Yu. N. Novikov

Iron-intercalated molybdenum disulfide obtained from single-layer dispersion

MoS[sub 2] intercalation compounds with transition metals could be of great interest for catalysis of petrochemical processes, and also from the magnetic point of view since, for two-dimensional metallic layers included into a diamagnetic matrix, unusual magnetic properties can be expected. Iron-intercalated molybdenum disulfide, obtained by flocculation of a MoS[sub 2] single-layer dispersion in the presence of ferrous sulfate, was studied by electron microscopy and Moessbauer spectroscopy. Iron was found to occur at both II and III oxidation states between the MoS[sub 2] layers. The formation mechanism of this intercalated compound and its composition are discussed.

NMR investigation on molecular mobility of pyrazole and pyridazineintercalated in layered α-zirconium phosphate

Abstract Intercalation compounds of α-zirconium phosphate with pyrazole and pyridazine have been investigated by solid state NMR measurements, in order to have information about the proton conduction mechanism.13C chemical shifts, obtained under CP MAS conditions, show that both heterocycle guest molecules are in the protonated state, at least partially. Proton spin-spin relaxation experiments have been carried out in the temperature range 200–400 K. At 273 K no molecular motions occur in either sample on the measurement time scale. With increasing temperature, a narrow component appears in the free induction decay of the pyrazole intercalate, which can be assigned to proton containing fragments involved in translational diffusion. This component is absent when all the mobile acidic protons are substituted by deuterons; this excludes translational mobility of the guest molecules and supports the Grotthus type mechanism previously proposed. No significant changes are observed in the free induction decay of the pyridazine intercalate with increasing temperature, thus indicating hindered rotation up to 350 K. These interpretations agree with the results obtained for both intercalation compounds from spin-lattice relaxation experiments in the temperature range 150–350 K.

A graphite oxide-based nickel catalyst for reductive dechlorination of polychlorinated aromatic hydrocarbons

Heterogeneous Ni-containing catalysts based on graphite oxide were prepared and their activity in the dechlorination of polychlorinated aromatic hydrocarbons by different organosilanes was studied.

Lamellar graphite compounds with potassium and benzene: structure and transformations

Abstract The thermal, oxidation and hydrolytic stabilities of the ternary lamellar graphite compound C 24 K(C 6 H 6 ) 3 have been investigated. The results of the study have suggested a model C 24 K(C 6 H 6 ) 3 structure according to which benzene penetrates both the interlayer space containing potassium and the unfilled interlayer graphite space, the benzene molecules being arranged at right angles to the carbon layers of graphite.

The formation of intercalation compounds of MoS2 with cations of alkali metals and alkylammonium from monolayer dispersion of molybdenum disulfide

Ion-exchange interaction of the monolayer aqueous dispersion obtained by hydration of crystalline LiMoS2 with Li, Na, K salts and alkyiammoniiim halides is studied. Intercalation compounds of MoS2 with hydrated inorganic cations as well as hitherto unattainable intercalation compounds of MoS2 with alkylammonium cations are shown to be formed under these conditions. The composition and structure of these compounds are investigated.

A novel type of reaction in the chemistry of graphite intercalation compounds. The preparation of alkali metal graphite intercalation compounds by ion exchange reactions

Abstract The treatment of KC8 or KC24 with a solution of LiCl or LiClO4 in tetrahydrofuran (THF) results in the exchange of K+ions in the GIC for Li+ ions. Depending on the ratio salt/GIC, ternary Li-THF-GICs with either d i = 12.5 A or d i = 7.16 A 5 have been obtained. Analogous reactions between KC8 or KC24 and solutions of NaI in THF lead to the formation of Na-THF-GIC with d i = 11.2 A . The same GIC was prepared by reactions of LiC6 or LiC12 and solutions of NaI in THF. Li-THF-GIC can be also obtained by reacting Na(NH3)xC14 with solutions of LiCl in THF. A model to explain the mechanism of ion exchange of intercalated alkali metal ions with ions in THF solution is proposed.

Comparative raman study of the Ti complex Cp2Ti(eta(2)-C-60) center dot C6H5CH3 and TixC60 films

Raman spectra from the first Ti fullerene complex Cp2Ti(η2-C60) · C6H5CH3 are presented. Compared to spectra of pure C60, the spectra of the Ti complex exhibit a number of new peaks due to the symmetry lowering for C60. The Ag(2) mode is downshifted by 12 cm−1 compared to C60, which corresponds to a charge transfer of one electron per Ti-C60 bond. This value (6 cm−1 for one transferred electron) is identical to the downshift of the Ag(2) mode in alkali metal fullerides with ionic bonding. The spectra of Cp2Ti(η2-C60) · C6H5CH3 were compared to the spectra of evaporated TixC60 films. The Ag(2) mode in Ti4C60 showed a downshift of about 25 cm−1 compared to pure C60, which corresponds to a charge transfer of one electron per Ti atom; this is similar to the ionic alkali metal fullerides and different from η2-C60-type bonding.

Radical functionalization of [60]fullerene and its derivatives initiated by the C(CF3)2C6H4F radical

It was found that the 2-(p-fluorophenyl)hexafluoroisopropyl radical produced by thermal dissociation of the Polishchuk dimer [C(CF3)2C6H4F]2 can withdraw, under mild conditions, the H atom from the methyl group of toluene and mesitylene to form the corresponding radicals, whose addition to [60]fullerene occurs more selectively than in the case of photochemical production of these radicals. Dynamics of the step-by-step multiaddition of the radicals to C60 was studied by ESR. It was found that the addition of benzyl radicals affords adducts containing from 3 to 5 benzyl groups, whereas no spin-adducts with five addends were observed for more bulky 3,5-dimethylphenylmethyl radicals. The interaction of 3,5-dimethylphenylmethyl radicals with the metal complexes (η2-C60[IrH(CO)(PPh3)2] and (η2-C60[Pd(PPh3)2] was studied for the first time. It was shown that the palladium derivative undergoes only demetallation. In the case of the Ir complex, up to 3 radicals add to the fullerene ligand in the same hemisphere where the transition metal is coordinated. The reaction rates are ∼5 times lower than those for C60. The ability of 2-(p-fluorophenyl)hexafluoroisopropyl radicals to dehydrogenate C60H36 was found.

Molecular dynamics in the ternary intercalation compounds of graphite with potassium and benzene

Abstract The proton spin-lattice relaxation was studied in the ternary graphite intercalation compound (GIC) KC 24 (C 6 H 6 ) 2.8 ± 0.2 . The relaxation was governed by the reorientations of the benzene molecules, and two types of benzene molecules with different reorientation behaviour were observed in this compound. In the thermal decomposition product of KC 24 (C 6 H 6 ) 2.8 ± 0.2 the relaxation proceeded via the paramagnetic centers.

New biintercalation GICs. The interaction of benzene with amalgam GICs

Abstract The interaction of benzene with ternary GICs MHgC8 (M = K, Rb) has been investigated and new quaternary compounds MHgC8(C6H6)2 were obtained. X-ray data, Fourier transform of 001 reflections and spin-lattice relaxation measurements show that benzene molecules intercalate into the empty galleries of the amalgam GICs.