FTIR STUDY OF REDOX SWITCHING OF PI-INTERACTIONS AND REORIENTATION OFADSORBED UBIQUINONE-10 ON GOLD

The reduction of ubiquinone-10 adsorbed onto a gold electrode in borax and sodium hydroxide solutions has been studied by subtractively norm alized interfacial Fourier transform infrared spectroscopy (SNIFTIRS). A reorientation of the adsorbed ubiquinone molecule on reduction coul d be observed. The SNIFTIRS spectra show that the molecule is anchored to the electrode surface through the isoprenoid groups, with the quin one ring away from the surface. Upon reduction, the aromatic ring form ed is adsorbed by pi interactions with the metal surface and is aligne d flat to the surface, slightly lifting the isoprenoid chains.