{"id":9186,"date":"2013-01-18T11:07:45","date_gmt":"2013-01-18T11:07:45","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=9186"},"modified":"2023-09-16T19:42:41","modified_gmt":"2023-09-16T18:42:41","slug":"the-%cf%80-complex-in-the-benzidine-rearrangement-a-molecular-orbital-analysis","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186","title":{"rendered":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis."},"content":{"rendered":"
\n

Michael Dewar[1]<\/a><\/span> famously implicated a so-called\u00a0\u03c0-complex in the benzidine rearrangement, back in the days when quantum mechanical calculations could not yet provide a quantitatively accurate reality check. Because this\u00a0\u03c0-complex actually remains a relatively unusual species to encounter in day-to-day chemistry, I thought I would try to show in a simple way how it forms.<\/p>\n

\"pi-complex\"<\/p>\n

I am actually illustrating it with the benzidine rearrangement of monoprotonated PhNHOPh, which I dealt with in the previous post<\/a>, if only because the energy of this\u00a0\u03c0-complex relative to\u00a0monoprotonated PhNHOPh is amazingly low (in other words, it is not one of these high energy molecules which only exist in the virtual world of computational modelling). The mechanism can be conceptually broken down to considering how the N-O bond can be cleaved in one of three ways. Route A is the homolytic route to give a 4-biradical (in one of the possible resonance forms), which of course can couple to form a 4,4′-biphenyl. Route B is a heterolytic route in which the two electrons from the N-O\u00a0\u03c3-bond are retained by 1<\/strong>, whilst for route C this electron pair is retained by 4<\/strong>.<\/p>\n

These two fragments can then interact in several ways to form the\u00a0\u03c0-complex. \u00a0Here I will illustrate just the two closed shell options (B\/C), whilst recognising that there may also be contribution from the open shell biradical (in water as solvent, the two ionic configurations are clearly going to be stabilised by solvation and so may contribute relatively more than the non-polar radical-pair ).<\/p>\n

    \n
  1. Route B (green), overlapping the HOMO of 1<\/strong> with the LUMO of 2 <\/strong>to create a new \u03c0-MO\u00a0<\/strong>to be occupied by the\u00a0two electrons extracted from the N-O\u00a0\u03c3-bond (a similar promotion of a \u03c3- to a \u03c0-pair was noted in this post<\/a>).<\/li>\n
  2. Route C (red), overlapping the HOMO of 4<\/strong> with the LUMO of 3 <\/strong>to achieve the same result.<\/li>\n<\/ol>\n\n\n\n\n\n\n\n\n
    Route B<\/th>\n<\/tr>\n
    \n
    \"HOMO

    LUMO of 2. Click for 3D.<\/p><\/div>\n<\/td>\n

    		\n
    \"HOMO

    HOMO for \u03c0-complex. Click for 3D.<\/p><\/div>\n<\/td>\n<\/tr>\n

    \n
    \"HOMO

    HOMO of 1. Click for 3D.<\/p><\/div>\n<\/td>\n<\/tr>\n

    Route C<\/th>\n<\/tr>\n
    \n
    \"HOMO

    LUMO of 3. Click for 3D.<\/p><\/div>\n<\/td>\n

    		\n
    \"HOMO

    HOMO for \u03c0-complex. Click for 3D.<\/p><\/div>\n<\/td>\n<\/tr>\n

    \n
    \"HOMO

    HOMO of 4. Click for 3D.<\/p><\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    The relative weight of these two combinations is largely determined by the difference in energies between the two HOMO\/LUMO pairs and their overlap.\u00a0\u0394E is different for the two combinations, being 0.021 Hartree (route B) and 0.091 (route C), with lower being better.<\/p>\n

    The overlap of the HOMO\/LUMO (in either orbital combination)\u00a0is almost perfect for the face-to-face\u00a0\u03c0-stacking of the complex. Note that this\u00a0\u03c0-\u03c0-stacked arrangement in effect returns some electrons to the N-O region, in what is now called \u03c3-\u03c0 conjugation, and which used to be called hyperconjugation (it also resembles the conjugation of a Si-C bond with a phenyl ring<\/a>\u00a0in the Wheland intermediate).<\/p>\n

    \n

    Acknowledgments<\/h4>\n

    This post has been cross-posted in PDF format at Authorea<\/a>.<\/p>\n

    References<\/h2>\n
    1. M. Dewar, and H. McNicoll, \"Mechanism of the benzidine rearrangement\", Tetrahedron Letters<\/i>, vol. 1, pp. 22-23, 1959. https:\/\/doi.org\/10.1016\/s0040-4039(01)82765-9<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

      Michael Dewar famously implicated a so-called\u00a0\u03c0-complex in the benzidine rearrangement, back in the days when quantum mechanical calculations could not yet provide a quantitatively accurate reality check. Because this\u00a0\u03c0-complex actually remains a relatively unusual species to encounter in day-to-day chemistry, I thought I would try to show in a simple way how it forms. I […]<\/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":[4],"tags":[24,985,591,843],"ppma_author":[2661],"class_list":["post-9186","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-energy","tag-high-energy-molecules","tag-michael-dewar","tag-reaction-mechanism"],"yoast_head":"\nThe \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis. - Henry Rzepa'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=9186\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"Michael Dewar famously implicated a so-called\u00a0\u03c0-complex in the benzidine rearrangement, back in the days when quantum mechanical calculations could not yet provide a quantitatively accurate reality check. Because this\u00a0\u03c0-complex actually remains a relatively unusual species to encounter in day-to-day chemistry, I thought I would try to show in a simple way how it forms. I […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2013-01-18T11:07:45+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2023-09-16T18:42:41+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.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=\"3 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis. - Henry Rzepa'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=9186","og_locale":"en_GB","og_type":"article","og_title":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis. - Henry Rzepa's Blog","og_description":"Michael Dewar famously implicated a so-called\u00a0\u03c0-complex in the benzidine rearrangement, back in the days when quantum mechanical calculations could not yet provide a quantitatively accurate reality check. Because this\u00a0\u03c0-complex actually remains a relatively unusual species to encounter in day-to-day chemistry, I thought I would try to show in a simple way how it forms. I […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186","og_site_name":"Henry Rzepa's Blog","article_published_time":"2013-01-18T11:07:45+00:00","article_modified_time":"2023-09-16T18:42:41+00:00","og_image":[{"url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.svg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis.","datePublished":"2013-01-18T11:07:45+00:00","dateModified":"2023-09-16T18:42:41+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186"},"wordCount":522,"commentCount":2,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.svg","keywords":["energy","high energy molecules","Michael Dewar","Reaction Mechanism"],"articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186","name":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis. - Henry Rzepa's Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.svg","datePublished":"2013-01-18T11:07:45+00:00","dateModified":"2023-09-16T18:42:41+00:00","author":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"breadcrumb":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#primaryimage","url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.svg","contentUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-complex.svg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9186#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"The \u03c0-complex in the benzidine rearrangement: a molecular orbital analysis."}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa's Blog","description":"Chemistry with a twist","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281","name":"Henry Rzepa","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g370be3a7397865e4fd161aefeb0a5a85","url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","caption":"Henry Rzepa"},"description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London.","sameAs":["https:\/\/orcid.org\/0000-0002-8635-8390"],"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?author=1"}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pDef7-2oa","jetpack-related-posts":[{"id":9135,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9135","url_meta":{"origin":9186,"position":0},"title":"Why is N,O-diphenyl hydroxylamine (PhNHOPh) unknown?","author":"Henry Rzepa","date":"January 16, 2013","format":false,"excerpt":"If you search e.g. Scifinder for N,O-diphenyl hydroxylamine (RN\u00a024928-98-1) there is just one literature citation, to a 1962 patent. Nothing else; not even a calculation (an increasing proportion of the molecules reported in Chemical Abstracts have now only ever been subjected to calculation, not synthesis).\u00a0A search of Reaxys also offers\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":9018,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9018","url_meta":{"origin":9186,"position":1},"title":"Hidden intermediates in the benzidine rearrangement. The monoprotonated mechanism.","author":"Henry Rzepa","date":"January 8, 2013","format":false,"excerpt":"Eagle-eyed footnote readers might have spotted one at the bottom of the post on the benzidine rearrangement. I was comparing the N-N bond lengths in crystal structures of known diprotonated hydrazines (~1.45\u00c5) with the computed N-N bond length at the start point of the intrinsic reaction coordinate for the [5,5]\u2026","rel":"","context":"In \"free energy barrier\"","block_context":{"text":"free energy barrier","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?tag=free-energy-barrier"},"img":{"alt_text":"Transition state between p-complex and N-N diprotonated diphenyhydrazine. Click for 3D.","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-TS.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":8961,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=8961","url_meta":{"origin":9186,"position":2},"title":"The mechanism of the Benzidine rearrangement.","author":"Henry Rzepa","date":"January 6, 2013","format":false,"excerpt":"The benzidine rearrangement is claimed to be an example of the quite rare\u00a0[5,5] sigmatropic migration, which is a ten-electron homologation of the very common [3,3] sigmatropic reaction (e.g. the Cope or Claisen). Some benzidine rearrangements are indeed thought to go through the [3,3] route. The topic has been reviewed here.\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"NCI surface. Click for 3D.","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/benzidinenci.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":9218,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9218","url_meta":{"origin":9186,"position":3},"title":"Aromaticity in the benzidine-like \u03c0-complex formed from PhNHOPh.","author":"Henry Rzepa","date":"January 19, 2013","format":false,"excerpt":"The transient \u03c0-complex formed during the \"[5,5]\" sigmatropic rearrangement of protonated N,O-diphenyl hydroxylamine can be (formally) represented as below, namely the interaction of a six-\u03c0-electron aromatic ring (the phenoxide anion 2) with a\u00a0four-\u03c0-electron phenyl dication-anion pair 1. Can one analyse this interaction in terms of aromaticity? I showed previously that\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"pi-QTAIM","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/01\/pi-QTAIM.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":10252,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10252","url_meta":{"origin":9186,"position":4},"title":"Why diphenyl peroxide does not exist.","author":"Henry Rzepa","date":"April 29, 2013","format":false,"excerpt":"A few posts back, I explored the \"benzidine rearrangement\" of diphenyl hydrazine. This reaction requires diprotonation to proceed readily, but we then discovered that replacing one NH by an O as in N,O-diphenyl hydroxylamine required only monoprotonation to undergo an equivalent facile rearrangement. So replacing both NHs by O to\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":9105,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9105","url_meta":{"origin":9186,"position":5},"title":"The Benzidine rearrangement. Computed kinetic isotope effects.","author":"Henry Rzepa","date":"January 11, 2013","format":false,"excerpt":"Kinetic isotope effects have become something of a lost art when it comes to exploring reaction mechanisms. But in their heyday they were absolutely critical for establishing the mechanism of the benzidine rearrangement. This classic mechanism proceeds via bisprotonation of diphenyl hydrazine, but what happens next was the crux. Does\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"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\/9186","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=9186"}],"version-history":[{"count":30,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/9186\/revisions"}],"predecessor-version":[{"id":26477,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/9186\/revisions\/26477"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9186"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=9186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}