Novel reactions of a neutral organic reductant : reductive coupling and nanoparticle synthesis

Abstract

A recently developed bis-pyridinylidene neutral organic electron donor captured our interest as a potential source of new chemistries for reductive coupling and the synthesis of group IV nanoparticles. This super electron donor was used as a co-reductant for nickel-catalyzed reductive coupling of aryl halides in order for the reaction to be homogeneous and avoid the traditional co-reductant, zinc, previously reported for these Yamamoto-type dehalogenative couplings. Reductive coupling was somewhat successful for specific substrates, including 4- bromoanisole and 2,5-dibromothiophene, but competing hydrodehalogenation of the aryl halide was problematic for both expanding the substrate scope and increasing the length of the polymers generated from this reaction. The attempt to synthesize silicon and germanium nanoparticles from reduction of the corresponding tetrachloride precursors using this super organic electron donor met limited success. Dimerization of silicon species occurred, but there was little conclusive evidence of nanoparticle formation. Finally, in a brief side-project to explore other applications of the organic reductant, the molecule was shown to successfully n-dope both p-type and n-type organic electronic materials.