{"id":28290,"date":"2025-02-01T09:53:41","date_gmt":"2025-02-01T09:53:41","guid":{"rendered":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=28290"},"modified":"2025-02-01T09:53:41","modified_gmt":"2025-02-01T09:53:41","slug":"au-pseudocarbyne-a-unusual-example-of-a-twelve-coordination-by-carbon","status":"publish","type":"post","link":"https:\/\/www.rzepa.net\/blog\/?p=28290","title":{"rendered":"Au-pseudocarbyne – a unusual example of a twelve coordination by carbon."},"content":{"rendered":"
\n

Derek Lowe tells the story of “carbyne”<\/a>, a potential further allotrope of carbon, comprising linear chains of carbon atoms, C-C\u2261C-C\u2261C-C. Whether such a molecule can exist on its own has long been the the topic of speculation. Now a report has appeared of a “pseudocarbyne”, stabilised by gold atoms.[1]<\/a><\/span><\/p>\n

The now thankfully almost ubiquitous data availability statement includes the DOI: https:\/\/doi.org\/10.48349\/ASU\/3TWEI0<\/a> [2]<\/a><\/span> as a data repository\u00a0source of replication data<\/em> and one of the files found there is a CIF containing the crystal data. Playing with this, I noticed one unusual feature of this structure, which oddly is not apparently mentioned in the article itself and so I thought I would tease it out here – 12 coordination.<\/p>\n

\"\"<\/p>\n

Ths simplest unit comprises three eight membered carbon rings, each connected by 4-membered rings to form a local structure with D3h symmetry and hence revealing twelve C-Au bonds of the same length; 2.415\u00c5. Click on the image above to view a\u00a03D model.<\/p>\n

A larger section of the (polymeric) structure is shown below, now with D2h symmetry and again with twelve identical C-Au bond lengths<\/p>\n

\"\"<\/p>\n

Is such coordination unusual?‡<\/sup> Well, not for metal clusters, including Au clusters. There are in fact 2014 hits (1985 examples where Y is constrained to be a metal, hence 29 where the central atom is NOT a metal) in the Cambridge crystal structure database for the general search X12<\/sub>Y where X and Y can be any atom, with 244 for X=Au and\u00a0576 for X=O but none yet for X=C (the current example has not yet appeared in the distributed database). So certainly Au-pseudocarbyne is a unique and unusual molecule. This also shows that 3D coordinates can always be a useful adjunct to articles to allow quick access for spotting perhaps unexpected features with just a single click!<\/p>\n

\n

‡<\/sup>You might be surprised that a similar search finds 138 hits for X14<\/sub>Y and 16 for X16<\/sub>Y<\/p>\n

References<\/h2>\n
  1. J. Wu, P. Tarakeshwar, S.G. Sayres, M. Meneghetti, H. Kim, J. Barreto, and P.R. Buseck, \"Crystal structure of Au-pseudocarbyne(C6)\", Scientific Reports<\/i>, vol. 15, 2025. https:\/\/doi.org\/10.1038\/s41598-024-80359-5<\/a>\n\n<\/li>\n
  2. J. Wu, P. Tarakeshwar, S.G. Sayres, M. Meneghetti, H. Kim, J. Barreto, and P.R. Buseck, \"Replication Data for: Crystal structure of Au-pseudocarbyne(C6)\", 2024. https:\/\/doi.org\/10.48349\/asu\/3twei0<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    Derek Lowe tells the story of “carbyne”, a potential further allotrope of carbon, comprising linear chains of carbon atoms, C-C\u2261C-C\u2261C-C. Whether such a molecule can exist on its own has long been the the topic of speculation. Now a report has appeared of a “pseudocarbyne”, stabilised by gold atoms. The now thankfully almost ubiquitous data […]<\/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,"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":[],"class_list":["post-28290","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p1gPyz-7mi","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/28290","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=28290"}],"version-history":[{"count":0,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/28290\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=28290"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=28290"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=28290"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}