{"id":26147,"date":"2023-06-18T15:36:29","date_gmt":"2023-06-18T14:36:29","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=26147"},"modified":"2023-07-12T12:43:44","modified_gmt":"2023-07-12T11:43:44","slug":"diberyllocene","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26147","title":{"rendered":"Diberyllocene — and Lithioborocene?"},"content":{"rendered":"
\n

Sometimes, the properties of a molecule are predicted long before it is synthesised. One such is diberyllocene. I first encountered a related molecule, beryllocene itself, many moons ago.[1]<\/a><\/span> This was unusual because unlike the original metallocenes, the metal atom was not symmetrically disposed between the two cyclopentadienyl faces. Now diberyllocene is finally reported in which replacing one Be by Be-Be induces (according to calculation, D2<\/sub>) symmetry[2]<\/a><\/span>. I will not repeat the excellent analysis of the wavefunction reported in this article, but confine myself to showing two molecular orbitals which examplify its bonding.<\/p>\n\n\n\n\n\n\n
Highest occupied molecular orbital<\/th>\n<\/tr>\n
\"\"<\/td>\n<\/tr>\n
Lowest occupied \u03c0-molecular orbital<\/th>\n<\/tr>\n
\"\"<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The HOMO (FAIR data 10.14469\/hpc\/12702<\/a>) essentially shows a Be-Be single bond, originating formally from the central Be2<\/sub>2+<\/sup> dication, balanced by the two cyclopentadienyl anion ligands. Click on the images to see this orbital in \u00a03D.<\/p>\n

Oddly, an excited state of Be2<\/sub> on its own actually carries a Be=Be double bond<\/a>, a property again predicted a long time ago by theory. The most stable \u03c0-MO in diberyllocene originates in the six electron aromatic cyclopentadienyl rings. By acquiring a share of six electrons from one Cp ring, and a share of the two electrons from the Be-Be bond, each Be atom achieves the octet of electrons known by generations of students. This is the sort of molecule that could be taught in schools at an early stage to illustrate the octet rule. And its good to know that simple new molecules illustrating this are still being discovered by chemists.<\/p>\n

\n

Since this started with experimental realisation of a predicted molecule, can I suggest as a new prediction, lithioborocene, in which a B and an Li replace two Be atoms? Individually, lithiocenes, boracenes and Li-B bonds are known from crystal structures. So its not a way out prediction to combine these observations. Any friendly synthetic chemist up for the challenge?
\n\"\"
\n\"\"
\n\"\"<\/p>\n

\"\"<\/p>\n

\n

This post has DOI: 10.14469\/hpc\/12704<\/p>\n

References<\/h2>\n
  1. M.J.S. Dewar, and H.S. Rzepa, \"Ground states of molecules. 45. MNDO results for molecules containing beryllium\", Journal of the American Chemical Society<\/i>, vol. 100, pp. 777-784, 1978. https:\/\/doi.org\/10.1021\/ja00471a020<\/a>\n\n<\/li>\n
  2. J.T. Boronski, A.E. Crumpton, L.L. Wales, and S. Aldridge, \"Diberyllocene, a stable compound of Be(I) with a Be\u2013Be bond\", Science<\/i>, vol. 380, pp. 1147-1149, 2023. https:\/\/doi.org\/10.1126\/science.adh4419<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    Sometimes, the properties of a molecule are predicted long before it is synthesised. One such is diberyllocene. I first encountered a related molecule, beryllocene itself, many moons ago. This was unusual because unlike the original metallocenes, the metal atom was not symmetrically disposed between the two cyclopentadienyl faces. Now diberyllocene is finally reported in which […]<\/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":[],"tags":[],"ppma_author":[2661],"class_list":["post-26147","post","type-post","status-publish","format-standard","hentry"],"yoast_head":"\nDiberyllocene - and Lithioborocene? - 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=26147\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Diberyllocene - and Lithioborocene? - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"Sometimes, the properties of a molecule are predicted long before it is synthesised. One such is diberyllocene. I first encountered a related molecule, beryllocene itself, many moons ago. This was unusual because unlike the original metallocenes, the metal atom was not symmetrically disposed between the two cyclopentadienyl faces. 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I had discussed even-numbered cyclocarbons in another post, where I also happened to include several odd-numbered examples,\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":10990,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10990","url_meta":{"origin":26147,"position":3},"title":"Molecule-sized pixels.","author":"Henry Rzepa","date":"August 11, 2013","format":false,"excerpt":"The ultimate reduction in size for an engineer is to a single molecule. It's been done for a car; now it has been reported for the pixel (picture-element). The molecule above (X=O, NR, R=aryl, etc) has been shown to be capable of acting as a molecular pixel. To give some\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":28233,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=28233","url_meta":{"origin":26147,"position":4},"title":"Molecules of the Year 2024: Molecular shuttle in a box.","author":"Henry Rzepa","date":"January 25, 2025","format":false,"excerpt":"This is another in the C&E News list of candidates for the Molecule of the Year, Molecular shuttle in a box Mirror-image cyclodextrin Molecular shuttle in a box Rule-bending strained alkene First soluble promethium complex Single-electron carbon-carbon bond Hot MOF for capturing carbon The molecule shown below inside the cavity\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":2046,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=2046","url_meta":{"origin":26147,"position":5},"title":"Chemistry with a super-twist: A molecular trefoil knot, part 1.","author":"Henry Rzepa","date":"May 31, 2010","format":false,"excerpt":"Something important happened in chemistry for the first time about 100 years ago. A molecule was built (nowadays we would say synthesized) specifically for the purpose of investigating a theory. It was cyclo-octatetraene or (CH)8, and it was made by Willst\u00e4tter and Waser to try to find out if benzene,\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\/2010\/05\/metallatrefoil.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\/26147","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=26147"}],"version-history":[{"count":17,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/26147\/revisions"}],"predecessor-version":[{"id":26184,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/26147\/revisions\/26184"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26147"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26147"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=26147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}