Enediyne isomers of tetraethynylethene.
Enediyne isomers of tetraethynylethene.
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四乙炔乙烯的烯二炔异构体。
DOI：
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发表时间：
2006
影响因子：
3.6
通讯作者：
R. McMahon
中科院分区：
文献类型：
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作者：
Nathan P. Bowling;R. McMahon
三甲基硅基丁二炔基锌试剂与溴代烯烃在钯催化下发生Negishi偶联反应，然后用碳酸钾在甲醇中温和脱保护，合成了三种四乙炔基乙烯（1，C_（10）H_4）异构体。未取代的烯炔，3-乙炔基辛-3-烯-1，5，7-三炔（2）、反式-癸-5-烯-1，3，7，9-四炔（3）和顺式-癸-5-烯-1，3，7，9-四炔（4），在-20 ℃下表现出适度的稳定性，但在室温下迅速分解。2、3和4的电子吸收光谱揭示了在260-320 nm处的特征振动过程。在较短波长的光谱特征之间的异构体的歧视，并允许分配2和3作为表观二聚产物的三重态卡宾H-CC-C-CC-H在矩阵中在低温下。这些C10 H4异构体（MP2/6- 31 G）的计算相对能量为1（14.0 kcal/mol）、2（6.8 kcal/mol）、3（0.0 kcal/mol）和4（1.0 kcal/mol）。
Three isomers of tetraethynylethene (1, C10H4) have been prepared by palladium-catalyzed Negishi coupling of a trimethylsilylbutadiynyl zinc reagent with a bromoalkene, followed by mild deprotection with potassium carbonate in methanol. The unsubstituted enynes, 3-ethynyloct-3-ene-1,5,7-triyne (2), trans-dec-5-ene-1,3,7,9-tetrayne (3), and cis-dec-5-ene-1,3,7,9-tetrayne (4), exhibit modest stability at -20 degrees C but decompose rapidly at room temperature. Electronic absorption spectra of 2, 3, and 4 reveal a characteristic vibronic progression at 260-320 nm. Spectral features at shorter wavelength discriminate among the isomers, and permit the assignment of 2 and 3 as apparent dimerization products of triplet carbene H-CC-C-CC-H in matrices at low temperature. Computed relative energies of these C10H4 isomers (MP2/6-31G) are 1 (14.0 kcal/mol), 2 (6.8 kcal/mol), 3 (0.0 kcal/mol), and 4 (1.0 kcal/mol).