X-RAY-DIFFRACTION PATTERNS OF MONTMORILLONITE ORIENTED FILMS EXCHANGED WITH ENANTIOMERIC AND RACEMIC TRIS(2,2'-BIPYRIDYL)RUTHENIUM(II)

X-ray diffraction patterns of oriented films of montmorillonite containing enantiomeric tris(2,2'-bipyridyl) ruthenium(II) chloride (Ru(bpy)2(2+)) show a peak corresponding to basal spacings of approximately 27 angstrom. This peak is absent from the X-ray patterns of montmorillonite films containing racemic cations. A basal spacing of 27 angstrom is consistent with the adsorption of 2 layers of the enantiomeric cations in each interlayer space. Under the same condition only one layer of the racemic cation was intercalated (basal spacings of 17.9 angstrom). These results are in accord with previous reports that montmorillonite can adsorb more of the optical isomers than of the racemic mixture of Ru(bpy)3(2+). Addition of NaCl to the mixtures resulted in an increase in the level of adsorption of the racemic cations and in the appearance of a peak at 27 angstrom in the X-ray pattern.