State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Departments of Physics and Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, 40014, Finland.
Angew Chem Int Ed Engl. 2018 Mar 19;57(13):3421-3425. doi: 10.1002/anie.201800327. Epub 2018 Feb 23.
A general method, using mixed ligands (here diphosphines and thiolates) is devised to turn an achiral metal cluster, Au Cu , into an enantiomeric pair by breaking (lowering) the overall molecular symmetry with the ligands. Using an achiral diphosphine, a racemic [Au Cu (DPPP) (SPy) ] was prepared which crystallizes in centrosymmetric space groups. Using chiral diphosphines, enantioselective synthesis of an optically pure, enantiomeric pair of [Au Cu ((2r,4r)/(2s,4s)-BDPP) (SPy) ] was achieved in one pot. Their circular dichroism (CD) spectra give perfect mirror images in the range of 250-500 nm with maximum anisotropy factors of 1.2×10 . DFT calculations provided good correlations with the observed CD spectra of the enantiomers and, more importantly, revealed the origin of the chirality. Racemization studies show high stability (no racemization at 70 °C) of these chiral nanoclusters, which hold great promise in applications such as asymmetry catalysis.
一种通用方法，使用混合配体（这里是二膦和硫醇），通过配体打破（降低）整体分子对称性，将手性金属簇 AuCu 转化为对映体对。使用非手性二膦，制备了外消旋的[AuCu(DPPP)(SPy)]，其在中心对称空间群中结晶。使用手性二膦，在手性环境中一锅法实现了光学纯、对映体的[AuCu((2r,4r)/(2s,4s)-BDPP)(SPy)]的对映选择性合成。它们的圆二色性（CD）光谱在 250-500nm 范围内给出了完美的镜像，最大各向异性因子为 1.2×10-3。DFT 计算与对映体的观察到的 CD 光谱很好地相关，更重要的是，揭示了手性的起源。外消旋研究表明这些手性纳米簇具有很高的稳定性（在 70°C 下没有外消旋），在手性催化等应用中具有很大的应用前景。
