Nanosystems Chemistry

>Bay-substituted perylene bisimide dye with an undistorted planar scaffold
and outstanding solid state fluorescence properties

M-J. Lin et al.
Chem. Commun. 2012, 48, 12050–12052
DOI:10.1039/c2cc36719j
Single crystal X-ray analysis reveals a flat perylene π-scaffold for a perylene bisimide bearing bulky 2,6-diphenylphenoxy substituents at the 1,7 bay positions. The flat structure provides sharp vibronic progressions in the absorption and fluorescence spectra, the sterical shielding outstanding fluorescence quantum yields in the solid state.

> Perylene Bisimide Dimer Aggregates:
Fundamental Insights into Self-Assembly by NMR and UV/Vis Spectroscopy

C. Shao et al.
Chem. Eur. J. 2012, 18, 13665–13677
DOI:10.1002/chem.201201661
The exclusive self-assembly of a novel perylene bisimide into π-stacked dimers was analyzed by NMR and UV/Vis spectroscopy. Solvent effects on the Gibbs free energy were elucidated and showed a pronounced nonlinearity in solvent mixtures originating from a further growth process into larger aggregates that occur in the absence of chloroform.

>Biosupramolecular Nanowires from Chlorophyll Dyes with Exceptional Charge-Transport Properties

S. Sengupta et al.
Angew. Chem. 2012, 124, 6484–6488; Angew. Chem. Int. Ed. 6378–6382
DOI:10.1002/anie.201201961

Conductive tubes: Self-assembled nanotubes of a bacteriochlorophyll derivative are reminiscent of natural chlorosomal light-harvesting assemblies. After deposition on a substrate that consists of a non-conductive silicon oxide surface (see picture, brown) and contacting the chlorin nanowires to a conductive polymer (yellow), they show exceptional charge-transport properties.

>Molecular Assemblies of Perylene Bisimide Dyes in Water

D. Görl, X. Zhang, F. Würthner
Angew. Chem. 2012, 124, 6434–6455; Angew. Chem. Int. Ed. 2012, 51, 6328–6348
DOI:10.1002/ange.201108690

Fascinating functional nanostrucures are formed in water by amphiphilic perylene bisimide dyes through strong hydrophobic interactions. This Review describes the current developments in the self-assembly of perylene bisimides in water to form π–π-stacked molecular aggregates.

>Halogen-Arene Interactions Assist in Self-Assembly of Dyes

U. Mayerhöffer, F. Würthner
Angew. Chem. 2012, 124, 5713–5717; Angew. Chem. Int. Ed. 2012, 51, 5615–5619
DOI:10.1002/anie.201200897

The "dye" is cast: An isodesmic self-assembly process of near-infared-absorbing, acceptor-substituted squaraine dyes, assisted by halogen–halogen and halogen–arene interactions, is observed in toluene. The aggregation process was monitored by UV/Vis/NIR absorption and NMR experiments, thus providing insight into the structural features (see figure; O red, I violet, N blue) as well as the binding strengths of the formed aggregates.

>Chiral J-Aggregates of Atropo-Enentiomeric Perylene Bisimides and Their Self-Sorting Behavior

Z. Xie, V. Stepanenko, K. Radacki, F. Würthner
Chem. Eur. J. 2012, 18, 7060–7070
DOI:10.1002/chem.201200089

Homochiral and heterochiral J-aggregates were created by nucleation-elongation assembly of atropo-enentiomerically pure and racemic perylene bisimides, which showed quite different morphological and optical properties. One dimensional helical nanowires with high photoluminescence efficiency were observed from the homochiral J-aggregates (see figure).

> Metallosupramolecular amphiphilic pi-systems

M. J. Mayoral Muñoz and G. Fernández
Chem. Sci. 2012, 3, 1395-1398
DOI:10.1039/c2sc01101h

Metallosupramolecular amphiphiles are emerging as a new class of adaptive materials with the ability to self-assemble into a wide variety of supramolecular structures through simultaneous pi-metallophilic and metal-ligand interactions.