Intercalates of Vanadyl Phosphate with Aliphatic Nitriles

Intercalates of vanadyl phosphate with aliphatic nitriles (acetonitrile, propionitrile, butyronitrile, valeronitrile and hexanenitrile) were prepared and characterized by X-ray powder diffraction, thermogravimetric analysis, IR and Raman spectroscopies. The basal spacings of all the intercalates prepared are practically identical. The nitrile intercalates (except acetonitrile) contain one nitrile molecule per formula unit. The nitrile molecules are anchored to the host layers by an N–V donor-acceptor bond and their aliphatic chains are parallel to the host layers. The acetonitrile intercalate contains two guest molecules per formula unit. Only half of them can be bonded to the vanadium atom, the second half is probably anchored by van der Waals interaction. The intercalates prepared are moisture-sensitive and the guest molecules are easily replaced by water molecules.     

Intercalation of Dyes Containing SO3H Groups into Zn–Al Layered Double Hydroxide

The intercalates of Naphthol Yellow S, Tropaeolin 000, and Tropaeolin 00 were prepared by heating [Zn_0.67Al_0.33(OH)₂](CO₃)_0.165 · 0.5H₂O with acidic forms of the dye solutions in an open reaction vessel. The intercalates were characterized by chemical and thermal analysis, X-ray powder diffraction and UV–VIS spectroscopy. A possible arrangement of the dye molecules in the intercalates was suggested on the basis of their chemical compositions and interlayer distances, by taking into account van der Waals dimensions of the guest molecules and by assuming that the structure of the host layers is not changed during the intercalation process.     

Intercalation of Dyes Containing SO3H Groups into Zn–Al Layered Double Hydroxide

The intercalates of Naphthol Yellow S, Tropaeolin 000, and Tropaeolin 00 were prepared by heating [Zn_0.67Al_0.33(OH)₂](CO₃)_0.165 · 0.5H₂O with acidic forms of the dye solutions in an open reaction vessel. The intercalates were characterized by chemical and thermal analysis, X-ray powder diffraction and UV–VIS spectroscopy. A possible arrangement of the dye molecules in the intercalates was suggested on the basis of their chemical compositions and interlayer distances, by taking into account van der Waals dimensions of the guest molecules and by assuming that the structure of the host layers is not changed during the intercalation process.This revised version was published online in July 2005 with a corrected issue number.     

Intercalation of cyclic ketones into vanadyl phosphate

Intercalation compounds of vanadyl phosphate with cyclic ketones (cyclopentanone, cyclohexanone, 4-methylcyclohexanone, and 1,4-cyclohexanedione) were prepared from corresponding propanol or ethanol intercalates by a molecular exchange. The intercalates prepared were characterized using powder X-ray diffraction and thermogravimetric analysis. The intercalates are stable in dry environment and decompose slowly in humid air. Infrared and Raman spectra indicate that carbonyl oxygens of the guest molecules are coordinated to the vanadium atoms of the host layers. The local structure and interactions in the cyclopentanone intercalate have been suggested on the basis of quantum chemical calculations.     

Intercalation of Dimethyl Carbonate, Diethyl Carbonate and Ethylene Carbonate into Vanadyl Phosphate

Intercalation compounds of vanadyl phosphate with dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were prepared from VOPO₄·2C₂H₅OH intercalate by a molecular exchange. The intercalates prepared were characterized using powder X-ray diffraction and thermogravimetric analysis. The EC intercalate is stable at ambient conditions, whereas the DMC and DEC intercalates transform to vanadyl phosphate dihydrate. Infrared spectra indicate that carbonyl oxygens of the guest molecules are coordinated to the vanadium atoms of the host layers. The arrangement of the guest molecules in the interlayer space was proposed.     

Intercalation of 1,2-alkanediols into Vanadyl and Niobyl Phosphate

Intercalation compounds of VOPO₄and NbOPO₄ with 1,2-alkanediols (from C3 to C16)have been prepared. The diol molecules are placedbetween host layers in a bimolecular way with theiraliphatic chains tilted at an angle of 70°. Itwas found that the intercalates contain 1.5 moleculesof diol per formula unit. Three ways of bonding of thediol molecules to the host layers are proposed. Twomolecules of diol are coordinated to the metal atomsby their first and second oxygen, respectively. Thethird diol molecule is anchored in the interlayerspace by H-bonds.     

Intercalation of 1,2-Alkanediols into α-Zirconium Hydrogenphosphate

Intercalation compounds of α-Zr(HPO₄)₂ · H₂O with 1,2-alkanediols (from C3 to C16) have been prepared by replacing 1-propanol in α-Zr(HPO₄)₂ · 2C₃H₇OH with the desired 1,2-alkanediols by a treatment in a microwave field. It was found that the intercalates contain 1.5 molecules of diol per formula unit. The diol molecules are placed between the host layers in a bimolecular way with their aliphatic chains tilted at an angle of 51°. The diol molecules are anchored in the interlayer space by H-bonds. A mixed intercalate, containing 1,2-butanediol and 1,2-decanediol in a roughly equimolar ratio, is formed when the α-Zr(HPO₄)₂ · 2C₃H₇OH intercalate, suspended in a mixture of 1,2-butanediol and 1,2-decanediol, is exposed to microwave radiation. No new phase containing both types of the guest molecules was observed when the 1-propanol intercalate, suspended in a mixture of 1-propanol and 1,2-octanediol, is exposed to microwave radiation.     

Intercalation of cyclic ethers into vanadyl phosphate

Two cyclic ethers, tetrahydrofuran (THF) and tetrahydropyran (THP), were intercalated into vanadyl phosphate and characterized by X-ray powder diffraction, thermogravimetry, and IR and Raman spectroscopy. Both compounds contain one molecule of ether per formula unit of VOPO(4) and show high thermal stability in comparison with VOPO(4) intercalates with other organic guest molecules. Both ethers are anchored to the VOPO(4) host layers by their oxygen atoms, which are coordinated to the vanadium atoms of the host. The probable arrangement of the tetrahydropyran molecules in the host interlayer space is derived from molecular simulations by the Cerius(2) 4.5 program.     

Fourier Transform Infrared Spectra of Naphthalene Disulfonates between Layers of Mg and Al double Hydroxide: Intercalation by Means of Coprecipitation and Direct Observation of Coordination from the Interlayer Anion to the Metal Cation in the Layer

A Mg/Al-layered double hydroxide with interlayernaphthalene-2,6-disulfonate having a basal spacing of1.68 nm was prepared by means of the coprecipitationmethod. The results of powder X-ray diffractionare compared with those of other intercalates whichhave interlayer naphthalene disulfonates. Fouriertransform infrared spectra of the LDH intercalatedcompounds reveal that the organic molecules located inthe interlayer region are stable. Coordinationfrom the oxygen atom in the –SO₃ ^- group of the interlayer molecules to the metal cation in the layeris observed.     

Intercalation of 2-Naphthol-3,6-disulfonate, 9,10-Anthraquinone-2,6-disulfonate, and 9,10-Anthraquinone-2-sulfonate Anions into Zn–Al Layered Double Hydroxide

The intercalates of 9,10-anthraquinone-2,6-disulfonate, 9,10-anthraquinone-2-sulfonate, and 2-naphthol-3,6-disulfonate anions were prepared by heating [Zn_0.67Al_0.33(OH)₂](CO₃)_0.165 · 0.5H₂O with a solution of corresponding acid in an open reaction vessel. The intercalates were characterized by chemical and thermal analysis, X-ray powder diffraction and UV-vis spectroscopy. Thermal behavior of the intercalates prepared was followed by in situ X-ray diffraction. Dehydration was reversible for all three intercalates. If the samples dehydrated at 400 °C reacted with water, brucite-like layers of the host were reconstructed. Received in final form: 14 January 2005     

Intercalation behavior of calcium phenylphosphonate dihydrate CaC6H5PO3·2H2O

Intercalates of calcium phenylphosphonate dihydrate with 1-alkylamines (C₂–C₁₀), 1-alkanols (C₃–C₁₀), 1,ω-amino alcohols (C₂–C₅), pyridine, morpholine, piperazine, aniline and 1-naphthylamine were prepared and characterized by powder X-ray diffraction and thermogravimetric analysis. The intercalates of alkanols and alkylamines are unstable at ambient conditions and the guest molecules are tilted to the host layers at an angle of 40°. The amino alcohol intercalates are stable and their basal spacings are very similar for all amino alcohols used and, in the case of ethanolamine and propanolamine, they contain co-intercalated water. Also arylamines and nitrogenous heterocycles form stable compounds. The general formula of these intercalates is CaC₆H₅PO₃·xH₂O·y(guest) and their basal spacings are from 15.39 to 15.78 Å.     

Host—guest Complementarity and Crystal Packing of Intercalated Layered Structures

Intercalated layered structures are analyzed in order to estimate the rules governing their crystal packing. An overview is given on structural types of layered intercalates based on various types of host structures and guest species. The factors describing the host–guest complementarity in intercalated layered structures like: the character of active sites, the host–guest and guest–guest interactions, the size of guests and topology of layers are investigated and their effect on crystal packing is illustrated on examples. Special attention will be paid to the conditions for the regular ordering of guests in the interlayer space, as the requirement of structure ordering is of great importance in design of intercalates for special applications, where one has to control the interlayer porosity or electronic properties of guest molecules etc. A method of structure analysis based on a combination of molecular modeling and experiments has been worked out for intercalates. Molecular modeling (force field calculations) in conjunction with experiments (diffraction methods and vibration spectroscopy) enables us to analyze the disordered intercalated structures, where the conventional diffraction analysis fails.     

Vibrational spectroscopic studies of three dimensional host lattices formed by pyrazine bridges between tetracyanonickelate layers

Three dimensional host lattices have been developed by forming bridges with bidentate pyrazine molecules between adjacent tetracyanonickelate polymeric layers of Ni(II) or Cd(II). The Fourier-transform IR and Raman spectra (4000-200 cm^–1) of the compounds with the general formula M(pyz)Ni(CN)₄, (where M = Ni or Cd) are reported. These host lattices can include benzene molecules but it is found that aniline molecules cannot be included in these structures. They, however, form complexes with the formula M(an)₂Ni(CN)₄, by replacing pyrazine ligands. A monodentate pyrazine complex of Cd(II) with the formula Cd(pyz)₂Ni(CN)₄ has also been prepared.     

Electrostatic complex of didodecyldimethylammonium and DNA: Langmuir monolayer, Langmuir–Blodgett film and dye recognition at air/water interface

DNA–didodecyldimethylammonium (DNA–DDDA) electrostatic complex was prepared and characterized through Fourier transformation infrared (FT-IR), ¹H NMR and circular dichroism (CD) spectroscopy. When the dye molecule aqueous solutions were used as the subphase, the interaction between three dye molecules, acridine orange (AO), ethidium bromide (EB) and 5,10,15,20-tetrakis(4-N-methylpyridyl)porphine tetra(p-toluenesulfonate) (TMPyP) and the complex at air/solution interface were investigated through the surface pressure–area (π–A) isotherms, Brewster angle microscopy and UV-Vis spectroscopy, respectively. Our investigation indicates that the interaction capabilities of the three dyes to DNA–DDDA complex are different and present an order of TMPyP>AO>EB. For the interaction forms, we believe that TMPyP intercalates into the double helix of DNA, and AO adsorbs onto the surface of the DNA. As for EB, the measured signal is too weak to give a definite interaction form in the present experiment.     

D-A-D type dinitriles with vapor-dependent luminescence in the solid state

D-A-D (Donor-Acceptor-Donor) type dinitriles linked by a styryl or phenylethynyl group have been prepared. These groups were introduced to increase the flexibility and the size of the π-conjugation in the chromophores. Both compounds showed strong emission in the solid state, AIE (aggregation-induced emission) behavior, and mechanochromism. The fluorescence color of ground powder changed by organic solvent vapor (vapochromism). Especially, the emission color of the styryl dinitrile after exposures depends on the solvent, while that of the phenylethynyl dinitrile is the same after exposure to different solvents. These results were explained by single crystal and powder XRD measurements, which revealed that the flexible styryl linker leads to a loose crystal packing, resulting in a dinitrile with multi-state microcrystalline structures. This methodology based on the flexible linker allows for the detection of small organic molecules without transition metals.     

Structure analysis of intercalated layer silicates: combination of molecular simulations and experiment

Na(+)-montmorillonite type Wyoming, cloisite Na(+) from Southern Clay Products, Inc., was intercalated (i) with octadecylammonium cations and subsequently intercalated with octadecylamine molecules, (ii) with dodecylamine molecules, and (iii) with octylamine molecules to determine the applicability of these intercalates for nanocomposite materials on the base of polymer/clay. The structures were determined on the basis of a combination of results from X-ray diffraction and molecular simulations. The calculated values of basal spacings are in good agreement with experimental basal spacings when experimental samples were prepared. The interlayer space of intercalated montmorillonite shows a monolayer or bilayer arrangement of alkyl chains in dependence on the concentration of the intercalation solution. The values of the total sublimation energy, interaction energy, and exfoliation energy were calculated for all investigated samples. Low values of exfoliation energies lead to better exfoliation of intercalated silicate layers and this material appears suitable for use as a precursor for polymer/clay nanocomposites. The values of exfoliation energy for the investigated samples show that montmorillonite intercalated with dodecylamine or octadecylamine molecules is suitable for exfoliation of silicate layers.     

Poly(ethylene-oxide)-para-disubstituted benzene intercalates. Molecular conformation of the polymer molecule from far infrared spectra

The far infrared spectra of various poly(ethylene oxide)-para-disubstituted benzene intercalates are reported. From a detailed discussion, it is strongly suggested that the formula of these intercalates is either [(p-C₆H₄XY)₃(CH₂CH₂O–)₁₀] _n (for XY=ClCl, BrBr, BrCl, ICl, ClF and CH₃Br) or [(p-C₆H₄XY)₂(CH₂CH₂O)₇] _n (for XY=BrF and IF). In both cases the conformation of the polymer molecule is nearly TTG. In addition the previously described relative disposition of the host and guest molecules is confirmed.     

Intercalation of Azo Compounds into Layered Aluminium Dihydrogentriphosphate and a Layered Double Hydroxide

The inner surfaces of inorganic layered compounds such as aluminium dihydrogen-triphosphate (ADHP) and layered double hydroxide (LDH) were modified by azo compounds. Upon intercalation of 4-phenylazoaniline and 4,4-azodianiline into ADHP, the interlayer spacing increased from 6.4 to 21.5 Å and 20.6 Å, respectively. The intensity of IR peaks due to P-–OH of ADHP and amino groups of guests decreased by the thermal treatment of the intercalates. The interlayer spacings also decreased to 16.9 Å and 16.7 Å, respectively, indicating a dehydration reaction between P–-OH and amino groups. The LDH inner surface was modified by the reaction with trans-p-phenylazobenzoylchloride (PAB-Cl). Upon surface modification, the interlayer spacing increased from 7.6 Å to about 27 Å. The absorption of this surface-modified LDH near 410 nm increased upon irradiation with UV light and decreased upon irradation with visible light, indicating the occurrence of trans–cis isomerization of PAB-Cl between the layers.     

Synthesis, characterization and spectroscopic properties of novel periphery – functionalized unsymmetrical porphyrazines containing mixed dithienylpyrrolyl and dimethylamino groups

Following our previous report on a novel class of C₄ symmetric porphyrazines bearing 2,5-dimethylpyrrolyl and methyl(3-pyridylmethyl)amino groups in the periphery, here we report the synthesis and characterization of unsymmetrical porphyrazines with peripheral 2,5-di(2-thienyl)pyrrolyl and dimethylamino groups that break the molecular C₄ symmetry. The porphyrazines were prepared via macrocyclization reactions of a dinitrile precursor. Variable-temperature ¹H NMR experiments, single crystal X-ray work and UV–Vis spectra in different solvents of the unsymmetrical magnesium porphyrazine provided information on the structural and electronic features of the entire macrocyclic system. A detailed discussion of the UV–Vis spectra in different solvents emphasizes the role played by the extended peripheral 2,5-di(2-thienyl)pyrrolyl substituent.