Supramolecular Solids Research Articles

Reactions Between or Within Molecular Crystals

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Reactions Between or Within Molecular Crystals

Reactions that occur within or between molecular crystals, in particular those reactions that are activated by mechanical methods, are reviewed. The focus is on processes (whether intrasolid or intersolid) that are controlled primarily by supramolecular bonding, such as template cycloadditions, formation of inclusion compounds, reactions between molecular crystals by the reassembling of noncovalent bonds, and the formation of complexes and coordination compounds. It is proposed that solvent-free mechanochemical methods, for example, cogrinding, milling, and kneading, represent viable "green" routes for the preparation of novel molecular and supramolecular solids.

Structure and Photoluminescence of a Benzil Nanocolumn in a C‐Methylcalix[4]resorcinarene‐Based Framework.

A new framework based on C-methylcalix[4]resorcinarene and the flexible nonconjugated spacer 1,4-bis(imidazol-1yl-methyl)benzene encloses a large one-dimensional channel, containing benzil nanocolumns. Unlike in a previously reported series of benzil-containing supramolecular solids with conjugated linker molecules, benzil luminescence is observed, but the lifetime of 580 ns at 77 K is considerably shorter than the 145 μs reported for neat benzil at room temperature.

Structure and photoluminescence of a benzil nanocolumn in a C-methylcalix[4]resorcinarene-based framework.

A new framework based on C-methylcalix[4]resorcinarene and the flexible nonconjugated spacer 1,4-bis(imidazol-1yl-methyl)benzene encloses a large one-dimensional channel, containing benzil nanocolumns. Unlike in a previously reported series of benzil-containing supramolecular solids with conjugated linker molecules, benzil luminescence is observed, but the lifetime of 580 ns at 77 K is considerably shorter than the 145 micros reported for neat benzil at room temperature.

Symmetry Mismatching as a Tool in the Synthesis of Complex Supramolecular Solids with Multiple Cavities

Rotational symmetry of different parity of node and linker molecules has been used as a strategy in the synthesis of two architectural isomers with very different frameworks but identical cavities, both based on 1,3,5-tri(4-pyridyl)-2,4,6-triazine and C-methylcalix[4]resorcinarene. One of the two cavities in each of the solids has an unusual pentagonal shape.

Exploiting Complementary Second-sphere Effects in Supramolecular Coordination Solids

In the design of extended supramolecular solids, reliable synthons are a valuable commodity. This work concerns the complementary second-sphere coordination interactions between a highly preorganized hexasulphonated ligand, L, and aquated metal ions. Four second-sphere inclusion complexes [M(H2O)6]2 L ·(S)3 (M/S: Mg/acetone, 1; Zn/acetone, 2, Mg/dioxane, 3; Zn/dioxane, 4) and three extended networks {[(M(H2O)3)2(L)]·(H2O)14.5}∞ (M=Cr, 5; Fe, 6; Al, 7) have been structurally characterized by X-ray crystallography. The second-sphere effects on the stabilization of the primary coordination sphere are illustrated by TGA experiments. In these assemblies, the potential of a new supramolecular synthon is illustrated, that being the complementary hydrogen-bonding interaction between cis-aquo ligands and sulphonate oxygen atoms.

Assembly of functional supramolecular solids from metal and organic building blocks

Assembly of functional supramolecular solids from metal and organic building blocks

Crystal engineering, solid state spectroscopy and time-resolved diffraction

The use of calixarene-based supramolecular solids in spectroscopy and time-resolved crystallography is discussed. A series of solids with, as guests, benzophenone, benzil, decamethylruthenocene and a binuclear Rh cationic complex have been synthesized and analyzed. The excited state lifetimes that have been measured show a pronounced dependence on the molecular environment.

The Host Guest Co-Crystal Approach to Supramolecular Structure

A host-guest co-crystal approach to supramolecular structure has been developed. Molecular functionalities have been identified that will self assemble via hydrogen bonds to give one dimensional α-networks with defined intermolecular distances. Host molecules based on these functionalites can be co-crystallized with guest molecules, the characteristic distance defined by the host is thus imposed on the guest. Using this strategy, functional supramolecular solids can be prepared. One molecule, the host determines the structure, while a second molecule, the guest, provides the function.

The chair conformation of C-methylcalix[4]resorcinarene in a novel, stepped, supramolecular framework

The previously unobserved chair conformation of C-methylcalix[4]resorcinarene has been found in three different supramolecular solids, prepared by hydrothermal synthesis. The existence of the chair, crown and flattened cone conformations of C-methylcalix[4]resorcinarene demonstrates the dependence of the molecular conformation upon the templating molecules, and upon the specifics of the crystallization process. A novel, three-dimensional framework capable of including guest molecules is described.

Silver(I)−Polynitrile Network Solids for Anion Exchange: Anion-Induced Transformation of Supramolecular Structure in the Crystalline State

Novel supramolecular solids whose topologies depend on the counteranion, [Ag(C14H20N6)(NO3)] (1), [Ag(C14H20N6)]CF3SO3 (2), and [Ag(C14H20N6)]ClO4 (3), have been prepared by the self-assembly of Ag...