Structure of Iron(III)-containing complexes based on the azomethine — 4,4′-dodecyloxy-benzoyloxybenzoyl-4-salicylidene-<Emphasis Type="Italic">N</Emphasis>′-Ethyl-<Emphasis Type="Italic">N</Emphasis>-ethylenediamine molecule

Iron(III)-containing complexes with an asymmetric tridentate azomethine 4,4′-dodecyloxybenzoyloxybenzoyl-4-salicylidene-N′-ethyl-N-ethylenediamine ligand with NO₃⁻, PF₆⁻, Cl⁻, and BF₄⁻ counterions are synthesized. The presence of the complexation ion is confirmed by the far FTIR spectra. The structure of the compounds is determined by the matrix-assisted laser desorption/ionizationtime of flight (MALDI-ToF) method. The results of mass-spectrometric studies are consistent with the elemental analysis data. The complexation of iron salts with the asymmetric tridentate ligand is found to yield compounds of the 1:1 composition with octahedral packing of iron in the complex.     

Sites for Methane Activation on Lithium‐Doped Magnesium Oxide Surfaces

Density functional calculations yield energy barriers for H abstraction by oxygen radical sites in Li‐doped MgO that are much smaller (12±6 kJ mol^?1) than the barriers inferred from different experimental studies (80–160 kJ mol^?1). This raises further doubts that the Li⁺O^.? site is the active site as postulated by Lunsford. From temperature‐programmed oxidative coupling reactions of methane (OCM), we conclude that the same sites are responsible for the activation of CH₄ on both Li‐doped MgO and pure MgO catalysts. For a MgO catalyst prepared by sol–gel synthesis, the activity proved to be very different in the initial phase of the OCM reaction and in the steady state. This was accompanied by substantial morphological changes and restructuring of the terminations as transmission electron microscopy revealed. Further calculations on cluster models showed that CH₄ binds heterolytically on Mg²⁺O^2? sites at steps and corners, and that the homolytic release of methyl radicals into the gas phase will happen only in the presence of O₂.     

Conversion of low spin states in a monochelate complex of Fe(III) with an asymmetric tridentate azomethine ligand

An iron(III)-containing complex with the asymmetric tridentate azomethine ligand 4,4′-dodecyloxybenzoyloxybenzoyl-4-salicylidene-N′-ethyl-N-ethylenediamine with a PF ₆ ^? counterion is obtained. The presence of the complexing ion is confirmed by far IR Fourier spectra. The structure of the compounds is determined by matrix-assisted laser desorption/ionization with a time-of-flight mass analyzer (MALDI-ToF). The results of mass spectrometric studies are consistent with the elemental analysis data. It is found that the complexation of iron salt with an asymmetric tridentate ligand results in the formation of compounds of the composition 1:1 with octahedral packing of a metal ion in the complex. The electrochemical behavior of the compound in organic solvents is examined. The EPR study shows that iron(III) ions are in both low spin (LS) and high spin (HS) states in the complex. The LS and HS iron(III) centers are coupled into dimers in which a water molecule and the PF ₆ ^? counterion act as bridges. It is also found that for LS complexes in the lowtemperature phase (4.2–300 K), the (d _xz ,d _yz )⁴(d _xy )¹ electronic state is the ground state. It is revealed that the conversion of the sample into a high-temperature liquid crystalline (387–405 K) phase is accompanied by the conversion of the LS states of the Fe(III) ion: (d _xz ,d _yz )⁴(d _xy )¹ ? (d _xy )²(d _xz ,d _yz )³. The conversion of LS states is temperature reversible and is driven by the temperature. X-ray crystallographic data confirm that the compound obtained consists of dimer formed by a hydrogen (O-H...F) bond.     

Preparation of 1-butyl-3-methylimidazolium salts and study of their phase behavior and intramolecular intractions

Seven organic salts of 1-butyl-3-methylimidazolium with anions Br⁻, BF₄ ⁻, NO₃ ⁻, SO₄ ²⁻, HSO₄ ⁻, SCN⁻, PO₄³⁻ were prepared. Structure of these compounds is elucidated and purity is confirmed. The products are characterized by melting point, thin layer chromatography, data of elemental analysis, cromatomass-, NMR and IR spectroscopy. All these compounds are ionic liquids, five are low temperature ones. Principal thermal characteristics are found that allow accounting for the phase behavior of the prepared compounds at their application. Existence of intramolecular and intermolecular interactions between the heterocyclic anion and inorganic cation in by means of the formation of hydrogen bond is established.