Intercalation of Rhodamine 6G and Oxazine 4 into Oriented Clay Films and Their Alignment

The cationic dyes rhodamine 6G (R6G) and oxazine 4 (Ox4) were intercalated into oriented lithium hectorite (LiHT, a synthetic fluor-mica) films by ion-exchange, and their orientation was studied by x-ray and polarized spectroscopy. Orientation of dyes was determined by basal spacing obtained by x-ray diffraction data, showing that angles of the long axis were 60° for R6G and 47° for Ox4 against the layer. Polarized ultraviolet-visible spectroscopy showed that the high-order H-aggregate of R6G and Ox4 were oriented at 64° and 52° against layers, respectively; other states of dyes were oriented at much lower angles. The interlayer distance was mostly determined by dimensions of the high-order H-aggregate.