PREFERENTIAL INTERCALATION OF ISOMERS OF NAPHTHALENECARBOXYLATE IONS INTO THE INTERLAYER OF LAYERED DOUBLE HYDROXIDES

Mixtures of naphthalenecarboxylate ions were intercalated into layered double hydroxides (LDHs) under alkaline conditions. In the case of the mixture of mono-, di-, and tetracarboxylate ions, nearly 90 % of 1,4,5,8-naphthalenetetracarboxylic acid was intercalated, whereas only 0.1 % of 2-naphthoic acid (2-NA) was co-intercalated into the interlayer of Mg/Al (0.7/0.3) LDH. 2-NA was preferably intercalated compared to its isomer, 1-NA, and the ratio of intercalated 2-NA and 1-NA reached 5. 2,6-Naphthalenedicarboxylic acid (2,6-NDCA) was preferably intercalated compared to its isomer, 2,7-NDCA. In the case of Zn/Al (0.7/0.3) LDH, more than 90 % of 2,6-NDCA and only 24 % of 2,7-NDCA were co-intercalated. These results indicate the existence of molecular recognition ability of layered double hydroxides.