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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head profile="http://gmpg.org/xfn/1"> <title>Computational Organic Chemistry » 2015 » September</title> <meta name="google-site-verification" content="g1Myv4tUVAmqRbwZeBi7IPuSZpP64RWjVJ6itIoouCo"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <style type="text/css" media="screen">@import url( /blog/wp-content/themes/comporg/style.css);</style> <link rel="stylesheet" id="wp-block-library-css" href="/blog/wp-includes/css/dist/block-library/style.min.css?ver=5.6.1" type="text/css" media="all"> <script type="text/javascript">  </script> </head> <body> <div id="header"> <div id="header_img"></div> </div> <div id="link_section"> <div style="float:left"> <a href="/blog/about">About this Blog</a> | <a href="/">Book Homepage</a> | <a href="http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471713422.html">Purchase the Book</a> </div> </div> <div id="after_links"></div> <div id="content"> <div id="main"> <h2 class="post-title">Archive for September, 2015</h2> <div class="box"> <h2><a href="/blog/archives/3588" rel="bookmark" title="Permanent Link: Triprotonated rosarin: singlet or triplet?">Triprotonated rosarin: singlet or triplet?</a></h2> <div class="post-content"> <p>What is the spin state of the ground state of an aromatic species? Can this be spin state be manipulated by charge? These questions are addressed by Borden, Kim, Sessler and coworkers<a href="#rosarin1"><sup>1</sup></a> for the hexaphyrin <b>1</b>. B3LYP/6-31G(d) optimization of <b>1</b> shows it to be a ground state singlet. This structure is shown in Figure 1.</p> <table align="center" border="0" cellspacing="0" cellpadding="3"> <tr align="center" valign="bottom"> <td> <p><img src="/blog/wp-content/rosarinImg1.png"><br><b>1</b></p> </td> <td> <p><img src="/blog/wp-content/rosarinImg2.png"><br><b>1<sup>3+</sup></b></p> </td> </tr> </table> <p>Protonation of the three pyrrole nitrogens creates <b>1<sup>3+</sup></b>, which has interesting frontier orbitals. The HOMO of <b>1<sup>3+</sup></b>, of a<sub>1</sub>” symmetry, has nodes running through all six nitrogens. The next higher energy orbital, of a<sub>2</sub>” symmetry, has a small π-contribution on each nitrogen. Protonation will therefore have no effect on the energy of the a<sub>1</sub>” orbital, but the charge will stabilize the a<sub>2</sub>” orbital. This will lower the energy gap between the two orbitals, suggesting that a ground state triplet might be possible. The lowest singlet and triplet states of <b>1<sup>3+</sup></b> are also shown in Figure 1.</p> <table align="center" border="0" cellspacing="0" cellpadding="3"> <tr align="center" valign="bottom"> <td colspan="2"> <p></p> <div class="jmol" id="rosarin"> <a onclick="return false"><br> <img src="/blog/wp-content/rosarin.jpg" onclick="insertJmol('rosarin',300,300,'rosarin.xyz')"></a> </div> <p><b>1</b></p> </td> </tr> <tr align="center" valign="bottom"> <td> <p></p> <div class="jmol" id="rosarinS"> <a onclick="return false"><br> <img src="/blog/wp-content/rosarinSing.jpg" onclick="insertJmol('rosarinS',300,300,'rosarinSing.xyz')"></a> </div> <p>Singlet <b>1<sup>3+</sup></b></p> </td> <td> <p></p> <div class="jmol" id="rosarinT"> <a onclick="return false"><br> <img src="/blog/wp-content/rosarinTrip.jpg" onclick="insertJmol('rosarinT',300,300,'rosarinTrip.xyz')"></a> </div> <p>Triplet <b>1<sup>3+</sup></b></p> </td> </tr> </table> <p align="center"><b>Figure 1</b>. (U)B3LYP/6-31G(d) optimized structures of <b>1</b> and singlet and triplet <b>1<sup>3+</sup></b>.</p> <p>This spin state change upon protonation was experimentally verified by synthesis of two analogues of <b>1</b>, shown below. The triprotonated versions of both are observed to have triplet character in their EPR spectrum.</p> <table align="center" border="0" cellspacing="0" cellpadding="3"> <tr align="center" valign="bottom"> <td> <img src="/blog/wp-content/rosarinImg3.png"> </td> <td> <p><img src="/blog/wp-content/rosarinImg4.png"></p> </td> </tr> </table> <h3>References</h3> <p><a href="#rosarin1"></a></p> <p>(1) Fukuzumi, S.; Ohkubo, K.; Ishida, M.; Preihs, C.; Chen, B.; Borden, W. T.; Kim, D.; Sessler, J. L. "Formation of Ground State Triplet Diradicals from Annulated Rosarin Derivatives by Triprotonation," <i>J. Am. Chem. Soc.</i> <b>2015</b>, <i>137</i>, 9780-9783, DOI: <a href="http://dx.doi.org/10.1021/jacs.5b05309">10.1021/jacs.5b05309</a>.</p> <h3>InChIs</h3> <p><b>1</b>: InChI=1S/C45H24N6/c1-2-8-29-28(7-1)34-16-22-13-24-18-36-30-9-3-4-10-31(30)38-20-26(50-43(38)42(36)48-24)15-27-21-39-33-12-6-5-11-32(33)37-19-25(49-44(37)45(39)51-27)14-23-17-35(29)41(47-23)40(34)46-22/h1-21,46,49-50H/b22-13-,23-14-,24-13-,25-14-,26-15-,27-15-<br>InChIKey=UMEHBSBBAUKCTH-UIJINECUSA-N</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/aromaticity" rel="category tag">Aromaticity</a> &<a href="/blog/archives/category/authors/borden" rel="category tag">Borden</a></span> <span class="user">Steven Bachrach</span> <span class="date">22 Sep 2015</span> <span class="comments"><a href="/blog/archives/3588#respond">No Comments</a></span> </p> </div> <div class="box"> <h2><a href="/blog/archives/3580" rel="bookmark" title="Permanent Link: Sumanene anions">Sumanene anions</a></h2> <div class="post-content"> <p>Spisak, et al. treated sumanene <b>1</b> with excess potassium in THF.<a href="#sumanene1"><sup>1</sup></a></p> <p align="center"><img src="/blog/wp-content/sumananeImg.png"></p> <p>They obtained an interesting structure, characterized by x-ray crystallography: a mixture of the dianion and trianion of <b>1</b> (well these are really conjugate di- and tribases of <b>1</b>, but we’ll call them di- and trianions for simplicity’s sake). A fragment of the x-ray structure is shown in Figure 1, showing that there is one potassium cation on the concave face and six potassium ions on the convex face.</p> <table align="center" border="0" cellspacing="0" cellpadding="0"> <tr align="center"> <td> <p></p> <div class="jmol" id="sumaneneXray"> <a onclick="return false"><br> <img src="/blog/wp-content/sumaneneXray.jpg" onclick="insertJmol('sumaneneXray',300,300,'sumaneneXray.xyz')"></a> </div> </td> </tr> </table> <p align="center"><b>Figure 1</b>. X-ray structure of <b>1</b> surrounded by six K<sup>+</sup> ions on the convex face and one K<sup>+</sup> on the concave face.</p> <p>To help understand this structure, they performed RIJCOSX-PBE0/cc-pVTZ computations on the mono-, di-, and trianion of <b>1</b>. The structure of <b>1</b> (which I optimized at ωB97X-D/6-311G(d)) and the trianion are displayed in Figure 2. The molecular electrostatic potential of the trianion shows highly negative regions in the 5-member ring regions, symmetrically distributed and prime for coordination with 6 cations.</p> <table align="center" border="0" cellspacing="0" cellpadding="4"> <tr align="center" valign="bottom"> <td> <p></p> <div class="jmol" id="sumanene"> <a onclick="return false"><br> <img src="/blog/wp-content/sumanene.jpg" onclick="insertJmol('sumanene',300,300,'sumanene.xyz')"></a> </div> <p><b>1</b></p> </td> <td> <p></p> <div class="jmol" id="sumanene3anion"> <a onclick="return false"><br> <img src="/blog/wp-content/sumanene3anion.jpg" onclick="insertJmol('sumanene3anion',300,300,'sumanene3anion.xyz')"></a> </div> <p>trianion of <b>1</b></p> </td> </tr> </table> <p align="center"><b>Figure 2</b>. Optimized structure of <b>1</b> and its trianion.</p> <h3>References</h3> <p><a href="#sumanene1"></a></p> <p>(1) Spisak, S. N.; Wei, Z.; O’Neil, N. J.; Rogachev, A. Y.; Amaya, T.; Hirao, T.; Petrukhina, M. A. "Convex and Concave Encapsulation of Multiple Potassium Ions by Sumanenyl Anions," <i>J. Am. Chem. Soc.</i> <b>2015</b>, <i>137</i>, 9768-9771, DOI: <a href="http://dx.doi.org/10.1021/jacs.5b06662">10.1021/jacs.5b06662</a>.</p> <h3>InChIs</h3> <p><b>1</b>: InChI=1S/C21H12/c1-2-11-8-13-5-6-15-9-14-4-3-12-7-10(1)16-17(11)19(13)21(15)20(14)18(12)16/h1-6H,7-9H2<br>InChIKey=WOYKPMSXBVTRKZ-UHFFFAOYSA-N</p> <p>Trianion of <b>1</b>: InChI=1S/C21H9/c1-2-11-8-13-5-6-15-9-14-4-3-12-7-10(1)16-17(11)19(13)21(15)20(14)18(12)16/h1-5,7-8H,9H2/q-3<br>InChIKey=IHJVIPHOCKVJDZ-UHFFFAOYSA-N</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/aromaticity" rel="category tag">Aromaticity</a></span> <span class="user">Steven Bachrach</span> <span class="date">14 Sep 2015</span> <span class="comments"><a href="/blog/archives/3580#comments">1 Comment</a></span> </p> </div> <p align="center"></p> </div> <div id="sidebar"> <ul> <li class="box"> <h2> Categories </h2> <ul> <li class="cat-item cat-item-25"> <a href="/blog/archives/category/acidity">Acidity</a> (12) </li> <li 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href="/blog/archives/category/tunneling">Tunneling</a> (26) </li> <li class="cat-item cat-item-1"> <a href="/blog/archives/category/uncategorized">Uncategorized</a> (57) </li> <li class="cat-item cat-item-82"> <a href="/blog/archives/category/vibrational-frequencies">vibrational frequencies</a> (3) </li> </ul> </li> <li class="box"> <h2> Monthly </h2> <ul> <li><a href="/blog/archives/date/2019/06">June 2019</a></li> <li><a href="/blog/archives/date/2019/04">April 2019</a></li> <li><a href="/blog/archives/date/2019/03">March 2019</a></li> <li><a href="/blog/archives/date/2019/02">February 2019</a></li> <li><a href="/blog/archives/date/2019/01">January 2019</a></li> <li><a href="/blog/archives/date/2018/12">December 2018</a></li> <li><a href="/blog/archives/date/2018/11">November 2018</a></li> <li><a href="/blog/archives/date/2018/10">October 2018</a></li> <li><a href="/blog/archives/date/2018/09">September 2018</a></li> <li><a href="/blog/archives/date/2018/08">August 2018</a></li> 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2017</a></li> <li><a href="/blog/archives/date/2017/03">March 2017</a></li> <li><a href="/blog/archives/date/2017/02">February 2017</a></li> <li><a href="/blog/archives/date/2017/01">January 2017</a></li> <li><a href="/blog/archives/date/2016/12">December 2016</a></li> <li><a href="/blog/archives/date/2016/11">November 2016</a></li> <li><a href="/blog/archives/date/2016/10">October 2016</a></li> <li><a href="/blog/archives/date/2016/09">September 2016</a></li> <li><a href="/blog/archives/date/2016/08">August 2016</a></li> <li><a href="/blog/archives/date/2016/07">July 2016</a></li> <li><a href="/blog/archives/date/2016/06">June 2016</a></li> <li><a href="/blog/archives/date/2016/05">May 2016</a></li> <li><a href="/blog/archives/date/2016/04">April 2016</a></li> <li><a href="/blog/archives/date/2016/03">March 2016</a></li> <li><a href="/blog/archives/date/2016/02">February 2016</a></li> <li><a href="/blog/archives/date/2016/01">January 2016</a></li> <li><a href="/blog/archives/date/2015/12">December 2015</a></li> <li><a href="/blog/archives/date/2015/11">November 2015</a></li> <li><a href="/blog/archives/date/2015/10">October 2015</a></li> <li><a href="/blog/archives/date/2015/09" aria-current="page">September 2015</a></li> <li><a href="/blog/archives/date/2015/08">August 2015</a></li> <li><a href="/blog/archives/date/2015/07">July 2015</a></li> <li><a href="/blog/archives/date/2015/06">June 2015</a></li> <li><a href="/blog/archives/date/2015/05">May 2015</a></li> <li><a href="/blog/archives/date/2015/04">April 2015</a></li> <li><a href="/blog/archives/date/2015/03">March 2015</a></li> <li><a href="/blog/archives/date/2015/02">February 2015</a></li> <li><a href="/blog/archives/date/2015/01">January 2015</a></li> <li><a href="/blog/archives/date/2014/12">December 2014</a></li> <li><a href="/blog/archives/date/2014/11">November 2014</a></li> <li><a href="/blog/archives/date/2014/10">October 2014</a></li> <li><a href="/blog/archives/date/2014/09">September 2014</a></li> <li><a href="/blog/archives/date/2014/08">August 2014</a></li> <li><a href="/blog/archives/date/2014/07">July 2014</a></li> <li><a href="/blog/archives/date/2014/06">June 2014</a></li> <li><a href="/blog/archives/date/2014/05">May 2014</a></li> <li><a href="/blog/archives/date/2014/04">April 2014</a></li> <li><a href="/blog/archives/date/2014/03">March 2014</a></li> <li><a href="/blog/archives/date/2014/02">February 2014</a></li> <li><a href="/blog/archives/date/2014/01">January 2014</a></li> <li><a href="/blog/archives/date/2013/12">December 2013</a></li> <li><a href="/blog/archives/date/2013/11">November 2013</a></li> <li><a href="/blog/archives/date/2013/10">October 2013</a></li> <li><a href="/blog/archives/date/2013/09">September 2013</a></li> <li><a href="/blog/archives/date/2013/08">August 2013</a></li> <li><a href="/blog/archives/date/2013/07">July 2013</a></li> <li><a href="/blog/archives/date/2013/06">June 2013</a></li> <li><a href="/blog/archives/date/2013/05">May 2013</a></li> <li><a href="/blog/archives/date/2013/04">April 2013</a></li> <li><a href="/blog/archives/date/2013/03">March 2013</a></li> <li><a href="/blog/archives/date/2013/02">February 2013</a></li> <li><a href="/blog/archives/date/2013/01">January 2013</a></li> <li><a href="/blog/archives/date/2012/12">December 2012</a></li> <li><a href="/blog/archives/date/2012/11">November 2012</a></li> <li><a href="/blog/archives/date/2012/10">October 2012</a></li> <li><a href="/blog/archives/date/2012/09">September 2012</a></li> <li><a href="/blog/archives/date/2012/08">August 2012</a></li> <li><a href="/blog/archives/date/2012/07">July 2012</a></li> <li><a href="/blog/archives/date/2012/06">June 2012</a></li> <li><a href="/blog/archives/date/2012/05">May 2012</a></li> <li><a href="/blog/archives/date/2012/04">April 2012</a></li> <li><a href="/blog/archives/date/2012/03">March 2012</a></li> <li><a href="/blog/archives/date/2012/02">February 2012</a></li> <li><a href="/blog/archives/date/2012/01">January 2012</a></li> <li><a href="/blog/archives/date/2011/12">December 2011</a></li> <li><a href="/blog/archives/date/2011/11">November 2011</a></li> <li><a href="/blog/archives/date/2011/10">October 2011</a></li> <li><a href="/blog/archives/date/2011/09">September 2011</a></li> <li><a href="/blog/archives/date/2011/08">August 2011</a></li> <li><a href="/blog/archives/date/2011/07">July 2011</a></li> <li><a href="/blog/archives/date/2011/06">June 2011</a></li> <li><a href="/blog/archives/date/2011/05">May 2011</a></li> <li><a href="/blog/archives/date/2011/04">April 2011</a></li> <li><a href="/blog/archives/date/2011/03">March 2011</a></li> <li><a href="/blog/archives/date/2011/02">February 2011</a></li> <li><a href="/blog/archives/date/2011/01">January 2011</a></li> <li><a href="/blog/archives/date/2010/12">December 2010</a></li> <li><a href="/blog/archives/date/2010/11">November 2010</a></li> <li><a href="/blog/archives/date/2010/10">October 2010</a></li> <li><a href="/blog/archives/date/2010/09">September 2010</a></li> <li><a href="/blog/archives/date/2010/08">August 2010</a></li> <li><a href="/blog/archives/date/2010/07">July 2010</a></li> <li><a href="/blog/archives/date/2010/06">June 2010</a></li> <li><a href="/blog/archives/date/2010/05">May 2010</a></li> <li><a href="/blog/archives/date/2010/04">April 2010</a></li> <li><a href="/blog/archives/date/2010/03">March 2010</a></li> <li><a href="/blog/archives/date/2010/02">February 2010</a></li> <li><a href="/blog/archives/date/2010/01">January 2010</a></li> <li><a href="/blog/archives/date/2009/12">December 2009</a></li> <li><a href="/blog/archives/date/2009/11">November 2009</a></li> <li><a href="/blog/archives/date/2009/10">October 2009</a></li> <li><a href="/blog/archives/date/2009/09">September 2009</a></li> <li><a href="/blog/archives/date/2009/08">August 2009</a></li> <li><a href="/blog/archives/date/2009/07">July 2009</a></li> <li><a href="/blog/archives/date/2009/06">June 2009</a></li> <li><a href="/blog/archives/date/2009/05">May 2009</a></li> <li><a href="/blog/archives/date/2009/04">April 2009</a></li> <li><a href="/blog/archives/date/2009/03">March 2009</a></li> <li><a href="/blog/archives/date/2009/02">February 2009</a></li> <li><a href="/blog/archives/date/2009/01">January 2009</a></li> <li><a href="/blog/archives/date/2008/12">December 2008</a></li> <li><a href="/blog/archives/date/2008/11">November 2008</a></li> <li><a href="/blog/archives/date/2008/10">October 2008</a></li> <li><a href="/blog/archives/date/2008/09">September 2008</a></li> <li><a href="/blog/archives/date/2008/08">August 2008</a></li> <li><a href="/blog/archives/date/2008/07">July 2008</a></li> <li><a href="/blog/archives/date/2008/06">June 2008</a></li> <li><a href="/blog/archives/date/2008/05">May 2008</a></li> <li><a href="/blog/archives/date/2008/04">April 2008</a></li> <li><a href="/blog/archives/date/2008/03">March 2008</a></li> <li><a href="/blog/archives/date/2008/02">February 2008</a></li> <li><a href="/blog/archives/date/2008/01">January 2008</a></li> <li><a href="/blog/archives/date/2007/12">December 2007</a></li> <li><a href="/blog/archives/date/2007/11">November 2007</a></li> <li><a href="/blog/archives/date/2007/10">October 2007</a></li> <li><a href="/blog/archives/date/2007/09">September 2007</a></li> <li><a href="/blog/archives/date/2007/08">August 2007</a></li> <li><a href="/blog/archives/date/2007/07">July 2007</a></li> </ul> </li> </ul> <a rel="license" href="https://creativecommons.org/licenses/by-nd/3.0/"> <img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nd/3.0/88x31.png"> </a> <br>This work is licensed under a <a rel="license" href="https://creativecommons.org/licenses/by-nd/3.0/">Creative Commons Attribution-No Derivative Works 3.0 Unported License</a>. </div>  <div 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