Synthesis and transformations of metallacycles. 29. Direct alumination of olefins, conjugated dienes, and acetylenes with alkylhaloalanes catalyzed by Zr and Ti complexes

Catalytic methods were developed for the synthesis of acyclic 1,2- and 1,4-dialuminum compounds by the reactions of olefins, dienes, or acetylenes with R₂AlCl (R = Et, Et₂N, (cyclo-C₆H₁₁)₂N, BuⁿO, or n-C₆H₁₃O) in the presence of Ti- or Zr-containing complex catalysts and magnesium metal as an acceptor of chloride ions.     

Synthesis and transformations of metallacycles

Cyclometallation of C₆₀ fullerene with excess AlEt₃ in the presence of Cp₂ZrCl₂ (2 mol % with respect to [Al]) in a toluene solution at 22–23 °C was carried out. The reaction gave 2,3-fullerene-substituted aluminacyclopentanes, whose hydrolysis led to a mixture of hydrogen-containing ethylfullerenes of the type H _m C₆₀Et _m containing 1 to 12 ethyl groups. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 572–574, March, 1999.     

Synthesis and transformations of metallacycles. 23. Cp2TiCl2-Catalyzed cyclometallation of fullerene C60 with EtAlCl2

1-Ethyl-2,3-fullerenoaluminacyclopropanes (EtAl)_n(²-C₆₀) were synthesized by the reaction of fullerene C₆₀ with an excess of EtAlCl₂ in the presence of Mg and using Cp₂TiCl₂ as the catalyst in a THF--toluene solution at 20 °C. Deuterolysis of fullerenoaluminacyclopropanes afforded a mixture of deuteriofullerenes C₆₀D_m, where m = 6--12.     

Synthesis and transformations of metallacycles. 28. Reactions of allenes with EtAlCl2 and Et2AlCl catalyzed by Ti and Zr complexes

Catalytic cycloalumination of allenes with EtAlCl₂ in the presence of Ti or Zr complexes afforded methylidene- and alkyl(benzyl)idenealuminacyclopropanes and the corresponding aluminacyclopentanes, which were identified by analyzing the hydrolysis products. The reactions with the use of Et₂AlCl instead of EtAlCl₂ produced 1,2- and 1,4-dialuminum compounds.     

Synthesis and transformations of metallacycles. 26. Cp2ZrCl2-Catalyzed cycloalumination of substituted allenes with Et3Al

Catalytic cycloalumination of 1-alkyl(phenyl)allenes with triethylaluminum (5 mol.% of Cp₂ZrCl₂ as the catalyst, 20 °C, 4 h, hexane) afforded methylene- and alkyl(benzyl)idene-substituted alumacyclopentanes.     

Synthesis and transformations of metallacycles. 24. Zr-Catalyzed cycloalumination of asymmetrical disubstituted acetylenes

Cp₂ZrCl₂-Catalyzed cycloalumination of asymmetrical alkyl-, phenyl-, and allyl-substituted acetylenes under the action of Et₃Al was studied. The reactions afforded regioisomeric 2,3-disubstituted aluminacyclopent-2-enes whose yields and ratio depend on the nature of the substituents in the starting acetylenes.     

Synthesis and transformations of metallocycles

A regioselective method for the synthesis of 3-alkylalumacyclopentanes and 2-alkyl-1,4-dialuminiobutanes by the reactions of α-olefins with EtAlCl₂, ROAlCl₂, R₂NAlCl₂, or Et₂AlCl and the Mg−ClCH₂CH₂Cl−Cp₂ZrCl₂ (ZrCl₄) system was developed. For Part 18, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 778–784, April, 1999.     

Synthesis and transformation of metallacycles. 25. On a mechanism of the Ni(acac)2-catalyzed conversion of 3-alkyl-1-ethylalumacyclopentanes into 1,1-disubstituted cyclopropanes

The reactions of 3-alkyl-1-ethylalumacyclopentanes with allyl halides in the presence of Ni(acac)₂ as a catalyst were studied by dynamic NMR spectroscopy. Under the action of Ni complexes, alumacyclopentanes initially undergo intramolecular hydride transfer to give but-3-enyl(ethyl)aluminum hydrides and then react with the starting allyl halide, yielding but-3-enyl(ethyl)aluminum halides. Subsequent intramolecular carboalumination affords the corresponding 1,1-disubstituted cyclopropanes.     

Synthesis and conversions of metallocycles. 8. Regioselective β-hydrovinylation of α-olefins with the participation of metallocomplex catalysts

A new method is proposed for the synthesis of 2-vinylalkanes by the reactions of aluminocyclopentanes with allyl halides or ethers in presence of catalytic amounts of nickel or cobalt complexes.For previous communication, see [1].Institute of Chemistry, Bashkir Scientific Center, Ural Branch, Russian Academy of Sciences, 450054 Ufa. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 382–385, February, 1992.     

Conformational changes of DNA molecules in interactions with bioactive compounds. II. DNA complexes with coordination compounds of cobalt and ruthenium

A comparative analysis is made of the character of conformational changes of the DNA molecule in its interaction with coordination compounds of cobalt and ruthenium with different ligand sets in the coordination sphere of the ion. It is shown that during complexation global conformational changes of DNA (e.g., the reduction of its volume) practically do not depend on the location and on the binding mode of the complex ion, but are primarily determined by its charge, whereas local conformational changes of the macromolecule are very sensitive to the type of the complex being formed, as indicated by the change of spectral properties of DNA. An assessment of sizes of the particles that are formed as a result of DNA condensation due to its binding with trivalent ions of cobalt and ruthenium was performed with the use of dynamic light scattering.     

Synthesis of triple-decker iron and cobalt complexes with a central tetramethylphospholyl ligand

30-Electron triple-decker complexes [(η-C₅H₅)Fe(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ and [(η-C₄Me₄)Co(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ with a central tetramethylphospholyl ligand were synthesized by stacking reactions of cationic fragments [(η-C₅H₅)Fe]⁺ and [(η-C₄Me₄)Co]⁺ with nonamethylphosphaferrocene (η-C₄Me₄P)Fe(η-C₅Me₅). Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1647–1649, September, 2000.     

Synthesis and transformations of metallacycles. 32. Novel method for the synthesis of cyclopentanols from aluminacyclopentanes

Cyclopentanols were synthesized by a one-pot method involving Cp₂ZrCl₂-catalyzed cycloalumination of -olefins with trialkylalanes followed by the in situ reactions of aluminacyclopentanes with esters in the presence of catalytic amounts of Cu, Ni or Pd salts and complexes.     

Synthesis and transformations of metallacycles. 30. Aluminacyclopentanes in the synthesis of secondary and tertiary alcohols

A method for the synthesis of secondary and tertiary alcohols was developed. The method is based on cycloalumination of olefins with trialkylalanes in the presence of Zr-containing catalysts followed by the CuCl-catalyzed in situ reaction of the corresponding aluminacyclopentanes with aldehydes or ketones.     

Synthesis,X-ray crystal structure and DFT studies of cobalt(II) and vanadium(V) complexes with N,N,O-tridentate aroyl-hydrazone based ligand

A new aroyl-hydrazone, 2-pyridine carboxaldehyde-derived hydrazone ligand and its cobalt(II) (1) and vanadium(V) (2) complexes were prepared. The structures of these compounds were investigated using elemental analysis, spectral (IR, UV), and X-ray diffraction measurements. The electrochemical properties of the complexes were studied by cyclic voltammetry. The hydrazone ligand acted as tridentate and coordinated to vanadium and cobalt via N-imine, N-pyridine, and O-benzohydrazide atoms. The Co(II) complex crystallizes in the monoclinic system, space group P2₁/c, and has a binuclear structure. Chloride ions behave as the linking bridge and a tridentate hydrazine ligand HL and water as the terminal capping ligands. The central Co(II) ion has distorted octahedral geometry. The vanadium(V) complex crystallizes in the monoclinic crystal system, space group P2₁/n, and can be described as having highly distorted trigonal-bipyramidal coordination. The geometries and electronic properties of the complexes were also obtained using DFT and TD-DFT calculations.     

Synthesis and transformations of metallacycles. 27. Quantum-chemical study of the mechanism of styrene catalytic cyclometallation with triethylaluminum in the presence of Cp2ZrCl2

Cyclometallation of olefins with AlEt₃ in the presence of Cp₂ZrCl₂ affording five-membered monosubstituted cyclic organoaluminum compounds, was studied by the semiempirical quantum-chemical PM3 method. The proposed model of catalytic cycloalumination of styrene catalyzed by Cp₂ZrCl₂ is in a good accordance with experimental data obtained by dynamic NMR spectroscopy.     

A novel reaction of cycloalumination of olefins and acetylenes mediated by metallocomplex catalysts

Results obtained in the discovered by the authors catalytic cycloalumination reaction of unsaturated compounds in the presence of complex Ti- and Zr-containing catalysts are generalized. Cycloalumination of olefins and acetylenes proceeds under the action of Ti and Zr complexes in one stage to give novel classes of organoaluminum compounds (OAC): alumacyclopentanes, alumacyclopropanes, alumacyclopropenes, 1,4-dialumabutanes, and 1,2-dialumaethylenes. Based on these cyclic and acyclic OAC, essentially new preparative synthetic methods were elaborated. Novel reactions (β-ethylation, β-vinylation, reductive β-ethylation, and reductive β-vinylation) allow transforming olefins and acetylenes into fivemembered heterocycles, cyclopropanes, cyclobutanes, conjugated 1,3-dienes, primary alkyl iodides, 3-substituted alk-1-enes, andthreo-2,3-disubstituted butane-1,4-diols under mild conditions in high yields. The mechanisms of the presented reactions are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 816–823, May, 1998.     

Reactions of organic halides with organometallic compounds and terminal acetylenes catalyzed by palladium complexes

The results of the investigation of the cross-coupling of organometallic compounds and terminal acetylenes with organic halides catalyzed by transition metal complexes are generalized and analyzed. The influence of different factors on the rate and selectivity of catalytic cross-coupling is discussed. A detailed mechanism of the cross-coupling of Grignard reagents with organic halides is suggested. The cross-coupling reaction involving organotin compounds proceeds under very mild conditions in the presence of a ligand-free Pd catalyst. Examples of using catalytic cross-coupling of organic halides with organomagnesium, organozinc, and organotin compounds are presented.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2148–2167, September, 1996.     

Selective oxidation of ethylbenzene by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic polyethers

The oxidation of alkylarenes by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic ethers 18-crown-6 and 15-crown-5 was studied. The conditions for selective catalytic oxidation of ethylbenzene to α-phenylethyl hydroperoxide were determined. The kinetics of the accumulation of all oxidation products was studied. The order of the formation of the products at different stages of chain oxidation was determined. The activity of the complexes at the elementary stages of the chain oxidation of ethylbenzene is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 689–693, April. 1997.     

Synthesis and transformations of metallacycles 33. The first example of cycloalumination of cyclonona-1,2-diene with Et<Subscript>3</Subscript>Al and EtAlCl<Subscript>2</Subscript> in the presence of Cp<Subscript>2</Subscript>ZrCl<Subscript>2</Subscript>

Catalytic cycloalumination of cyclonona-1,2-diene upon treatment with Et₃Al and EtAlCl₂ in the presence of Cp₂ZrCl₂, leading to 10-ethyl-10-aluminabicyclo[7.3.0^1,9]dodec-8-ene (1) and 11-ethyl-11-aluminatricyclo[10.7.0^1,12.0^2,10]nonadeca-9,12-diene, respectively, was accomplished in high yields. A possibility for the selective transformation of compound 1 to 1-allyl-9-(pent-4-enyl)cyclonon-1-ene and 10-hydroxybicyclo[7.3.0^1,9]dodec-8-ene in one preparative step was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2156–2159, November, 2007.     

Thermal and structural studies of the chloro complexes of cobalt and copper with 2-amino-3-methylpyridine

The chloro complexes of 2-amino-3-methylpyridine with cobalt(II) and copper(II) have been prepared in ethanolic solution and solid compounds have been isolated. The compounds have stoichiometry ML₂Cl₂ whereM is Co²⁺ or Cu²⁺ and L is 2-amino-3-methylpyridine. Spectral and magnetic studies have been used to obtain information about the environment of the metal ion in these compounds. The compounds have tetrahedral structures. The thermal decomposition of each compound has been studied using thermogravimetry and differential thermal analysis. Thermogravimetry studies show that the cobalt complex forms an intermediate compound before the metal oxide is produced while the copper compound undergoes decomposition with loss of organic ligand and the formation of copper chloride which then decomposes to give an oxide of copper. The enthalpy of reaction for each of the processes has been calculated from the thermal analysis curves.