{"id":17252,"date":"2016-12-21T07:52:19","date_gmt":"2016-12-21T07:52:19","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=17252"},"modified":"2016-12-21T07:52:19","modified_gmt":"2016-12-21T07:52:19","slug":"forking-the-most-polar-neutral-compound-synthesized-into-m-benzyne","status":"publish","type":"post","link":"https:\/\/www.rzepa.net\/blog\/?p=17252","title":{"rendered":"Forking “The most polar neutral compound synthesized” into m-benzyne."},"content":{"rendered":"
\n

A project fork<\/a> is defined (in computing) as creating a distinct and separate strand from an existing (coding) project. Here I apply the principle to the polar azulene 4<\/strong> explored in an earlier post<\/a>, taking m-benzyne as a lower homologue of azulene as my starting point.<\/p>\n

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

m-Benzyne<\/a> is a less\u00a0stable 1,3 isomer of o-benzyne (1,2-dehydrobenzene), and is often represented as a 1,3-biradical of 1,3-dehydrobenzene. But, could it be stabilized with cyano and amino groups as shown in 5<\/strong> above? Here the idea is that charge transfer from the 3-ring to the 5-ring will create a lower homologue of azulene (a well known molecule), with the 3-ring a 4n+2 \u03c0-electron aromatic (n=0) and the five ring similarly so\u00a0(n=1).<\/p>\n

I start with the computed (wB97XD\/Def2-TZVPP\/SCRF=thf) structure of m-benzyne itself, as a closed shell molecule (DOI:\u00a010.14469\/hpc\/1995<\/a>). The C-C bond connecting the two rings is long (with a biradical tendency) and hence the conjugation is restricted to the outer periphery. The dipole moment is 0.51D (the dipole vector as shown in blue has the expected direction of polarity).<\/p>\n

\"\"<\/p>\n

Now compare this to the substituted version 5;<\/strong>\u00a0the bond lengths are all more characteristic of aromatic values and most significantly the central bond is as well (DOI:\u00a010.14469\/hpc\/1996<\/a>). The dipole moment is augmented thirty fold to 14.6D<\/span><\/strong>, which would rank alongside that reported for the most polar neutral molecule.<\/p>\n

\"\"<\/p>\n

So I suggest this is substituted “m-benzyne” well worth trying to make and one very much unlikely to have any dispute about the nature of its wavefunction, i.e.<\/em> biradical or closed shell.<\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

A project fork is defined (in computing) as creating a distinct and separate strand from an existing (coding) project. Here I apply the principle to the polar azulene 4 explored in an earlier post, taking m-benzyne as a lower homologue of azulene as my starting point. m-Benzyne is a less\u00a0stable 1,3 isomer of o-benzyne (1,2-dehydrobenzene), […]<\/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":true,"_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":[1965,1966,1968,1416,1432,1972],"class_list":["post-17252","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-aryne","tag-azulene","tag-chemical-polarity","tag-chemistry","tag-dipole","tag-extreme-umpolung"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p1gPyz-4ug","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17252","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=17252"}],"version-history":[{"count":0,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17252\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rzepa.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}