3-Ligated Phenothiazinyl-terephthalonitrile Dyads and Triads - Synthesis, Electronic Properties, Delayed Fluorescence and Electronic Structure.

The bromine-lithium exchange-borylation-Suzuki sequence efficiently furnishes phenothiazine-terephthalonitrile donor-acceptor dyads and triads in high yields. In contrast to most phenothiazine-acceptor conjugates the title compounds are ligated in p-position to the phenothiazine nitrogen atom. Moreover, the acceptors are either directly linked or ligated by an arylene bridge and p-anisyl N-substituents on the phenothiazine are chosen to lock the tricycle into an intra-configuration.

A Thermally Activated Delayed Fluorescence Emitter Investigated by Time-Resolved Near-Infrared Spectroscopy.

Emitters for organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) require small singlet (S )-triplet (T ) energy gaps as well as fast intersystem crossing (ISC) transitions. These transitions can be mediated by vibronic mixing with higher excited states S and T (n=2, 3, 4, …). For a prototypical TADF emitter consisting of a triarylamine and a dicyanobenzene moiety (TAA-DCN) it is shown that these higher states can be located energetically by time-resolved near-infrared (NIR) spectroscopy.