{"id":24027,"date":"2021-07-11T09:54:36","date_gmt":"2021-07-11T08:54:36","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=24027"},"modified":"2021-07-21T14:29:16","modified_gmt":"2021-07-21T13:29:16","slug":"molecules-with-very-large-dipole-moments-cyclopropenium-acetylide","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=24027","title":{"rendered":"Molecules with very large dipole moments: cyclopropenium acetylide"},"content":{"rendered":"
\n

Occasionally, someone comments about an old post here, asking a question. Such was the case here<\/a>, 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.<\/p>\n

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

Of the two resonance forms show above, the one on the left is a zwitterion resulting in the formation of an aromatic cyclopropenium ring, with the charge balanced by the acetylide anion.‡<\/sup> The calculated structure (\u03c9B97XD\/Def2-TZVPP\/SCRF=chloroform, Data DOI 10.14469\/hpc\/8399<\/a> ) shows a short terminal CC bond which indicates a significant degree of delocalisation of the three membered ring.<\/p>\n

\"\"

Molecular electrostatic potential<\/p><\/div>\n

The molecular electrostatic potential (above) agrees with a large dipole moment of 11.9D. This is certainly up there with the molecule suggested in 2016 as being the most polar molecule neutral compound synthesised[1]<\/a><\/span> and is a fair bit smaller than that candidate. A brief search of the literature (Scifinder) suggest that the molecule is currently unknown. Anybody fancy making it?<\/p>\n

The Data DOI by the way gives you access to the other outputs from the calculation, which would include the molecular orbitals and the molecular vibrations which I have not shown here.<\/p>\n

\n

‡<\/sup> Such zwitterions are known as unstable intermediates. See e.g. [2]<\/a><\/span> for examples.<\/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. H.S. Rzepa, \"Routes involving no free C\n <sub>2<\/sub>\n in a DFT-computed mechanistic model for the reported room-temperature chemical synthesis of C\n <sub>2<\/sub>\", Physical Chemistry Chemical Physics<\/i>, vol. 23, pp. 12630-12636, 2021. https:\/\/doi.org\/10.1039\/d1cp02056k<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    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, the one on the left […]<\/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":[],"ppma_author":[2661],"class_list":["post-24027","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"yoast_head":"\nMolecules with very large dipole moments: cyclopropenium acetylide - 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=24027\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Molecules with very large dipole moments: cyclopropenium acetylide - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"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. 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