3 research outputs found
ImidazolylâSubstituted Benzoâ and Naphthodithiophenes as Precursors for the Synthesis of Transient OpenâShell Quinoids
The synthesis of three novel imidazolyl-substituted sulfur-containing heteroacenes is reported. These heteroacenes consisting of annelated benzo- and naphthothiophenes serve as precursors for the generation of open-shell quinoid heteroacenes by oxidation with alkaline ferric cyanide. Spectroscopic and computational experiments support the formation of reactive open-shell quinoids, which, however, quickly produce paramagnetic polymeric material
Impact of Heterocycle Annulation on NIR Absorbance in Quinoid Thioacene Derivatives
The synthesis and characterisation of a homologous series of quinoid sulfur-containing imidazolyl-substituted heteroacenes is described. The optoelectronic and magnetic properties were investigated by UV/vis, fluorescence and EPR spectroscopy as well as quantum-chemical calculations, and were compared to those of the corresponding benzo congener. The room-temperature and atmospherically stable quinoids display strong absorption in the NIR region between 678 and 819â
nm. The dithieno[3,2-b:2â˛,3â˛-d]thiophene and the thieno[2â˛,3â˛:4,5]thieno[3,2-b]thieno[2,3-d]thiophene derivatives were EPR active at room temperature. For the latter, variable-temperature EPR spectroscopy revealed the presence of a thermally accessible triplet state, with a singlet-triplet separation of 14.1â
kJâmol
ImidazolylâSubstituted Benzoâ and Naphthodithiophenes as Precursors for the Synthesis of Transient OpenâShell Quinoids
Abstract The synthesis of three novel imidazolylâsubstituted sulfurâcontaining heteroacenes is reported. These heteroacenes consisting of annelated benzoâ and naphthothiophenes serve as precursors for the generation of openâshell quinoid heteroacenes by oxidation with alkaline ferric cyanide. Spectroscopic and computational experiments support the formation of reactive openâshell quinoids, which, however, quickly produce paramagnetic polymeric material