Subsolidus phase diagram of binary system in the perovskite type layer compounds (<Emphasis Type="Italic">n</Emphasis>-C<Subscript>n</Subscript>H<Subscript>2n+1</Subscript>NH<Subscript>3</Subscript>)<Subscript>2</Subscript>MnCl<Subscript>4</Subscript>

The thermotropic phase transitions in the perovskite type layer compound (n-C₁₀H₂₁NH₃)₂MnCl₄ and (n-C₁₄H₂₉NH₃)₂MnCl₄ were synthesized and, at the same time, a series of their mixtures C₁₀Mn-C₁₄Mn were prepared. The experimental binary phase diagram of C₁₀Mn-C₁₄Mn was established by differential thermal analysis (DTA), IR and X-ray diffraction. In the phase diagram new material (n-C₁₀H₂₁NH₃)(n-C₁₄H₂₉NH₃)MnCl₄ and two eutectoid invariants were observed, two eutectic points temperatures are about 29.8 and 27.9°C. Contrasting other similar system, there are three noticeable solid solution ranges (α, β, γ) at the left and right boundary and middle of the phase diagram.     

Solution ozonolysis of C<Subscript>70</Subscript>: stable products and chemiluminescence

For the first time the total and relative contents of the stable ozonolysis products of fullerene C₇₀ solutions were identified by IR spectroscopy and elemental and chemical analyses. At the 100% conversion of C₇₀ a mixture of products corresponding to the empirical formula C₇₀O_14.3H_0.21 (epoxides: polyketones: polyesters: secondary fullerene ozonides (SFOZ): acids = 1.07: 6: 6: 0.21: 1.02) is formed. The content of polyketones, polyesters, acids, and SFOZ increases during the whole ozonolysis time (1 h). The number of oxygen atoms in epoxides C₇₀O _n (n = 1–4) is lower than that in epoxides C₆₀O _n (n = 1–6) formed by the ozonolysis of fullerene C₆₀. The kinetic curve of accumulation of epoxides C₇₀O _n (n = 1–4) passes through a maximum, which is observed 0.5 min after the beginning of ozonolysis. No epoxides were identified among the products 3.5 min after the ozonolysis. The photoluminescence (PL) (λ_max = 645 and 685 nm) of fullerene polyketones in glassy EtO₂/EtOH solutions frozen at 77 K was observed. This PL is much brighter, than that of polyketones formed upon the ozonolysis of fullerenes C₆₀. For the first time the chemiluminescence (CL) was detected and studied upon the ozonolysis of C₇₀ solutions at 300 K. The CL emitters are excited states of fullerene polyketones. The CL spectrum is partially overlapped with the known CL spectrum appeared upon the ozonolysis of C₆₀ (λ_max = 685 nm) but contains the greater number of maxima (λ_max = 645 and 685 nm), which is related to a lower symmetry of the C₇₀ oxidation products.     

Electron interactions in the (η<Superscript>2</Superscript>-C<Subscript>60</Subscript>)Pd[P(Ph<Subscript>2</Subscript>)C<Subscript>5</Subscript>H<Subscript>4</Subscript>]<Subscript>2</Subscript>Fe complex

The electronic structure of the (η²-C₆₀)Pd[P(Ph₂)C₅H₄]₂Fe complex was calculated by the “hybrid” B3LYP method. Comparison of the experimental X-ray emission C-Kα spectrum and theoretical spectrum of the compound demonstrated that the electron interactions between the C₆₀ core, palladium atom, and organometallic fragment are described correctly in the framework of the quantum chemical method used. The electronic structure of the organometallic fullerene complex can be presented as a set of blocks of orbitals corresponding to different types of chemical bond. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2640–2644, December, 2005.     

Octafluorocyclohexa derivatives of [60]fullerene: C<Subscript>60</Subscript>(C<Subscript>4</Subscript>F<Subscript>8</Subscript>)<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> (<Emphasis Type="Italic">n</Emphasis> = 2, 3, 4, and 6)

Fluorocyclohexa adducts C₆₀(C₄F₈) _n were synthesized by high-temperature reaction of fullerene C₆₀ with 1,2-C₂F₄I₂ or 1,4-C₄F₈I₂ in sealed tubes. Their separation by HPLC allowed us to determine molecular structure (X-ray diffraction) of four new compounds C₆(C₄F₈) _n (n = 2, 3, 4, and 6). Structures of isomers C₆₀(C₄F₈) _n were discussed in terms of a concept of consecutive addition of C₄F₈ groups to the fullerene cage.     

Synthesis and structures of C<Subscript>60</Subscript> fullerene chlorides

Systematic study of chlorination of fullerene C₆₀ with inorganic chlorides SbCl₅, VCl₄, MoCl₅, and KICl₄ was carried out. Higher chlorofullerenes, viz., T _h -C₆₀Cl₂₄, C₆₀Cl₂₈, C ₂-C₆₀Cl₃₀, and D _3d -C₆₀Cl₃₀, can be prepared depending on the temperature and time of chlorination. The molecular and crystal structures of C₆₀Cl₂₄⋅VOCl₃, C₆₀Cl₃₀⋅2CS₂, and C₆₀Cl₃₀O_1.22 were determined by single-crystal X-ray diffraction. Fullerenes C₆₀Cl₂₈ and C ₂-C₆₀Cl₃₀ were shown to be only kinetically stable, whereas D _3d -C₆₀Cl₃₀ is a thermodynamically stable product. Transformations of less chlorinated fullerenes into more chlorinated products are accompanied by substantial changes in the addition patterns. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1608–1618, July, 2005.     

Electrochemical properties of transition metal complexes with C<Subscript>60</Subscript> and C<Subscript>70</Subscript> fullerne ligands (review)

t-The electrochemical properties of exohedral complexes of transition metals with metallofragments coordinated to C₆₀ and C₇₀ fullerene ligands in different coordination modes are surveyed. The effect of the nature, composition, and structure of metal-containing fragments on the electrochemical properties of these complexes and stability of products formed in the oxidation and reduction of complexes is discussed.     

Synthesis and EPR investigation of nitroxyl derivatives of fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript>

Nitroxide derivatives of C₆₀ and C₇₀ were obtained by [3+2] cycloaddition of 4-(4-azidophenyl)-2,2,5,5-tetramethyl-3-oxy-2,5-dihydroimidazol-1-oxyl to fullerenes. The products were isolated by TLC and studied by EPR and optical spectroscopy. Molecular rotation of the adducts was shown to slow down on successive addition of the nitroxides, rotational correlation times depending nearly linearly on the number of the nitroxides added. Investigation of photochemical stability of nitroxide derivatives of C₆₀ and C₇₀ in benzene-ethanol medium reveal that the dissolved oxygen quenches efficiently the excitation of nitroxide (λ = 250–400 nm). In the absence of oxygen photoexcitation converts nitroxides to diamagnetic products, presumably, hydroxylamines formed through the interaction with the solvent.     

Distribution coefficients in the water-dodecane system and the heats of adsorption of C<Subscript>1</Subscript>-C<Subscript>8</Subscript> alcohols on silica

Distribution coefficients in the water-dodecane system and the heats of adsorption of C₁-C₈ alcohols on silica (Silochrom S-80) were determined by gas chromatography. At low temperatures, C₁-C₄ alcohols were largely distributed in the aqueous phase, and C₆-C₉ alcohols were predominantly dissolved in the organic phase; C₅ alcohols had intermediate properties. Permittivity was found to correlate with log K _d, which allowed us to predict the character of the distribution of alcohols in the water-oil system. The heats and isotherms of adsorption were determined for the alcohols studied. The heats of adsorption of alcohols on silica monotonically increased in the series under consideration. For C₅-C₈ alcohols, they exceeded the heat of adsorption of water. The isotherms of adsorption were described by the Freundlich equation.     

Theoretical study of the structure of the C<Subscript>60</Subscript>@C<Subscript>450</Subscript> nanoparticle and relative motion of the encapsulated C<Subscript>60</Subscript> molecule

The equilibrium state of the C₆₀@C₄₅₀ nanoparticle was studied. The compound was found to be stable during the encapsulation of C₆₀ tubelene. The motions of tubelene in the confinement potential field of a closed C₄₅₀ nanotube, namely, the translational motion along the tubule axis and the rotational motion were investigated in detail. It is predicted that there is a nanogyroscope inside C₄₅₀, rotating in the field of the C₆₀ capsule. Its quantized rotational states were calculated. The nanoparticle structure and energy were investigated by the tight binding method using modified parameters.     

[η<Superscript>5</Superscript>-C<Subscript>9</Subscript>H<Subscript>5</Subscript>(1,3-SiMe<Subscript>3</Subscript>)<Subscript>2</Subscript>]HfCl<Subscript>3</Subscript>: A monomeric 12-electron half-sandwich complex

The half-sandwich hafnium complex [gh⁵-C₉H₅(1,3-SiMe₃)₂]HfCl₃ (II) has been synthesized for the first time. The molecular structures of II and its synthetic precursor C₉H₅(1,1,3-SiMe₃)₃ (I) have been determined by X-ray crystallography. Compound II in the crystalline state, is a rare example of a monomeric 12-electron half-sandwich complex.     

Generation of fullerenyl radicals and chemiluminescence in the (C<Subscript>60</Subscript>—R<Subscript>3</Subscript>Al)—O<Subscript>2</Subscript> system

Fullerenyl radicals (FR) RC₆₀ ^· and chemiluminescence (CL) are generated in the presence of O₂ in C₆₀—R₃Al (R = Et, Buⁱ) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R^· radical, which is an intermediate of R₃Al autooxidation, to C₆₀. Mass spectroscopy and HPLC were used to identify Et_nC₆₀H_m (n, m = 1–6), Et_pC₆₀ (p = 2–6), and dimer EtC₆₀C₆₀Et as stable products of FR transformations. As found by ESR, the EtC₆₀ ^· radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C₆₀— R₃Al)—O₂ system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O₂, which appear as broadening of the ESR signals. Chemiluminescence arising in the (C₆₀—R₃Al)—O₂ system is much brighter (I _max = 1.86·10⁸ photon s⁻¹ mL⁻¹) than the known background CL (I _max = 6.0·10⁶ photon s⁻¹ mL⁻¹) for the autooxidation of R₃Al and is localized in a longer-wavelength spectral region (λ_max = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter ³CH₃CHO* to the products of FR transformation: R_nC₆₀H_m, R_pC₆₀, and EtC₆₀C₆₀Et. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 205–213, February, 2007.     

Sorption of light fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript> on NORIT-AZO carbon

Sorption of fullerenes C₆₀ and C₇₀ from o-xylene, toluene, and dichlorobenzene solutions on NORIT-AZO carbons was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1638–1642.Original Russian Text Copyright © 2004 by Semenov, Seregin, Arapov, Charykov.     

Endohedral Complex of Fullerene C<Subscript>60</Subscript> with Tetrahedral N<Subscript>4</Subscript>, N<Subscript>4</Subscript>@C<Subscript>60</Subscript>

B3LYP/6-31G(d) hybrid HF/DFT and BLYP/6-31G(d, p) DFT calculations were carried out to determine the structural and electronic properties of the endohedral complex of C₆₀ with Tetrahedral N₄ (T_d N₄), N₄@C₆₀. It was demonstrated that N₄ was seated in the center of the fullerene cage and the tetrahedral structure of N₄ is remained in the cage. The formation of this complex is endothermic with inclusion energy of 37.92 kcal/mol. N₄ endohedral doping perturbs the molecular orbitals of C₆₀ not so much, the calculated HOMO–LUMO gaps, the electron affinity (EA) and the ionizational potential (IP) of N₄@C₆₀ are similar to that of C₆₀.     

Structure of heteroassociates formed in the HF-(C<Subscript>2</Subscript>H<Subscript>5</Subscript>)<Subscript>2</Subscript>O liquid system

The aim of this work was to determine the structure of stable heteroassociates (HAs) with the stoichiometric ratios 1:2, 2:1, and 4:1 of molecules formed in the HF-(C₂H₅)₂O binary liquid system. The stretching frequencies of HF molecules found for each HA using a special procedure for processing IR spectra were compared with the calculated frequencies V HF of the stable molecular complexes (HF)_m ((C₂H₅)₂O)_n (m = 1, 2, 4, 8; n = 1, 2) with different topologies by the density functional method (B3LYP/6-31++G(d,p)). As a result, it was shown that the most stable (among H-bonded complexes with the same stoichiometric ratio of molecules) HAs HF((C₂H₅)₂O)₂, (HF)₄ ((C₂H₅)₂O)₂, and (HF)₈-((C₂H₅)₂O)₂ formed in HF solutions in diethyl ether. All of them had a cyclic structure and a common peculiarity of structure: only one lone electron pair of the oxygen atom of the (C₂H₅)₂O molecules is involved in hydrogen bonding.     

Thermodynamic properties of aqueous-alcoholic solutions of sodium chloride. H<Subscript>2</Subscript>O-2-C<Subscript>3</Subscript>H<Subscript>7</Subscript>OH-NaCl

The temperature-concentration dependences of the NaCl activity coefficient in aqueous solutions of isopropanol (propanol-2) at temperatures of 298.15 and 323.15 K (solution ionic force, 0.01 to 3m; alcohol content, 10–60 wt %) were determined through the electromotive force method with an ion-selective electrode. A Pitzer model was used to mathematically describe the thermodynamic properties. The integral Gibbs energy of the solution formation of the H₂O-2-C₃H₇OH-NaCl ternary system was performed according to Darken’s method. The dissociation degree of salt in the investigated solutions was estimated using the literature data on the association constant of NaCl in aqueous-isopropanol solution.     

Features of the oxidation of C<Subscript>60</Subscript> and C<Subscript>70</Subscript> fullerites as studied by IR spectroscopy

Features of the oxidation of C₆₀ and C₇₀ fullerites were studied by infrared spectroscopy. It was shown that for C₆₀ fullerite, the presence of toluene residue reduces the temperature at which oxidation starts. The form of the toluene (solvate or nonsolvate) is not important. A low-frequency shift in the valence C-O-C vibrations of C₇₀ fullerene due to local steric strains was discovered.     

A Quantum Chemical Study of C<Subscript>60</Subscript>Cl<Subscript>30</Subscript>, C<Subscript>60</Subscript>(OH)<Subscript>30</Subscript> Molecules and Fe@C<Subscript>60</Subscript>(OH)<Subscript>30</Subscript> Endocomplex

(U)PBE0/cc-pVDZ method is used to study the structure of C₆₀Cl₃₀, C₆₀(OH)₃₀ molecules and Fe@C₆₀(OH)₃₀ endocomplex. The triplet state of the endocomplex is shown to be the lowest in energy among its four states corresponding to different spin multiplicities and positions of Fe nucleus within the fullerene cavity. This state is characterized by bonding between the iron atom and one of two benzenoid cycles of the carbon cage, six internuclear Fe–C distances (208 pm), and 1s²2s²2p⁶3s²3p⁶3d^7.24s^0.14p^0.3 electron configuration of iron with spin population of 2.36.     

Molecular structure of NiO<Subscript>2</Subscript>N<Subscript>2</Subscript>C<Subscript>16</Subscript>H<Subscript>14</Subscript> from gas-phase electron diffraction and quantum chemical data

Gas-phase electron diffractometry was used to study the molecular structure of N,N′-ethylenebis(salicylaldiminato)nickel(II), NiO₂N₂C₁₆H₁₄, [hereinafter Ni(salen)] at 583(5) K. The molecule has C ₂ symmetry with a practically planar structure of the NiN₂O₂ coordination unit and with internuclear distances r _α (Ni-O) = 1.882(21) Å and r _α (Ni-N) = 1.889(22) Å. The results of B3LYP/CEP-31G molecular structure calculations are in good agreement with experimental data, whereas the RHF/CEP-31G method significantly overestimates the Ni-N internuclear distance and gives worse results for other structural parameters. According to 3LYP/CEP-31G calculations, the ¹ A low-spin state is 28 kJ/mole lower in energy than the ³ B high-spin state.     

Arene complexes [(η-C<Subscript>5</Subscript>H<Subscript>5</Subscript>)M(η-C<Subscript>6</Subscript>R<Subscript>6</Subscript>)]<Superscript>2+</Superscript> (M = Rh,Ir)

The dicationic arene complexes [CpM(arene)](BF₄)₂ (arene = C₆H₆, 1,3,5-C₆H₃Me₃, or C₆Me₆) were synthesized by the reactions of the solvated complexes [CpM(MeNO₂)₃](BF₄)₂ (M = Rh, Ir) with benzene and its derivatives. The solvated complexes were generated in situ by abstraction of I^– from [CpMI₂]₂ with AgBF₄. A procedure was developed for the synthesis of the iodide [CpRhI₂]₂ based on the reaction of the cyclooctadiene derivative CpRh(1,5-C₈H₁₂) with I₂. The structure of the [CpRh(C₆Me₆)](BF₄)₂ complex was established by X-ray diffraction analysis.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1871–1874, September, 2004.     

Sorption of Light Fullerenes (C<Subscript>60</Subscript> and C<Subscript>70</Subscript>) on Materials Prepared by Sublimation of Graphite Rods

Sorption of fullerenes C₆₀ and C₇₀ from o-xylene, toluene, and o-dichlorobenzene solutions under static conditions on a sorbent prepared by sublimation of graphite rods was studied. The sorption isotherms of both fullerenes at 25°C were measured.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 345–346.Original Russian Text Copyright © 2005 by Semenov, Arapov, Charykov, Nekrasov, Alekhin, Gerasimov, Seregin.