Click functionalization in the synthesis of sorption materials. Communication I. Preparation and some sorption characteristics of silical gel with immobilized formazan with regard to Pd(II) and Cu(II)

Abstract

One of trends in the chemistry of formazans is the search of approaches to the preparation of tailor-made materials on their basis. Among such approaches is covalent immobilization of formazans onto different matrices, such as celluloses, organic resins, and silica gels.  The click reactions is the interesting application creation of the molecules and materials suitable for use in the chemical analysis – ionofor, phases for a chromatography, electrochemical sensors. The examples of use of click chemistry in the field of receiving new substances and materials for analytical chemistry have caused the interest of our research group in receiving clickable hydrazone and formazan. The aims of the present were to obtain a silica gel functionalized with formazan groups through the click reaction between the alkyne group forming a part of the formazan molecule and the azido group at the silica gel surface, as well as to study some its sorption characteristics. The maximum sorption capacity of the obtained sorption material with regard to Pd(II) and Cu(II) was established, and optimum conditions for their concentration in a steady-state mode were determined. It was shown that the sorption kinetics of Cu(II) and Pd(II) on silica gel with covalently immobilized formazan can be described by the pseudo-second-order equation. The modified silica gel was illustrated to retain selectivity upon recovery of Cu(II) from systems containing a pair of competing components Cu(II)-Ni(II), Cu(II)-Co(II), and Cu(II)-Cd(II) when n_(sorbate):n_{(functional groups capable of complexation)} = 1:1.