Tellura(benzo)bithiophenes: Synthesis, Oligomerization, and Phosphorescence

Abstract

A series of planar π-extended Te-containing heteroacenes, termed tellura(benzo)bithiophenes, were synthesized. This new structural class of heterocycle features a tellurophene ring fused to a benzobithiophene unit with aromatic side groups (either −C 6 H 4 i Pr or −C 6 H 4 OCH 3 ) positioned at the 2-and 5-positions of the tellurophene moiety. Although attempts to enhance molecular rigidity and extend ring-framework πdelocalization in a cumenyl (−C 6 H 4 i Pr)-capped tellura(benzo)bithiophene led to oxidation (and Te−C bond scission) to form a diene−one, the formation of an oligomeric tellura(benzo)bithiophene was possible via Kumada catalyst-transfer polycondensation (KCTP). Furthermore, one tellura(benzo)bithiophene derivative exhibits orange-red phosphorescence at room temperature in air when incorporated into a poly(methyl methacrylate) host; accompanying TD-DFT computations provided insight into a potential mechanism for the observed phosphorescence.

Rongalite in PEG-400 as a general and reusable system for the synthesis of 2,5-disubstituted chalcogenophenes

“…10 On the other hand, 2,5-diarylselenophenes can exhibit antioxidant and anticonvulsant properties, 11 antidepressant effects, 12 anticancer activities, 13 and they have also been described as a promising family of high-performance conducting polymers and small molecules for optoelectronic devices 14 exploiting the unique properties of the selenium atom, as well as the selenophene ring. 15 Similarly, as a lesser-explored class of π-extended chalcogenophenes, 2,5-diaryltellurophenes are a useful platform for polymeric 16 and molecular materials, 17 and anion recognition, 18 owing to their relevant photophysical properties and the ability of tellurium to adopt various stable oxidation states and provide strong intermolecular interactions (Fig. 1).…”

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“…More recently, Rivard and coworkers published a paper in which the complex Cp 2 Zr(py)(η 2 -Me 3 SiC 2 SiMe 3 ) was used to synthesize tellura(benzo)bithiophenes (Scheme 7). [10] Several planar π-extended tellura(benzo)bithiophenes were synthesized with a tellurophene ring fused to a benzobisthio-phene. In the 2-and 5-positions of the tellurophenes, aromatic substituents like À C 6 H 4 iPr or À C 6 H 4 OCH 3 are located.…”

“…More recently, Rivard and coworkers published a paper in which the complex Cp 2 Zr(py)(η 2 ‐Me 3 SiC 2 SiMe 3 ) was used to synthesize tellura(benzo)bithiophenes (Scheme 7). [10] …”