Adsorption of some functionalized aliphatic compounds on plasma-grown thin-film aluminium and magnesium oxides

Abstract

Abstract A study of the inelastic electron tunnelling (IET) spectra of N , N -diethyl-1,2-diaminoethane, N , N′ -diethyl-1,2-diaminoethane, N , N′ -dimethyl-1,2-diaminoethane, N , N , N′ , N′ -tetraethyl-1,2-diamino-ethane and N , N , N′ , N′ -tetramethyl-1,2-diaminoethane, shows all five systems to form five-membered chelate structures with both nitrogen atoms present in the adsorbate acting as Lewis donors at the same cation on either aluminium oxide or magnesium oxide. The IET spectra for the N -ethyl-2-aminoethanol, N , N -diethyl-2-aminoethanol and N , N -dimethyl-2-aminoethanol also examined indicate that similar alkoxy-amino chelated structures are formed with these adsorbates. For the aminoethanols adsorption—chelation appears to involve adsorbate deprotonation and hydroxyl depletion of the oxide surfaces involved with concomitant binding of the nitrogen atom present to the surface metal ion involved in alkoxide formation.