Preparation, Structures, and Theoretical Calculations of Novel Silacalixarene Derivatives: Silacalix[4]quinone and Silacalix[4]hydroquinone Octamethyl Ether
Preparation, Structures, and Theoretical Calculations of Novel Silacalixarene Derivatives: Silacalix[4]quinone and Silacalix[4]hydroquinone Octamethyl Ether
复制标题
新型Silacalixarene衍生物：Silacalix[4]醌和Silacalix[4]氢醌八甲醚的制备、结构和理论计算
DOI：
10.1021/om0499310
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发表时间：
2004
期刊：
影响因子：
2.8
通讯作者：
K. Sakamoto
中科院分区：
文献类型：
--
作者：
Shinobu Tsutsui;Hiromasa Tanaka;K. Sakamoto
合成了一种新型硅桥杯[4]芳烃衍生物2，8，14，20-四硅杯[4]对苯二酚八甲基醚（6）。硝酸铈铵氧化6得到第一个杂原子桥连杯[4]醌衍生物2，8，14，20-四硅杯[4]醌（5）。化合物5和6的结构经1 H、1 3 C和2 9 Si NMR和质谱测定。X射线晶体学分析证实了5和6的结构。X-射线晶体结构表明5和6采用1，3-交替构象。并通过理论计算对5和6的构象进行了研究。在B3 LYP/6- 31 G（d）水平上优化的5的1，3-交替构象至少比其他构象稳定4.9 kcal/mol。这一发现与固态结构一致。相比之下，6的优化的1，3-交替构象比相应的1，2-交替构象稳定性低1.3 kcal/mol。结果表明，6具有显著的构象柔性。
A novel silicon-bridged calix[4]arene derivative, 2,8,14,20-tetrasilacalix[4]hydroquinone octamethyl ether (6), has been successfully prepared. Cerium ammonium nitrate oxidation of 6 gave the first heteroatom-bridged calixquinone derivative, 2,8,14,20-tetrasilacalix[4]-quinone (5). The structures of 5 and 6 were determined by 1 H, 1 3 C, and 2 9 Si NMR spectroscopy and mass spectroscopy. X-ray crystallographic analysis confirmed the structures of 5 and 6. X-ray crystal structures revealed that 5 and 6 adopted 1,3-alternate conformations. The conformations of 5 and 6 were also studied by theoretical calculations. The optimized 1,3-alternate conformer of 5 is at least 4.9 kcal/mol more stable than the other conformers at the B3LYP/6-31G(d) level. This finding is in agreement with the solid-state structure. In contrast, the optimized 1,3-alternate conformer of 6 is 1.3 kcal/mol less stable than the corresponding 1,2-alternate conformer. The result suggests that 6 has significant conformational flexibility.