{"id":19550,"date":"2018-04-13T11:05:29","date_gmt":"2018-04-13T10:05:29","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=19550"},"modified":"2018-08-13T14:15:49","modified_gmt":"2018-08-13T13:15:49","slug":"a-record-polarity-for-a-neutral-compound","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19550","title":{"rendered":"A record polarity for a neutral compound?"},"content":{"rendered":"
\n

In several posts<\/a> a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed[1]<\/a><\/span> for a synthesized molecule of ~14.1\u00b10.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family of compounds which have the potential to extend the dipole moment for a formally neutral molecule up still further.<\/p>\n

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

These molecules derive from a well-known class of molecule known as ortho-quinomethides. If the methide part is substituted with an electron donating substituent such as an amino group in 3<\/strong>, a push-pull opportunity now arises, which is strongly driven by aromatisation of the quinomethide ring. This allows one to design “neutral” molecules such as 1<\/strong> and 2<\/strong>, which now contain respectively two and three rings that will be aromatised by the process. The aromatisation stabilization energy is balanced of course by an opposing increase in energy resulting from charge separation.\u00a0You can observe that partially aromatising three independent rings as in 2<\/strong> can drive a great deal of charge separation. One may indeed wonder how much charge separation can be sustained before a triplet instability occurs, driving the molecule back to being neutral. In the case of 2<\/strong>, the wavefunction is in fact stable to such an open shell state, but higher homologues may not be. An aspect worth investing!<\/p>\n\n\n\n\n\n\n
1<\/th>\n2<\/th>\n<\/tr>\n
\"\"<\/td>\n\"\"<\/td>\n<\/tr>\n
DM 12.3<\/td>\nDM 31.5<\/td>\n<\/tr>\n
DOI: 10.14469\/hpc\/4004<\/a><\/td>\nDOI: 10.14469\/hpc\/4059<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Molecule 1<\/b>\u00a0does have some precedent in 3<\/strong>[2]<\/a><\/span> but this system exists as a phenol, having abstracted a proton from an acid and leaving behind the acid anion, as per below for 1<\/strong>. Any attempts to deprotonate this phenol with a superstrong base were unreported.<\/p>\n

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

Unsurprisingly therefore, molecules such as 1<\/strong> and 2<\/strong>\u00a0could be regarded as even more highly potent bases than 3<\/strong>, driven again by further aromatisation. The properties of such a potential superbase will be investigated in the next post.<\/p>\n

References<\/h2>\n
  1. J. Wudarczyk, G. Papamokos, V. Margaritis, D. Schollmeyer, F. Hinkel, M. Baumgarten, G. Floudas, and K. M\u00fcllen, \"Hexasubstituted Benzenes with Ultrastrong Dipole Moments\", Angewandte Chemie International Edition<\/i>, vol. 55, pp. 3220-3223, 2016. https:\/\/doi.org\/10.1002\/anie.201508249<\/a>\n\n<\/li>\n
  2. N.R. Candeias, L.F. Veiros, C.A.M. Afonso, and P.M.P. Gois, \"Water: A Suitable Medium for the Petasis Borono\u2010Mannich Reaction\", European Journal of Organic Chemistry<\/i>, vol. 2009, pp. 1859-1863, 2009. https:\/\/doi.org\/10.1002\/ejoc.200900056<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed for a synthesized molecule of ~14.1\u00b10.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family […]<\/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":[4],"tags":[2463,1957,558,1395,1463,1965,1669,24,1964,1871,1962,1872,1670],"ppma_author":[2661],"class_list":["post-19550","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-aromatisation-stabilization-energy","tag-chemical-polarity","tag-chemical-properties","tag-chemistry","tag-dipole","tag-electric-dipole-moment","tag-electromagnetism","tag-energy","tag-moment","tag-nature","tag-physical-quantities","tag-physics","tag-potential-theory"],"yoast_head":"\nA record polarity for a neutral compound? - 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=19550\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A record polarity for a neutral compound? - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed for a synthesized molecule of ~14.1\u00b10.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19550\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2018-04-13T10:05:29+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-08-13T13:15:49+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2018\/04\/sb1-page001.svg\" \/>\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":"A record polarity for a neutral compound? - 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=19550","og_locale":"en_GB","og_type":"article","og_title":"A record polarity for a neutral compound? - Henry Rzepa's Blog","og_description":"In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed for a synthesized molecule of ~14.1\u00b10.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. 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The most polar neutral compound synthesized…","author":"Henry Rzepa","date":"December 18, 2016","format":false,"excerpt":"This, the fourth candidate provided by C&EN for a vote for the molecule of the year\u00a0as discussed here,\u00a0lays claim to the World's most polar neutral molecule (system 1 shown below). Here I explore\u00a0a strategy for extending that record. The claim for 1 (3 in\u00a0) is on the basis of its\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":24027,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=24027","url_meta":{"origin":19550,"position":1},"title":"Molecules with very large dipole moments: cyclopropenium acetylide","author":"Henry Rzepa","date":"July 11, 2021","format":false,"excerpt":"Occasionally, someone comments about an old post here, asking a question. Such was the case here, when a question about the dipole moment of cyclopropenylidene arose. It turned out to be 3.5D, but this question sparked a thought about the related molecule below. Of the two resonance forms show above,\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.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/07\/C5H5-esp-1024x690.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":17252,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17252","url_meta":{"origin":19550,"position":2},"title":"Forking “The most polar neutral compound synthesized” into m-benzyne.","author":"Henry Rzepa","date":"December 21, 2016","format":false,"excerpt":"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\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":17279,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17279","url_meta":{"origin":19550,"position":3},"title":"The dipole moments of highly polar molecules: glycine zwitterion.","author":"Henry Rzepa","date":"December 24, 2016","format":false,"excerpt":"The previous posts produced discussion about the dipole moments of highly polar molecules. Here to produce some reference points for further discussion I look at the dipole moment of glycine, the classic\u00a0zwitterion (an internal ion-pair). Dielectric relaxation studies of glycine-water mixtures yield values that range from\u00a015.7D to 11.9D although these\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\/2016\/12\/051.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":13394,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13394","url_meta":{"origin":19550,"position":4},"title":"How many water molecules does it take to ionise HCl?","author":"Henry Rzepa","date":"February 14, 2015","format":false,"excerpt":"According to Guggemos, Slavicek and Kresin, about 5-6!. This is one of those simple ideas, which is probably quite tough to do experimentally. It involved blasting water vapour through a pinhole, adding HCl and\u00a0measuring the dipole-moment induced deflection by an electric field. They\u00a0found\u00a0\"evidence for a noticeable rise in the dipole\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":20886,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=20886","url_meta":{"origin":19550,"position":5},"title":"An Ambimodal Trispericyclic Transition State: the effect of solvation?","author":"Henry Rzepa","date":"May 2, 2019","format":false,"excerpt":"Ken Houk's group has recently published this study of cycloaddition reactions, using a combination of classical transition state location followed by molecular dynamics trajectory calculations, and to which Steve Bachrach's blog alerted me. The reaction struck me as being quite polar (with cyano groups) and so I took a look\u2026","rel":"","context":"In "reaction mechanism"","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2019\/04\/Screenshot-32-1024x662.jpg?resize=350%2C200&ssl=1","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\/19550","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=19550"}],"version-history":[{"count":15,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19550\/revisions"}],"predecessor-version":[{"id":19602,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19550\/revisions\/19602"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19550"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19550"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=19550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}