Large optical activity of gold nanocluster enantiomers induced by a pair of optically active penicillamines
Large optical activity of gold nanocluster enantiomers induced by a pair of optically active penicillamines
复制标题
一对具有光学活性的青霉胺诱导金纳米簇对映体的大光学活性
DOI：
10.1021/ja053504b
复制
发表时间：
2005-11-09
影响因子：
15
通讯作者：
Kimura, K
中科院分区：
文献类型：
--
作者：
Yao, H;Miki, K;Kimura, K
我们首次成功地制备了一对由光学活性硫醇保护的金纳米簇对映体：D-和L-青霉胺（D-Pen和L-Pen）。圆二色性（CD）光谱证实了D-Pen-capped和L-Pen-capped金纳米团簇之间的镜像关系，表明表面改性剂充当手性选择剂，并且纳米团簇具有像常见手性分子那样的明确的立体结构。当通过使用外消旋混合物（rac-Pen）合成金纳米团簇时，不能获得CID信号。通过聚丙烯酰胺凝胶电泳（PAGE）研究了每个金纳米簇（D-Pen-封端的、L-Pen-封端的或rac-Pen-封端的簇）的三个分离的级分的这些手性性质。每个分级组分的平均直径为0.57、1.18或1.75 nm，其通过溶液相小角X射线散射测定。随着平均团簇直径的减小，光学活性或各向异性因子逐渐增加。基于动力学和结构的考虑，讨论了金纳米簇对映体大光学活性的来源。
We have succeeded for the first time in preparing a pair of gold nanocluster enantiomers protected by optically active thiols: D- and L-penicillamine (D-Pen and L-Pen). Circular dichroism (CD) spectroscopy confirmed the mirror image relationship between the D-Pen-capped and the L-Pen-capped gold nanoclusters, suggesting that the surface modifier acts as a chiral selector, and that the nanoclusters have well-defined stereostructures as common chiral molecules do. No CID signals could be obtained when the gold nanoclusters were synthesized by using a racemic mixture (rac-Pen). These chiroptical properties were investigated for the three separated fractions of each of the gold nanoclusters (D-Pen-capped, L-Pen-capped, or rac-Pen-capped clusters) by polyacrylamide gel electrophoresis (PAGE). Each fractioned component has the mean diameter of 0.57, 1.18, or 1.75 nm that was determined by a solution-phase small-angle X-ray scattering. With a decrease in the mean cluster diameter, optical activity or anisotropy factors gradually increased. On the basis of the kinetic and the structural considerations, the origins of large optical activity of the gold nanocluster enantiomers are discussed.