Structure transformation from Sierpinski triangles to chains assisted by gas molecules

Structure transformations from fractals to chains are realized by the coassemby of carbon monoxide and catassembly of carbon dioxide. 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 Sierpinski triangles (STs) assembled from Fe atoms and 4,4 & DPRIME;-dicyano-1,1 & PRIME;:3 & PRIME;,1 & DPRIME;-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.

Automated summary

Structure transformations from fractals to chains are achieved through the coassembly of carbon monoxide and the catassembly of carbon dioxide. Reversible transformations between fractals and periodic structures are important for understanding fractal formation, but controllably achieving such transformations remains a challenge. We investigate the effect of CO and CO2 molecules on Sierpinski triangles assembled from Fe atoms and C3PC molecules on Au surfaces, and discover that gas molecules induce a transition from STs into 1D chains. Based on density functional theory modeling, 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.