Intercalates of pyridine

The MNX a-polymorphs adopt the FeOCl type layered structure (see Section 3.4) and exist for all combinations of MNX (M = Zr, Hf X = Cl, Br, I) and for TiNX (X = Cl, Br, I). Superconductivity at 11K is observed on intercalation of lithium in a-ZrNBr and a-ZrNI using BuLi. Intercalation of pyridine into TiNCl gives pyridinei/3 TiNCl, which superconducts at 4 6 K. The latter is reminiscent of the effect of intercalation of organic bases into the superconducting dichalcogenides. 

T. Sasaki, F. Izumi, M. Watanabe, Intercalation of pyridine in layered titanates, Chem. Mater. 

Layered chalcogenides such as TaS2 can accommodate large molecules such as stearamide. We shall be discussing the intercalation chemistry of these and other layered materials in Chapter 8. TaS2 is metallic and superconducting [T = 0.8 K) and the superconducting transition is increased to 3.5 K by incorporation of pyridine the interlayer separation increases from 3 to 6 A. Octadecylamine increases the interlayer... 

If the components are mixed in a 2 8 1 molar ratio, a molecule of pyridine N-oxide intercalates between the pentaanions, as shown in Figure 42, and these... 

The microporosity of a new tubular silicatelayered silicate nanocomposite formed by the intercalation of imogolite in Na -montmorillonite has been characterized by nitrogen and m-xylene adsorption. The nitrogen adsorption data yielded liquid micropore volume of -0.20 cm g as determined by both the t-plot and the Dubinin-Radusikevich methods. The t-plot provided evidence for a bimodal pore structure which we attributed to intratube and intertube adsorption environments. The m-xylene adsorption data indicated a much smaller liquid pore volume (-0.11 cm g ), most likely due to incomplete filling of intratubular pores by the planar adsorbate. The FTIR spectrum of pyridine adsorbed on the TSLS complex established the presence of both Bronsted and Lewis acid sites. The TSLS complex was shown to be active for the acid-catalyzed dealkylation of cumene at 350 C, but the complex was less reactive than a conventional alumina pillared montmorillonite. 

Figure 8 One-dimensional projection of nuclear scattering density perpendicular to (001) for pyridine intercalates of NdC-exchanged montmorillonite...

Molecular intercalates of MPXj phases have been prepared with amines as well as metallocenes. By heating MnPSej at 30°C for 4 d under the saturated vapor pressure of pyridine, a complex MnPSe3(py)i,3 is obtained. This compound can partially lose its pyridine amount to give MnPSe3(py)i/4. These two compounds present two different orientations of the intercalated molecules. According to one-dimensional electron density... 

Herein are described the preparations of the charge-transfer-type intercalation compound FeOCl (pyridine derivative), of grafted-type intercalation compounds FeO(OCH3) and Fe0(02C2H4)1/2 and of some organic intercalates of HTiNbOs. 

LB films of tetra-4-tert-butyl- and tetra-(3-nitro-5-tcrt-butyl)-substituted CoPcs were used to detect pyridine, primary aliphatic amines, and benzylamine, by means of microgravimetry, UV-Vis spectroscopy, and optic microscopy [59], The sorption occurs as stepwise intercalation of the sorbate molecules into the supramolecular 3D structure of the phthalocyanine assembly followed by formation of the donor-acceptor complexes. Both intercalation depth and stoichiometry of the complexes are determined by the molecular structure of amines. The supramolecular factor allows discrimination between amines in air but not in aqueous solutions because of concurrent intercalation of water. 

Odink et al. (1992) intercalated the (hexagonal) layered SmSI-t] YbOCl with pyridine (py) to obtain 3R structure-type (py)o jYbOCl with a 7A increase in the interlayer separation. The additional increase in the interlayer separation upon intercalation of 4-ethylpyridine and IR spectroscopic data support the conclusion that the lone pair of electrons on the nitrogen and the plane of the molecule are oriented perpendicular to the YbOCl layers. 

Intercalation of ruthenium poly(pyridine) complexes into other layered materials has been reported (95-106). The intercalation is not as facile as in smectite systems, which is partly due to the higher charge densities of these host materials. Consequently, quantitative ion exchange of ruthenium complexes with the interlayer cations is difficult. Synthetic efforts have been made to introduce ruthenium polypyridine chelate complexes into magadiite, zirconium phosphate and phos-phonates, LDH, MnPSs, and a transition metal oxide and to control the adsorption states. 

Our recent interest is, however, on the in-situ intercalative polymerization of pyridine substituted acetylenic monomer (2-ethynylpyridine (2EPy)) within the galleries of Ca -montmorillonite (Ca -MMT) (5). In this process, it is believed that monomer first intercalates into the galleries of montmorillonite, and then the interaction with clay surface initiates the polymerization (5). The X-ray... 

The intercalation of platinum complexes containing bidentate or tridentate aromatic amines was first proposed for binding to tRNA and then to DNA [53]. The structures of the relevant complexes of palladium and platinum are shown in Figure 1.5 and a requisite is the presence of planar ligands such as bipyridine, terpyridine, or o-phenanthroline, which are coplanar with the coordination plane formed by the four ligand donor atoms and the metal ion. The similar pyridine derivative, [Pt(en)py2], where the pyridine Ugands are forced by nonbonded steric constraints to be out of the coordination plane, does not intercalate. 

With respect to the details of intercalation of this porphyrin and the 4,7-diphenylphenanthroline complexes discussed earlier, some rotation of the pyridine and phenyl rings into the plane of the phenanthroline and porphyrin rings, respectively, must occur for maximum overlap and intercalation to occur. The 2-A-methylpyridyl porphyrin, in agreement with the expected larger steric restraint, does not react with DNA. Even full planarity of one 4-A-methylpyridyl group, however, will barely give the minimal surface area for good overlap. 

The acidity of clays and pillared clays has been studied by infrared spectroscopy using pyridine as a probe molecule. Fig. 3.57 shows the infrared spectra of pyridine adsorbed on beidelite pillared with aluminum hydroxide oligomers after thermal treatment under vacuum at increasing temperatures. The intercalated beidellite contains Lewis acid sites and Bransted acid sites characterized by 1454 cm" and 1540 cm , respectively. The intense band at 1454 cm is associated to Lewis acid sites on the pillars, since the band does not show up in the spectra of proton exchange clays. 

Steed JW, Atwood JL (2000) Supramolecular chemistry. Wiley, New York Tomasik P (1985) Pyridine-metal complexes (Newkome GR, Strekowski L). Wiley, New York Usuki A, Kojima Y, Kawasumi M, Okada A, Fukushima Y, Kurauchi T, Kamigaito O (1993) Synthesis of nylon 6-clay hybrid. J Mater Res 8 1179 Vaia RA, Giaimelis EP (2001) Liquid crystal polymer nanocomposites direct intercalation of thermotropic liquid crystalline polymers into layered silicates. Polymer 42 1281 Villemore G (1990) Effect of negative surface-charge densities of smeetite clays on the adsorption isotherms of racemic and enantiomeric tris (2,2 -bipyridyl) ruthenium(ii) chloride. Clays Clay Miner 38 622... 

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