Synthesis and inhibitory activity of alkyl(hydroxyaryl)amines

The reaction of ω-(4-hydroxyaryl)haloalkanes with various nitrogen-containing agents afforded primary, secondary, and tertiary amino derivatives of 2,6-dialkylphenols. For the compounds synthesized, the reaction rate constants with peroxide radicals were measured for cumene and methyl oleate oxidation. The total inhibitory activity in the model reactions of thermal autooxidation of lard and hexadecane was studied. The rate constants of alkyl(hydroxylaryl)amines are the same as those of the corresponding alkylphenols, whereas the total inhibitory activity of some alkyl(hydroxylaryl)amines exceeds substantially that for alkylphenols. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1107–1112, June, 2007.     

Structural aspect of the adduct formation mechanism of metal β-diketonate complexes with macrocyclic polyethers. The structure of the intermediate—The 1:1 guest-host complex of calcium nitrate with 18-crown-6

We compare the structures of intermediate and final products in adduct formation of metal β-diketonate complexes with macrocyclic polyethers using [Ca(NO₃)₂(18C6)] (I) and [Ca(HFA)₂(18C6)] (II), where 18C6 is 18-crown-6 and HFA is hexafluoroacetylacetone. Adduct formation occurs by replacement of nitrate groups in I by HFA ligands with preservation of the coordination number of calcium and the conformation of the macrocycle but with variation in the coordination polyhedron of calcium. Both structures have the same packing mode: the centers of the complexes (Ca atoms) are located in the nodes of planar nets (Shlafly symbol 4⁴) forming two stories parallel to the shortest translations of the monoclinic cell in the same space group C2/c. Because of great size and nonisometricity of HFA ligands as compared to the nitrate group, the planar nets in (II) are well separated, and the tetragons are substantially distorted as compared to those in (I). This structural mechanism of adduct formation is supposed to be true for other complex-forming metals and β-diketonate ligands. X-ray structural analysis and interpretation of results. Synthesis of single crystals. Instute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 3, pp. 56–66, May–June, 1994. Translated by T. Yudanova     

Intramolecular Dynamics and Molecular Structure of Europium(III) Chelate Complexes with Crown Ethers as Studied by NMR Spectroscopy

Earlier the intramolecular inversion of the 18-crown-6 molecules was found in the complex ion pairs [Ln(ptfa)₂ (18-crown-6)]⁺ [Ln(ptfa)₄]⁻ (H₂O)₄ where Ln = La(1), Ce (2), Pr (3), Nd (4), and ptfa is 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione. In this work the peculiarities of the molecular structure and dynamics were studied for [Eu(ptfa)₂ (18-crown-6)]⁺ [Eu(ptfa)₄]⁻ (H₂O)₄ (5) by NMR spectroscopy techniques. Through VT-NMR spectra analysis the temperature dependence was obtained for the rate constant. The free energy ΔG^‡(320) of 18-crown-6 ring inversion activation was found to be 65 ± 5 kJ mol⁻¹ for 5 in CDCl₃. This result is comparable with the earlier data [S.P. Babailov and D.A. Mainichev: J. Inclusion Phenom. Macrocyclic Chem. 43, 187–193 (2002)] for complexes 2, 3, 4 in deuterated toluene (ΔG^‡(320)=65 ± 9, 64 ± 9, 64 ± 9 kJ mol⁻¹ respectively). It was found by relaxation NMR spectroscopy that the effective distance between Ln and protons of the crown molecule is 4.5 ± 0.2 Å. The analysis of structural parameters testifies that the crown ether and chelated anions are in the first coordination sphere of a Ln cation. Obtained geometrical parameters show that the complex cations of Eu, Ce and Pr have similar spatial structures.This revised version was published online in July 2005 with a corrected issue number.     

NMR Studies of Mixed-Ligand Lanthanide Complexes in Solution: Pseudorotation and Ring Inversion of 18-Crown-6 Molecule in Cerium Subgroup Chelates

¹H and ¹³C NMR measurements are reported for the CDCl₃ and CD₂Cl₂ solutions of [La(NO₃)₃(18-crown-6)] (I), [Pr(NO₃)₃(18-crown-6)] (II) and [Ce(NO₃)₃(18-crown-6)] (III) complexes. Temperature dependencies of the ¹H NMR spectra of II have been analyzed using the dynamic NMR methods for multi-site exchange. Two types of conformational dynamic processes in II were identified (the first one with activation enthalpy ΔH ^‡=26 ± 4 kJ/mol is conditioned by interconversion of complex enantiomeric form and pseudorotation of macrocycle molecule upon the C ₂ symmetry axis, the second one with ΔH ^‡=46 ± 5 kJ/mol is conditioned by macrocycle molecule inversion). Studies of the values of the lanthanide-induced shifts revealed that the structure of complexes in solution is similar to that reported for the complex I in the crystal state.This revised version was published online in July 2005 with a corrected issue number.     

Synthesis and Antioxidant Properties of Unsymmetrical Sulfides Based on ω-(3,5-Di-tert-butyl-4-hydroxyphenyl)alkanethiols

Unsymmetrical sulfides were prepared by reactions of -(3,5-di-tert-butyl-4-hydroxyphenyl)alkanethiols with various alkyl halides, and their antioxidant activity with respect to thermal autooxidation of lard was studied in relation to their structure.     

Surface microstructure and morphology study of thin films produced from volatile fluorine-containing rare-earth β-diketonate complexes and their adducts

We present the results of a surface microstructure and morphology study of thin films produced from volatile fluorine-containing rare-earth β-diketonate complexes and their adducts. Films 0.2–0.4 μm in thickness were synthesized in vacuum by means of thermal deposition of the parent substances at a pressure of 5 × 10^?4?1 × 10^?3 Pa and a deposition rate of 3 × 10^?3 μm s^?1 (for NaNd(FOD)₄ films, the deposition rate was 8 × 10^?2 μm s^?1). The microstructure of films depends on the deposition conditions. The films of [NaNd(PTFA)₄] and [NaNd(FOD)₄] complexes and Ln(PTFA)₃ · S₁ adducts have an amorphous structure. The [NaNd(PTFA)₄(Phen)] and Nd(PTFA)₃ · S₂ films are characterized by a more ordered polycrystalline structure with the grain size ranging from 0.2 to 1.5 μm.     

NMR studies of mixed-ligand lanthanide complexes. Reaction of β-diketonates of the yttrium subgroup with 18-crown-6

Institute of Inorganic Chemistry, Siberian Branch, USSR Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 3, pp. 44–47, May–June, May–June, 1990.     

N-substituted hexamethyldisilazanes as new substances for the synthesis of functional films in the system Si-Ge-C-N-H

N-Organylbis(trimethylsilyl)amines of the general formula RN(SiMe₃)₂ (R = Me₃Si, Et₃Ge) were synthesized by reaction of sodium bis(trimethylsilyl)amide with the corresponding trialkylsilyl(germyl) halide. Their IR, UV, and ¹H, ¹³C, and ²⁹Si NMR spectra were studied, and saturated vapor pressures and thermal stabilities were determined. The possibility of using the RN(SiMe₃)₂ compounds as precursors in chemical vapor deposition of films with specified composition was estimated by thermodynamic modeling.     

Diol lipids

Conclusions We synthesized some diol analogs of phosphatidylcholine that contained an unsaturated aliphatic acid moiety, and specifically: 2-oleoyloxyethyl choline phosphate, 3-oleoyloxypropyl choline phosphate, 4-oleoyl-oxybutyl choline phosphate, 5-oleoyloxypentyl choline phosphate, and 6-oleoyloxyhexyl choline phosphate.See [1] for Communication 22.Translated from Izvestiya Akademii NaukSSSR, Seriya Khimicheskaya, No. 2, pp. 410–414, February, 1973.