Impact of local compressive stress on the optical transitions of single organic dye molecules.

The ability to mechanically control the optical properties of individual molecules is a grand challenge in nanoscience and could enable the manipulation of chemical reactivity at the single-molecule level. In the past, light has been used to alter the emission wavelength of individual molecules or modulate the energy transfer quantum yield between them. Furthermore, tensile stress has been applied to study the force dependence of protein folding/unfolding and of the chemistry and photochemistry of single molecules, although in these mechanical experiments the strength of the weakest bond limits the amount of applicable force.

Energy transfer pathways in a rylene-based Triad.

Herein, a study on the excitation energy migration is reported for a newly synthesized Triad with a well-defined architecture consisting of a central terrylenediimide decorated with four perylenediimide and sixteen naphthalenemonoimide chromophores. Steady-state femto- and picosecond time-resolved spectroscopy were employed to unveil the excited states dynamics in solution. Compared with the results obtained from the corresponding model compounds, the Triad is an efficient light collector over the entire visible spectral range and the fluorescence occurs mostly from the core with a quantum yield as high as 60%.

Multichromophoric polyphenylene dendrimers: toward brilliant light emitters with an increased number of fluorophores.

Two routes for the introduction of highly fluorescent peryleneimide chromophores into the scaffolding of polyphenylene dendrimers via iterative Diels-Alder cycloadditions are presented. The key intermediates for the divergent dendrimer buildup were two cyclopentadienone branching units carrying two peryleneimides and two masked terminal alkynes. The difference between the two reagents is the mode of incorporation of the chromophores.

Synthesis of a bis(pyridyl)-substituted perylene diimide ligand and incorporation into a supramolecular rhomboid and rectangle via coordination driven self-assembly.

The synthesis of a bis(pyridyl)-substituted perylene diimide ligand and its incorporation into a supramolecular rhomboid and rectangle via platinum-mediated self-assembly is reported. Both ensembles are characterized by multinuclear NMR and electrospray ionization mass spectrometry. In addition, the UV/vis spectra of the ensembles exhibit displaced and enhanced absorptions relative to the starting ligand.