对于金属复合酸盐二体的水解改变的机制
Tim Humphry1, Marcello Forconi, Nicholas H Williams
1Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA.
Journal of the American Chemical Society
|December 12, 2002
概括
双核复合物通过一种新的添加-消除机制,极大地加速甲基p-基酸盐的水解. 动态同位素效应在限制速率的阶段显示出显著的PO键裂变,与非复杂的体不同.
科学领域:
- 无机化学 无机化学 有机化学
- 反应机制 反应机制
- 生物模拟化学 生物模拟化学
背景情况:
- 酸二水解在生物系统中至关重要.
- 双核金属复合体可以模仿酶活性位点.
- 了解反应机制有助于设计催化剂.
研究的目的:
- 为了阐明甲基p-nitrophenyl酸盐复合到双核复合物的水解机制.
- 为了研究水解反应的过渡状态.
- 为了比较该机制与不复杂的死机.
主要方法:
- 水解的动力学研究.
- 使用氧 (18O) 和 (15N) 的同位素测量动态同位素效应 (KIEs).
- 复合和非复合二聚的水解速率的比较.
主要成果:
- 复杂的二甲醇的水解速度比不复杂的二甲醇快10^11倍.
- 桥接氧化核的大型反向18O KIE表明了预先确定速度的核性攻击步骤.
- 对于甲脱离组,大型18O和15NKIEs在速率决定步骤中表明了显著的P-O Ester键裂变.
结论:
- 复合型二的水解通过一种添加-消除机制进行,与非复合型二的协同机制不同.
- 速率限制步骤涉及从中间体中驱逐p-nitrophenyl离开组.
- 复杂的二聚水解的过渡状态表现出广泛的PO键裂变.
相关概念视频
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