Direct synthesis of bifunctional mesoporous organosilicas containing chelating groups in the framework and reactive functional groups in the channel pores

Abstract

This paper describes the direct synthesis of bifunctional organosilica containing chelating groups in the framework and reactive functional groups in the channel pores. These materials were obtained in one step by direct synthesis using co-condensation of a bridged organosilica with chelating properties, tetraethylorthosilicate (TEOS) and an organotrialkoxysilane ZSi(OR)₃ with Z = cyanopropyl, mercaptopropyl, chloropropyl in the presence of a non-ionic triblock co-polymer (P123) as structure directing agent. Bridged organosilicas used in this study include: 1,4,8,11-tetrakis(triethoxysilylpropyl)-1,4,8,11-tetraazacyclotetradecane and the corresponding copper(II) chloride complex. The influence of different parameters (concentration of the triblock copolymer P123, cosurfactant, hydrothermal treatment) on the textural and structural characteristics of the materials was investigated. The materials were characterized by ¹³C and ²⁹Si NMR experiments, nitrogen gas adsorption, powder X-ray diffractrion (XRD), elemental analysis and thermogravimetric analysis (TGA). The activity of the chelating groups for complexation–decomplexation reactions was also investigated.