Synthesis of Diphenylchalcogenophene Diboronic Acid Bis(pinacol) Esters and Halogen Photoelimination from Tellurium by Triplet–Triplet Annihilation

Abstract

The synthesis of diphenylthiophene‐, diphenylselenophene‐, and diphenyltellurophene‐based diboronic bis(pinacol) esters and their optoelectronic properties is reported. The addition of bromine to the borylated diaryltellurophene and subsequent photoelimination are investigated. The photochemical quantum yield of bromine photoelimination is (9.7±0.2) % at a 4.4 m trap (2,3‐dimethyl‐1,3‐butadiene) concentration. It is found that the bromine photoelimination reaction can also be driven by the incorporation of a triplet sensitizer through a triplet–triplet annihilation process.

Photoreductive Elimination of Chlorine from Antimony in an [SbPd]VII Complex

“…Emerging efforts in this area of photochemistry suggest that the photoreductive elimination of halogens can also be supported by redox active main group elements. Research in this area remains limited to derivatives featuring a Te­(IV) atom incorporated within the π-conjugated scaffold of tellurophenes . When flanked with electron-withdrawing substituents, such systems become very efficient platforms for the photoelimination of halogen which can occur with yields as high as 42% in the case of the dibromide of 2,5-bis­(pentafluorophenyl)­tellurophene .…”

Ring Opening of π-Delocalized 2,5-Diphenyltellurophene by Chemical or Self-Sensitized Aerobic Photooxidation

“…Materials containing the five-membered tellurium-containing heterocycle tellurophene have been receiving increasing attention for organic electronic applications such as solar cells, − organic field effect transistors, − and more recently solid-state phosphors. − Our group has been interested in studying the redox chemistry of tellurium as part of the conjugated tellurophene platform. In particular, we have studied the effect of halogen oxidation on the optoelectronic properties of 2,5-disubstituted conjugated tellurophenes in extensive detail. − In contrast to the tellurapyrylium system, the formation of the Te­(IV) tellurophene adducts leads to red-shifted absorption spectra. This is attributed to the introduction of charge transfer character in the excited state, which generally leads to a narrowing of the frontier molecular orbital energy gap.…”

Versatile telluracycle synthesis via the sequential electrophilic telluration of C(sp2)–Zn and C(sp2)–H bonds

“…Tellurophene has gained growing interest as a structural element of polymeric materials for organic electronics and other applications with features such as narrow band gaps, low LUMO levels, high charge carrier mobilities, the redox capability of Te, and Te–Te interactions. 1 , 2 Studies of tellurophene-containing small molecules focused on their redox and photochemical reactivity, 3 photoluminescence properties, 4 and anion recognition ability through chalcogen bonds 5 have also emerged ( Chart 1 ). In these studies, the synthesis and functionalization of substituted tellurophenes have been achieved using a variety of methods, such as the cyclization of 1,3-diyne with sodium telluride 6 and zirconacyclopentadiene transfer to TeCl 2 ·bpy.…”