Study of Extremely Long C - C Bond

超长C-C键的研究

• 批准号: 11640537
• 负责人: TODA Fumio
• 金额: $ 2.3万
• 依托单位: Okayama University of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640537/
• 关键词: naphthocyclobutenes; extremely long C - C bond; steric repulsion; through bond interaction; anthradicyclobutenes; phenanthradicyclobutenes; 最も長い炭素-炭素結合; 立体的効果; 電子的効果; スル-ボンド相互作用

Some naphthocyclobutenes substituted with four phenyl groups and with two phenyl and two t Bu groups are prepared. X-ray analysis of these naphthocyclobutenes showed that the cyclobutene C - C bonds are extremely long, 1.72 - 1.73 Å. Especially, the C - C cyclobutene bond of the naphthocyclobutene substituted with two phenyl and two t Bu groups is the longest 1.73 Å. π-Electron locarization in the naphthalene ring is also observed.Reason for the extremely long C - C bond in naphthocyclobutenes would be a steric repulsion among bulky substituents on the four-membered ring. There is one another possible reason, namely, through bond interaction. In order to clarify which reason is more important, naphthocyclobutene derivatives substituted with cis- and trans-diphenyl groups were prepared. X-ray structural analysis of these showed there is no big difference between the bond length of cis- and trans-isomers. These results suggest that the steric repulsion is more important factor.Similarly, anthradicyclobutenes and phenanthradicyclobutenes substituted with phenyl groups were prepared. X-ray structural analysis of these showed that the cyclobutene C - C bonds are also extremely long. Stabilities of these cyclobutane derivatives would be due to the following reasons : ring opening of the cyclobutene should produce sterically crowded biradical or resonance energy lost quinodimethane.

合成了四个苯基取代的萘并环丁烯和两个苯基和两个叔丁基取代的萘并环丁烯。这些萘并环丁烯的X射线分析表明，环丁烯C-C键非常长，1.72 - 1.73 π。特别是被两个苯基和两个叔丁基取代的萘环丁烯的C-C环丁烯键最长为1.73 π。萘环上的π电子局域化现象也被观察到，萘环丁烯中极长的C-C键可能是由于四元环上大体积取代基之间的空间排斥作用。还有另一个可能的原因，即通过键的相互作用。为了阐明哪个原因更重要，制备了顺式和反式二苯基取代的萘并环丁烯衍生物。X射线结构分析表明，顺式和反式异构体之间的键长没有很大的差异。这些结果表明，空间位阻是影响环丁烯结构的重要因素。X射线结构分析表明，环丁烯的C-C键也非常长。这些环丁烷衍生物的稳定性将是由于以下原因：环丁烯的开环应产生空间拥挤的双自由基或共振能量损失的醌二甲烷。

项目成果

F.Toda: "A novel photochromism of biindenylidene in crystal form."J.Chem.Soc.,Perkin Trans.1. 873-874 (2000)

F.Toda：“晶体形式的联茚基的新型光致变色现象。”J.Chem.Soc.，Perkin Trans.1。

F.Toda: "The crystal and molecular structure of 2,7-di-tert-butyl-4,5,9,10-tetraphenylbenzo[1,2,: 4,5] dicyclobutadiene : an exceptionally long C-C aromatic bond."Chem.Commun.. 319-320 (1999)

F.Toda：“2,7-二叔丁基-4,5,9,10-四苯基苯并[1,2,:4,5]二环丁二烯的晶体和分子结构：极长的 C-C 芳香键。”

F.Toda: "Guest-dependent novel photochromism of 7-bromo-1,4,8-triphenyl-2,3-benzo[3.3.0]octa-2,4,7-trien-6-one in its inclusion crystals."Chem.Commun.. 1361-1362 (2000)

F.Toda：“7-溴-1,4,8-三苯基-2,3-苯并[3.3.0]八-2,4,7-三烯-6-酮在其包合物晶体中的客体依赖性新型光致变色现象

F.Toda: "Extremely Long C-C Bond in (-)-trans-1,2-Di-tert-butyl-1,2-diphenyl-and 1,1-Di-tert-butyl-2,2-diphenyl-3,8-dichlorocyclobuta[b]naphthalenes."J.Org.Chem.. 64. 3102-3105 (1999)

F.Toda：“(-)-反式-1,2-二叔丁基-1,2-二苯基-和 1,1-二叔丁基-2,2-二苯基-3 中的极长 C-C 键

F.Toda: "Naphthocyclobutenes and Benzodicyclobutadienes : Synthesis in the Solid State and Anomalies in the Bond Lengths."Eur.J.Org.Chem.. 1377-1386 (2000)

F.Toda：“萘并环丁烯和苯并二环丁二烯：固态合成和键长异常。”Eur.J.Org.Chem.1377-1386 (2000)