Organic–Inorganic Hybrids Based on Ultrathin Oxide Layers: Designed Nanostructures for Molecular Recognition

Abstract

The application of layered solids for molecular recognition is summarized. By using layered solids (silicates, aluminosilicates, titanates, hydroxides, and so on), ions and molecules can be concentrated from aqueous and vapor phases. The large surface area and tunable surface properties derived from the layered structures contribute to molecular recognition. The choice of materials and modification of the nanostructure were carefully investigated to optimize the performance based on molecular recognition (selective adsorption, substrate selective reaction, detection, etc.). The progress made in materials syntheses (variation of layered materials, sophisticated modification, controlled morphology, and processing) has made the design of materials more attractive and realistic.

Crystal architectures of a layered silicate on monodisperse spherical silica particles cause the topochemical expansion of the core-shell particles

“…Nanospaces in interlayer space have been controlled by controlling the spatial distributions of the organic moieties by varying the numbers, positions and sizes (molecular geometries) of the organic moieties. [11][12][13][14][15][16][17] This nanostructural versatility has encouraged us to seek further applications for these systems in selective adsorption, separation, catalysis and photochemical reactions. [16] The smectite group of layered clay minerals has been more extensively studied than have other layered inorganic solids.…”

“…[11][12][13][14][15][16][17] This nanostructural versatility has encouraged us to seek further applications for these systems in selective adsorption, separation, catalysis and photochemical reactions. [16] The smectite group of layered clay minerals has been more extensively studied than have other layered inorganic solids. [18,19] Smectites are composed of ultrathin (ca.…”

“…Cationexchange reactions between the interlayer cations and organoammonium ions are well known, and they are used in such applications as modifying surfaces, producing hydrophobic and microporous inorganic-organic hybrids for the uptake of specific molecules, [21,22] producing controlled release materials, achieving selective catalysis and achieving efficient photo-induced processes. [16,23] The cation exchange capacity (CEC), which directly correlates with the negative-layer charge density, is an important determiner of the distance between adjacent interlayer cations (the spatial density). Achieving an appropriate distance can allow the material to act as a molecular sieve for nonionic organic compounds [24][25][26][27][28][29] or to improve the photofunctions of photoactive molecules.…”

Manipulation of supramolecular 2D assembly of functional dyes toward artificial light-harvesting systems

“…My approach toward efficient artificial LHSs is based on method (c), in which clay nanosheets are used as the host material to build the 2D dye assembly using host (nanosheet)-guest (molecule) interactions. A clay nanosheet [27][28][29][30][31], saponite, is an attractive material characterized by (1) nanostructured flat sheets that can be formed by elements with large Clarke numbers (expressing the average content of the chemical elements in the earth), (2) negatively charged surfaces, (3) exfoliation or stacking ability of individual nanosheets in water, and (4) optical transparency in the visible light region in the exfoliated state when the particle size is small (ca. < 200 nm).…”

Photochromic Intercalation Compounds

“…Layered materials offer a two-dimensional expandable interlayer space for organizing guest species, among available ordered or constrained nano-environments [7,[12][13][14][15][16][17][18][19][20]. The study on the intercalation reactions has been motivated by the facts that the optical and electronic properties of both guest and host can be altered by the reactions [21][22].…”