Simulation Studies of the Self-Assembly of Halogen-Bonded Sierpinski Triangle Fractals

In this study, a coarse-grained lattice Monte Carlo model was used to investigate the formation of Sierpinski triangle (ST) fractals through self-assembly on a triangular lattice surface. In the simulations, both symmetric and asymmetric molecular building blocks can spontaneously form ST fractal patterns, although the mixture of enantiomers of asymmetric molecule is more difficult to self-organize into ST of a high order owing to the presence of a large variety of competing three-membered nodes. The formation of ST fractals is favored at low surface coverage and is sensitive to temperature. Furthermore, to test whether the assembly pathway and outcome could be controlled by molecular design, we guided the self-assembly process forming ST fractal into the otherwise disfavored self-assembled structures using templates different from the assembling molecules. The templates are designed to act as "catassemblers" that initiate the self-assembling but are excluded from the final assembled structure.