Paddle wheels and pillars : Layered 3D metal–organic frameworks comprised of paddle‐wheel coordination units are constructed under a variety of conditions to incorporate bridging ligands (as illustrated) that impart desired properties, such as guest‐exchange behavior, luminescence, microporosity, and stability, to the material.
Novel thin‐film materials have been produced from indolo[3,2,1‐jk]carbazole (see picture). These are conducting and redox‐active and, unusually, consist of three distinct covalently coupled luminescent dimer species, consistent with a specific radical‐cation coupling mechanism.
Cohesion matters! The correlation between the conformational rigidity of the polyelectrolyte and the size and stability of the globular assembly is discussed in this review article. Some examples of models for the association of polyelectrolytes to globular assemblies are shown here.
Roll up : A peptide–dendron hybrid (PDH) is capable of self‐assembling into either a soluble nanotube or an amyloid‐like fibrillar network. The structures interconvert on adjusting the salt concentration or pH value. Their hydrophobic interfaces efficiently encapsulate hydrophobic molecules in water which can then be released by lowering the pH value.
Join or attack : meso‐Cyclam‐substituted heptamethine cyanine dye 1 responds very differently to the presence of metal ions and protons. Whereas the former are embraced in a host–guest complex, the latter attack the cyanine π system (see picture). In the presence of CuII, 1 selectively forms near‐infrared absorbing aggregates in buffered solution that allow the determination of citrate by using colourimetry.
A remarkable twosome : Four‐coordinate square‐planar complexes based on [Zn(salen)] derivatives are conveniently captured inside a crystal matrix using a supramolecular protecting strategy (see figure). The four‐coordinate species is accompanied by a five‐coordinate complex that binds an axial ligand able to hydrogen bond to an N‐heterocycle positioned in the axial region of the coordinative unsaturated derivative. The size of the N‐heterocycle is a decisive stabilization parameter.
Insider dealing : Self‐assembled hosts applied as “molecular flasks” can alter and control the reactivity and properties of molecules encapsulated within their well‐defined, confined spaces. A variety of functional hosts of differing sizes, shapes, and utility have been prepared by using the facile and modular concepts of self‐assembly.
Size matters: Nanometer‐sized gaps in aggregates of silver nanoparticles are generated by covering the nanoparticle surface with a bilayer of cetyltrimethylammonium bromide. The nanometer‐ to micrometer‐sized wells are lithographically generated on polydimethylsiloxane surfaces. The wells filled with the modified nanoparticles (see picture) and the effect of the aggregate size on SERS enhancement are investigated.
Easily disrupted : Micelles of a new amphiphilic block copolymer that bear coumarin groups are sensitive to near infrared light by two‐photon absorption of the chromophore. Disruption of the micelles under irradiation at 794 nm results in release of both photocleaved coumarin and encapsulated nile red from the hydrophobic core of micelle into aqueous solution, which results in opposing changes in fluorescence emission intensity.
Down to the wire : Photobleaching dynamics show the exciton delocalization length of directly linked porphyrin arrays (see picture) to be about four or five porphyrin units at the single‐molecule level. This result provides a better understanding of how light‐signal transmission occurs in the solid state and gives a perspective for the porphyrin arrays to be used as single‐molecule photonic wires.
