{"id":22391,"date":"2020-05-25T12:35:33","date_gmt":"2020-05-25T11:35:33","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=22391"},"modified":"2020-05-25T12:35:33","modified_gmt":"2020-05-25T11:35:33","slug":"the-strongest-bond-in-the-universe-a-crystallographic-reality-check","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=22391","title":{"rendered":"The strongest bond in the universe: A crystallographic reality check?"},"content":{"rendered":"
\n

My previous<\/a> two posts on the topic of strongest bonds have involved mono and diprotonating N2<\/sub> and using quantum mechanics to predict the effect this has on the N-N bond via<\/em> its length and vibrational stetching mode. Such species are very unlikely to be easily observed for verification. But how about a metal M+<\/sup> instead of H+<\/sup>? It turns out that structures containing the fragment Ru-N\u2261N-Ru are a small but well studied class of organometallic. Here is a search of the CSD crystal database for this motif.<\/p>\n

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

The three examples showing the shortest N-N distances are shown below.[1]<\/a><\/span>,[2]<\/a><\/span>[3]<\/a><\/span><\/p>\n

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

The NN distances for these three examples are in the region of 1.1\u00c5. There are 39 structures in total, for a variety of other transition metals, with a length <1.15\u00c5. The angles subtended at N are close to linear;<\/p>\n

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

 <\/p>\n

For comparison, N2<\/sub> itself entrained into a crystal structure has the value of ~1.096<\/a>\u00c5 as measured at 80K (R-factor 0.84%)[4]<\/a><\/span>) which is pretty similar to the value computed in the previous post (1.103\u00c5). \u00a0<\/p>\n

So the question to ask is whether any of these organometallic examples have an NN bond at least as strong as that in dinitrogen itself? Only a reliable value for the force constant will give us a clear picture, which however would be non-trivial for such species. But it does suggest that asking whether there could be a real candidate for the strongest bond in the universe other than N2<\/sub> itself may not be entirely futile.<\/p>\n

 <\/p>\n

References<\/h2>\n
  1. Y. Sun, H. Chan, and Z. Xie, \"Reaction Scope and Mechanism of Sterically Induced Ruthenium-Mediated Intramolecular Coupling of<i>o<\/i>-Carboranyl with Cyclopentadienyl. Synthesis and Structure of Ruthenium Complexes Incorporating Doubly Linked Cyclopentadienyl\u2212Carboranyl Ligands\", Organometallics<\/i>, vol. 25, pp. 4188-4195, 2006. https:\/\/doi.org\/10.1021\/om0604122<\/a>\n\n<\/li>\n
  2. Y. Tanabe, S. Kuriyama, K. Arashiba, K. Nakajima, and Y. Nishibayashi, \"Synthesis and Reactivity of Ruthenium Complexes Bearing Arsenic-Containing Arsenic-Nitrogen-Arsenic-Type Pincer Ligand\", Organometallics<\/i>, vol. 33, pp. 5295-5300, 2014. https:\/\/doi.org\/10.1021\/om5006116<\/a>\n\n<\/li>\n
  3. K. Abdur-Rashid, D.G. Gusev, A.J. Lough, and R.H. Morris, \"Synthesis and Characterization of RuH<sub>2<\/sub>(H<sub>2<\/sub>)<sub>2<\/sub>(P<sup>i<\/sup>Pr<sub>3<\/sub>)<sub>2<\/sub> and Related Chemistry. Evidence for a Bis(dihydrogen) Structure\", Organometallics<\/i>, vol. 19, pp. 1652-1660, 2000. https:\/\/doi.org\/10.1021\/om990669i<\/a>\n\n<\/li>\n
  4. C. Dou, W. Kosaka, and H. Miyasaka, \"Gate-open-type Sorption in a Zigzag Paddlewheel Ru Dimer Chain Compound with a Phenylenediamine Linker Instructed by a Preliminary Structural Change of Desolvation\", Chemistry Letters<\/i>, vol. 46, pp. 1288-1291, 2017. https:\/\/doi.org\/10.1246\/cl.170509<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    My previous two posts on the topic of strongest bonds have involved mono and diprotonating N2 and using quantum mechanics to predict the effect this has on the N-N bond via its length and vibrational stetching mode. Such species are very unlikely to be easily observed for verification. But how about a metal M+ instead […]<\/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":[1745],"tags":[],"ppma_author":[2661],"class_list":["post-22391","post","type-post","status-publish","format-standard","hentry","category-crystal_structure_mining"],"yoast_head":"\nThe strongest bond in the universe: A crystallographic reality check? - 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=22391\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The strongest bond in the universe: A crystallographic reality check? - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"My previous two posts on the topic of strongest bonds have involved mono and diprotonating N2 and using quantum mechanics to predict the effect this has on the N-N bond via its length and vibrational stetching mode. 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N. Lewis suggested a model for single and double bonds that involved sharing either 2 or 4 electrons between a pair of atoms. We tend to think\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":"Click for 3D","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/03\/PYRDRE.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":16819,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=16819","url_meta":{"origin":22391,"position":1},"title":"What\u2019s in a name? Stabilised “nitrenes”.","author":"Henry Rzepa","date":"September 19, 2016","format":false,"excerpt":"I previously explored stabilized \"carbenes\" with the formal structures (R2N)2C:, concluding that perhaps the alternative ionic representation R2N+=C-NR2\u00a0might reflect their structures better. Here I take a broader look at the \"carbene\" landscape before asking the question \"what about nitrenes?\" The top row shows the compounds for which no crystal structure\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"nitrene1","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/09\/nitrene1-1024x655.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":15635,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=15635","url_meta":{"origin":22391,"position":2},"title":"Bond stretch isomerism. Did this idea first surface 100 years ago?","author":"Henry Rzepa","date":"February 9, 2016","format":false,"excerpt":"The phenomenon of bond stretch isomerism, two isomers of a compound differing predominantly in just one bond length, is one of those chemical concepts that wax and occasionally\u00a0wane. Here I explore such isomerism for the elements Ge, Sn and Pb. In one earlier post, I noted a form of\u00a0bond stretch\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"lewis1","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/02\/lewis1-1-1024x421.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":30890,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=30890","url_meta":{"origin":22391,"position":3},"title":"Valence bond representations with +ve charges on adjacent atoms? An odd titanium complex analysed.","author":"Henry Rzepa","date":"March 8, 2026","format":false,"excerpt":"A few posts back, I contemplated the curly arrows appropriate for the formation of nitrosobenzene dimer from nitrosobenzene, and commented on the odd nature of the N=N double bond formed in this process.. Odd, because the valence bond representation of this dimer (1 below) has two formally positive adjacent nitrogen\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":8961,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=8961","url_meta":{"origin":22391,"position":4},"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":18205,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18205","url_meta":{"origin":22391,"position":5},"title":"\u03c0-Facial hydrogen bonds to alkynes (revisited): how close can an acidic hydrogen approach?","author":"Henry Rzepa","date":"April 17, 2017","format":false,"excerpt":"Following on from my re-investigation of close hydrogen bonding contacts to the \u03c0-face of alkenes, here now is an updated scan for H-bonds to alkynes. The search query (dataDOI: 10.14469\/hpc\/2478) is similar to the previous one: QA is any of N,O,F,Cl. X is any atom, including metals and non-metals. The\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/04\/triple-inter-1024x672.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\/22391","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=22391"}],"version-history":[{"count":7,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/22391\/revisions"}],"predecessor-version":[{"id":22403,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/22391\/revisions\/22403"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=22391"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=22391"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=22391"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=22391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}