Sumanenemonoone Imines Bridged by Redox-Active [pi]-Conjugated Unit: Synthesis, Stepwise Coordination to Palladium(II), and Laser-Induced Formation of Nitrogen-Doped Graphitic Carbon

Sumanenemonoone imine compounds bridged by a redox-active π-conjugated unit on the basis of the conversion between 1,4-phenylenediamine and 1,4-benzoquinonediimine were synthesized and characterized. The stepwise coordination of the imino groups to PdII in the sumanenemonoone imine compound bridged by 1,4-benzoquinonediimine was indicated by the titration experiment. Laser irradiation of a film of the metal-free quionediimine gave nitrogen-doped graphitic carbon, which was supported by an increase in conductivity and by Raman spectroscopy. The obtained graphitic carbon corresponds to carbonous compounds thermally treated at approximately 700-1000°C. The ratio of nitrogen and carbon relative to that in the starting compound was nearly completely retained (5.4% decrease).