價鍵異構體

價鍵異構體(Valence isomer),或稱作價異構體,是結構異構的一種,因分子中的價電子分佈發生了變化,並改變了分子的幾何形狀,故稱作價鍵異構。在有機化學中,特指能經週環反應進行互換的化合物。[1]例如的化學式C6H6就不只有目前的模樣,杜瓦苯就是另一種擁有完全相同化學式,但其幾何形狀卻不同的化合物。除了杜克苯,在拓樸學的角度上,(CH)6這一家族還有極多可能的組合。但並非所有可能的組合都實際存在;這是因為環狀化合物的鍵長及鍵角的張力限制了其可能性。

環丁二烯

環丁二烯最簡單的[n]-輪烯([4]-輪烯),它也有幾種異構體。

環辛四烯

除了(CH)6有為數不少的價鍵異構體,(CH)8家族同樣有價鍵異構體。而且與其他異構體的情況一樣,當分子體積增加,可能的異構體的數目亦會相對增加。

[10]輪烯

[10]輪烯的價鍵異構體

 
[10]annulenes

參考文獻

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  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
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  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
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