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From Symmetry Breaking to Unraveling the Origin of the Chirality of Ligated Au 13 Cu 2 Nanoclusters
Author(s) -
Deng Guocheng,
Malola Sami,
Yan Juanzhu,
Han Yingzi,
Yuan Peng,
Zhao Chaowei,
Yuan Xiting,
Lin Shuichao,
Tang Zichao,
Teo Boon K.,
Häkkinen Hannu,
Zheng Nanfeng
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201800327
Subject(s) - diphosphines , nanoclusters , racemization , enantiomer , chirality (physics) , chemistry , crystallography , enantioselective synthesis , axial chirality , circular dichroism , stereochemistry , symmetry breaking , chiral symmetry breaking , catalysis , physics , organic chemistry , quantum mechanics , nambu–jona lasinio model
A general method, using mixed ligands (here diphosphines and thiolates) is devised to turn an achiral metal cluster, Au 13 Cu 2 , into an enantiomeric pair by breaking (lowering) the overall molecular symmetry with the ligands. Using an achiral diphosphine, a racemic [Au 13 Cu 2 (DPPP) 3 (SPy) 6 ] + was prepared which crystallizes in centrosymmetric space groups. Using chiral diphosphines, enantioselective synthesis of an optically pure, enantiomeric pair of [Au 13 Cu 2 ((2r,4r)/(2s,4s)‐BDPP) 3 (SPy) 6 ] + 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 −3 . 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.