/revisions\/24378"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=24348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24348"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=24348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}