Dithiazolo[5,4‐b:4′,5′‐d]phosphole: A Highly Luminescent Electron‐Accepting Building Block

Abstract

A family of highly emissive dithiazolo[5,4-b:4',5'-d]phospholes has been designed and synthesized. The structures of two trivalent P species, as well as their corresponding P oxides, have been confirmed by X-ray crystallography. The parent dithiazolo[5,4-b:4',5'-d]phosphole oxide exhibits strong blue photoluminescence at λem = 442 nm, with an excellent quantum yield efficiency of ϕPL = 0.81. The photophysical properties of these compounds can be easily tuned by extension of the conjugation and modification of the phosphorus center. Compared with the established dithieno[3,2-b:2',3'-d]phosphole system, the incorporation of electronegative nitrogen atoms leads to significantly lowered frontier orbital energy levels, as validated by both electrochemistry and theoretical calculations, thus suggesting that the dithiazolo[5,4-b:4',5'-d]phospholes are valuable, air-stable, n-type conjugated materials. These new building blocks have been further applied to the construction of an extended oligomer with fluorene. Extension of the dithiazolophosphole core with triazole units through click reactions also provides a suitable N,N-chelating moiety for metal binding and a representative molecular species was successfully used as a selective colorimetric and fluorescent sensor for Cu(II) ions.

Bithiazole: An Intriguing Electron‐Deficient Building for Plastic Electronic Applications

“…The bithiazole building block however is not only of interest for air‐stable n‐type semiconductors, but some derivatives have shown promising emissive properties . Baumgartner and co‐workers were interested in combining the excellent photophysical properties of dithienophosphole with the high electron affinity of thiazole‐based building blocks.…”

“…The synthesized dithiazolophosphole derivatives ( M31 ) proved extremely versatile and several chemical modifications were performed on the phosphorus bridge, i.e., oxidation, sulfuration, and complexations with Au. The tricyclic dithiazolophosphole unit was also introduced into polymers ( P73 ) via a Huisgen alkynyl‐azide click reaction . Unfortunately, the polymer showed rather weak emissive properties, but proved to be a promising candidate for selective colorimetric and fluorescent Cu II sensing.…”

The Dawn of Functional Organoarsenic Chemistry

“…The group of Heeney synthesized dithiazoloarsole (Scheme ), and its properties were compared with those of dithiazolophosphole and dithienoarsole, which were reported by Baumgartner et al . and us, respectively (Figure ).…”

Organophosphorus Compounds in Organic Electronics

“…Over the last years several approaches have been developed that allowed large variations in substitution patterns or the synthesis of annulated phosphole derivatives. Most salt elimination routes (Scheme , A and B) are highly suited for the synthesis of (hetero‐)aryl‐annulated derivatives due to easily available precursors, which furnished a large variety of fused dithieno‐, azadibenzo‐, benzoalkynyl‐, dithiazolophospholes . In a similar fashion, route C proceeds by means of a phosphination elimination procedure; however, it generally requires significantly higher temperatures.…”

“…This material showeds trong impact of absorption ande mission towards Cu 2+ ions, albeit insensitivet owards other ions such as Li + ,K + , and Zn 2+ .T he decrease of fluorescence yields is associated with as elective Cu 2+ coordination to the bridging triazole moiety. [16] Twoc onstitutional isomers of bisindole-fused phosphole oxide (21;F igure 4) have been prepared through as traightforward salt-elimination procedure. Their longest wavelength absorptions stretch into the visible (409 and 430 nm) and are associated with HOMO-LUMO transitions (pp*, optical band gaps of 2.65 and 2.40 nm, respectively).…”