{"id":7643,"date":"2012-09-12T16:11:23","date_gmt":"2012-09-12T15:11:23","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=7643"},"modified":"2012-09-14T08:24:27","modified_gmt":"2012-09-14T07:24:27","slug":"what-is-the-range-of-values-for-a-sp3c-csp3-carbon-single-bond","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643","title":{"rendered":"What is the range of values for a (sp3)C-C(sp3) single bond length?"},"content":{"rendered":"
\n

Here is a challenge: what is the longest C-C bond actually determined (in which both carbon termini are sp3<\/sup> hybridised)? I pose this question since Steve Bachrach has posted<\/a> on how to stabilize long bonds by attractive dispersive interactions, and more recently\u00a0commenting<\/a> on what the longest straight chain alkane might be before dispersive interaction start to fold it (the answer appears to be C17<\/sub>).<\/p>\n

A search of the Cambridge database (the following conditions apply; structure determined at less than 160K, no errors, no disorder, and a minimum separation of 1.7\u00c5) reveals only 7 entries longer than 1.7A. The reference codes for these are FIBBOI, HOLKOI, LAGHOQ01, RIRTUH, RUNHOY, XIQRIZ, BATSIA, the latter having a value of 1.731\u00c5 (T=123K, R=4.44%, DOI: 10.1246\/cl.2012.541<\/a>). Of course, a very close inspection of the crystallography would also be needed to determine if these values are to be taken at face value.<\/p>\n

\"\"

BATSIA. Click for 3D model.<\/p><\/div>\n

If one relaxes the temperature constraint for measurement, CAZFUE01 has a claimed C-C length of 1.99\u00c5 (R=4.5%, DOI: 10.1246\/cl.2012.541<\/a>). This however represents the so-called frozen transition state for a [3,3] sigmatropic rearrangement. A\u00a0\u03c9B97XD\/6-311G(d,p)\/SCRF=dichloromethane calculation seems to indicate that this species is in fact a transition state for the [3,3] reaction, and hence that the crystal structure may in fact correspond to the mean position of the two end points of the reaction, and so be an artefact. More on this in a later post.\u00a0<\/p>\n

\"\"

CAZFUE. Click for 3D model.<\/p><\/div>\n

And I suppose one should ask what the shortest such single bond is as well as the longest. This is currently claimed to be 1.436\u00c5 for KAVKUO (10.1002\/anie.200501605<\/a>) and 1.434\u00c5 for WUDKAH (10.1016\/S0040-4020(02)00695-6<\/a>). The origins of this contraction also deserve to be more fully explored in a later post.<\/p>\n

\"\"

KAVKUO. Click for 3D<\/p><\/div>\n

 <\/p>\n

\"\"

WUDKAH. Click for 3D.<\/p><\/div>\n

Certainly, the (sp3<\/sup>)C-C(sp3<\/sup>) bond does seem to be capable of a large range of values ranging from 1.44 to at least 1.73 and possibly 1.99\u00c5.<\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

Here is a challenge: what is the longest C-C bond actually determined (in which both carbon termini are sp3 hybridised)? I pose this question since Steve Bachrach has posted on how to stabilize long bonds by attractive dispersive interactions, and more recently\u00a0commenting on what the longest straight chain alkane might be before dispersive interaction start […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_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":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[4],"tags":[144,20],"ppma_author":[2661],"class_list":["post-7643","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-cambridge","tag-steve-bachrach"],"yoast_head":"\nWhat is the range of values for a (sp3)C-C(sp3) single bond length? - 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=7643\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What is the range of values for a (sp3)C-C(sp3) single bond length? - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"Here is a challenge: what is the longest C-C bond actually determined (in which both carbon termini are sp3 hybridised)? I pose this question since Steve Bachrach has posted on how to stabilize long bonds by attractive dispersive interactions, and more recently\u00a0commenting on what the longest straight chain alkane might be before dispersive interaction start […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2012-09-12T15:11:23+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2012-09-14T07:24:27+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg\" \/>\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=\"2 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"What is the range of values for a (sp3)C-C(sp3) single bond length? - 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=7643","og_locale":"en_GB","og_type":"article","og_title":"What is the range of values for a (sp3)C-C(sp3) single bond length? - Henry Rzepa's Blog","og_description":"Here is a challenge: what is the longest C-C bond actually determined (in which both carbon termini are sp3 hybridised)? I pose this question since Steve Bachrach has posted on how to stabilize long bonds by attractive dispersive interactions, and more recently\u00a0commenting on what the longest straight chain alkane might be before dispersive interaction start […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643","og_site_name":"Henry Rzepa's Blog","article_published_time":"2012-09-12T15:11:23+00:00","article_modified_time":"2012-09-14T07:24:27+00:00","og_image":[{"url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"What is the range of values for a (sp3)C-C(sp3) single bond length?","datePublished":"2012-09-12T15:11:23+00:00","dateModified":"2012-09-14T07:24:27+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643"},"wordCount":368,"commentCount":8,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg","keywords":["Cambridge","Steve Bachrach"],"articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643","name":"What is the range of values for a (sp3)C-C(sp3) single bond length? - 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=7643#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg","datePublished":"2012-09-12T15:11:23+00:00","dateModified":"2012-09-14T07:24:27+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=7643#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#primaryimage","url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg","contentUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/BATSIA.jpg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7643#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"What is the range of values for a (sp3)C-C(sp3) single bond length?"}]},{"@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\/pDef7-1Zh","jetpack-related-posts":[{"id":1210,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=1210","url_meta":{"origin":7643,"position":0},"title":"The nature of the C\u2261S triple bond","author":"Henry Rzepa","date":"December 1, 2009","format":false,"excerpt":"Steve Bachrach has just blogged on a recent article (DOI: 10.1002\/anie.200903969) claiming the isolation of a compound with a C\u2261S triple bond; Steve notes that Schreiner and co claim a \u201cstructure with a rather strong CS double bond or a weak triple bond\u201d. With this size of molecule, the proverbial\u2026","rel":"","context":"In "Hypervalency"","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"A compound with a CS triple bond","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2009\/12\/CSCC.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":21096,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21096","url_meta":{"origin":7643,"position":1},"title":"CH…O hydrogen bonding competing with layered dispersion attractions.","author":"Henry Rzepa","date":"July 19, 2019","format":false,"excerpt":"I have previously looked at the topic of hydrogen bonding interactions from the hydrogen of chloroform Here I generalize\u00a0C-H...O interactions by conducting searches of the CSD (Cambridge structure database) as a function of the carbon hybridisation.\u00a0I am going to jump straight to a specific molecule XEVJIR (DOI: 10.5517\/cc5fgpq) identified from\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\/2019\/07\/XEVJIR-1024x839.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":16889,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=16889","url_meta":{"origin":7643,"position":2},"title":"More stereoelectronics galore: hexamethylene triperoxide diamine.","author":"Henry Rzepa","date":"September 22, 2016","format":false,"excerpt":"Compounds with O-O bonds often have weird properties. For example, artemisinin, which has some fascinating stereoelectronics. Here is another such, recently in the news\u00a0and\u00a0known as HMTD (hexamethylene triperoxide diamine).\u00a0The crystal structure was reported some time ago and the article included an inspection of the computed wavefunction. However this did not\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":"hmtd","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/09\/HMTD-1024x986.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":11421,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=11421","url_meta":{"origin":7643,"position":3},"title":"Six vs ten aromatic electrons?","author":"Henry Rzepa","date":"October 20, 2013","format":false,"excerpt":"Homoaromaticity is a special case of\u00a0aromaticity\u00a0in which\u00a0\u03c0-conjugation\u00a0is interrupted by a single sp3\u00a0hybridized\u00a0carbon atom (it is sometimes referred to as a suspended \u03c0-bond with no underlying \u03c3-foundation).\u00a0But consider the carbene shown below. This example comes from a recently published article which was highlighted on Steve Bachrach's blog. Here aromaticity has resulted\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\/10\/B10-sigma.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":9360,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=9360","url_meta":{"origin":7643,"position":4},"title":"\u03c3-\u03c0-Conjugation: seeking evidence by a survey of crystal structures.","author":"Henry Rzepa","date":"February 3, 2013","format":false,"excerpt":"The electronic interaction between a single bond and an adjacent double bond is often called \u03c3-\u03c0-conjugation (an older term for this is hyperconjugation), and the effect is often used to e.g. explain why more highly substituted carbocations are more stable than less substituted ones. This conjugation is more subtle in\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":"C-H\/alkene interaction. Click for 3D.","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/02\/cis-butene-orbitals.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":4224,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=4224","url_meta":{"origin":7643,"position":5},"title":"D\u00e9j\u00e0 vu all over again. Are H…H interactions attractive or repulsive?","author":"Henry Rzepa","date":"May 31, 2011","format":false,"excerpt":"The Pirkle reagent is a 9-anthranyl derivative (X=OH, Y=CF3). The previous post on the topic had highlighted DIST1, the separation of the two hydrogen atoms shown below. The next question to ask is how general this feature is. Here we take a look at the distribution of lengths found in\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":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/05\/9-anthranyl1.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\/7643","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=7643"}],"version-history":[{"count":29,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7643\/revisions"}],"predecessor-version":[{"id":7676,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7643\/revisions\/7676"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7643"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=7643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}