{"id":21720,"date":"2019-12-22T12:30:02","date_gmt":"2019-12-22T12:30:02","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=21720"},"modified":"2019-12-22T12:30:02","modified_gmt":"2019-12-22T12:30:02","slug":"molecules-of-the-year-2019-twisty-tetracene","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21720","title":{"rendered":"Molecules of the year \u2013 2019: twisty tetracene."},"content":{"rendered":"
\n

All of the molecules in this year’s C&EN list<\/a> are fascinating in their very different ways. Here I take a look at the twisty tetracene (dodecaphenyltetracene) which is indeed very very twisty.[1]<\/a><\/span><\/p>\n

\"\"

Click on image to view 3D model<\/p><\/div>\n

\nUnfortunately, the authors point that the twisty-ness does not lead to a stable helical configuration at room temperatures and so separate enantiomers cannot be isolated. But its still worth speculating what the optical rotation of such a species might be if measured. An ωB97XD\/Def2-SVP\/SCRF=dichloromethane calculation (DOI: 10.14469\/hpc\/6527<\/a>) gives the following values:<\/p>\n

[α]589<\/sub> -11178°
\n[α]800<\/sub> -2310°<\/p>\n

Of course, mere helicity (however twisty) does not necessarily map to high optical rotation! This would be a nice molecule to 3D print<\/a> and sit on a coffee table for people to admire!<\/p>\n

References<\/h2>\n
  1. Y. Xiao, J.T. Mague, R.H. Schmehl, F.M. Haque, and R.A. Pascal, \"Dodecaphenyltetracene\", Angewandte Chemie International Edition<\/i>, vol. 58, pp. 2831-2833, 2019. https:\/\/doi.org\/10.1002\/anie.201812418<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    All of the molecules in this year’s C&EN list are fascinating in their very different ways. Here I take a look at the twisty tetracene (dodecaphenyltetracene) which is indeed very very twisty. Unfortunately, the authors point that the twisty-ness does not lead to a stable helical configuration at room temperatures and so separate enantiomers cannot […]<\/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_feature_clip_id":0,"_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},"jetpack_post_was_ever_published":false},"categories":[4],"tags":[],"ppma_author":[2661],"class_list":["post-21720","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"yoast_head":"\nMolecules of the year \u2013 2019: twisty tetracene. - 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=21720\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Molecules of the year \u2013 2019: twisty tetracene. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"All of the molecules in this year’s C&EN list are fascinating in their very different ways. Here I take a look at the twisty tetracene (dodecaphenyltetracene) which is indeed very very twisty. 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Here I extend that by probing\u00a0the role of water molecules\u00a0in the mechanism of acetal hydrolysis. Water molecules can participate in three ways: One water acts as a nucleophile to\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":"","width":0,"height":0},"classes":[]},{"id":13458,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13458","url_meta":{"origin":21720,"position":1},"title":"How many water molecules does it take to ionise HF and HBr?","author":"Henry Rzepa","date":"February 27, 2015","format":false,"excerpt":"No doubt answers to the question posed in the previous post\u00a0are already being obtained by experiment. Just in case that does not emerge in the next day or so, I offer a prediction here. The methodology is the same as before, and I have not tried to look for new\u2026","rel":"","context":"In "General"","block_context":{"text":"General","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":13618,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13618","url_meta":{"origin":21720,"position":2},"title":"Ionizing ultra-strong acids with water molecules.","author":"Henry Rzepa","date":"March 15, 2015","format":false,"excerpt":"My previous posts have covered the ionization by a small number of discrete water molecules of the series of halogen acids, ranging from HI (the strongest,\u00a0pKa -10) via HF (weaker, pKa 3.1) to the pseudo-halogen HCN (the weakest, pKa 9.2). Here I try out some even stronger acids to see\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":13676,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13676","url_meta":{"origin":21720,"position":3},"title":"Ionizing yet more ultra-strong acids with water molecules.","author":"Henry Rzepa","date":"March 20, 2015","format":false,"excerpt":"This might be seen as cranking a handle by producing yet more examples of acids ionised by a small number of water molecules. I justify it (probably only to myself) as an exercise in how a scientist might approach a problem, and how it linearly develops with time, not necessarily\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":21720,"position":4},"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":31140,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=31140","url_meta":{"origin":21720,"position":5},"title":"The fast disappearance of hydroxycarbene through hydrogen tunnelling – or is it really tunnelling?","author":"Henry Rzepa","date":"April 11, 2026","format":false,"excerpt":"In 2008, the previously elusive hydroxycarbene, H-C-OH was finally reported as having been captured by matrix isolation, accompanied by the observation that \"we unexpectedly find that H\u2013C\u2013OH rearranges to formaldehyde with a half-life of only 2h at 11K by pure hydrogen tunnelling through a large energy barrier in excess of\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":[]}],"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","author_category":"1","first_name":"Henry","last_name":"Rzepa","user_url":"https:\/\/orcid.org\/0000-0002-8635-8390","job_title":"","description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London."}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21720","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=21720"}],"version-history":[{"count":2,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21720\/revisions"}],"predecessor-version":[{"id":21724,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21720\/revisions\/21724"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21720"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21720"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21720"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=21720"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}