Vertex and edge truncated octahedron gold crystals. N-alkylimidazole and silver(I) ion controlled morphology transformation.
Two interesting morphology transformations of Au crystals are observed through reacting a mixture of N-alkylimidazole (denoted as C(n)-im, where C(n) = C(n)H(2n+1), and n = 18 and 1), AgNO(3), and HAuCl(4) at 200 degrees C. The long chain C(18)-im with increasing AgNO(3) concentration leads to a progressive truncation of octahedrons at {100} vertices to produce cubes. On the other hand, increasing the concentrations of C(1)-im and AgNO(3), results in a progressive truncation of octahedrons at {110} edges to give rhombic dodecahedrons, which further transform to the unprecedented tetrahexahedrons. The phenomenon could be understood by considering that while both C(18)-im and C(1)-im function as a capping agent with preferential adsorption on Au {111} facets, Ag(+) adsorbs and is subsequently reduced to Ag on Au {110} facets for the sterically demanding C(18)-im, but on the Au {100} facets for C(1)-im. The competition between the growth of the facets protected by imidazole and Ag controls the morphology transformation via truncation of octahedrons at vertices or edges.
Hsu
S J
SJ
Department of Chemistry and Nanotechnology Research Center, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
Su
Padi Y S
PY
Jian
L Y
LY
Chang
A H H
AH
Lin
Ivan J B
IJ
D003460:Crystallization; D006046:Gold / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D010316:Particle Size; D012835:Silver Nitrate / Q000737:chemistry*
D007093:Imidazoles; D006046:Gold; D012835:Silver Nitrate