Packing Biomolecules into Sierpiński Triangles with Global Organizational Chirality
Chao Li, Ruoning Li, Zhen Xu, Jie Li, Xue Zhang, Na Li, Yajie Zhang, Ziyong Shen, Hao Tang, Yongfeng Wang
Abstract
Fractals are found in nature and play important roles in biological functions. However, it is challenging to controllably prepare biomolecule fractals. In this study, a series of Sierpiński triangles with global organizational chirality is successfully constructed by the coassembly of l-tryptophan and 1,3-bi(4-pyridyl)benzene molecules on Ag(111). The chirality is switched when replacing l-tryptophan by d-tryptophan. The fractal structures are characterized by low-temperature scanning tunneling microscopy at the single-molecule level. Density functional theory calculations reveal that intermolecular hydrogen bonds stabilize the Sierpiński triangles.