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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 » non-classical</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 the 'non-classical' Category</h2> <div class="box"> <h2><a href="/blog/archives/3027" rel="bookmark" title="Permanent Link: The complex PES for sesquiterpene formation">The complex PES for sesquiterpene formation</a></h2> <div class="post-content"> <p>Hong and Tantillo<a href="#bisabolyl"><sup>1</sup></a> report a real tour de force computational study of multiple pathways along the routes towards synthesis of a variety of sesquiterpenes. The starting point is the bisabolyl cation <b>1</b>, and a variety of rearrangements, cyclizations, proton and hydride transfers are examined to convert it into such disparate products as barbatene <b>2</b>, widdradiene <b>3</b>, and champinene <b>4</b>. The pathways are explored at mPW1PW91/6-31+G(d,p)//B3LYP/6-31+G(d,p). Some new pathways are proposed but the main points are the sheer complexity of the C<sub>15</sub>H<sub>25</sub><sup>+</sup> potential energy surface and the interconnections between potential intermediates.</p> <p align="center"><img src="/blog/wp-content/bisabolyl.png"></p> <h3>References</h3> <p><a href="#bisabolyl"></a></p> <p>(1) Hong, Y. J.; Tantillo, D. J. "Branching Out from the Bisabolyl Cation. Unifying Mechanistic Pathways to Barbatene, Bazzanene, Chamigrene, Chamipinene, Cumacrene, Cuprenene, Dunniene, Isobazzanene, Iso-γ-bisabolene, Isochamigrene, Laurene, Microbiotene, Sesquithujene, Sesquisabinene, Thujopsene, Trichodiene, and Widdradiene Sesquiterpenes," <i>J. Am. Chem. Soc.</i> <b>2014</b>, <i>136</i>, 2450-2463, DOI: <a href="http://dx.doi.org/10.1021/ja4106489">10.1021/ja4106489</a>.</p> <h3>InChIs</h3> <p><b>1</b>: InChI=1S/C15H25/c1-12(2)6-5-7-14(4)15-10-8-13(3)9-11-15/h6,8,15H,5,7,9-11H2,1-4H3/q+1<br>InChIKey=YKHXORRQMGBNFI-UHFFFAOYSA-N</p> <p><b>2</b>: InChI=1S/C15H24/c1-11-6-9-13(2)10-12(11)14(3)7-5-8-15(13,14)4/h6,12H,5,7-10H2,1-4H3/t12-,13-,14+,15-/m0/s1<br>InChIKey=RMKQBFUAKZOVPQ-XQLPTFJDSA-N</p> <p><b>3</b>: InChI=1S/C15H24/c1-12-6-7-13-14(2,3)9-5-10-15(13,4)11-8-12/h6-7H,5,8-11H2,1-4H3/t15-/m0/s1<br>InChIKey=SJUIWFYSWDVOEQ-HNNXBMFYSA-N</p> <p><b>4</b>: InChI=1S/C15H24/c1-11-6-9-15-10-12(11)14(15,4)8-5-7-13(15,2)3/h6,12H,5,7-10H2,1-4H3/t12-,14-,15-/m1/s1<br>InChIKey=XRDHEPAYTVHOPC-BPLDGKMQSA-N</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/molecules/non-classical" rel="category tag">non-classical</a> &<a href="/blog/archives/category/molecules/terpenes" rel="category tag">terpenes</a></span> <span class="user">Steven Bachrach</span> <span class="date">13 Mar 2014</span> <span class="comments"><a href="/blog/archives/3027#comments">2 Comments</a></span> </p> </div> <div class="box"> <h2><a href="/blog/archives/2774" rel="bookmark" title="Permanent Link: The x-ray structure of norbornyl cation">The x-ray structure of norbornyl cation</a></h2> <div class="post-content"> <p>A long sought-after data point critical to the non-classical cation story has finally been obtained. The elusive x-ray crystal structure of a norbornyl cation was finally solved.<a href="#norbonylXray1"><sup>1</sup></a> The [C<sub>7</sub>H<sub>11</sub>]<sup>+</sup>[Al<sub>2</sub>Br<sub>7</sub>]<sup>–</sup> salt was crystallized in CH<sub>2</sub>Br<sub>2</sub> at low temperature (40 K). This low temperature was needed to prohibit rotation of the norbornyl cation within the crystal (the cation is near spherical and so subject to relatively easy rotation within the crystal matrix) and hydride scrambling among the three carbons (C<sub>1</sub>, C<sub>2</sub>, and C<sub>6</sub>) involved in the non-classical cation structure.</p> <p>The authors report a number of different structures, all very similar, depending on slight differences in the crystals used. However, the important features are consistent with all of the structures. The cation is definitely of the non-classical type (see Figure 1) with the basal C<sub>1</sub>-C<sub>2</sub> bond length of 1.39 Å similar that in benzene and long non-classical C<sub>1</sub>-C<sub>6</sub> and C<sub>2</sub>-C<sub>6</sub> distances of 1.80 Å. These distances match very well with the MP2(FC)/def2-QZVPP optimized distances of 1.393 and 1.825 Å, respectively.</p> <table align="center" border="0"> <tr align="center"> <td> <p></p> <div class="jmol" id="nbXray"> <a onclick="return false"><br> <img src="/blog/wp-content/norbornylXray.png" onclick="insertJmol('nbXray',220,220,'norbornylXray.xyz')"><br> </a> </div> </td> </tr> </table> <p align="center"><b>Figure 1.</b> X-ray structure of norbornyl cation.</p> <h3>References</h3> <p><a name="norbonylXray1"></a></p> <p>(1) Scholz, F.; Himmel, D.; Heinemann, F. W.; Schleyer, P. v. R.; Meyer, K.; Krossing, I. "Crystal Structure Determination of the Nonclassical 2-Norbornyl Cation," <i>Science</i> <b>2013</b>, <i>341</i>, 62-64, DOI: <a href="http://dx.doi.org/10.1126/science.1238849">10.1126/science.1238849</a>.</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/molecules/non-classical" rel="category tag">non-classical</a> &<a href="/blog/archives/category/molecules/norbornyl-cation" rel="category tag">norbornyl cation</a> &<a href="/blog/archives/category/authors/schleyer" rel="category tag">Schleyer</a></span> <span class="user">Steven Bachrach</span> <span class="date">16 Sep 2013</span> <span class="comments"><a href="/blog/archives/2774#respond">No Comments</a></span> </p> </div> <div class="box"> <h2><a href="/blog/archives/2759" rel="bookmark" title="Permanent Link: Nonamethylcyclopentyl cation">Nonamethylcyclopentyl cation</a></h2> <div class="post-content"> <p>The nine methyl groups of nonamethylcyclopentyl cation <b>1</b> all interconvert with a barrier of 7 kcal mol<sup>-1</sup>. However, at low temperature only partial scrambling occurs: there are two sets of methyl groups, one containing five groups and the other containing four methyl groups. The barrier for this scrambling is only 2.5 kcal mol<sup>-1</sup>. While this behavior was found more than 20 years ago, Tantillo and Schleyer<a href="#Me9CPr1"><sup>1</sup></a> only now have offered a complete explanation.</p> <p align="center"><img src="/blog/wp-content/Me9CPimg1.png"><br><b>1</b></p> <p>The ground state structure of <b>1</b> is shown in Figure 1 and has <i>C<sub>1</sub></i> symmetry. The two pseudo-axial methyl groups adjacent to the cationic center show evidence of hyperconjugation: long C-C bonds and Me-C-C<sup>+</sup> angles of 100°.</p> <p>The transition state <b>TS1</b>¸also in Figure 1, is of <i>C<sub>s</sub></i> symmetry. This transition state leads to interchange of the pseudo-axial methyls, and interchange of the pseudo-equatorial methyls, but no exchange between the members of these two groups. The M06-2x/6-31+G(d,p) and mPW1PW91/6-31+G(d,p) estimate of this barrier is 1.5 and 2.5 kcal mol<sup>-1</sup>, respectively. This agrees well with the experiment.</p> <table align="center" border="0" cellspacing="0" cellpadding="3"> <tr align="center" valign="middle"> <td colspan="2"> <p></p> <div class="jmol" id="Me9CP1"> <a onclick="return false"><br> <img src="/blog/wp-content/Me9CP1.jpg" onclick="insertJmol('Me9CP1',300,300,'Me9CP1.xyz')"><br> </a> </div> <p><b>1</b></p> </td> </tr> <tr align="center" valign="middle"> <td> <p></p> <div class="jmol" id="Me9CPTS1"> <a onclick="return false"><br> <img src="/blog/wp-content/Me9CPTS1.jpg" onclick="insertJmol('Me9CPTS1',300,300,'Me9CPTS1.xyz')"><br> </a> </div> <p><b>TS1</b></p> </td> <td> <p></p> <div class="jmol" id="Me9CPTS2"> <a onclick="return false"><br> <img src="/blog/wp-content/Me9CPTS2.jpg" onclick="insertJmol('Me9CPTS2',300,300,'Me9CPTS2.xyz')"><br> </a> </div> <p><b>TS2</b></p> </td> </tr> </table> <p align="center"><b>Figure 1</b>. B3LYP/6-3+G(d,p) optimized geometries.</p> <p>A second transition state <b>TS2</b> was found and it corresponds with a twisting motion that interconverts an axial methyl with an equatorial methyl. This TS has <i>C<sub>s</sub></i> symmetry (shown in Figure 1) and the eclipsing interaction give rise to a larger barrier: 7.3 (M06-2x/6-31+G(d,p)) and 6.7 kcal mol<sup>-1</sup> (mPW1PW91/6-31+G(d,p)). So twisting through <b>TS2</b> and scrambling through <b>TS1</b> allows for complete exchange of all 9 methyl groups.</p> <p>An interesting point also made by these authors is that these three structures represent the continuum of cationic structure: a classical (localized) cation in <b>TS2</b>, a bridged structure in <b>TS1</b> and hyperconjugated cation in <b>1</b>.</p> <h3>References</h3> <p><a name="Me9CPr1"></a></p> <p>(1) Tantillo, D. J.; Schleyer, P. v. R. “Nonamethylcyclopentyl Cation Rearrangement Mysteries Solved,” <i>Org. Lett.</i> <b>2013</b>, <i>15</i>, 1725-1727, DOI: <a href="http://dx.doi.org/10.1021/ol4005189">10.1021/ol4005189</a>.</p> <h3>InChIs</h3> <p><b>1</b>: InChI=1S/C14H27/c1-10-11(2,3)13(6,7)14(8,9)12(10,4)5/h1-9H3/q+1<br>InChIKey=WUGVCUSQGLXERW-UHFFFAOYSA-N</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/molecules/non-classical" rel="category tag">non-classical</a> &<a href="/blog/archives/category/authors/schleyer" rel="category tag">Schleyer</a></span> <span class="user">Steven Bachrach</span> <span class="date">23 Jul 2013</span> <span class="comments"><a href="/blog/archives/2759#comments">4 Comments</a></span> </p> </div> <div class="box"> <h2><a href="/blog/archives/70" rel="bookmark" title="Permanent Link: Hexacoordinate carbon">Hexacoordinate carbon</a></h2> <div class="post-content"> <p>The search for the elusive hypervalent carbon atom took an interesting turn for the positive with the report of the synthesis and characterization of <b>1</b> and especially its dication <b>2</b>.<a href="#hexCref"><sup>1</sup></a> The x-ray structure was obtained for both compounds along with computing their B3PW91/6-31G(d) geometries. These computed geometries are shown in Figure 1.</p> <table border="0" cellspacing="2" cellpadding="2" align="center"> <tr> <td align="center" valign="middle"> <p><img src="/blog/wp-content/hexC1.gif"><br><b>1</b></p> </td> <td align="center" valign="middle"> <p><img src="/blog/wp-content/hexC2.gif"><br><b>2</b></p> </td> </tr> <tr> <td align="center" valign="middle"> <p></p> <div class="jmol" id="hexc1"> <a onclick="return false"><br> <img src="/blog/wp-content/hexC-c1.gif" onclick="insertJmol('hexc1',200,200,'hexC-c1.xyz')"><br> </a> </div> <p><b>1</b></p> </td> <td align="center" valign="middle"> <p></p> <div class="jmol" id="hexc2"> <a onclick="return false"><br> <img src="/blog/wp-content/hexC-c2.gif" onclick="insertJmol('hexc2',200,200,'hexC-c2.xyz')"><br> </a> </div> <p><b>2</b></p> </td> </tr> </table> <p align="center"><b>Figure 1.</b> B3PW91/6-31G(d) optimized geometries of <b>1</b> and <b>2</b>.<a href="#hexCref"><sup>1</sup></a></p> <p>The allene fragment is bent in both structures: 168.5° (169.9° at B3PW91) in <b>1</b> and 166.8° (172.7° at B3PW91) in <b>2</b>. The distances between the central carbon atom of the allene and the four oxygen atoms are 2.66 to 2.82 Å, and computed to be a little longer. Interestingly, these distance contract when the dication <b>2</b> is created; ranging from 2.64 to 2.75 Å (again computed to be a little longer). These distances, while significantly longer than normal covalent C-O bonds, are less than the sum of the C and O van der Waals radii. But are they really bonds?</p> <p>This is not a trivial answer to solve. The authors opt to employ topological electron density analysis (Bader’s atoms-in-molecules approach). Using the electron density from both the high resolution x-ray density map and from the DFT computations, bond paths between the central allene carbon and each oxygen are found, though with, as expected, low values of ρ. The Laplacian of the density at the critical point are positive, indicative of ionic interactions. So according to Bader’s model, the existence of a bond path in a ground state molecule is the necessary and sufficient condition for bonding.</p> <p>The others conclude by proposing that O<sup>…</sup>C intermolecular interactions with separations of around 2.6 to 2.8 Å may also suggest hypervalent cases. They note that about 2000 structures in the Cambridge crystallographic database fit this criterion.</p> <h3>References</h3> <p>(1) Yamaguchi, T.; Yamamoto, Y.; Kinoshita, D.; Akiba, K.-y.; Zhang, Y.; Reed, C. A.; Hashizume, D.; Iwasaki, F., "Synthesis and Structure of a Hexacoordinate<br> Carbon Compound," <i>J. Am. Chem. Soc.</i>, <b>2008</b>, <i>130</i>, 6894-6895, DOI: <a href="http://dx.doi.org/10.1021/ja710423d">10.1021/ja710423d</a>.</p> <h3>InChIs</h3> <p><b>1</b>: <span class="inchi">InChI=1/C31H24O4S2/c1-32-20-9-5-13-24-28(20)18(29-21(33-2)10-6-14-25(29)36-24)17-19-30-22(34-3)11-7-15-26(30)37-27-16-8-12-23(35-4)31(19)27/h5-16H,1-4H3</span><br> InChiKey= RJBVLFYVIBCWKW-UHFFFAOYAD</p> <p><b>2</b>: <span class="inchi">InChI=1/C33H30O4S2/c1-34-22-11-7-15-26-30(22)20(31-23(35-2)12-8-16-27(31)38(26)5)19-21-32-24(36-3)13-9-17-28(32)39(6)29-18-10-14-25(37-4)33(21)29/h7-18H,1-6H3/q+2</span><br> InChIKey= MVHOSIVPHPDYJJ-UHFFFAOYAM</p>  </div> <p class="bottom"> <span class="cat"><a href="/blog/archives/category/qm-method/dft" rel="category tag">DFT</a> &<a href="/blog/archives/category/molecules/non-classical" rel="category tag">non-classical</a></span> <span class="user">Steven Bachrach</span> <span class="date">03 Jun 2008</span> <span class="comments"><a href="/blog/archives/70#comments">3 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href="/blog/archives/category/molecules/nanohoops">nanohoops</a> (4) </li> <li class="cat-item cat-item-41 current-cat"> <a aria-current="page" href="/blog/archives/category/molecules/non-classical">non-classical</a> (4) </li> <li class="cat-item cat-item-34"> <a href="/blog/archives/category/molecules/norbornyl-cation">norbornyl cation</a> (2) </li> <li class="cat-item cat-item-49"> <a href="/blog/archives/category/molecules/nucleic-acids">nucleic acids</a> (4) </li> <li class="cat-item cat-item-36"> <a href="/blog/archives/category/molecules/oximes">oximes</a> (1) </li> <li class="cat-item cat-item-75"> <a href="/blog/archives/category/molecules/phenyloxenium">phenyloxenium</a> (1) </li> <li class="cat-item cat-item-8"> <a href="/blog/archives/category/molecules/polycyclic-aromatics">polycyclic aromatics</a> (7) </li> <li class="cat-item cat-item-50"> <a href="/blog/archives/category/molecules/propellane">propellane</a> (2) </li> <li class="cat-item cat-item-79"> <a href="/blog/archives/category/molecules/stilbene">stilbene</a> (1) </li> <li class="cat-item cat-item-80"> <a href="/blog/archives/category/molecules/sugars">sugars</a> (5) </li> <li class="cat-item cat-item-85"> <a href="/blog/archives/category/molecules/terpenes">terpenes</a> (2) </li> <li class="cat-item cat-item-89"> <a href="/blog/archives/category/molecules/twistane">twistane</a> (1) </li> </ul> </li> <li class="cat-item cat-item-22"> <a href="/blog/archives/category/nmr">NMR</a> (40) </li> <li class="cat-item cat-item-31"> <a href="/blog/archives/category/optical-rotation">Optical Rotation</a> (16) </li> <li class="cat-item cat-item-28"> <a href="/blog/archives/category/qm-method">QM Method</a> (96) <ul class="children"> <li class="cat-item cat-item-20"> <a href="/blog/archives/category/qm-method/caspt2">CASPT2</a> (1) </li> <li class="cat-item cat-item-7"> <a href="/blog/archives/category/qm-method/dft">DFT</a> (71) </li> <li class="cat-item cat-item-45"> <a href="/blog/archives/category/qm-method/focal-point">focal point</a> (7) </li> <li class="cat-item cat-item-14"> <a href="/blog/archives/category/qm-method/g3">G3</a> (3) </li> <li class="cat-item cat-item-60"> <a href="/blog/archives/category/qm-method/mp">MP</a> (11) </li> </ul> </li> <li class="cat-item cat-item-56"> <a href="/blog/archives/category/reactions">Reactions</a> (83) <ul class="children"> <li class="cat-item cat-item-13"> <a href="/blog/archives/category/reactions/12-addition">1,2-addition</a> (1) </li> <li class="cat-item cat-item-35"> <a href="/blog/archives/category/reactions/aldol">aldol</a> (4) </li> <li class="cat-item cat-item-32"> <a href="/blog/archives/category/reactions/bergman-cyclization">Bergman cyclization</a> (6) </li> <li class="cat-item cat-item-44"> <a href="/blog/archives/category/reactions/claisen-rearrangement">Claisen rearrangement</a> (2) </li> <li class="cat-item cat-item-10"> <a href="/blog/archives/category/reactions/cope-rearrangement">Cope Rearrangement</a> (5) </li> <li class="cat-item cat-item-69"> <a href="/blog/archives/category/reactions/cycloadditions">cycloadditions</a> (12) </li> <li class="cat-item cat-item-23"> <a href="/blog/archives/category/reactions/diels-alder">Diels-Alder</a> (26) </li> <li class="cat-item cat-item-47"> <a href="/blog/archives/category/reactions/electrocyclization">electrocyclization</a> (11) </li> <li class="cat-item cat-item-76"> <a href="/blog/archives/category/reactions/electrophilic-aromatic-substitution">electrophilic aromatic substitution</a> (1) </li> <li class="cat-item cat-item-5"> <a href="/blog/archives/category/reactions/ene-reaction">ene reaction</a> (1) </li> <li class="cat-item cat-item-52"> <a href="/blog/archives/category/reactions/hajos-parrish-reaction">Hajos-Parrish Reaction</a> (1) </li> <li class="cat-item cat-item-61"> <a href="/blog/archives/category/reactions/mannich">Mannich</a> (2) </li> <li class="cat-item cat-item-64"> <a href="/blog/archives/category/reactions/michael-addition">Michael addition</a> (5) </li> <li class="cat-item cat-item-40"> <a href="/blog/archives/category/reactions/ozonolysis">ozonolysis</a> (1) </li> <li class="cat-item cat-item-43"> <a href="/blog/archives/category/reactions/proton-transfer">proton transfer</a> (1) </li> <li class="cat-item cat-item-38"> <a href="/blog/archives/category/reactions/pseudopericyclic">pseudopericyclic</a> (4) </li> <li class="cat-item cat-item-63"> <a href="/blog/archives/category/reactions/strecker">Strecker</a> (1) </li> <li class="cat-item cat-item-24"> <a href="/blog/archives/category/reactions/substitution">Substitution</a> (6) </li> <li class="cat-item cat-item-93"> <a href="/blog/archives/category/reactions/wittig">Wittig</a> (1) </li> </ul> </li> <li class="cat-item cat-item-87"> <a href="/blog/archives/category/second-edition">Second Edition</a> (3) </li> <li class="cat-item cat-item-11"> <a href="/blog/archives/category/solvation">Solvation</a> (17) </li> <li class="cat-item cat-item-77"> <a href="/blog/archives/category/stereochemistry">Stereochemistry</a> (2) </li> <li class="cat-item cat-item-68"> <a href="/blog/archives/category/stereoinduction">stereoinduction</a> (4) </li> <li class="cat-item cat-item-71"> <a 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> <li><a href="/blog/archives/date/2018/07">July 2018</a></li> <li><a href="/blog/archives/date/2018/06">June 2018</a></li> <li><a href="/blog/archives/date/2018/05">May 2018</a></li> <li><a href="/blog/archives/date/2018/04">April 2018</a></li> <li><a href="/blog/archives/date/2018/03">March 2018</a></li> <li><a href="/blog/archives/date/2018/02">February 2018</a></li> <li><a href="/blog/archives/date/2018/01">January 2018</a></li> <li><a href="/blog/archives/date/2017/12">December 2017</a></li> <li><a href="/blog/archives/date/2017/11">November 2017</a></li> <li><a href="/blog/archives/date/2017/10">October 2017</a></li> <li><a href="/blog/archives/date/2017/09">September 2017</a></li> <li><a href="/blog/archives/date/2017/08">August 2017</a></li> <li><a href="/blog/archives/date/2017/07">July 2017</a></li> <li><a href="/blog/archives/date/2017/06">June 2017</a></li> <li><a href="/blog/archives/date/2017/05">May 2017</a></li> <li><a href="/blog/archives/date/2017/04">April 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">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 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