Complexation and thermodynamic studies of polysiloxane iminobis (N-diethylenediamineacetamide) ligand system with some transition metal ions

Abstract

Many research concerning the synthesis of insoluble polysiloxane immobilized ligand systems, have been reported [1-21]. These functionalized polysiloxanes have been prepared by two methods. The first method; using the sol-gel process by hydrolytic polycondensation of tetraethylorthosilicate (TEOS) and the appropriate silane coupling agent (RO) 3 SiX, where X= ligand group)[1, 2]. The second method is by modification of a pre-prepared polysiloxane with a silane coupling agent containing the appropriate functional group [13-21]. These hybrid materials show high thermal, hydrolytic and mechanical stability over the organic polymers [5, 6]. These polysiloxane immobilized ligand systems have several applications such as extraction, recovery and separation of metal ions [13-21]. They also used as supports for heterogeneous catalysis and chromatography [2, 11, 22]. These materials have been characterized recently by many techniques including high-resolution solid state NMR [23-26], XPS analysis and thermal analysis [27-35]. In this work iminobis (N-diethylenediamineacetamide) polysiloxane-immobilized ligand system was prepared as previously reported [36] and complexed with Co2+, Ni2+ and Cu2+ metal ions from aqueous solutions. This study may be useful because the selection and separation of the chelating functionalized ligand system closely related to the stability of the complexes formed.