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Abstract: A new route for the synthesis of immobilized-polysiloxane ligand system bearing iminodiacetic acid chelating ligand of the general formula P-(CH2)3N-(CH2COOEt)2, (where P represents [Si–O] n polysiloxane network) was accomplished. The preparation of the immobilized iminodiethylacetate was achieved by the reaction of 3-aminopropyltrimethoxysilane with ethyl chloroacetate followed by hydrolytic polycondensation of the diethyliminodiacetate silane agent and tetraethylorthosilicate via the sol–gel process. The immobilized iminodiacetic acid P-(CH2)3N-(CH2COOH)2 was obtained by hydrolysis of the ethyl acetate groups using diluted hydrochloric acid. The new functionalized ligand system exhibits high capacities for uptake of the metal ions (Co2+, Ni2+, Cu2+ and Zn2+), and forms 1:1 metal to ligand ratio complexes in the case of Ni2+ and Cu2+. [Copyright &y& Elsevier]

A new chelating porous polysiloxane-immobilized tetraacetic acid ligand system has been prepared. This material was made by chemical modification of the iminodiacetic acid polysiloxane with thionyl chloride and diethyliminodiacetate, respectively. The polysiloxane functionalized with di(amidomethyl)aminetetraacetic acid of the general formula P-(CH 2 ) 3 N(CH 2 C(O)N) 2 (CH 2 COOH) 4 [where P represents the polysiloxane backbones (Si&sbnd;O&sbnd;Si) n ] was characterized by Thermogravimetric Analysis (TGA) and FTIR spectra. The FTIR results proved that tetraacetic acid groups are successfully grafted onto the polysiloxane surface. This ligand system exhibits high potential for extraction of divalent metal ions (Co +2 , Ni +2 , Cu +2 , and Zn +2 ) from aqueous solution. [ABSTRACT FROM AUTHOR]

Abstract: Insoluble solid porous ethyl-2-iminobenzoate immobilized polysiloxane ligand system of the general formula P–(CH2)3–NH(C6H4)COOC2H5, (where P represents [Si–O] n siloxane network) has been prepared by the reaction of 3-iodopolysiloxane P–(CH2)3–I with ethyl-2-aminobenzoate. The modified polysiloxane derivatives; imino(N-2-aminoethyl)benzamide P–(CH2)3–NH(C6H4)CONH(CH2)2NH2, and imino(N-diethylenediamine)benzamide P–(CH2)3–NH(C6H4)CONH(CH2)2NH(CH2)2NH2 ligand systems were prepared by the reaction of ethyl-2-iminobenzoate ligand system with ethylenediamine and diethylenetriamine, respectively. The new modified polysiloxane ligand systems exhibit high potential for the uptake of the metal ions (Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2 +) with an efficiency of 92–98% after recovery from its primary metal complexes. These immobilized-polysiloxane ligand systems undergo chemical degradation the level of which depends on pH. [Copyright &y& Elsevier]

A porous solid iminobis(N-2-aminoethylacetamide) polysiloxane ligand system of the general formula P–(CH2)3–N(CH2CONHCH2CH2NH2)2, (where P represents [Si–O]n siloxane network) has been prepared by modification of immobilized diethyliminidiacetate P–(CH2)3N(CH2CO2Et)2 with ethylenediamine in toluene. The new modified polysiloxane system exhibits high potential for the uptake of metal ions (Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+). This ligand system shows higher capacity toward the metal ions than its parent iminiodiacetate precursor. Complexation of ligand system for the metal ions at the optimum conditions was found in the order: Cu2+ > Fe3+ > Ni2+ > Co2+ > Mn2+ > Zn2+.Stability studies of the immobilized ligand system show that a degradation of the siloxane network and leaching of some species occurred upon treatment with acid or basic aqueous solutions in addition to metal ion solution. [Copyright &y& Elsevier]

The polysiloxane-immobilized triamine ligand system of the formula P-(CH 2 ) 3 NH(CH 2 ) 2 NH(CH 2 ) 2 NH 2 (where P represents the siloxane network) has been prepared via the sol-gel process by hydrolytic polycondensation of (EtO) 4 Si and (MeO) 3 Si(CH 2 ) 3 NH(CH 2 ) 2 NH(CH 2 ) 2 NH 2 . An alternative method was used by the reaction of the iodopolysiloxane P-(CH 2 ) 3 -I and diethylenetriamine in the presence of triethylamine. The immobilized triamine ligand forms metal chelate complexes when treated with aqueous metal(II) ion solutions (Co 2+ , Ni 2+ , and Cu 2+ ). The elemental analysis and FTIR results suggest that this ligand system undergoes a substantial leaching of diethylenetriamine ligand moieties from the siloxane framework. [ABSTRACT FROM AUTHOR]

Insoluble porous solid polysiloxane immobilized ligand system bearing chelating ligand group of the general formula P&z.sbnd;(CH2)3N[CH2CONH(CH2)2NH(CH2)2NH2]2 (where P represents [Si&z.sbnd;O]n polysiloxane network) has been prepared by the reaction between the polysiloxane immobilized diethyliminodiacetate ligand system, P&z.sbnd;(CH2)3N(CH2CO2Et)2 and diethylenetriamine in toluene. The XPS and FTIR results showed that all ethylacetate groups (&z.sbnd;COOEt) are converted into the amide groups (&z.sbnd;N&z.sbnd;C&z.dbnd;O). The new functionalized ligand system exhibits high capacity for the uptake of the metal ions (Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+). Complexation of the prepared ligand system for these metal ions at the optimum conditions was found in the order: Cu2+>Ni2+>Fe3+>Co2+>Mn2+>Zn2+. This ligand system shows higher capacity toward the metal ions than its iminiodiactate precursor which we have been reported. Stability studies of the immobilized ligand system show high degradation of the siloxane network and leaching of some species upon treatment with strong acidic or basic aqueous solutions in addition to metal ion solutions. Minimum leaching was observed at pH 6–8. [Copyright &y& Elsevier]