价键异构体

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。例如苯的化學式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。 环丁二烯最简单的[n]-轮烯（[4]-轮烯），它也有几种异构体。 环丁二烯的價鍵異構體 环丁二烯 正四面体烷 Bicyclo-1.1.0-but-1(3)-ene 苯的價鍵異構體 苯，6個C-H鍵合連成環狀 杜瓦苯，另一個結合6個C-H鍵而環狀的方法 稜柱烷，呈稜柱體的結構 盆苯，另一個苯的異構體 聯環丙烯，兩個環丙烯連結起來的化合物，這是其中較穩定的異構體 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。 環辛四烯及其價鍵異構體 環辛四烯 1,3,5,7-cyclooctatetraene 桶烯 Bicyclo[2.2.2]octa-2,5,7-triene 立方烷 Pentacyclo[4.2.0.02,5.03,8.04,7]octane 楔形烷 Pentacyclo[3.3.0.0 2,4.03,7.06,8]octane 半瞬烯 (4as,4bs)-2a,2b,4a,4b-Tetrahydrocyclopropa[cd]pentalene 1,5-dihydropentalene 2a,2b,4a,4b-Tetrahydrocyclopropa[cd]pentalene Bicyclo[4.2.0]octa-2,4,7-triene. Tricyclo[3,3,0,02,6]octa-3,8-diene. Tricyclo[4,2,0,02,5]octa-3,7-diene. Tetracyclo[3,3,0,02,4,03,6] octa-7-ene. Tetracyclo[4,2,0,02,4,03,5] octa-7-ene. Pentacyclo[5.1.0.02,4. 03,5.06,8]octane (octabisvalene). Tricyclo[5.1.0.02,8]octa-3,5-diene (octavalene). [10]轮烯的價鍵異構體 萘的價鍵異構體 萘 薁 2a,4a,6a,6b-tetrahydrocyclopenta[cd]pentalene Isotriquinacene 4,4a,6a,6b-tetrahydro-Cyclopenta[cd]pentalene 1,3-dicyclopentylcyclopentane 1-Cyclodecene-3,9-diyne 1,1'-Bi(cyclopentane)-1,2',3,4'-tetraene 1-phenyl-bicyclo[1.1.0]butane 3-phenylcyclobutene (5E,7Z)-1,3,5,7,9-Cyclodecapentaene (1β,2α,3β,6β,7α,8β)-Tetracyclo[6.2.0.02,7.03,6]deca-4,9-diene 1,3,4,5-Tetrahydrocycloprop[f]indene 1,1a,6,6a-tetrahydro-Cycloprop[a]indene 1,4-Cyclo-1,4,4a,8a-tetrahydronaphthalene Tricyclo[6.2.0.03,6]deca-1,3(6),7-triene 2,5-dimethoxythiophene Tricyclo[5.3.0.02,8]deca-3,5-diene 4,7-dihydro-4,7-Methano-2H-indene 3a,4,5,7a-tetrahydro-1,4,5-Metheno-1H-indene Snoutene 2,2a,2b,3,5a,5b-hexahydro-1,2,3-metheno-1H-cycloprop[cd]indene Lumibullvalene 1,3a,4,6a-tetrahydro-1,4-Ethenopentalene Bicyclo[4.2.2]deca-2,4,7,9-tetrene 2a,2b-Ethano-4a,4b-dihydrocyclopropa[cd]pentalene Hypostrophene Tetracyclo[5.3.0.02,6.03,10]deca-4,8-diene Octahydro-3-methylene-1,2-Methanodicyclopropa(cd,gh)pentalene Basketene Pentacyclo[4.4.0.02,5.03,8.04,7]dec-9-ene Pentacyclo[5.3.0.02,5.03,9.04,8]decane-2-ene Pentaprismane Hexacyclo[4.4.0.02,5.03,9.04,8.07,10]decane Diademane Octahydro-1,2,3-metheno-1H-dicycloprop[cd,hi]indene 瞬烯 Tricyclo[3.3.2.02,8]deca-3,6,9-triene 2,3-dihydro-1,3-methano-1h-indene Bicyclo[4.3.1]deca-2,4,6,8-tetraene 4,7-Methano-4,7-dihydro-1H-indene Tricyclo[4.2.2.02,5]deca-3,7,9-triene Bicyclo[4.2.2]deca-2,4,7,9-tetraene Hexacyclo[6.2.0.01,9.02,4.03,5.07,9]decane 2a,2b,6a,6b-Tetrahydrocyclopropa[cd]azulene (2S,3S,6S,7S)-Pentacyclo[4.4.0.02,5.03,8.04,7]dec-9-ene (1R,5R,6S,7S,8R,10S)-Hexacyclo[6.2.0.02,4.02,10.03,6.05,7]decane 國際純化學和應用化學聯合會，化學術語概略，第二版。（金皮書）(1997)。在線校正版: (1994) "Valence isomer"。doi:10.1351/goldbook.V06590 Huisgen, R.; Mietzsch, F. The Valence Tautomerism of Cyclooctatetraene. Angewandte Chemie International Edition in English. 1964, 3 (2): 83. doi:10.1002/anie.196400831.  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 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.  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.  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.  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.  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.  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 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 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 (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 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 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