A palladium-catalyzed synthesis of dibenzothiophenes from 2-biphenylthiols is described. This highly efficient reaction employs a simple PdCl/DMSO catalytic system, in which PdCl is the sole metal catalyst and DMSO functions as an oxidant and solvent. This transformation has broad substrate scope and operational simplicity and proceeds in high yield. The synthetic utility was demonstrated by the facile synthesis of helical dinapthothiophene 3 and an eminent organic semiconductor DBTDT 4. Importantly, highly strained trithiasumanene 5, a buckybowl of considerable synthetic challenge, was observed under this catalytic system.

Functionalization of polycyclic aromatic hydrocarbons (PAHs) with functional groups is essential for tuning the optoelectronic properties, solid stacking and solubility. α-Iminonitriles are composite functional groups (CFGs) containing imine (C=NÀ R) and nitrile (CN) moieties with strong electron-withdrawing character and good stability, which could be readily introduced through several effective synthetic methods. α-Iminonitriles have been widely used as intermediates for organic transformations but hold untapped potential for modification of organic functional materials. We herein disclose that α-iminonitriles are eminent groups for modifying the properties of pyrene. The introduction of αiminonitriles to pyrene causes many changes: significantly lowering the LUMOs, red-shift in absorption and emission spectra, tuning the solid-stacking, triggering aggregationinduced emission and white-light emission. This work indicates that CFGs such as α-iminonitriles may provide extra toolkits for the functionalization of organic functional materials which would help to tap the potentials of novel or existed materials.

ChemInform Abstract In a deuterated solvent the photoreduction of title compounds such as (I) leads to β-deuterated main products (cf. (II)). In contrast to the thermal reduction, which affords α-deuterated products, the mechanism of the photoreaction is discussed in erms of sequential electron-hydrogen atom transfer from Hantzsch ester (HAE), an NAD(P)H model, to the substrate in the solvent cage. An electron-proton-electron transfer to the substrate is eliminated.