In−situ complexation of o−phenanthroline in the interlayer of Fe(II)−montmorillonite

Abstract

Abstract The solid state reaction between Fe(II)−montmorillonite (Mt) and o−phenanthroline (L) resulted in the in-situ complexation of interlayer Fe(II) ions with L. The formation of the [FeL3]2+ complex in the interlayer was confirmed from X−ray diffraction (XRD), thermal analysis (TG/DTA), infrared (FT−IR) and diffused reflectance (DR) UV−Vis spectra. The basal spacing (d001) of this inorganic-organic hybrid material, Fe(II)−Mt−L, was found to be 18 A at room temperature. The XRD pattern shows the self-oriented (stacked) layer structure, which is independent of relative humidity. The TG−DTA curve shows the decomposition of interlayer complex at about 450 °C. The FTIR spectra show the prominent C−H bending for L around 720 cm−1 and 845 cm−1 in addition to other structural features of clay mineral. The DR UV−Vis spectra shows the absorption at about 510 nm, which is a characteristic value for [FeL3]2+ complex. The FE−SEM image and magnetic behaviour of the Fe(II)−Mt−L are compared with Fe(II)−Mt. The Fe(II)−Mt−L was heated upto 500 °C, and it was found that the structural integrity remained same until 350 °C as indicated by XRD, FTIR and TG-DTA. The d001 was reduced to 11.7 A at about 400 °C and then the clay interlayer collapsed irreversibly to d001 of 9.6 A. These hybrid materials are expected to show selective adsorption and catalytic property in organic (ca. Bigineli-type) reactions. As a first step, we have focused here only on preparation and characterization of these modified clay minerals by innovative approach.