Self-assembly of polycyclic supramolecules using linear metal-organic ligands

Abstract

Coordination-driven self-assembly as a bottom-up approach has witnessed a rapid growth in building giant structures in the past few decades. Challenges still remain, however, within the construction of giant architectures in terms of high efficiency and complexity from simple building blocks. Inspired by the features of DNA and protein, which both have specific sequences, we herein design a series of linear building blocks with specific sequences through the coordination between terpyridine ligands and Ru(II). Different generations of polycyclic supramolecules (C1 to C5) with increasing complexity are obtained through the self-assembly with Cd(II), Fe(II) or Zn(II). The assembled structures are characterized via multi-dimensional mass spectrometry analysis as well as multi-dimensional and multinuclear NMR (1H, COSY, NOESY) analysis. Moreover, the largest two cycles C4 and C5 hierarchically assemble into ordered nanoscale structures on a graphite based on their precisely-controlled shapes and sizes with high shape-persistence.

Intra- and intermolecular self-assembly of a 20-nm-wide supramolecular hexagonal grid

“…As noted above, treatment of 4 with an additional two equivalents of Fe(ii) led to grid 5. This construct, with a calculated molecular weight of 65,790 Da, is to our knowledge one of the largest 2D discrete metallo-supramolecules prepared so far 13,23,24 . ESI-MS analysis revealed a series of peaks from 29+ to 66+ ( Fig.…”

“…8,9,19,20 ) or infinite coordination-based polymers 21,22 . Meso-sized (10-100nm) discrete architectures with specific sizes and shapes are rare 13,23,24 , probably due to the challenges associated with the fact that they are difficult to design and reliably synthesize, the intricate self-assembly processes required for their synthesis and difficulties in their characterization. Here we describe discrete two-dimensional (2D) ensembles in the 20-nmsize domain that have been produced by coordination-driven self-assembly.…”

Hydrogen and Halogen Bond Mediated Coordination Polymers of Chloro-Substituted Pyrazin-2-Amine Copper(I) Bromide Complexes

“…Unlike organic co-crystals, engineering inorganic compounds is dependent on two principals; primary coordination sphere (metal-ligand interactions) and secondary coordination sphere (non-covalent interactions) [11]. Despite several factors (e.g., pH, temperature) [12,13] could influence these two "parameters" for structurally diverse outcomes, modulation of networks based on the metal-ions geometry, organic ligands and their functional groups stand out in coordination chemistry research [14][15][16][17][18][19][20][21]. This fact is due to reproducible outcomes, that reflect the strong metal-ligand coordination bonds, and can be achieved with the judicious choice of organic ligands and metal-ions [14][15][16][17][18][19][20][21].…”

“…Despite several factors (e.g., pH, temperature) [12,13] could influence these two "parameters" for structurally diverse outcomes, modulation of networks based on the metal-ions geometry, organic ligands and their functional groups stand out in coordination chemistry research [14][15][16][17][18][19][20][21]. This fact is due to reproducible outcomes, that reflect the strong metal-ligand coordination bonds, and can be achieved with the judicious choice of organic ligands and metal-ions [14][15][16][17][18][19][20][21]. In this context, for example, O-and N-atoms are typical donors for the coordination bond formation; the former are derived from functional groups such as -COOH, -SO 3 H and phosphonates [22][23][24], and the latter primarily from N-heterocycles [25].…”

Blue light-induced low mechanical stability of ruthenium-based coordination bonds: an AFM-based single-molecule force spectroscopy study

“…Coordinative bonds are considerably weaker than covalent bonds but stronger than hydrogen bonding, van der Waal interactions, and hydrophobic interactions, and they are widely found in natural organisms. [3][4][5][6] They provide sufficient mechanical stability while acting as a sacricial motif to dissipate external force to protect covalent linkages from fracture. [7][8][9][10] These peculiar properties of coordination bonds endow natural organisms with both high strength and toughness for load-bearing processes and energy consumption, and have inspired the development of many articial materials.…”