School of Chemical Engineering and Technology, Tianjin Key Laboratory of Applied Catalysis Science and Technology, Tianjin University , Tianjin 300354, China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300354, China.
J Am Chem Soc. 2017 Oct 4;139(39):13701-13712. doi: 10.1021/jacs.7b01445. Epub 2017 Sep 20.
The chirality of nanoparticles (NPs) and their assemblies has been investigated predominantly for noble metals and II-VI semiconductors. However, ceramic NPs represent the majority of nanoscale materials in nature. The robustness and other innate properties of ceramics offer technological opportunities in catalysis, biomedical sciences, and optics. Here we report the preparation of chiral ceramic NPs, as represented by tungsten oxide hydrate, WO·HO, dispersed in ethanol. The chirality of the metal oxide core, with an average size of ca. 1.6 nm, is imparted by proline (Pro) and aspartic acid (Asp) ligands via bio-to-nano chirality transfer. The amino acids are attached to the NP surface through C-O-W linkages formed from dissociated carboxyl groups and through amino groups weakly coordinated to the NP surface. Surprisingly, the dominant circular dichroism bands for NPs coated by Pro and Asp are different despite the similarity in the geometry of the NPs; they are positioned at 400-700 nm and 500-1100 nm for Pro- and Asp-modified NPs, respectively. The differences in the spectral positions of the main chiroptical band for the two types of NPs are associated with the molecular binding of the two amino acids to the NP surface; Asp has one additional C-O-W linkage compared to Pro, resulting in stronger distortion of the inorganic crystal lattice and greater intensity of CD bands associated with the chirality of the inorganic core. The chirality of WO·HO atomic structure is confirmed by atomistic molecular dynamics simulations. The proximity of the amino acids to the mineral surface is associated with the catalytic abilities of WO·HO NPs. We found that NPs facilitate formation of peptide bonds, leading to Asp-Asp and Asp-Pro dipeptides. The chiroptical activity, chemical reactivity, and biocompatibility of tungsten oxide create a unique combination of properties relevant to chiral optics, chemical technologies, and biomedicine.
我们报告了手性陶瓷纳米粒子（代表为氧化钨水合物，WO·HO）的制备，这些纳米粒子分散在乙醇中。金属氧化物核的手性是通过脯氨酸（Pro）和天冬氨酸（Asp）配体通过生物到纳米手性传递赋予的。氨基酸通过与 NP 表面弱配位的氨基和从解离的羧基形成的 C-O-W 键连接到 NP 表面。令人惊讶的是，尽管 NP 的几何形状相似，但涂覆 Pro 和 Asp 的 NP 的主要圆二色性带的主导圆二色性带不同；它们分别位于 400-700nm 和 500-1100nm 处。两种类型的 NP 的主要手性带的光谱位置的差异与两种氨基酸与 NP 表面的分子结合有关；与 Pro 相比，Asp 具有一个额外的 C-O-W 键，导致无机晶格的更大扭曲和与无机核的手性相关的 CD 带的更大强度。WO·HO 原子结构的手性通过原子分子动力学模拟得到证实。氨基酸与矿物表面的接近程度与 WO·HO NPs 的催化能力有关。我们发现 NPs 促进了肽键的形成，导致 Asp-Asp 和 Asp-Pro 二肽的形成。氧化钨的手性光学活性、化学反应性和生物相容性创造了与手性光学、化学技术和生物医学相关的独特性质组合。
