**6. Preparation of chiral ladder-like PSQs and hybridization with dye compounds by ion-exchange reaction**

82 Ion Exchange Technologies

*i.e.*, a hybrid.

saturated saponite.

m2/g, respectively).

interlayer of SAP. On the basis of the CHN analysis data, the exchange amount of a repeating unit of the PSQ component in PSQ–SAP was calculated to be 126 meq/100 g SAP. This value is higher than that of the cation exchange capacity (CEC) of Na-SAP (92 meq/100 g SAP) (Bujdák et al., 2002). The distance between the charges of PSQ would be shorter than that of SAP. Therefore, excess ammonium groups and counter anions (Cl–) of PSQ-NH3+Cl– were inserted into the interlayer of SAP, which was confirmed by a Cl elemental analysis. The XRD pattern of PSQ–SAP was completely different from that of Na-SAP and PSQ-NH3+Cl–. Accordingly, PSQ–SAP was not a mixture, but an intercalated nano-order material,

**Scheme 4.** Preparation of a clay pillared with PSQ by ion-exchange reaction of PSQ-NH3+Cl– with Na-

From the nitrogen adsorption–desorption isotherms at 77K, the surface area and pore volume of PSQ–SAP derived from the *t*-plot were estimated to be 370m2/g and 0.15 cm3/g, respectively. This indicates that a porous material was prepared from the starting materials with dense structures (BET surface areas of Na-SAP and PSQ-NH3+Cl– were *ca*. 26 and 5

When a clay mineral with high CEC such as Li-saturated taeniolite was employed, such a porous material was not obtained by combination with PSQ-NH3+Cl– (BET surface area of the resulting product was *ca*. 53 m2/g), although a sufficient interlayer spacing existed as confirmed by the XRD measurement (*d*-value of the product was *ca*. 1.83 nm). Because the distance between the PSQs in the interlayer of taeniolite is short due to the higher CEC of the Li-saturated taeniolite (exchange amount of a repeating unit of PSQ was calculated to be 140 meq/100 g taeniolite), sufficient space was not provided. Furthermore, when polyallylamine hydrochloride (PAA-Cl) —a common cationic polymer— was used for pillaring in the SAP interlayer, a porous structure was not obtained (BET surface area of the product was *ca*. 52 m2/g). It was difficult for PAA-Cl to pillar the interlayer of SAP due to the lack of rigidity and bulkiness. From these results, it was considered that the rigidity and Self-assembled hybrids formed by noncovalent interactions between photofunctional compounds and chiral molecules have attracted much attention because of their potential applications in circularly polarized luminescent (CPL) materials. To achieve the preparation of these hybrids by chiral induction from chiral molecules to photofunctional compounds, several combinations have been investigated with respect to supramolecular organization, *e.g.*, anionic dye/cationic chiral surfactants (Franke et al., 2006), laser dye/cholesteric liquid crystal (Uchimura et al., 2010), pyrene derivatives/cyclodextrins (Kano et al., 1988), porphyrins/helical polyacetylene (Onouchi et al., 2006), and -conjugated polymers/polysaccharides such as amylose (Ikeda et al., 2006), and schizophyllan (Li et al., 2005). On the other hand, there have been no reports regarding hybridization using inorganic compounds such as siloxane (SiO)-based materials as chiral inductors. The chiral inductors derived from SiO-based materials may enable the development of durable and thermostable hybrids with photofunctional compounds because the SiO-based materials exhibit superior thermal, mechanical, and chemical stabilities. In this section, therefore, the author describes the preparation of chiral ladder-like PSQs as the SiO-based chiral inductors and their chiral induction behaviors into dye compounds.

**Scheme 5.** Preparation of ladder-like PSQs containing chiral and ammonium chloride side-chain groups by (a) copolycondensation method and (b) polymer reaction method.
