Knoppe Stefan, Bürgi Thomas
University of Geneva, Department of Physical Chemistry, Quai Ernest-Ansermet 30, CH-1211 Genève 4.
Chimia (Aarau). 2013;67(4):236-9. doi: 10.2533/chimia.2013.236.
Chiral thiolate-protected gold clusters of atomic precision have gained increasing interest in recent years due to their potential use in catalysis, sensing or bioapplications. While the protection of gold clusters with chiral ligands is a rather trivial task, it was found that the clusters can bear intrinsically chiral features, most obvious in the arrangement of the protecting ligands on the surface of the cluster. Recent efforts showed the separation of the enantiomers of such intrinsically chiral gold clusters. This technique can be used for the prediction of chirality in structurally unknown clusters. Activation barriers for the racemization of Au38(SR)24 were determined. As this involves a huge rearrangement of the ligands, the flexibility of the gold-thiolate interface is demonstrated. Furthermore, the ligand exchange reactions between intrinsically chiral clusters and bidentate chiral thiols were studied. A limited, regioselective exchange was found. Most importantly, the reaction is diastereoselective and allows tailoring of gold clusters that are protected with a defined layer of ligands.
近年来，具有原子精度的手性硫醇盐保护的金簇因其在催化、传感或生物应用中的潜在用途而越来越受到关注。虽然用手性配体保护金簇是一项相当简单的任务，但人们发现这些簇可以具有内在的手性特征，这在簇表面保护配体的排列中最为明显。最近的研究表明可以分离这种具有内在手性的金簇的对映体。该技术可用于预测结构未知簇的手性。测定了Au38(SR)24消旋化的活化能垒。由于这涉及配体的巨大重排，证明了金-硫醇盐界面的灵活性。此外，还研究了具有内在手性的簇与双齿手性硫醇之间的配体交换反应。发现了有限的区域选择性交换。最重要的是，该反应具有非对映选择性，并且可以定制由确定的配体层保护的金簇。
