Self-Assembly of Extended Head-to-Tail Triangular Pt₃ Macrocycles into Nanotubes

Abstract

New pyridylsalicylaldimine-based ligands with extended conjugation have been synthesized. The reaction of these ligands with KPtCl yielded triangular Pt macrocycles rather than the anticipated Pt macrocycles. The macrocycles have been analyzed in solution by variable-temperature and variable-concentration H NMR, NOESY, and DOSY spectroscopy studies. These investigations show that the macrocycles aggregate at room temperature in solution by an entropy-driven process. In the solid state, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and transmission electron microscopy studies show that the macrocycles aggregate into nanotubular structures. Triangular platinum-containing macrocycles with the expanded pyridylsalicylaldimine ligands are promising for constructing nanotubes and discotic liquid crystals.

Enforced Tubular Assembly of Electronically Different Hexakis(m-Phenylene Ethynylene) Macrocycles: Persistent Columnar Stacking Driven by Multiple Hydrogen-Bonding Interactions

“…Organic nanotubes offer unique advantages such as ready functionalization, versatile compatibility, and modular molecular recognition. Among known strategies, ,− the stacking of cavity-containing building blocks ,− provides a conceptually straightforward route for constructing organic nanotubes. Such an approach combines the high efficiency of self-assembly with the synthetic availability and modifiability of small molecules.…”

“…Such an approach combines the high efficiency of self-assembly with the synthetic availability and modifiability of small molecules. Examples of tubular stacks include those based on cyclic peptides, cyclic oligosaccharides, metallo-macrocycles, cyclic oligo­(amide/urea)­s, cyclic aromatic oligoamides, and aromatic oligoamide foldamers …”

Recent Advances in the Synthesis and Applications of Nitrogen-Containing Macrocycles

“…Nitrogen and oxygen atoms could also serve as electron-donor centers for the construction of platinum-containing macrocycles that could be used as stable catalysts. A new salicylaldehyde moiety containing a ligand with an extended conjugation multiple-bond system was synthesized, and a [3 + 3] macrocycle was formed by a reaction with K 2 PtCl 4 ( Figure 40 ) [ 68 ].…”

Chiral nanotubes self-assembled from discrete non-covalent macrocycles

“…Metals can also be used to construct macrocycles and to form tubular structures. [59][60][61][62][63][64][65] An interesting example published also by Lee and co-workers describes a stimuli-responsive supramolecular structure able to be rearranged into metalorganic nanotubes with the addition of metal ions taking advantage of pyridine specific coordination to Ag (I) ions (Fig. 10).…”