有机化物与固体表面的反应:表面催化自组合的一个例子
Roy Helmy1, Robert W Wenslow, Alexander Y Fadeev
1Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey 07079, USA.
Journal of the American Chemical Society
|June 17, 2004
概括
八甲基通过催化水解在金属氧化物上形成密集的,水平交叉连接的单层. 表面的酸性和基本性决定了反应性,通过控制条件实现最佳接种.
科学领域:
- 表面化学 表面化学
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
背景情况:
- 八甲基西兰 (C18H37SiH3) 是一种用于表面修饰的多功能前体.
- 自组装单层 (SAM) 对于定制材料特性至关重要.
- 了解西兰与金属氧化物的反应机制是控制表面功能化的关键.
研究的目的:
- 为了研究八甲基西兰与各种高表面积金属氧化物的溶液相反应.
- 描述由此产生的支单层的结构和特性.
- 阐明金属氧化物表面特性在反应机制中的作用.
主要方法:
- 八甲基西兰与10种不同的金属氧化物发生溶液相反应.
- 福里埃变换红外光谱 (FTIR) 用于化学表征.
- (29) Si核磁共振 (NMR) 光谱用于结构分析.
- 气相色谱用于量化的演变.
主要成果:
- 在大多数金属氧化物上实现了八甲基单层的高接种密度 (4.5-5组/nm2).
- 形成具有Si-O-Si和Si-OH.HO-Si键的水平交联SAM,并与氧化物进行最小的垂直结合.
- 八甲基西兰的完整水解,产生大约3H2每移植的西兰.
- 反应速率是由金属氧化物在易斯和布伦斯特德酸/位上被吸附的水催化.
结论:
- 八甲基的水解是速度限制的步骤,由表面酸度/度催化.
- 具有较弱酸性/基本性质的材料 (,碳,聚合物) 不会发生反应.
- 反应温度和用酸/的表面剂显著提高了反应活性.
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