Immobilisation of amine-functionalised nickel(II) Schiff base complexes onto activated carbon treated with thionyl chloride

Two Schiff base nickel complexes with amine groups, bis[o-[N-(3-aminopropyl)formimidoyl]phenolato-O,N,N']nickel(II) and bis[4-methoxy-o-[N-(3-aminopropyl)formimidoyl]phenolato-O,N,N']nickel(II), were anchored onto a chemically oxidised activated carbon treated with thionyl chloride. Complex anchoring was made in three consecutive steps: (i) oxidation of activated carbon with nitric acid, (ii) treatment with thionyl chloride that converts primarily the carboxylic acid carbon surface groups into acyl chloride functionalities, and (iii) reaction between the amine functionalities of the metal complexes with the carbon surface acyl chloride functionalities. The resulting carbon-based materials were characterised by elemental analysis, surface techniques (SEM and XPS), nitrogen adsorption isotherms and thermal analysis (temperature-programmed desorption and thermogravimetry). The data from all the techniques provided evidence that both nickel complexes were anchored onto the activated carbon via an amide ligation originated by the reaction between the acyl chloride carbon surface functionalities and the amine groups of both metal complexes. (C) 2002 Elsevier Science Inc. All rights reserved.