Synthesis, characterization and applications of polysiloxane networks with immobilized pyrogallol ligands

A porous, solid insoluble polysiloxane-immobilized ligand system bearing pyrogallol active sites of the general formula P-(CH2)(3)-NH(CH2)(3)OC6H3(OH)(2) (where P represents [Si-O](n) siloxane network) has been prepared by the reaction of 3-aminopropylpolysiloxane with 1,3-dibromopropane followed by the reaction with pyrogallol. C-13 CP-MAS NMR and X-ray photoelectron spectroscopy confirmed that the pyrogallol is chemically bonded to the siloxane backbone. Thermal analysis showed that the ligand system is stable under nitrogen at relatively high temperature. The polysiloxane-pyrogallol ligand system exhibits high potential for the uptake of the metal ions (Fe3+, CO2+, Ni2+ and Cu2+). Complexation of the pyrogallol ligand system for the metal ions at the optimum conditions was found to be in the order Fe3+ > Cu2+ > Ni2+ > Co2+. Copyright (c) 2005 John Wiley & Sons, Ltd.