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Chimica

分离游离卡本内斯、其混合二聚体和有机自由基

Published: April 19, 2019
doi:
10.3791/59389
, ,
1Department of Chemistry and Pharmacy,Friedrich-Alexander-Universität Erlangen-Nürnberg

Summary

我们提出了分离稳定的杂环卡本的方案。利用滤器插管和施伦克技术, 研究了一种循环 (烷基) (氨基) 卡本 (caac) 和n-杂环卡本 (nhc) 的合成方法。此外, 我们还提出了合成相关的氧敏感, 富含电子的混合 “Wanzlick 二聚体” 和减少稳定的有机自由基。

Abstract

报道了常用的环状 (烷基) (氨基) 卡本 (caac) 和n-杂环卡本 (nhc) 的分离方案。此外, 还介绍了混合 CAAC-NHC “Wanzlick” 二聚体的合成和相关稳定有机 “烯烃” 自由基的合成。本手稿的主要目的是给合成化学家一个详细的和一般的协议, 任何技能水平如何准备游离杂环车本使用滤镜插管。由于合成化合物的空气灵敏度, 所有实验都是在惰性气氛下使用施伦克技术或二硝基填充手套箱进行的。控制 Wanzlick 的平衡 (即游离车的二聚化), 是在配位化学或有机合成中应用游离车的关键要求。因此, 我们详细阐述了有利于二聚体、异质体或单体形成的具体电子和公共要求。我们将展示质子催化是如何允许二聚体形成的, 以及卡本斯及其二聚体的电子结构是如何影响水分或空气的反应性的。根据所报告化合物的核磁共振光谱, 讨论了其结构同一性。

Introduction

半个多世纪前, Wanzlick 报告说, 这是首次尝试合成 n -杂环卡本斯 1,2,3。然而, 他并没有孤立自由的车本, 而是成功地描述了它们的二聚体。这一观察促使他提出了烯烃二聚体和相应的自由车本之间的平衡, 这现在通常被称为 “万兹利克的平衡” (图 1, i.)。4 个,5,6. 后来, 有人认为, 自由车的二聚化, 当然也同样是反向反应 (即相关烯烃二聚体的分离), 是由质子7,8, 9 催化的. 10,11,12。又过了 3 0年, 伯特兰13、1 4岁的报道, 第一辆在室温下没有去渗透的 “可装瓶” 卡本。特别是n-杂环卡本 (nhc; 咪唑啉-2-i 化) 成为深入研究的课题, 此前 Arduengo 报告了稳定的结晶 nhc, 1, 3-二达丹-咪唑啉-2-i 里定 15.由于体积庞大的己基取代物以及与芳香n-杂环相关的电子效应, 这种卡本的惊人稳定性首先被胸骨效应的组合合理化。然而, 墨菲后来的一项优雅研究表明, 即使是 “单体” 1, 3-二甲基咪唑啉-2-i i 烷 16 (即从 n,n-二甲基咪唑唑盐中提取的游离卡本), 含有非常小的甲基取代物比它的二聚体17更稳定。Lavallo 和 Bertrand 相反地表明, 通过分离循环 (烷基) (氨基) carbene (CAAC) 所报告的一个稳定氮原子的去除, 可以通过引入笨重的 2, 6-二异丙基苯基 (Dip) 取代物来平衡18岁

Nhc 和 caac 在 d 和 p-块元素、过渡金属催化或有机催化的配位化学方面证明了非凡的卓有成效 (关于 nhc 的专题问题和书籍, 见19、20、21,22,23, 关于 caac 的评论, 见24、25、26、27、28,关于caac 的综合, 见18、29、30,环卡本配体令人印象深刻的成功故事主要有两个原因 32.首先, 电子和 steric 特性都可以很容易地进行调整, 以满足特定应用的要求。其次, 隔离稳定的自由车本提供了一种方便的方法, 可以通过与金属前体的直接组合合成金属配合物。因此, 重要的是要了解控制自由车本在室温下或室温以下是否稳定, 或是否将其二聚形成烯烃的因素。请注意, 衍生的电子丰富烯烃通常33不形成复合物处理时, 与金属前体, 这至少部分原因是他们的高度还原特性。

免费车本不仅是当今合成化学的关键角色。事实上, 它们的电子富烯烃二聚体34,35,36 (例如, 四氮唑富洛维列在 nhc37或四硫富 vale 的情况下,四氮素1, 3-二硫醇-2-脂质;图 1, ii.), 不仅发现了广泛的应用作为还原剂41,42,43,但更是在有机电子学。

TTF 实际上被称为有机电子产品的 “实体”44。这主要是由于富含电子烯烃的特殊电子特性–值得注意的是, 其中许多在氧化时表现出三种稳定的氧化还原状态, 包括开壳有机自由基 (关于卡本衍生有机自由基的评论, 见:45 , 46, 47,最近在卡本稳定有机自由基领域的贡献, 见:48,49,50,51,52,53,54). 因此, ttf 允许根据磁性材料、有源效应晶体管 (ofet)、有机发光二极管 (oled) 和分子开关或传感器的需要制造导电/半导体材料55,56,57,58,59。

在此, 我们提出了分离两个稳定的卡本具有巨大的影响, 在配位化学和同质催化 (图 2), 即循环 (烷基) (氨基) 卡本 1 18,和二甲基咪唑啉-2-i i-i-i-LHC nhc 2 15。我们将讨论为什么两个车本在室温下都是稳定的, 不去二化。然后, 我们将详细阐述与 wanzlick 的平衡有关的质子催化和混合 caac-nhc 异质剂360,61, 62的形成。这种三嗪-烯烃令人兴奋的电子特性与相关有机自由基4 63 令人印象深刻的稳定性有关。

方法的重点在于 Schlenk 技术, 该技术使用配备玻璃超细纤维过滤器的滤芯, 用于在惰性条件下将上清液从沉淀物中分离出来。二硝基填充手套箱用于起始材料的称重和空气敏感化合物的储存。

Protocol

注意: 在通风良好的通风罩中进行所有合成。穿戴合适的个人防护设备 (PPE), 包括实验室外套和安全护目镜。 注: 起始材料是根据文献合成的: 1-(2, 6-二异丙基苯基)-2, 2, 4, 4-四甲基-3, 4-二氢-2h-吡咯-1-四氟硼酸 (1Prot) (关于 caac 的合成, 见:18 、30、31、</s…

Representative Results

游离车本通常很容易与水发生反应66。因此, 需要小心干燥的玻璃器皿和溶剂67。在上述过程中, 我们使用装有玻璃超细纤维过滤器的插管, 以便在惰性条件下将空气敏感溶液与沉淀物分离开来。我们使用这种技术提取固体 (即, 所需的产品被溶解), 以及清洗固体化合物 (即, 所需的产品是不溶性固体)。 <p class="jove_content" fo:keep-together.withi…

Discussion

在此, 我们提出了一个通用的和适应性的协议, 合成稳定的卡本斯 (NHC, 中国民航) 及其电子富二聚体。所有步骤都可以很容易地升级到至少25克的比例。成功合成的关键是严格排除水分 (空气, 分别) 的合成卡贝内斯, 氧气 (空气, 分别) 的电子丰富的烯烃。本文采用的滤过插管技术与施伦克线相结合, 是在惰性条件下将溶液与沉淀物分离的一种非常简便的方法。本文介绍的滤芯是通过将 PTFE 胶带缠绕在…

Divulgazioni

The authors have nothing to disclose.

Acknowledgements

作者感谢 Chemischen 工业基金的一项名团契, 并感谢 Hertha 和 Helmut Schmauser 基金会的财政支持。感谢 K. Meyer 的支持。

Materials

Equipment
Glass micro fiber filter, 691, 24 mm. Particle retention 1.6 mm VWR 516-0859
magnetic stir bar FengTecEx various
PTFE tape Sigma-Aldrich Z148814-1PAK PTFE tape used in this manuscript was obtained from a local supplier. Tape from Sigma Aldrich should show comparable performance.
rubber septum FengTecEx RS112440 Joint size: 24/29
rubber septum FengTecEx RS111420 Joint size: 14/23
rubber septum FengTecEx RS111922 Joint size: 19/26
schlenk flasks FengTecEx various 100 mL
steel cannula FengtecEx C702024 Attachment of a steel joint by a machine shop not required, but facilitates preparation of filter cannula
syringe cannula FengtecEx S380221
Name Company Catalog Number Comments
Reactants
1-(2,6-diisopropylphenyl)-2,2,4,4-tetramethyl-3,4-dihydro-2H-pyrrol-1-ium tetrafluoroborate Synthesized according to: Jazzar, R., Dewhurst, R. D., Bourg, J. B., Donnadieu, B., Canac, Y., Bertrand, G. Intramolecular “Hydroiminiumation” of alkenes: Application to the synthesis of conjugate acids of cyclic alkyl amino carbenes (CAACs). Angewandte Chemie International Edition 46 (16), 2899-2902, (2007).
1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium iodide Synthesized according to: Benac, B. L., Burgess, E. M., Arduengo, A. J. 1,3-Dimethylimidazole-2-Thione. Organic Synthesis 64, 92, (1986).
potassium hexamethyldisilazide Sigma-Aldrich 324671-100G CAS 40949-94-8
silver trifluoromethanesulfonate Sigma-Aldrich 85325-25G CAS 2923-28-6
Name Company Catalog Number Comments
Solvents
acetonitrile-D3 Deutero 00202-10m distilled from CaH2, stored over activated molecular sieves
benzene-D6 Deutero 00303-100ml dried over activated molecular sieves, stored over potassium
diethylether – – dried by two-column, solid-state purification system and degassed by three freeze-pump-thaw cycles, stored over activated molecular sieves
hexanes – – dried by two-column, solid-state purification system and degassed by three freeze-pump-thaw cycles, stored over activated molecular sieves
tetrahydrofuran – – dried by two-column, solid-state purification system and degassed by three freeze-pump-thaw cycles, stored over activated molecular sieves
toluene – – dried by two-column, solid-state purification system and degassed by three freeze-pump-thaw cycles, stored over activated molecular sieves
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Riferimenti

  1. Wanzlick, H. W., Schikora, E. Ein neuer Zugang zur Carben-Chemie. Angewandte Chemie. 72, 494 (1960).
  2. Wanzlick, H. W., Kleiner, H. J. Nucleophile Carben-Chemie. Angewandte Chemie International Edition. 73 (14), 493 (1961).
  3. Wanzlick, H. W., Schikora, E. Ein nucleophiles Carben. Chemische Berichte. 94 (94), 2389-2393 (1961).
  4. Böhm, V. P. W., Herrmann, W. A. The "Wanzlick Equilibrium". Angewandte Chemie International Edition. 39 (22), 4036-4038 (2000).
  5. Hahn, F. E., Wittenbecher, L., Le Van, D., Fröhlich, R. Evidence for an Equilibrium between an N-heterocyclic Carbene and Its Dimer in Solution. Angewandte Chemie International Edition. 39 (3), 541-544 (2000).
  6. Denk, M. K., Hatano, K., Ma, M. Nucleophilic Carbenes and the Wanzlick Equilibrium: A Reinvestigation. Tetrahedron Letters. 40 (11), 2057-2060 (1999).
  7. Liu, Y., Lemal, D. M. Concerning the Wanzlick equilibrium. Tetrahedron Letters. 41, 599-602 (2000).
  8. Arduengo, A. J., Goerlich, J. R., Marshall, W. J. A Stable Thiazol-2-ylidene and its Dimer. Liebigs Annalen der Chemie. , 365-374 (1997).
  9. Alder, R. W., Blake, M. E., Chaker, L., Harvey, J. N., Paolini, F., Schutz, J. When and how do diaminocarbenes dimerize?. Angewandte Chemie International Edition. 43 (44), 5896-5911 (2004).
  10. Chen, Y. -. T., Jordan, F. Reactivity of the Thiazolium C2 Ylide in Aprotic Solvents: Novel Experimental Evidence for Addition Rather Than Insertion Reactivity. Journal of Organic Chemistry. 56 (17), 5029-5038 (1991).
  11. Lemal, D. M., Lovald, R. A., Kawano, K. I. Tetraaminoethylenes. The Question of Dissociation. Journal of the American Chemical Society. 86 (12), 2518-2519 (1964).
  12. Alder, R. W., Chaker, L., Paolini, F. P. V. Bis(diethylamino)carbene and the mechanism of dimerisation for simple diaminocarbenes. Chemical Communications. 19 (19), 2172-2173 (2004).
  13. Baceiredo, A., Bertrand, G., Sicard, G. Synthesis of the First α-Diazo Phosphines. Phosphorus-Carbon Multiple-Bond Character of Phosphinocarbenes. Journal of the American Chemical Society. 107 (16), 4781-4783 (1985).
  14. Igau, A., Gruetzmacher, H., Baceiredo, A., Bertrand, G. Analogous alpha,alpha’ Bis-Carbenoid Triply Bonded Species: Synthesis of a Stable lambda3-Phosphinocarbene-lambda5-Phosphaacetylene. Journal of the American Chemical Society. 110 (19), 6463-6466 (1988).
  15. Arduengo, A. J., Harlow, R. L., Kline, M. A Stable Crystalline Carbene. Journal of the American Chemical Society. 113 (1), 363-365 (1991).
  16. Schaub, T., Backes, M., Radius, U. Nickel (0) Complexes of N-Alkyl-Substituted N-Heterocyclic Carbenes and Their Use in the Catalytic Carbon−Carbon Bond Activation of Biphenylene. Organometallics. 25, 4196-4206 (2006).
  17. Jolly, P. I., Zhou, S., Thomson, D. W., Garnier, J., Parkinson, J. A., Tuttle, T., Murphy, J. A. Imidazole-derived carbenes and their elusive tetraazafulvalene dimers. Chemical Science. 3 (5), 1675-1679 (2012).
  18. Lavallo, V., Canac, Y., Prasang, C., Donnadieu, B., Bertrand, G. Stable Cyclic (Alkyl)(Amino)Carbenes as Rigid or Flexible, Bulky, Electron-Rich Ligands for Transition-Metal Catalysts: A Quaternary Carbon Atom Makes the Difference. Angewandte Chemie International Edition. 44 (35), 5705-5709 (2005).
  19. Hahn, F. E. Introduction: Carbene Chemistry. Chemical Reviews. 118 (19), 9455-9456 (2018).
  20. Rovis, T., Nolan, S. P. Stable carbenes: from "laboratory curiosities" to catalysis mainstays. Synlett. 24 (10), 1188-1189 (2013).
  21. Arduengo, A. J., Bertrand, G. Carbenes introduction. Chemical Reviews. 109 (8), 3209-3210 (2009).
  22. Diez Gonzalez, S. . N-Heterocyclic Carbenes: From Laboratory Curiosities to Efficient Synthetic Tools. , (2010).
  23. Nolan, S. P. . N-Heterocyclic Carbenes: Effective Tools for Organometallic Synthesis. , (2014).
  24. Soleilhavoup, M., Bertrand, G. Cyclic (alkyl)(amino) carbenes (CAACs): Stable carbenes on the rise. Accounts of Chemical Research. 48 (2), 256-266 (2015).
  25. Roy, S., Mondal, K. C., Roesky, H. W. Cyclic alkyl (amino) carbene stabilized complexes with low coordinate metals of enduring nature. Accounts of Chemical Research. 49 (3), 357-369 (2016).
  26. Melaimi, M., Soleilhavoup, M., Bertrand, G. Stable cyclic carbenes and related species beyond diaminocarbenes. Angewandte Chemie International Edition. 49 (47), 8810-8849 (2010).
  27. Melaimi, M., Jazzar, R., Soleilhavoup, M., Bertrand, G. Cyclic (Alkyl)(amino) Carbenes (CAACs): recent developments. Angewandte Chemie International Edition. 56 (34), 10046-10068 (2017).
  28. Paul, U. S. D., Radius, U. What Wanzlick Did Not Dare To Dream: Cyclic (Alkyl)(amino) carbenes (CAACs) as New Key Players in Transition‐Metal Chemistry. European Journal of Inorganic Chemistry. 2017 (28), 3362-3375 (2017).
  29. Jazzar, R., Bourg, J. B., Dewhurst, R. D., Donnadieu, B., Bertrand, G. Intramolecular "Hydroiminiumation and-amidiniumation" of alkenes: A convenient, flexible, and scalable route to cyclic iminium and imidazolinium salts. Journal of Organic Chemistry. 72, 3492-3499 (2007).
  30. Zeng, X., Frey, G. D., Kinjo, R., Donnadieu, B., Bertrand, G. Synthesis of a Simplified Version of Stable Bulky and Rigid Cyclic (Alkyl)(Amino)Carbenes (CAACs), and Catalytic Activity of the Ensuing Gold(I) Complex in the Three-Component Preparation of 1,2-Dihydroquinoline Derivatives. Journal of the American Chemical Society. 131 (24), 8690-8696 (2009).
  31. Chu, J., Munz, D., Jazzar, R., Melaimi, M., Bertrand, G. Synthesis of hemilabile cyclic (alkyl)(amino) carbenes (CAACs) and applications in organometallic chemistry. Journal of the American Chemical Society. 138 (25), 7884-7887 (2016).
  32. Munz, D. Pushing Electrons—Which Carbene Ligand for Which Application?. Organometallics. 37 (3), 275-289 (2018).
  33. Cardin, D. J., Cetinkaya, B., Lappert, M. F., Manojlovic-Muir, L. J., Muir, K. W. An electron-rich olefin as a source of co-ordinated carbene; synthesis of trans-PtCl2[C(NPhCH2)2]PEt3. Chemical Communications. 8 (8), 400-401 (1971).
  34. Hocker, J., Merten, R. Reactions of Electron-Rich Olefins with Proton-Active Compounds. Angewandte Chemie International Edition. 11 (11), 964-973 (1972).
  35. Hoffmann, R. W. Reactions of Electron-Rich Olefins. Angewandte Chemie International Edition. 7 (10), 754-765 (1968).
  36. Deuchert, K., Hünig, S. Multistage Organic Redox Systems—A General Structural Principle. Angewandte Chemie International Edition. 17 (12), 875-886 (1978).
  37. Taton, T. A., Chen, P. A Stable Tetraazafulvalene. Angewandte Chemie International Edition. 35 (9), 1011-1013 (1996).
  38. Wudl, F., Wobschall, D., Hufnagel, E. J. Electrical conductivity by the bis(1,3-dithiole)-bis(1,3-dithiolium) system. Angewandte Chemie International Edition. 94 (2), 670-672 (1972).
  39. Wudl, F., Smith, G. M., Hufnagel, E. J. Bis-1,3-dithiolium Chloride: an Unusually Stable Organic Radical Cation. Chemical Communications. (21), 1453-1454 (1970).
  40. Ferraris, J., Cowan, D. O., Walatka, V., Perlstein, J. H. Electron transfer in a new highly conducting donor-acceptor complex. Angewandte Chemie International Edition. 95 (3), 948-949 (1973).
  41. Broggi, J., Terme, T., Vanelle, P. Organic electron donors as powerful single-electron reducing agents in organic synthesis. Angewandte Chemie International Edition. 53 (2), 384-413 (2014).
  42. Murphy, J. A. Discovery and Development of Organic Super-Electron-Donors. Journal of Organic Chemistry. 79 (9), 3731-3746 (2014).
  43. Garnier, J., et al. Hybrid super electron donors – preparation and reactivity. Beilstein. Journal of Organic Chemistry. 8, 994-1002 (2012).
  44. Bendikov, M., Wudl, F., Perepichka, D. F. Tetrathiafulvalenes, Oligoacenenes, and Their Buckminsterfullerene Derivatives: The Brick and Mortar of Organic Electronics. Chemical Reviews. 104 (11), 4891-4946 (2004).
  45. Martin, C. D., Soleilhavoup, M., Bertrand, G. Carbene-stabilized main group radicals and radical ions. Chemical Science. 4, 3020 (2013).
  46. Mondal, K. C., Roy, S., Roesky, H. W. Silicon based radicals, radical ions, diradicals and diradicaloids. Chemical Society Reviews. 45, 1080-1111 (2016).
  47. Kim, Y., Lee, E. Stable Organic Radicals Derived from N-Heterocyclic Carbenes Chemistry. Chemistry: A European Journal. 24 (72), 19110-19121 (2018).
  48. Messelberger, J., Grünwald, A., Pinter, P., Hansmann, M. M., Munz, D. Carbene derived diradicaloids – building blocks for singlet fission?. Chemical Science. 9, 6107-6117 (2018).
  49. Hansmann, M. M., Melaimi, M., Munz, D., Bertrand, G. Modular Approach to Kekulé Diradicaloids Derived from Cyclic (Alkyl)(amino)carbenes. Journal of the American Chemical Society. 140 (7), 2546-2554 (2018).
  50. Hansmann, M. M., Melaimi, M., Bertrand, G. Organic Mixed Valence Compounds Derived from Cyclic (Alkyl)(amino)carbenes. Journal of the American Chemical Society. 140 (6), 2206-2213 (2018).
  51. Rottschäfer, D., Neumann, B., Stammler, H. -. G., van Gastel, M., Andrada, D. M., Ghadwal, R. S. Crystalline Radicals Derived from Classical N‐Heterocyclic Carbenes. Angewandte Chemie. 130 (7), 4765-4768 (2018).
  52. Rottschäfer, D., Neumann, B., Stammler, H. -. G., Andrada, D. M., Ghadwal, R. S. Kekulé diradicaloids derived from a classical N-heterocyclic carbene. Chemical Science. 9 (22), 4970-4976 (2018).
  53. Rottschäfer, D., Ho, N. K. T., Neumann, B., Stammler, H. -. G., van Gastel, M., Andrada, D. M., Ghadwal, R. S. N‐Heterocyclic Carbene Analogues of Thiele and Chichibabin Hydrocarbons. Angewandte Chemie International Edition. 57 (20), 5838-5842 (2018).
  54. Barry, B. M., Soper, R. G., Hurmalainen, J., Mansikkamaki, A., Robertson, K. N., McClennan, W. L., Veinot, A. J., Roemmele, T. L., Werner-Zwanziger, U., Boere, R. T., Tuononen, H. M., Clyburne, J. A. C., Masuda, J. D., Barry, B. M. Mono- and Bis(imidazolidinium ethynyl) Cations and Reduction of the Latter To Give an Extended Bis-1,4-([3]Cumulene)-p-carboquinoid System. Angewandte Chemie International Edition. 57 (3), 749-754 (2018).
  55. Nielsen, M. B., Lomholt, C., Becher, J. Tetrathiafulvalenes as building blocks in supramolecular chemistry II. Chemical Society Reviews. 29 (3), 153-164 (2000).
  56. Bergkamp, J. J., Decurtins, S., Liu, S. -. X. Current advances in fused tetrathiafulvalene donor-acceptor systems. Chemical Society Reviews. 44 (4), 863-874 (2015).
  57. Kirtley, J. R., Mannhart, J. Organic electronics: When TTF met TCNQ. Nature Materials. 7 (7), 520-521 (2008).
  58. Lorcy, D., Bellec, N., Fourmigué, M., Avarvari, N. Tetrathiafulvalene-based group XV ligands: Synthesis, coordination chemistry and radical cation salts. Coordination Chemistry Reviews. 253 (9-10), 1398-1438 (2009).
  59. Goetz, K. P., Vermeulen, D., Payne, M. E., Kloc, C., McNeil, L. E., Jurchescu, O. D. Charge-transfer complexes: new perspectives on an old class of compounds. Journal of Materials Chemistry. 2 (17), 3065-3076 (2014).
  60. Munz, D., Chu, J., Melaimi, M., Bertrand, G. NHC-CAAC Heterodimers with Three Stable Oxidation States. Angewandte Chemie International Edition. 55 (41), 12886-12890 (2016).
  61. Mandal, D., et al. Stepwise Reversible Oxidation of N-Peralkyl-Substituted NHC-CAAC Derived Triazaalkenes: Isolation of Radical Cations and Dications. Organic Letters. 19 (20), 5605-5608 (2017).
  62. Antoni, P. W., Hansmann, M. M. Pyrylenes: A New Class of Tunable, Redox-Switchable, Photoexcitable Pyrylium-Carbene Hybrids with Three Stable Redox-States. Journal of the American Chemical Society. 140 (44), 14823-14835 (2018).
  63. Back, O., Henry-Ellinger, M., Martin, C. D., Martin, D., Bertrand, G. (PNMR)-P-31 Chemical Shifts of Carbene-Phosphinidene Adducts as an Indicator of the pi-Accepting Properties of Carbenes. Angewandte Chemie International Edition. 52 (10), 2939-2943 (2013).
  64. Jazzar, R., Dewhurst, R. D., Bourg, J. B., Donnadieu, B., Canac, Y., Bertrand, G. Intramolecular "Hydroiminiumation" of alkenes: Application to the synthesis of conjugate acids of cyclic alkyl amino carbenes (CAACs). Angewandte Chemie International Edition. 46 (16), 2899-2902 (2007).
  65. Benac, B. L., Burgess, E. M., Arduengo, A. J. 1,3-Dimethylimidazole-2-Thione. Organic Syntheses. 64, 92 (1986).
  66. Arduengo, A. J., Davidson, F., Dias, H. V. R., Goerlich, J. R., Khasnis, D., Marshall, W. J., Prakasha, T. K. An air stable carbene and mixed carbene "dimers&#34. Journal of the American Chemical Society. 119, 12742-12749 (1997).
  67. Frey, G. D., Lavallo, V., Donnadieu, B., Schoeller, W. W., Bertrand, G. Facile Splitting of Hydrogen and Ammonia by Nucleophilic Activation at a Single Carbon Center. Science. 316 (5827), 439-441 (2007).
  68. Verlinden, K., Buhl, H., Frank, W., Ganter, C. Determining the Ligand Properties of N-Heterocyclic Carbenes from 77Se NMR Parameters. European Journal of Inorganic Chemistry. 2015 (14), 2416-2425 (2015).
  69. Vummaleti, S. V. C., et al. What can NMR spectroscopy of selenoureas and phosphinidenes teach us about the [small pi]-accepting abilities of N-heterocyclic carbenes?. Chemical Science. 6 (3), 1895-1904 (2015).
  70. Hahn, F. E., Jahnke, M. C. Heterocyclic Carbenes: Synthesis and Coordination Chemistry. Angewandte Chemie International Edition. 47 (17), 3122-3172 (2008).
  71. Braun, M., Frank, W., Reiss, G. J., Ganter, C. An N-Heterocyclic Carbene Ligand with an Oxalamide Backbone. Organometallics. 29 (20), 4418-4420 (2010).
  72. Moerdyk, J. P., Schilter, D., Bielawski, C. W. N,N’-Diamidocarbenes: Isolable Divalent Carbons with Bona Fide Carbene Reactivity. Accounts of Chemical Research. 49 (8), 1458-1468 (2016).
  73. Mandal, D., et al. Stepwise Reversible Oxidation of N-Peralkyl-Substituted NHC-CAAC Derived Triazaalkenes: Isolation of Radical Cations and Dications. Organic Letters. 19 (20), 5605-5608 (2017).
  74. Torres, A. J., Dorsey, C. L., Hudnall, T. W. Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus. Journal of Visualized Experiments. (92), e52149 (2014).
  75. Hahn, F. E., Wittenbecher, L., Van Le, D., Fröhlich, R. Evidence for an Equilibrium Between an N-heterocyclic Carbene and Its Dimer in Solution. Angewandte Chemie International Edition. 3 (39), 5441-5544 (2000).
  76. Weinstein, C. M., Martin, C. D., Liu, L., Bertrand, G. Cross-Coupling Reactions Between Stable Carbenes. Angewandte Chemie International Edition. 53 (25), 6550-6553 (2014).

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Schlenk LineAir-sensitive CompoundsCarbenesDimersFree RadicalsFilter CannulaDry And Degassed SolventsIminium SaltKHMDSDinitrogenDiethyl EtherIsopropanol Slush BathPotassium Tetrafluoroborate
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Grünwald, A., Goodner, S. J., Munz, D. Isolating Free Carbenes, their Mixed Dimers and Organic Radicals. J. Vis. Exp. (146), e59389, doi:10.3791/59389 (2019).
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