价键异构体(Valence isomer),或称作价异构体,是结构异构的一种,因分子中的价电子分布发生了变化,并改变了分子的几何形状,故称作价键异构。在有机化学中,特指能经周环反应进行互换的化合物。[1]例如的化学式C6H6就不只有目前的模样,杜瓦苯就是另一种拥有完全相同化学式,但其几何形状却不同的化合物。除了杜克苯,在拓朴学的角度上,(CH)6这一家族还有极多可能的组合。但并非所有可能的组合都实际存在;这是因为环状化合物的键长及键角的张力限制了其可能性。

环丁二烯

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环丁二烯最简单的[n]-轮烯([4]-轮烯),它也有几种异构体。

环辛四烯

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除了(CH)6有为数不少的价键异构体,(CH)8家族同样有价键异构体。而且与其他异构体的情况一样,当分子体积增加,可能的异构体的数目亦会相对增加。

[10]轮烯

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[10]轮烯的价键异构体

 
[10]annulenes

参考文献

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  1. ^ 国际纯化学和应用化学联合会化学术语概略,第二版。(金皮书)(1997)。在线校正版: (1994) "Valence isomer"。doi:10.1351/goldbook.V06590
  2. ^ Huisgen, R.; Mietzsch, F. The Valence Tautomerism of Cyclooctatetraene. Angewandte Chemie International Edition in English. 1964, 3 (2): 83. doi:10.1002/anie.196400831. 
  3. ^ Bicyclo[4,2,0]octa-2,4,7-triene Emanuel Vogel, H. Kiefer, W. R. Roth Volume 3, Issue 6, pages 442–443, June 1964 doi:10.1002/anie.196404422
  4. ^ Huisgen, Rolf.; Konz, Will E.; Gream, George E. Evidence for different valence tautomers of bromocyclooctatetraene. Journal of the American Chemical Society. 1970, 92 (13): 4105. doi:10.1021/ja00716a048. 
  5. ^ Meinwald, Jerrold; Tsuruta, Haruki. Tricyclo[3.3.0.02,6]octa-3,7-diene. Journal of the American Chemical Society. 1969, 91 (21): 5877. doi:10.1021/ja01049a034. 
  6. ^ Meinwald, Jerrold; Schmidt, Douglass. Semibullvalene from tricyclo[3.3.0.02,6]octane. Journal of the American Chemical Society. 1969, 91 (21): 5877. doi:10.1021/ja01049a033. 
  7. ^ Zimmerman, Howard Elliot; Robbins, Jeffrey D.; Schantl, Joachim. C8H8 interconversions. An unusual rearrangement providing a new route to semibullvalene. Journal of the American Chemical Society. 1969, 91 (21): 5878. doi:10.1021/ja01049a035. 
  8. ^ Meinwald, Jerrold.; Tsuruta, Haruki. (CH)8 hydrocarbons. Photochemistry of tricyclo[3.3.0.02,6]octa-3,7-diene. Journal of the American Chemical Society. 1970, 92 (8): 2579. doi:10.1021/ja00711a078. 
  9. ^ Untersuchungen in der Cyclobutanreihe, XII. Zwei stereoisomere Dimere des Cyclobutadiens Margarete Avram, Ilie G. Dinulescu, Elise Marica, Georg Mateescu, Elvira Sliam, Costin D. Nenitzescu Chemische Berichte Volume 97, Issue 2, pages 382–389, February 1964 doi:10.1002/cber.19640970210
  10. ^ Methyl tetracyclo[3.3.0.02,4O3,6]cot-7-ene-4-carboxylate Gerhard W. Klumpp, W. G. J. Rietman, J. J. Vrielink J. Am. Chem. Soc., 1970, 92 (17), pp 5266–5267 doi:10.1021/ja00720a071
  11. ^ Synthesis and reactions of tetracyclo[4.2.0.02,4.03,5]octanes Leverett R. Smith, George E. Gream, Jerrold Meinwald J. Org. Chem., 1977, 42 (6), pp 927–936 doi:10.1021/jo00426a001
  12. ^ (Z)-3,7 Bis(phenylsulfonyl)pentacyclo[5.1.0.02,4.03,5.06,8]octane, an Octabisvalene Derivative (1985) Angewandte Chemie International Edition in English Volume 24, Issue 5, pages 411–412 doi:10.1002/anie.198504111
  13. ^ The synthesis of octavalene (tricyclo[5.1.0.02,8]octa-3,5-diene) and several substituted octavalenes Tetrahedron Volume 42, Issue 6, 1986, Pages 1585-1596 Manfred Christl, Reinhard Lang and Clemens Herzog doi:10.1016/S0040-4020(01)87575-X
  14. ^ Electronic structure of octavalene. Photoelectron spectroscopic investigations Rolf Gleiter, Peter Bischof, Manfred Christl J. Org. Chem., 1986, 51 (15), pp 2895–2898 doi:10.1021/jo00365a007