{"id":17366,"date":"2017-01-20T14:47:17","date_gmt":"2017-01-20T14:47:17","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=17366"},"modified":"2017-01-20T14:47:17","modified_gmt":"2017-01-20T14:47:17","slug":"braiding-a-molecular-knot-with-eight-crossings","status":"publish","type":"post","link":"https:\/\/www.rzepa.net\/blog\/?p=17366","title":{"rendered":"Braiding a molecular knot with eight crossings."},"content":{"rendered":"
\n

This is one of those posts of a molecule whose very structure is interesting enough to merit a picture and a 3D model. The study[1]<\/a><\/span> reports a molecular knot with the remarkable number of eight crossings.<\/p>\n

\"\"<\/a><\/p>\n

The DOI for the 3D model is 10.5517\/CCDC.CSD.CC1M85Y0<\/a>\u00a0(or click on the image above). Such topology intersects with work we did a few years back on high-order\u00a0crossings in fully conjugated\u00a0\u03c0-systems[2]<\/a><\/span>, which were then illustrated[3]<\/a><\/span> with hypothetical charged higher order annulenes exhibiting linking numbers Lk\u00a0of up to 6\u03c0. A fully\u00a0\u03c0-conjugated system, also with a linking number in the \u03c0-framework\u00a0of\u00a06\u03c0 but in the form of a trefoil braid was even suggested on this blog<\/a>, with a common feature of a central templating atom (a cation rather than an anion). Another example of a previously reported\u00a0pentadecanuclear manganese metallacycle[4]<\/a><\/span> was also assigned a linking number of\u00a06\u03c0.<\/p>\n

The molecule above is not completely\u00a0\u03c0-conjugated around the braid and so special properties related to aromaticity and associated ring currents<\/a> resulting from the topology of the cyclic conjugation[5]<\/a><\/span> are not expected to accrue in the eight-crossing molecular braid[1]<\/a><\/span>. We might also look forward to examples of the characterisation of\u00a0braids with an odd-number<\/strong> of crossings such as trefoils, pentafoils, heptafoils, etc, as associated with the name\u00a0M\u00f6bius<\/a>.<\/p>\n

References<\/h2>\n
  1. J.J. Danon, A. Kr\u00fcger, D.A. Leigh, J. Lemonnier, A.J. Stephens, I.J. Vitorica-Yrezabal, and S.L. Woltering, \"Braiding a molecular knot with eight crossings\", Science<\/i>, vol. 355, pp. 159-162, 2017. https:\/\/doi.org\/10.1126\/science.aal1619<\/a>\n\n<\/li>\n
  2. S.M. Rappaport, and H.S. Rzepa, \"Intrinsically Chiral Aromaticity. Rules Incorporating Linking Number, Twist, and Writhe for Higher-Twist M\u00f6bius Annulenes\", Journal of the American Chemical Society<\/i>, vol. 130, pp. 7613-7619, 2008. https:\/\/doi.org\/10.1021\/ja710438j<\/a>\n\n<\/li>\n
  3. C.S. Wannere, H.S. Rzepa, B.C. Rinderspacher, A. Paul, C.S.M. Allan, H.F. Schaefer, and P.V.R. Schleyer, \"The Geometry and Electronic Topology of Higher-Order Charged M\u00f6bius Annulenes\", The Journal of Physical Chemistry A<\/i>, vol. 113, pp. 11619-11629, 2009. https:\/\/doi.org\/10.1021\/jp902176a<\/a>\n\n<\/li>\n
  4. H.S. Rzepa, \"Linking Number Analysis of a Pentadecanuclear Metallamacrocycle: A M\u00f6bius-Craig System Revealed\", Inorganic Chemistry<\/i>, vol. 47, pp. 8932-8934, 2008. https:\/\/doi.org\/10.1021\/ic800987f<\/a>\n\n<\/li>\n
  5. P.L. Ayers, R.J. Boyd, P. Bultinck, M. Caffarel, R. Carb\u00f3-Dorca, M. Caus\u00e1, J. Cioslowski, J. Contreras-Garcia, D.L. Cooper, P. Coppens, C. Gatti, S. Grabowsky, P. Lazzeretti, P. Macchi, ?. Mart\u00edn Pend\u00e1s, P.L. Popelier, K. Ruedenberg, H. Rzepa, A. Savin, A. Sax, W.E. Schwarz, S. Shahbazian, B. Silvi, M. Sol\u00e0, and V. Tsirelson, \"Six questions on topology in theoretical chemistry\", Computational and Theoretical Chemistry<\/i>, vol. 1053, pp. 2-16, 2015. https:\/\/doi.org\/10.1016\/j.comptc.2014.09.028<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    This is one of those posts of a molecule whose very structure is interesting enough to merit a picture and a 3D model. The study reports a molecular knot with the remarkable number of eight crossings. The DOI for the 3D model is 10.5517\/CCDC.CSD.CC1M85Y0\u00a0(or click on the image above). Such topology intersects with work we […]<\/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":true,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"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":[6],"tags":[1700,1416,2024,1437,1480,1987,1881,341,2051,968],"class_list":["post-17366","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-cheminformatics","tag-chemistry","tag-drug-discovery","tag-education","tag-matter","tag-molecule","tag-nature","tag-spectroscopy","tag-structure-validation","tag--systems"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p1gPyz-4w6","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17366","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=17366"}],"version-history":[{"count":0,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17366\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17366"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17366"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17366"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}