{"id":2811,"date":"2010-11-19T09:22:15","date_gmt":"2010-11-19T07:22:15","guid":{"rendered":"http:\/\/localhost\/azgad\/wordpress\/?p=2811"},"modified":"2010-11-20T06:24:59","modified_gmt":"2010-11-20T04:24:59","slug":"catching-a-chemical-butterfly-bulky-molecules-help-trap-boron-compounds-into-a-never-before-seen-structural-arrangement","status":"publish","type":"post","link":"https:\/\/azgad.com\/?p=2811","title":{"rendered":"Catching a chemical butterfly – Bulky molecules help trap boron compounds into a never-before-seen structural arrangement"},"content":{"rendered":"

.
\nWhen it comes to chemical bonding, boron has a reputation for
\n being unconventional. While covalent bonds are usually formed by
\n sharing two electrons between two atoms, some compounds\u2014including
\n diboranes (B2H6) \u2014contain B\u2013H\u2013B bonds in which an electron pair is
\n distributed over three sites. The electron-deficient nature of these
\n \u20183-center, 2-electron\u2019 bonds can generate a variety of distinct
\nchemical structures, some of which\u2014such as triple-bonded diborane
\n derivatives\u2014have only been seen theoretically.
\n.
\n.
\n\"\"<\/a>
\n.
\nFigure 1: X-ray measurements (bottom) reveal that a butterfly-shaped
\n boron compound (top left) has an intense electron distribution in its B2H2
\ncore (red areas) that is stabilized by exterior bulky ligands (white lines).
\n The human eye (top right) shows the direction from which you look at
\nthe electron density map<\/strong>.
\n.
\n.
\nKohei Tamao and colleagues from the RIKEN Advanced Science Institute
\n in Wako and Kyoto University have now isolated the first stable diborane
\nmolecule with butterfly-shaped B\u2013H\u2013B bonds and a boron\u2013boron link with
\ntriple bond characteristics1. This discovery unlocks new insights into the
\n workings of 3-center, 2-electron boron interactions and puts scientists
\none step closer to synthesizing the elusive boron\u2013boron triple bond.
\n.
\nThe key to this approach is a bulky molecule known as \u2018Eind\u2019 that contains
\na rigid core of fused hydrocarbon rings covered with ethyl side chains.
\n Previously, the researchers used Eind ligands to stabilize heavy elements
\n into multiply bonded species2. This time, the team hoped to generate
\na neutral boron\u2013boron double bond by substituting Eind groups for
\n hydrogen atoms in diborane.
\n.
\nHowever, after characterizing the structure of the diborane\u2013Eind
\ncompound\u2014a difficult task requiring synchrotron x-rays to detect
\nhydrogen atom positions\u2014the researchers saw a previously
\nunidentified arrangement at the B2H2 core: a central boron\u2013boron
\nconnection nearly as short as a theoretical triple bond, flanked by
\ntwo symmetric B\u2013H\u2013B \u2018wings\u2019 (Fig. 1). \u201cWe did not expect this butterfly
\n-shaped structure at first, and finding it was a kind of serendipity,\u201d says
\nco-author Yoshiaki Shoji.
\n.
\nQuantum computations revealed that the Eind ligands enforced a
\n levels closely related to the triple-bond species. Furthermore, the
\nbridging hydrogen atoms enhanced the multiple bonding characteristics.
\n \u201cBased on this analysis, it is possible to consider triple bonding
\n interactions between the two boron atoms,\u201d says team-member
\nTsukasa Matsuo.
\n.
\nMatsuo notes that the butterfly-shaped molecule already displays unique
\nchemical reactivity, and the insights gained from this new structure
\ncould lead to additional multiply-bonded diboranes. \u201cWe may be able
\nto synthesize a more triply bonded species in the near future by replacing
\n the bridging hydrogen atoms with alkali metals,\u201d he says. \u201cAt the
\nmoment, this compound is just a dream but I think we have a chance
\n to obtain it.\u201d
\n.<\/p>\n

.
\n.<\/p>\n","protected":false},"excerpt":{"rendered":"

. When it comes to chemical bonding, boron has a reputation for being unconventional. While covalent bonds are usually formed by sharing two electrons between two atoms, some compounds\u2014including diboranes (B2H6) \u2014contain B\u2013H\u2013B bonds in which an electron pair is distributed over three sites. The electron-deficient nature of these \u20183-center, 2-electron\u2019 bonds can generate a … <\/p>\n

\u05d4\u05de\u05e9\u05d9\u05db\u05d5 \u05d1\u05e7\u05e8\u05d9\u05d0\u05d4<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[10],"tags":[328,154,513],"class_list":["post-2811","post","type-post","status-publish","format-standard","hentry","category-10","tag-328","tag-154","tag-513","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2811"}],"version-history":[{"count":10,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2811\/revisions"}],"predecessor-version":[{"id":2822,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2811\/revisions\/2822"}],"wp:attachment":[{"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2811"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2811"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}