Incorporating selenium or tellurium into photoactive species imparts new photophysical properties that may be exploited in materials applications.

Organic emitters exhibiting delayed fluorescence (DF) are promising luminescent materials for next-generation organic light-emitting diodes (OLEDs). Faster intersystem crossing rates and shorter emission lifetimes can be achieved in luminescent molecules through the incorporation of heavy atoms, which enhance spin−orbit coupling and promote intersystem crossing between singlet and triplet states. DF molecules often contain a sulfur atom, and reports of selenium-containing DF OLEDs also exist. However, the literature lacks a direct exploration of the effect of spin−orbit coupling on reverse intersystem crossing in a delayed fluorescence emitter by the substitution of selenium for sulfur. Here we show that substitution of selenium for sulfur in a modified thioxanthenone-triphenylamine analogue increases the rate of forward intersystem crossing by a factor of over 250 and the rate of reverse intersystem by a factor of 22. We attribute the increased rates to enhanced spin−orbit coupling from heavy atom substitution, and computational and electron spin resonance studies support this. This work provides an insight into future molecular design strategies for heavy-atomcontaining, DF emitters.

In undergraduate chemistry curricula that include computational modeling, students may gain first-hand experience in both introductory and advanced applications of this technique. However, although students can be exposed to the predictive power of computational work, its capabilities are often limited to determining the intrinsic properties of the molecules being modeled, rather than potential applications of functional materials intended for devices. To address this disconnect, we have designed and implemented a computational module for upper-year undergraduate and graduate students within an organic materials chemistry course. The module is conducted over 7 weeks and is based on an increasingly important phenomenon in organic photochemistry known as thermally activated delayed fluorescence (TADF). TADF emitters are ideal for display technologies (organic light emitting diodes). Students connect molecular structure with predicted properties and function by performing computational modeling on known TADF emitters, before correlating their results with the experimental performance of the emitters. They also address potential limitations of density functional theory (DFT) that they have not encountered previously, attempt to rationalize outlying data points based on content presented in class, and summarize their calculations and conclusions in a communications-style manuscript. Overall, students learn how DFT can be used to inform molecular materials chemistry and engineering as well as identify some limitations of in silico design.

The monoanion of dihydrogenated corannulene isolated in the form of its potassium salt, namely tris(diglyme-κ(3)O,O',O'')potassium hexacyclo[11.5.2.0(4,17).0(7,16).0(10,15).0(14,18)]icosa-1,3,5,7(16),8,10(15),11,13,17-nonaenide, [K(C6H14O3)3](C20H12), has been structurally characterized for the first time. The X-ray study confirms the previous NMR spectroscopic prediction that the two H atoms are attached to the same six-membered ring to form 1,2-dihydrocorannulene, thus destroying the aromaticity of only one arene ring of the corannulene core. The direct comparison of (C20H12)(-) with the parent corannulene anion, (C20H10)(-), is provided to illustrate the geometry perturbations caused by rim hydrogenation.

An asymmetric thiol-modified tellurophene was designed and synthesized, and the ability of the compound to form a monolayer on a gold electrode was confirmed. The surface-active tellurophene was synthesized using Cadiot–Chodkiewicz coupling followed by ring closing and thiol modification. The tellurophene compound forms a monolayer on gold surfaces from a concentrated solution within 24 h. The ability of the compound to conjugate to gold is confirmed by X-ray photoelectron spectroscopy (XPS). A surface blocking experiment was used to evaluate the extent of formation of a monolayer on a gold electrode.