From chemical gardens to chemobrionics

Chemical gardens in laboratory chemistries ranging from silicates to polyoxometalates, in applications ranging from corrosion products to the hydration of Portland cement, and in natural settings ranging from hydrothermal vents in the ocean depths to brinicles beneath sea ice. In many chemical-garden experiments, the structure forms as a solid seed of a soluble ionic compound dissolves in a solution containing another reactive ion. In general any alkali silicate solution can be used due to their high solubility at high pH. The cation should not precipitate with the counterion of the metal salt used as seed. A main property of seed chemical-garden experiments is that initially, when the fluid is not moving under buoyancy or osmosis, the delivery of the inner reactant is diffusion controlled. Another experimental technique that isolates one aspect of chemical-garden formation is to produce precipitation membranes between different aqueous solutions by introducing the two solutions on either side of an inert carrier matrix. Chemical gardens may be grown upon injection of solutions into a so-called Hele-Shaw cell, a quasi-two-dimensional reactor consisting in two parallel plates separated by a small gap

A novel copper (II) metallacycle as a building block for the assembly of an extended supramolecular array containing channels and helical chains

Complexation of copper (II) perchlorate with <i>cis,cis</i>-1,3,5-cyclohexanetricarboxylic acid (CTA) and <i>cis,trans</i>-1,3,5-triaminocyclohexane (<i>trans</i>-tach) in the presence of triethylamine leads to the formation of a dinuclear metallacycle; [Cu<sub>2</sub>(<i>trans</i>-tach)<sub>2</sub> (CTA)<sub>2</sub>] · 14H<sub>2</sub>O (<b>1</b>). The crystal structure of <b>1</b> shows an extended hydrogen bonded network comprising linear chains of metallacycles running perpendicular to solvent occupied channels

Facile synthesis and structures of infinite one-dimensional silver(I) coordination polymers

The synthesis and characterization of the isolated, infinite tubular coordination polymers {[Ag(<i>cis</i>-tach)]ClO<sub>4</sub>}<sub>∞</sub> (<b>1</b>), {[Ag(<i>trans</i>-tach)]ClO<sub>4</sub>}<sub>∞</sub> (<b>2</b>) and {[Ag(<i>cis</i>-tach)]BF<sub>4</sub>}<sub>∞</sub> (<b>3</b>) has been achieved with the isomers <i>cis,cis</i>-1,3,5-triaminocyclohexane and <i>cis,trans</i>-1,3,5-triaminocyclohexane. Each new material has been fully characterized by single crystal X-ray diffraction, NMR, IR and elemental analysis. Compounds <b>1</b>–<b>3</b> form definite channels by the trigonal planar coordination of silver(I) metal centres to rigid, aliphatic triamino ligands, forming 4<sup>2</sup>·6 topological networks

Trading templates: Supramolecular transformations between {Co-13(II)} and {Co-12(II)} nanoclusters

'Nuclearity switching' from a {Co-13} supercluster to a {Co-12} species via the addition of Co-3(2-) anions is reported and can be traced in solution using electrospray MS techniques. In addition, cryospray MS can be used to identify the entire cluster in solution despite the relative lability of its constituents

Pentadecadentate chelating ligands as building blocks for a {Fe<SUB>6</SUB>} cage with 12 exo-coordinated sodium cations

Complexation of the highly branched, pentadecadentate chelating ligand &lt;I&gt;cis&lt;/I&gt;,&lt;I&gt;cis&lt;/I&gt;-1,3,5-cyclohexanetriamine-&lt;I&gt;N&lt;/I&gt;,&lt;I&gt;N&lt;/I&gt;,&lt;I&gt;N&lt;/I&gt;',&lt;I&gt;N&lt;/I&gt;',&lt;I&gt;N&lt;/I&gt;' ',&lt;I&gt;N&lt;/I&gt;' '-hexaacetic acid (H&lt;SUB&gt;6&lt;/SUB&gt;&lt;B&gt;L&lt;/B&gt;) with iron(III) and sodium cations in the presence of carbonate anions leads to the formation of an {Fe&lt;SUB&gt;6&lt;/SUB&gt;L&lt;SUB&gt;2&lt;/SUB&gt;} cluster comprising an {Fe&lt;SUB&gt;6&lt;/SUB&gt;} cage linked by 12 exo-coordinated sodium cations to form an extended 3D array

Supramolecular Architectures of Copper(II) Perchlorate Complexes of cis,trans-1,3,5-Triaminocyclohexane Assembled Exploiting the Delicate Balance Between Weak and Strong Interactions

The complexation of copper(1) perchlorate with cis,trans-1,3,5-triamino-cyclohexane (trans-tachH) yields four related mononuclear complexes, [Cu(traus-tachH)(2)](CIO4)(4)center dot(H2O) (1),[Cu(trans-tachH)(2)](CIO4)(4)center dot 2MeOH (2), [Cu(trans-tachH)(2)(CIO4)](CIO4)(3) (3) and [Cu(trans-tach)(trans-tachH)(CIO4)(2)](CIO4)center dot H2O (4). These complexes only differ with respect to ligand protonation, solvent coordination / content, and counterion binding, yet these small differences manifest as vast differences in the supramolecular structures, and we also show that certain crystalline phases of these four compounds persist for different lengths of time in the mother liquor

Unveiling the transient template in the self-assembly of a molecular oxide nanowheel

Self-assembly has proven a powerful means of preparing structurally intricate nanomaterials, but the mechanism is often masked by the common one-pot mixing procedure. We employed a flow system to study the steps underlying assembly of a previously characterized molybdenum oxide wheel 3.6 nanometers in diameter. We observed crystallization of an intermediate structure in which a central {Mo&lt;sub&gt;36&lt;/sub&gt;} cluster appears to template the assembly of the surrounding {Mo&lt;sub&gt;150&lt;/sub&gt;} wheel. The transient nature of the template is demonstrated by its ejection after the wheel is reduced to its final electronic state. The template’s role in the self-assembly mechanism is further confirmed by the deliberate addition of the template to the reaction mixture, which greatly accelerates the assembly time of the {Mo&lt;sub&gt;150&lt;/sub&gt;} wheel and increases the yield

Following the self assembly of supramolecular MOFs using X-ray crystallography and cryospray mass spectrometry

We describe the ligand directed self assembly of two mesoscopic supramolecular MOF architectures based upon the rigid ligand cis, trans-1,3,5-triaminocyclohexane with copper(II) salts. The use of copper fluoride results in the assembly of an unprecedented cubic 3D network with 1 nm void spaces while the use of copper sulfate yields a hexagonal 3D layered network containing nanotubes which are 1.5 nm in diameter. Further, experiments probing the self assembly of the structures after complexation using cryospray mass spectrometry show it is possible to follow the nucleation events that lead to the supramolecular MOFs, and this opens up a new avenue for the direct observation and control of the assembly of complex inorganic architectures