Structure transformation from Sierpiński triangles to chains assisted by gas molecules.

Li, Chao; Xu, Zhen; Zhang, Yajie; Li, Jie; Xue, Na; Li, Ruoning; Zhong, Mingjun; Wu, Tianhao; Wang, Yifan; Li, Na; Shen, Ziyong; Hou, Shimin; Berndt, Richard; Wang, Yongfeng; Gao, Song

Reversible transformations between fractals and periodic structures are of fundamental importance for understanding the formation mechanism of fractals. Currently, it is still a challenge to controllably achieve such a transformation. We investigate the effect of CO and CO2 molecules on Sierpiński triangles (STs) assembled from Fe atoms and 4,4″-dicyano-1,1′:3′,1″-terphenyl (C3PC) molecules on Au surfaces. Using scanning tunneling microscopy, we discover that the gas molecules induce a transition from STs into 1D chains. Based on density functional theory modeling, we propose that the atomistic mechanism involves the transformation of a stable 3-fold coordination Fe(C3PC)3 motif to Fe(C3PC)4 with an axially bonded CO molecule. CO2 causes the structural transformation through a molecular catassembly process.

SCANNING tunneling microscopy; DENSITY functional theory; SCANNING probe microscopy; TRIANGLES; MOLECULES

National Science Review, 2023, Vol 10, Issue 7, p1

2095-5138

Academic Journal

10.1093/nsr/nwad088