Fig. 4: Helical assembly of Ag40 and S-Ag40 supported by the diverse non-covalent interactions in their supercrystals.
a Self-assembly of Ag40 NCs into a triple-helical structure. Color codes: yellow, red, and turquoise, nanowheels in the different strands. b Helical linear chain of the triple-helical superstructure oriented and connected by two different surface motif pairs of Ag40 (A1/D1 and B1/C1). c Four types of motif matching between the neighboring nanowheels in the Ag40 supercrystal. d Intermolecular interactions of the two different surface motif pairs of Ag40, including π−π stacking (dark red), hydrogen bonding (C‒H···F, blue; and C/N‒H···O, pink), and C−H···π (black) interactions. e Self-assembly of S-Ag40 NCs into a double-helical structure. Color codes: pale blue and tan, nanowheels in the different strands. f Helical linear chain of the double-helical superstructure is orientally connected by two different surface motif pairs of S-Ag40 (A2/C2 and B2/D2). g Four types of motif matching between neighboring nanowheels in the S-Ag40 supercrystal. h Intermolecular interactions of two different surface motif pairs of S-Ag40, A2/C2: HQL-2-S···NO3‒···H2O···NO3‒···HQL-2-S hydrogen bonding path supported by C/N‒H···O (pink) and O‒H···O (dark blue); B2/D2: π−π stacking (dark red) interactions and hydrogen bonding (C/N‒H···O, pink). Color codes: Ag green, S yellow, C gray, N blue, F cyan, O red, H white.
