Organogermanium chemistry

<h2 id="synthesis">Synthesis</h2>
<p>The great majority of organogermanium compounds are tetrahedral with the formula GeR4−nXn where X = H, Cl, etc.  Ge-C bonds are air-stable, although Ge-H bonds can undergo air-oxidation. The first organogermanium compound, tetraethylgermane, synthesized by Winkler in 1887,<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> by the reaction of <a href="/facts/Germanium_tetrachloride/jYAjcTbS">germanium tetrachloride</a> with <a href="/facts/Diethylzinc/b7eYFsy3">diethylzinc</a>. More commonly, these Ge(IV) compounds are prepared by alkylation of germanium halides by <a href="/facts/Organolithium/xgYnjhP3">organolithium</a> and <a href="/facts/Grignard_reagent/0vkLtPo1">Grignard reagents</a>, including surfaces terminated with Ge-Cl bonds.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>  Recent work, however, has developed <a href="/facts/Chlorine-free_germanium_processing/xCQYPNu0">chlorine-free germanium processing</a>.
</p><p>Some organogermanes are prepared by nucleophilic substitution or Pd-catalyzed cross-coupling reactions.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> Hydrogermylation provides another route to organogermanium compounds.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
</p>

<h3>Catenation</h3>

<p>Akin to <a href="/facts/Hydrocarbon/Dcg95Ju5">hydrocarbons</a> and <a href="/facts/Polysilane/ctjIMTAw">polysilanes</a>, many organogermanium compounds are known with Ge-Ge bonds.  An early example is hexaphenyldigermane, (C6H5)3Ge−Ge(C6H5)3.  It is prepared by <a href="/facts/Wurtz_coupling/teXQemUj">Wurtz coupling</a> of the bromide:<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
</p>
2 (C6H5)3GeBr  +  2 Na  →  (C6H5)3Ge−Ge(C6H5)3 +  2 NaBr
<p>Many cyclic polygermanes are known, e.g. [Ge(C6H5)2]4, [Ge(C6H5)2]5, and [Ge(C6H5)2]6.
</p>
<h3>Germanols</h3>
<p>Triphenylgermanol ((C6H5)3GeOH) is a colorless solid. Like the isostructural <a href="/facts/Silanol/3f58wE1l">silanol</a>, it engages in hydrogen bonding in the solid-state.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
</p>
<h2 id="multiple-bonds-to-ge">Multiple bonds to Ge</h2>
<p>Compounds with multiple bonds to Ge are usually highly reactive or require bulky organic substituents for their isolation.  This situation follows from the <a href="/facts/Double_bond_rule/kxtnRvH8">double bond rule</a>. Digermynes only exist for extremely bulky substituents. According to <a href="/facts/X-ray_crystallography/WtI0F5DN">X-ray crystallography</a>, the C–Ge≡Ge–C core of digermynes is bent. Such compounds are prepared by the reduction of bulky arylgermanium(II) halides.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
</p><p>Compounds containing Ge=C (germenes) double bonds require bulky organic substituents for their isolation.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> and Ge=Ge (digermylenes)<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> Other examples include the bulky derivatives of germabenzene and 1,2-digermabenzene,<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> analogues of benzene.
</p>

<h2 id="germylenes-and-germanium-radicals">Germylenes and germanium radicals</h2>
<p><a href="/facts/Germylene/NGW1IozS">Germylenes</a> (carbene analogues) and germyl free radicals have been investigated.  Reaction of a Ge(II) chloride with a lithium trialkylgermanide affords a germylene:<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a>
</p>
ArGeCl  +  LiGe(C(CH3)3)3   →   ArGeGe((C(CH3)3)3  +  LiCl  (Ar = 2,6-(mesityl)2C6H3)
<h2 id="reactions-of-organogermanium-compounds">Reactions of organogermanium compounds</h2>
<p class="note">Further information: Organogermanium compounds in cross-coupling reactions</p>
<p>Some organogermanium compounds participate in cross coupling reactions.
</p>
<h2 id="applications">Applications</h2>
<p>Organogermanium compounds are used in relatively few commercial applications. <a href="/facts/Isobutylgermane/jL6slpED">Isobutylgermane</a>, a volatile colorless liquid, is used in <a href="/facts/MOVPE/Ldg0BICo">MOVPE</a> (<a href="/facts/Metalorganic/WFv2Ypum">Metalorganic</a> Vapor Phase <a href="/facts/Epitaxy/etjSn1D3">Epitaxy</a>) in the deposition of Ge <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> films.
</p><p><a href="/facts/Propagermanium/mcBj4URI">Propagermanium</a>, also known as Ge-132, and spirogermanium are drugs.
</p>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Fricke, Christoph; Schoenebeck, Franziska (2020-11-17). "Organogermanes as Orthogonal Coupling Partners in Synthesis and Catalysis". Accounts of Chemical Research. 53 (11): 2715–2725. doi:10.1021/acs.accounts.0c00527. ISSN 0001-4842. PMID 33118804. S2CID 226044725. <a href="https://pubs.acs.org/doi/10.1021/acs.accounts.0c00527" target="_blank">https://pubs.acs.org/doi/10.1021/acs.accounts.0c00527</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Akiyama Takahiko (2004). "Germanium in Organic Synthesis". In Yamamoto Hisashi; Oshima Koichiro (eds.). Main Group Metals in Organic Synthesis. ISBN 3-527-30508-4. <a href="3-527-30508-4" target="_blank">3-527-30508-4</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Winkler, Clemens (1887-08-27). "Mittheilungen über das Germanium". Journal für Praktische Chemie. 36 (1): 177–209. doi:10.1002/prac.18870360119. <a href="https://onlinelibrary.wiley.com/doi/10.1002/prac.18870360119" target="_blank">https://onlinelibrary.wiley.com/doi/10.1002/prac.18870360119</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Buriak, Jillian M. (2002). "Organometallic Chemistry on Silicon and Germanium Surfaces". Chemical Reviews. 102 (5): 1271–1308. doi:10.1021/cr000064s. PMID 11996538. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Fricke, Christoph; Schoenebeck, Franziska (2020-11-17). "Organogermanes as Orthogonal Coupling Partners in Synthesis and Catalysis". Accounts of Chemical Research. 53 (11): 2715–2725. doi:10.1021/acs.accounts.0c00527. ISSN 0001-4842. PMID 33118804. S2CID 226044725. <a href="https://pubs.acs.org/doi/10.1021/acs.accounts.0c00527" target="_blank">https://pubs.acs.org/doi/10.1021/acs.accounts.0c00527</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Selmani, Aymane; Schoenebeck, Franziska (2023). "Anti-Markovnikov Hydrogermylation of Alkenes via Lewis Acid Catalysis". Synthesis. 55 (11): 1792–1798. doi:10.1055/a-2036-3868. ISSN 0039-7881. S2CID 256969453. <a href="http://www.thieme-connect.de/DOI/DOI?10.1055/a-2036-3868" target="_blank">http://www.thieme-connect.de/DOI/DOI?10.1055/a-2036-3868</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Amadoruge, Monika L.; Weinert, Charles S. (2008). "Singly Bonded Catenated Germanes: Eighty Years of Progress". Chemical Reviews. 108 (10): 4253–4294. doi:10.1021/cr800197r. PMID 18816144. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Ferguson, G.; Gallagher, J. F.; Murphy, D.; Spalding, T. R.; Glidewell, C.; Holden, H. D. (1992-07-15). "The Structure of Triphenylgermanium Hydroxide". Acta Crystallographica Section C Crystal Structure Communications. 48 (7): 1228–1231. doi:10.1107/S0108270191015056. <a href="https://scripts.iucr.org/cgi-bin/paper?S0108270191015056" target="_blank">https://scripts.iucr.org/cgi-bin/paper?S0108270191015056</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>Sugiyama, Yusuke; Sasamori, Takahiro; Hosoi, Yoshinobu; Furukawa, Yukio; Takagi, Nozomi; Nagase, Shigeru; Tokitoh, Norihiro (2006-01-01). "Synthesis and Properties of a New Kinetically Stabilized Digermyne: New Insights for a Germanium Analogue of an Alkyne". Journal of the American Chemical Society. 128 (3): 1023–1031. doi:10.1021/ja057205y. ISSN 0002-7863. PMID 16417395. <a href="https://pubs.acs.org/doi/10.1021/ja057205y" target="_blank">https://pubs.acs.org/doi/10.1021/ja057205y</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>Meiners, Frank; Saak, Wolfgang; Weidenbruch, Manfred (2000-07-01). "Acetylene-Linked Bis(germaethenes): The First Molecules with Conjugated Germanium−Carbon Double Bonds 1". Organometallics. 19 (15): 2835–2836. doi:10.1021/om000284w. ISSN 0276-7333. <a href="https://pubs.acs.org/doi/10.1021/om000284w" target="_blank">https://pubs.acs.org/doi/10.1021/om000284w</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
<li id="fn:11"><p>Schäfer, Helmut; Saak, Wolfgang; Weidenbruch, Manfred (1999-08-01). "Azadigermiridines by Addition of Diazomethane or Trimethylsilyldiazomethane to a Digermene 1". Organometallics. 18 (16): 3159–3163. doi:10.1021/om990337d. ISSN 0276-7333. <a href="https://pubs.acs.org/doi/10.1021/om990337d" target="_blank">https://pubs.acs.org/doi/10.1021/om990337d</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li>
<li id="fn:12"><p>Sasamori, Takahiro; Sugahara, Tomohiro; Agou, Tomohiro; Guo, Jing-Dong; Nagase, Shigeru; Streubel, Rainer; Tokitoh, Norihiro (2015-06-08). "Synthesis and Characterization of a 1,2-Digermabenzene". Organometallics. 34 (11): 2106–2109. doi:10.1021/om501204u. ISSN 0276-7333. <a href="https://pubs.acs.org/doi/10.1021/om501204u" target="_blank">https://pubs.acs.org/doi/10.1021/om501204u</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li>
<li id="fn:13"><p>Setaka, Wataru; Sakamoto, Kenkichi; Kira, Mitsuo; Power, Philip P. (2001). "Synthesis and Structure of Stable Tri-tert-butylgermyl-Substituted Stannylene and Germylene". Organometallics. 20 (22): 4460–4462. doi:10.1021/om010591h. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li>
</ol>

Organogermanium chemistry open-in-new

Organogermanium chemistry