Self-assembly of nanotubes and ordered mesostructures using weak interactions

<p>Two simple organic compounds, 5-nitroisophthalic acid (npa) and 4,4′-bipyridine (bpy), were used as building blocks for supramolecular self-assembly by hydrothermal synthesis. SEM, TEM, and XRD were used to analyse the multi-step assembly process in which npa and bpy assembled into nanotubes (or nanobelts) of about 30–100 nm in diameter and several millimetres in length and microtubes (or microbelts). The tubes then further assembled to form complex ordered structures, such as pom-pom-shaped and flower-like mesostructures.</p> <p>Hydrothermal-promoted, self-assembly of 5-nitroisophthalic acid and 4,4′-bipyridine generates nanotubes possessing a diameter of ~30–100 nm diameter and length of several millimeters as well as novel pom-pom- and flower-shaped mesostructures.</p

Stoichiometric Self-Assembly of Isomeric, Shape-Persistent, Supramacromolecular Bowtie and Butterfly Structures

Two novel macromolecular constitutional isomers have been self-assembled from previously unreported terpyridine ligands in a three-component system. The terpyridine ligands were synthesized in high yields via a key Suzuki coupling. Restrictions of the possible outcomes for self-assembly ultimately provided optimum conditions for isolation of either a molecular bowtie or its isomeric butterfly motif. These isomers have been characterized by ESI-MS, TWIM-MS, ¹H NMR, and ¹³C NMR. Notably, these structural isomers have remarkably different drift times in ion mobility separation, corresponding to different sizes and shapes at high charge states

Probing a Hidden World of Molecular Self-Assembly: Concentration-Dependent, Three-Dimensional Supramolecular Interconversions

A terpyridine-based, concentration-dependent, facile self-assembly process is reported, resulting in two three-dimensional metallosupramolecular architectures, a bis-rhombus and a tetrahedron, which are formed using a two-dimensional, planar, tris-terpyridine ligand. The interconversion between these two structures is concentration-dependent: at a concentration higher than 12 mg mL^–1, only a bis-rhombus, composed of eight ligands and 12 Cd²⁺ ions, is formed; whereas a self-assembled tetrahedron, composed of four ligands and six Cd²⁺ ions, appears upon sufficient dilution of the tris-terpyridine-metal solution. At concentrations less than 0.5 mg mL^–1, only the tetrahedron possessing an <i>S</i>₄ symmetry axis is detected; upon attempted isolation, it quantitatively reverts to the bis-rhombus. This observation opens an unexpected door to unusual chemical pathways under high dilution conditions

Terpyridine-Based, Flexible Tripods: From a Highly Symmetric Nanosphere to Temperature-Dependent, Irreversible, 3D Isomeric Macromolecular Nanocages

A three-dimensional, highly symmetric sphere-like nanocage was synthesized using a terpyridine (tpy)-based, flexible tris-dentate ligand and characterized by single crystal X-ray analysis. To introduce more rigidity, one of the tpy units of the tris-dentate ligand was preblocked by stable 2+-tpy> connectivity to form the corresponding Ru²⁺-dimer. The complexation between Ru²⁺-dimer and Fe²⁺ demonstrates an unexpected temperature-dependent assembly between two irreversible isomeric 3D nanocages. Investigation of the coordination process and structural configurations of the metal–ligand framework, affected by the introduction of rigidity and in the presence of external stimuli (temperature), is reported

Terpyridine-Based, Flexible Tripods: From a Highly Symmetric Nanosphere to Temperature-Dependent, Irreversible, 3D Isomeric Macromolecular Nanocages

A three-dimensional, highly symmetric sphere-like nanocage was synthesized using a terpyridine (tpy)-based, flexible tris-dentate ligand and characterized by single crystal X-ray analysis. To introduce more rigidity, one of the tpy units of the tris-dentate ligand was preblocked by stable 2+-tpy> connectivity to form the corresponding Ru²⁺-dimer. The complexation between Ru²⁺-dimer and Fe²⁺ demonstrates an unexpected temperature-dependent assembly between two irreversible isomeric 3D nanocages. Investigation of the coordination process and structural configurations of the metal–ligand framework, affected by the introduction of rigidity and in the presence of external stimuli (temperature), is reported

Controlled Interconversion of Superposed-Bistriangle, Octahedron, and Cuboctahedron Cages Constructed Using a Single, Terpyridinyl-Based Polyligand and Zn²⁺

Metallomacromolecular architectural conversion is expanded by the characterization of three different structures. A quantitative, single-step, self-assembly of a shape-persistent monomer, containing a flexible crown ether moiety, gives an initial Archimedean-based cuboctahedron that has been unequivocally characterized by 1D and 2D NMR spectroscopy, mass spectrometry, and collision cross section analysis. Both dilution and exchange of counterions, transforms this cuboctahedron into two identical octahedrons, which upon further dilution convert into four, superposed, <i>bis</i>trianglar complexes; increasing the concentration reverses the process. Ion binding studies using the cuboctahedral cage were undertaken

Amphiphilic [tpy-M^II-tpy] metallotriangles: synthesis, characterisation and hierarchical ordering

<p>Long chain (C₁₆) alkylated metallocycles are synthesised and characterised. Their ordered aggregation was studied via TEM to gauge to the effects of molecular topology, solvent, counterion and metal centre(s) on morphology and nanoscale structure. The results indicate that their amphiphilicity significantly enhanced their self-ordering characteristics relative to controls and enabled the formation of nanoscale structures. Similar ordering was observed for both labile and non-labile analogues with SAXD showing comparable d-spacing values, suggesting the presence of intramolecular π–π stacking. Effect of counterion and solvent was studied with the non-labile system. Nanotubular, ribbon, or sheet-like structures were afforded depending upon conditions.</p

Construction of a Highly Symmetric Nanosphere via a One-Pot Reaction of a Tristerpyridine Ligand with Ru(II)

A three-dimensional, highly symmetric, terpyridine-based, spherical complex was synthesized via the coordination of four novel, trisdentate ligands and six Ru²⁺ ions, and it exhibits excellent stability over a wide range of pH values (1–14). Structural confirmation was obtained by NMR and ESI-TWIM-MS