We have prepared a thermally activated delayed fluorescence (TADF) capable molecular system carrying halogen substituents at the carbazole units. The attachment of the halogen atoms considerably decreases the half-life of the delayed fluorescence. The effect is significant. The heavier the halogen, the greater the effect. Our materials have the shortest reported emissive lifetimes for TADF achieved to date. Intersystem crossing (ISC) is improved through the heavy atom effect, yet high quantum yields are achieved both in solution as well as in thin doped films. The simple and efficient synthesis of our targets uses inexpensive and easily obtained starting materials.

We herein describe synthesis and property evaluation of two aldehyde-appended nonconjugated distyrylbenzene polymers as amine sensing platforms and compare their performance to that of their monomers. The monomers and polymers were dissolved in organic solvents and spraydeposited onto silica gel and neutral alox TLC plates so as to give small strip-shaped sensor arrays. With these, differential amine detection was achieved; we find that a neutral silica gel support is better able to discern the amines than alox TLC plates.

Eight acceptor-substituted distyrylbenzene (DSB) derivatives were obtained by postfunctionalization of dialdehyde precursor 1 using Knoevenagel condensation. Solubility in a water/THF 9:1 mixture was achieved through the addition of branched oligoethylene glycol side chains. The acceptor compounds discriminate primary and secondary amines in aqueous solution. The fluorescence responses were analyzed by the multivariate analysis of variance (MANOVA) protocol, a statistical tool. In contrast to 1, the adducts show reactivity toward secondary and aromatic amines. Nitroolefin 2f is the most active dosimeter molecule. Reaction with amines is completed after less than 3 min, and the limit of detection (LOD) is improved by a factor of 10. Propylenediamine can be detected at 75 μM. This is a 10-fold improvement for the detection limit when compared to the detection limit of the starting dialdehyde.

We have prepared a series of water-soluble, pyridine-containing poly(aryleneethynylene)s (PAEs), consisting of alternating units of substituted ethynylpyridines and ethynylbenzenes. Water solubility is achieved by branched oligoethylene glycol (swallowtail) side chains. The fluorescence quantum yield (ϕ) of these PAEs was studied in dependence of their structure. The emissive quantum yield is not very dependent upon the number and position of the swallowtail substituents as long as their number suffices to dissolve the PAE in water. Attachment of a carboxylate group onto the pyridine unit decreases ϕ of the PAEs. All of the PAEs were metallo-reactive. Hg 2+ and Fe 3+ ions quench the fluorescence of the PAEs, while other metal cations (Cd 2+ , Zn 2+ , Cu + , Cu 2+ ) only quench the fluorescence of some of the PAEs. According to the Stern−Volmer quenching constants, some of the PAEs are more sensitive toward quenching than the well-documented dicarboxylate-PPEs.

Combining the molecular wire effect with a biphasic sensing approach (analyte in water, sensor-dye in 2-methyltetrahydrofuran) and a microfluidic flow setup leads to the construction of a mercury-sensitive module. We so instantaneously detect Hg(2+) ions in water at a 500 μM concentration. The sensor, conjugated non-water soluble polymer 1 (XFPF), merely supports dibutylaniline substituents as binding units. Yet, selective and sensitive detection of Hg(2+) -ions is achieved in water. The enhancement in sensory response, when comparing the reference compound 2 to that of 1 in a biphasic system in a microfluidic chip is >10(3) . By manipulation of the structure of 1, further powerful sensor systems should be easily achieved.