Thermal and spectroscopic studies on the decomposition of [Ni{di(2-aminoethyl)amine}(2)]- and [Ni(2,2 ': 6 ',2 ''-terpyridine)(2)]-Montmorillonite intercalated composites

Intercalated [Ni{di(2-aminoethyl)amine}(2)]-Montmorillonite (I) and [Ni(2,2 ':6',2 "-terpyridine)(2)]-Montmorillonite (II) composites have been synthes ized and their thermal behavior studied by TG, DTG and DTA substantiated by XRD and IR spectroscopy. Thermal stabilities of the composites I and II we re about 50 and 150 degrees C higher, respectively, compared to their respe ctive free metal complex salts. These results indicate that the metal compl ex with aromatic backboned ligands had higher thermal stability than that o f the aliphatic one upon intercalation into layered clay. XRD data showed t hat on heating, the basal spacing (d(001)) of the I composite decreased gra dually from 14.5 Angstrom at 50 degrees C to about 13.5 Angstrom at 250 deg rees C which may correspond with the transformation to a distorted octahedr al metal complex in the interlamellar spacing of the clay. On the other han d, the II composite showed a basal spacing (d(001)) of about 19.4 Angstrom at 50 degrees C, which decreased slightly to 19.0 Angstrom at about 350 deg rees C indicating the presence of intercalated octahedral metal complex and thus corroborates the thermal analyses. IR spectra show characteristic ban ds of I and II composites up to about 250 and 350 degrees C, respectively, which also support the data of thermal as well as XRD analyses. Such metal- complex-clay composites may be utilized for developing microporous layered materials exhibiting comparatively higher thermal stability. (C) 2000 Elsev ier Science B.V. All rights reserved.