设计C2 - 奇拉型二胺,其计算预测比原始质子海绵更基本一百万倍
1School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom. rog.alder@bris.ac.uk
Journal of the American Chemical Society
|May 26, 2005
概括
研究人员设计了具有高性 (pKa ~23-6) 和低核友性的新型C2-性二胺. 应变缓解和有限的形状自由是提高这些有机化合物基础强度的关键.
科学领域:
- 有机化学 有机化学
- 计算化学的计算化学
- 物理化学 物理化学
背景情况:
- 设计有力的有机基对于各种化学应用至关重要.
- 了解分子结构和基本性之间的关系是一个持续的挑战.
- 1,6-二甲基衍生物为探索新型基本化合物提供了一个有前途的支架.
研究的目的:
- 为了合成和表征基于1,6-diazacyclodecane的新型C2 - 奇拉二胺.
- 通过计算预测这些二胺衍生物的基本性 (pKa) 和核性.
- 研究影响这些循环二胺基的基本性结构因素.
主要方法:
- 合成C2 - 奇拉二胺 (化合物18-21).
- 使用B3LYP/6-31G进行pKa预测的密度函数理论 (DFT) 计算.
- 在质子化时对形状自由和应变缓解的分析.
主要成果:
- 鉴定了C2 - 奇拉二胺,预测的pKa值约为23-6 (水量级) 和30-33 (乙二量级).
- 这些化合物被预测是动态活跃的,但基本上是非核爱的.
- 质子化的应变缓解被确定为基本性的主要驱动因素.
- 15,16-Dimethyl-15,16-diazatricyclo[9.3.1.1(4,8) ]六甲 (20) 存在于10种二聚体形式,预测的pKa值跨越14个逻辑单位.
结论:
- 由于在质子化时的应变缓解,新型C2 - 奇拉型二胺呈现出显著的基本性.
- 限制形状自由,特别是通过额外的环融合进行逆转,可以提高基体强度.
- 化合物20的二聚体显示了广泛的预测基本性,突出显示了立体化学的影响.
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