Acetylacetonate Anchors for Robust Functionalization of TiO2 Nanoparticles with Mn(II)-Terpyridine Complexes
Acetylacetonate Anchors for Robust Functionalization of TiO2 Nanoparticles with Mn(II)-Terpyridine Complexes
复制标题
DOI：
10.1021/ja805498w
复制
发表时间：
2008-10-29
影响因子：
15
通讯作者：
Batista, Victor S.
中科院分区：
文献类型：
--
作者：
McNamara, William R.;Snoeberger, Robert C.;Batista, Victor S.
报道了一类新的衍生化乙酰丙酮酸（acac）连接剂，用于在水和氧化条件下实现TiO2纳米粒子（NPs）的强大功能化。由此产生的表面吸附物锚点与工程光催化和光催化装置特别相关，因为它们可以应用于附着广泛的光敏剂和光催化复合物，并且不受湿度的影响。Acac很容易通过cui介导的偶联反应进行修饰，以提供各种支架，包括取代的terpy配合物（terpy = 2,2':6,2 '-terpyridine），这些配合物与过渡金属离子配位组装。由于已知Mn-terpy配合物是氧化化学的有效催化剂，因此研究了Mn（II）的功能化。胶体薄膜和水悬浮液的紫外可见光谱证明，由于界面电子转移，TiO2纳米颗粒可以在可见光下敏化。通过光泵-太赫兹探针瞬态测量和计算机模拟监测，潜在的超快界面电子注入在亚皮秒时间尺度上完成。6 K时Mn(II) EPR信号的时间分辨测量表明，界面电子注入诱导Mn（II）—>Mn（III）光氧化，Mn（II）配合物的再生半时间约为23 s。
A novel class of derivatized acetylacetonate (acac) linkers for robust functionalization of TiO2 nanoparticles (NPs) under aqueous and oxidative conditions is reported. The resulting surface adsorbate anchors are particularly relevant to engineering pholocatalytic and photovoltaic devices since they can be applied to attach a broad range of photosensitizers and photocatalytic complexes and are not affected by humidity. Acac is easily modified by CuI-mediated coupling reactions to provide a variety of scaffolds, including substituted terpy complexes (terpy = 2,2':6,2 ''-terpyridine), assembled with ligands coordinated to transition-metal ions. Since Mn-terpy complexes are known to be effective catalysts for oxidation chemistry, functionalization with Mn(II) is examined. This permits visible-light sensitization of TiO2 nanoparticles due to interfacial electron transfer, as evidenced by UV-vis spectroscopy of colloidal thin films and aqueous suspensions. The underlying ultrafast interfacial electron injection is complete on a subpicosecond time scale, as monitored by optical pump-terahertz probe transient measurements and computer simulations. Time-resolved measurements of the Mn(II) EPR signal at 6 K show that interfacial electron injection induces Mn(II)-->Mn(III) photooxidation, with a half-time for regeneration of the Mn(II) complex of ca. 23 s.