One‐Step Multicomponent Self‐Assembly of a First‐Generation Sierpiński Triangle: From Fractal Design to Chemical Reality

Abstract

A novel terpyridine-based architecture that mimics a first-generation Sierpiński triangle has been synthesized by multicomponent assembly and features tpy-Cd(II)-tpy connectivity (tpy=terpyridine). The key terpyridine ligands were synthesized by the Suzuki cross-coupling reaction. Mixing two different terpyridine-based ligands and Cd(II) in a precise stoichiometric ratio (1:1:3) produced the desired fractal architecture in near-quantitative yield. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and transmission electron microscopy.

Sierpiński-triangle fractal crystals with the C3v point group

“…It has been theoretically predicted that fractal frameworks comprising Sierpiń ski-triangle (ST) units could exhibit peculiar mechanical, electronic, and magnetic properties [2]. In this context, various fractals, including a first-generation ST, have been successfully synthesized in solutions through sophisticated design [3][4][5][6][7][8]. However, synthesis of larger fractals usually encounters difficulties due to their poor solubility.…”

Assembling molecular Sierpiński triangle fractals

“…Fractal patterns are very complicated and yet fascinating because of their importance in aesthetics, mathematics, science and engineering. Scientists have been struggling to build molecular fractals through various strategies, but only scattered and even fragmented untunable molecular fractals could be obtained with strong intermolecular interactions, such as covalent or coordination bonds in synthetic chemistry [2][3][4][5][6][7] .…”

Vertical Assembly of Giant Double‐ and Triple‐Decker Spoked Wheel Supramolecular Structures

“…For example, Newkome and co-workers reported the self-assembly of the first generation Sierpiński triangle fractal and hexagonal gasket. [14] Li and co-workers prepared two species of concentric hexagons using tetratopic pyridine and terpyridine ligands coordinating with metal ions. [15] Furthermore, a well-defined spiderweb-like ring-in-ring-in-ring superstructure was successfully synthesized through self-assembly of the multivalent terpyridine ligands with metal ions by Chan et al [16] It is worth noting that the above-mentioned super-structures were constructed by extending the structure in a 2D plane, just like the concentric ring system (Figure 1a).…”