{"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:\/\/rzepa.net\/blog\/2025\/02\/01\/au-pseudocarbyne-a-unusual-example-of-a-twelve-coordination-by-carbon\/","title":{"rendered":"Au-pseudocarbyne – a unusual example of a twelve coordination by carbon."},"content":{"rendered":"

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.[cite]10.1038\/s41598-024-80359-5[\/cite]<\/p>\n

The now thankfully almost ubiquitous data availability statement includes the DOI: https:\/\/doi.org\/10.48349\/ASU\/3TWEI0<\/a> [cite]10.48349\/ASU\/3TWEI0[\/cite] 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","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.[cite]10.1038\/s41598-024-80359-5[\/cite] The now thankfully almost ubiquitous data […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-28290","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"_links":{"self":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts\/28290","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/comments?post=28290"}],"version-history":[{"count":0,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts\/28290\/revisions"}],"wp:attachment":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/media?parent=28290"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/categories?post=28290"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/tags?post=28290"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}