Inclusion of poly-aromatic hydrocarbon (PAH) molecules in a functionalized layered double hydroxide

The internal surface of an Mg-Al layered double hydroxide has been functionalized by anchoring carboxy-methyl derivatized β-cyclodextrin cavities to the gallery walls. Neutral polyaromatic hydrocarbon (PAH) molecules have been included within the functionalized solid by driving the hydrophobic aromatic molecules from a polar solvent into the less polar interior of the anchored cyclodextrin cavities by a partitioning process. The optical (absorption and emission) properties of the PAH molecules included within the functionalized Mg-Al layered double hydroxide solid are similar to that of dilute solutions of the PAH in non-polar solvents. The unique feature of these hybrid materials is that they are thermally stable over a wide temperature range with their emission properties practically unaltered

Functionalization of the internal surfaces of layered cadmium thiophosphate with cationic surfactants: adsolubilization of uncharged organic molecules

Ion-exchange intercalation of the cationic surfactant cetyl trimethylammonium in layered CdPS3 leads to the formation of an intercalated bilayer within the galleries, thereby converting the internal surface of the layers from hydrophilic to hydrophobic. Several uncharged organic 'guest' molecules were found to be solubilized in the intercalated bilayer 'host'

Inclusion of Ferrocene in a Cyclodextrin-Functionalized Layered Metal Hydroxide: A New Organometallic-Organic-LDH Nanohybrid

Cyclodextrin cavities have been grafted into a layered metal hydroxide to create hydrophobic nanopockets within the galleries of the inorganic solid. Neutral ferrocene molecules can be included within the grafted cavities by partitioning from a polar solvent to generate a new organometallic-organic-inorganic hybrid. The included ferrocene has been characterized by electronic and Raman spectroscopy. The capability of the cyclodextrin-functionalized solid to separate hydrophobic and hydrophilic derivatives of ferrocene is demonstrated

Anionic Clays Containing Anti-Inflammatory Drug Molecules: Comparison of Molecular Dynamics Simulation and Measurements

Three representative nonsteroidal anti-inflammatory drug molecules, Ibuprofen, Diclofenac, and Indomethacin, have been intercalated within the galleries of an anionic clay, Mg-Al layered double hydroxide (LDH). X-ray diffraction, IR and Raman vibrational spectroscopy and ^1^3C cross-polarization magic-angle spinning NMR have been used to characterize the confined drug molecules, while molecular dynamics (MD) simulations were used to probe the interlayer structure, arrangement, orientation, and geometry of the intercalated species. All three drug molecules are arranged as bilayers in the interlamellar space of the anionic clay. But while the structure of the intercalated Ibuprofen is identical to that of the molecule outside the layers, spectroscopy as well as MD simulation shows that there is a change in the geometry of Diclofenac and Indomethacin upon confinement within the galleries of the LDH. The change in geometry of Diclofenac and Indomethacin upon intercalation is shown to originate from the electrostatic interaction between the electronegative chlorine atoms on the drug molecule and the positively charged metal hydroxide sheets of the anionic clay. It is shown that these changes in the geometry of the intercalated drug molecules allow for the observed interlayer spacing to be realized without the bilayers having to interdigitate, which would otherwise have been necessary if the structure of the drug molecules had remained identical to that outside the layers. Comparisons of experimental measurements with simulation have provided a more detailed understanding of the geometry and organization of flexible drug molecules confined in the anionic clay

Aromatic Molecules in Restricted Geometries: Photophysics of Naphthalene Included in a Cyclodextrin Functionalized Layered Solid

The galleries of an Mg-Al layered double hydroxide have been functionalized by intercalation of carboxymethyl, \beta -cyclodextrin cavities. The anchored cavities form a random array of identical-sized hydrophobic nanopockets arranged in a bilayer fashion in the interlamellar space of the layered solid. Naphthalene molecules have been included within these cavities by partitioning from a polar solvent. The fluorescence from the included naphthalene shows an unusual behaviorsthe excimer to monomer emission intensity decreases with increasing concentration of included naphthalene. This is shown to be a consequence of the absence of translational mobility of the naphthalene-cyclodextrin adduct in the functionalized solid. Two types of included naphthalene have been identified: a preformed excimer-like species characterized by the absence of rise time in decay measurements and a monomeric species that is incapable of excimer formation due to the absence of suitably located included naphthalenes in its proximity. The concentration of each species and the enthalpy for excimer formation have been determined from the temperature variation of fluorescence intensities

Anionic Clays Containing Anti-Inflammatory Drug Molecules: Comparison of Molecular Dynamics Simulation and Measurements

Three representative nonsteroidal anti-inflammatory drug molecules, Ibuprofen, Diclofenac, and Indomethacin, have been intercalated within the galleries of an anionic clay, Mg-Al layered double hydroxide (LDH). X-ray diffraction, IR and Raman vibrational spectroscopy and ^1^3C cross-polarization magic-angle spinning NMR have been used to characterize the confined drug molecules, while molecular dynamics (MD) simulations were used to probe the interlayer structure, arrangement, orientation, and geometry of the intercalated species. All three drug molecules are arranged as bilayers in the interlamellar space of the anionic clay. But while the structure of the intercalated Ibuprofen is identical to that of the molecule outside the layers, spectroscopy as well as MD simulation shows that there is a change in the geometry of Diclofenac and Indomethacin upon confinement within the galleries of the LDH. The change in geometry of Diclofenac and Indomethacin upon intercalation is shown to originate from the electrostatic interaction between the electronegative chlorine atoms on the drug molecule and the positively charged metal hydroxide sheets of the anionic clay. It is shown that these changes in the geometry of the intercalated drug molecules allow for the observed interlayer spacing to be realized without the bilayers having to interdigitate, which would otherwise have been necessary if the structure of the drug molecules had remained identical to that outside the layers. Comparisons of experimental measurements with simulation have provided a more detailed understanding of the geometry and organization of flexible drug molecules confined in the anionic clay

Aromatic molecules in restricted geometries: photophysics of naphthalene included in a cyclodextrin functionalized layered solid

The galleries of an Mg-Al layered double hydroxide have been functionalized by intercalation of carboxymethyl β-cyclodextrin cavities. The anchored cavities form a random array of identical-sized hydrophobic nanopockets arranged in a bilayer fashion in the interlamellar space of the layered solid. Naphthalene molecules have been included within these cavities by partitioning from a polar solvent. The fluorescence from the included naphthalene shows an unusual behavior - the excimer to monomer emission intensity decreases with increasing concentration of included naphthalene. This is shown to be a consequence of the absence of translational mobility of the naphthalene-cyclodextrin adduct in the functionalized solid. Two types of included naphthalene have been identified: a preformed excimer-like species characterized by the absence of rise time in decay measurements and a monomeric species that is incapable of excimer formation due to the absence of suitably located included naphthalenes in its proximity. The concentration of each species and the enthalpy for excimer formation have been determined from the temperature variation of fluorescence intensities

Insertion of iodine in a functionalized inorganic layered solid

The galleries of a Mg-Al layered double hydroxide have been functionalized by intercalation of (carboxymethyl)-β-cyclodextrin cavities. The functionalized inorganic solid can adsorb iodine molecules from vapor as well as nonaqueous and aqueous solutions. The adsorbed iodine complexes with the grafted cyclodextrin cavities, disassociating heterolytically to form polyiodide species. Electronic and Raman spectra provide conclusive evidence for the existence of linear symmetric triodide, I3−, and pentaiodide, I5−, species within the cyclodextrin cavities confined in the layered double hydroxide