Synthesis, structure, and stabilities of trans-1,2-diphenyl-4,4,5,5,6,6-hexamethyl-4,5,6-trisilacyclohetene
Synthesis, structure, and stabilities of trans-1,2-diphenyl-4,4,5,5,6,6-hexamethyl-4,5,6-trisilacyclohetene
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反式1,2-二苯基-4,4,5,5,6,6-六甲基-4,5,6-三硅杂环己烯的合成、结构和稳定性
DOI：
10.1021/ja00001a049
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发表时间：
1991
影响因子：
15
通讯作者：
W. Andō
中科院分区：
文献类型：
--
作者：
Toshio Shimizu;K. Shimizu;W. Andō
x射线：6= 147.3,,= 19.9,2= 19.2,x,= 12.8, X2= 13.5 MM2（对称）：131.5 42.2 40.7 6.3 7.8 MM2（不对称）：147.7 31.0 17.2 1.3 15.1分别为19.6和13.2。trans-1环原子周围的键角除了Si (1)-Si (2)-Si(3)键角扩展外，几乎都是正常的。有趣的是，C (l)-C(2)和C (3)-C(4)的键长略有缩短，而C (l)-Si(1)、C (4)-Si(3)、Si (1) -Si(2)和Si (2)-Si(3)的键长则从相应的正常键长拉长。这些键角和长度的变形必须发生，以减轻C= C双键的扭曲。C= C双键[C (2)-C (3)= 1.344 A]与固态（1.228-1.330 A）的反式二苯乙烯相比，C= C双键的扩展可能是由于双键的扭曲。此外，两个苯环分别从C (3)-C (2)-C(5)和C (2)-C-(3)-C(6)平面倾斜47.3和51.1，尽管在固体状态下，伊朗-二苯乙烯的扭转角在3.6和5.7之间。12考察了反式-1光化学反应作为烯烃的一般性质。反式-1在苯- 6中辐照（254 nm）得到光异构的顺式-1。在此异构化过程中，发现存在光平衡，光定反/顺比为0.49（图2）。该值高于反式环庚烯光敏异构化。14对trans-1的热稳定性进行了研究。当苯
X-ray: 6= 147.3,,= 19.9, 2= 19.2, x,= 12.8, X2= 13.5 MM2 (symmetrical): 131.5 42.2 40.7 6.3 7.8 MM2 (unsymmetrical): 147.7 31.0 17.2 1.3 15.1 to be 19.6 and 13.2, respectively. The bond angles around the ring atoms of trans-1 are almost normal except for the expanded Si (l)-Si (2)-Si (3) bond angle. Interestingly, the bond lengths of C (l)-C (2) and C (3)-C (4) are slightly shortened while those of C (l)-Si (l), C (4)-Si (3), Si (1)—Si (2), and Si (2)-Si (3) are stretched from corresponding normal bond lengths. These deformations of the bond angle and lengths must occur to mitigate the twist of the C= C double bond. The C= C double bond [C (2)-C (3)= 1.344 A] is slightly stretched compared with thatof trans-stilbene in the solid state (1.228-1.330 A). 12· 13 The expansion of the C= C double bond may result from the twistingof the double bond. Furthermore, two benzene rings incline at 47.3 and 51.1 from the planes of C (3)-C (2)-C (5) and C (2)-C-(3)-C (6), respectively, though the torsion angles of irans-stilbene are ranged between 3.6 and 5.7 in the solid state. 12 Photochemical reaction of trans-1 was examined as a general property of the olefins. Irradiation (254 nm) of trans-1 in benzent-d6 gave photoisomerized cis-l. In this isomerization, it was found that a photoequilibrium existed and the photostationary trans/cis ratio was 0.49 (Figure 2). This value is higher than the photosensitized isomerization of frans-cycloheptene. 14 Thermal stabilities of trans-1 were also examined. When a benzene-