Counterion-assisted shaping of nanocluster supracrystals.
Ag44 (p-MBA)30 (4-) (p-MBA=para-mercaptobenzoic acid) nanocluster (NC) supracrystals (SCs) with customizable shapes can be obtained by simply altering the type and concentration of the counterions of the p-MBA ligands in the dimethylsulfoxide (DMSO)/water crystallization system. Changing the counterion of the p-MBA ligand from H(+) to Cs(+) eliminates the directional hydrogen bonds in the SCs, resulting in the packing of deprotonated Ag44 (p-MBA)30 (4-) NCs into octahedral SCs, which is in stark contrast to the rhombohedral SCs that were formed by the packing of protonated Ag44 (p-MBA)30 (4-) NCs in previous studies. Furthermore, the double layer of deprotonated Ag44 (p-MBA)30 (4-) NCs is sensitive to charge screening induced by increasing the Cs(+) concentration, thereby providing a means to regulate the precipitation kinetics of the Ag44 (p-MBA)30 (4-) NCs for SC shape engineering. Slow precipitation kinetics was found to favor over-growth at the corners and edges of the octahedral SC nuclei, shaping the SCs into concave octahedra.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore).
Qiaofeng
Q
Yao
Yue
Y
Yu
Xun
X
Yuan
Yong
Y
Yu
Dan
D
Zhao
Jianping
J
Xie
Jim Yang
JY
Lee
nanoclusters; noble metals; self-assembly; shape control; supracrystals