Using light intensity to control reaction kinetics and reversibility in photomechanical crystals.

4-Fluoro-9-anthracenecarboxylic acid () is a thermally reversible (T-type) photomechanical molecular crystal. The photomechanical response is driven by a [4 + 4] photodimerization reaction, while the photodimer dissociation determines the reset time. In this paper, both the chemical kinetics of dimer dissociation (using a microscopic fluorescence-recovery-after-photobleaching experiment) and mechanical reset dynamics (by imaging bending microneedles) for single crystals are measured.

Boosting the Heavy Atom Effect by Cavitand Encapsulation: Room Temperature Phosphorescence of Pyrene in the Presence of Oxygen.

A deep cavitand is used to encapsulate the aromatic molecule pyrene in its interior while also binding Tl ions with its terminal carboxylates. Steady-state and time-resolved spectroscopic experiments, along with quantum yield measurements, quantify the enhancements of intersystem crossing and room temperature phosphorescence due to cavitand encapsulation. These results are compared to those obtained for pyrene contained in sodium dodecyl sulfate micelles, which is the usual system used to generate room temperature phosphorescence.

Site selective reading of epigenetic markers by a dual-mode synthetic receptor array.

Variably functionalized self-folding deep cavitands form an arrayed, fluorescent indicator displacement assay system for the detection of post-translationally modified (PTM) histone peptides. The hosts bind trimethyllysine (KMe) groups, and use secondary upper rim interactions to provide more sensitive discrimination between targets with identical KMe binding handles. The sensor array uses multiple different recognition modes to distinguish between miniscule differences in target, such as identical lysine modifications at different sites of histone peptides.

Exciplex-Sensitized Triplet-Triplet Annihilation in Heterojunction Organic Thin-Film.

A new concept for organic light-emitting diodes (OLEDs) is presented, which is called exciplex-sensitized triplet-triplet annihilation (ESTTA). The exciplex formed at the organic heterojunction interface of 4,4',4″-tris(N-3-methyphenyl-N-phenyl-amino) triphenylamine and 9,10-bis(2'-naphthyl) anthracene (ADN) is used to sensitize the triplet-triplet annihilation (TTA) process on the ADN molecules. This results in a turn-on voltage (2.

Self-Aggregating Deep Cavitand Acts as a Fluorescence Displacement Sensor for Lysine Methylation.

A dual-mode aggregative host:guest indicator displacement sensing system has been created for the detection of trimethylated peptides and determination of histone demethylase activity. The combination of selective recognition of suitably sized trimethylammonium salts and reversible lipophilic aggregation of the host:guest complex provides a unique quenching mechanism that is not only dependent on affinity for sensitivity but the lipophilicity of the indicator. In addition, aggregation can be controlled by the application of chaotropic anions in the mixture, allowing a second level of discrimination between hard lysine groups and softer trimethyllysines.