4142-59-0Relevant academic research and scientific papers
Mono(aryloxido)titanium(IV) Complexes and their application in the selective dimerization of ethylene
Cazaux, Jean-Benoit,Braunstein, Pierre,Magna, Lionel,Saussine, Lucien,Olivier-Bourbigou, Helene
experimental part, p. 2942 - 2950 (2011/05/13)
We report on the synthesis of mono(aryloxido)titanium(IV) complexes of general formula [Ti[O(o-R)Ar]X3), with X = OiPr, ArO = 2-ie.rr-but:yl-4-methylphenoxy and. R = CMe3 (2a), CMe2Ph (2b) and CH2NMe2 (2c). Attempts to reach pure mono(aryloxido) complexes when R = CH2NMe(CH2Ph) (2d) or CH2N(CH2Ph)2 (2e) were unsuccessful, When R = CH2OMe, the analogous mononuclear complex was not obtained, and instead, a dinuclear complex [(2-ieri-butyl-4methyl-6- methoxymethylphenoxy) TiCl(OiPr)(H2-OiPr)2TiCl(OiPr) 2] (3) was formed. Complexes 2b and 3 were characterized by single-crystal X-ray diffraction, The former contains a tetrahedrally coordinated. TiIV centre, whereas in the latter the aryloxido ligand behaves as a chelating-bridging ligand between the two, chemically very different metal centres that form two face-sharing octahedra, Different synthetic approaches starting from. [Ti(OiPr)4] or [TiCl(OiPr) 3] were evaluated and are discussed, The hemllabile behaviour of the aryloxido ligand. resulting from, reversible coordination of its side arm was studied by variable-temperature 1H NMR spectroscopy for 2c (R = CH 2NMe2). Complexes 2a-d were contacted, with ethylene and AlEt3 as cocatalyst, When activated with AlEt3 (3 equiv.) at 20 bar and 60 ° C, complex 2c exhibits interesting activity (2100 g/gTi/h) for the selective dimerization of ethylene to 1-butene (92% C 4"=; 99+% C4=1), Noticeable differences in catalyst activity were observed when the R group was modified,
Synthesis and study of the antiradical activity of substituted hydroxybenzylamines and their hydrogen chloride salts
Dyubchenko,Nikulina,Terakh,Kandalintseva,Markov,Grigor'Ev,Prosenko
, p. 330 - 334 (2007/10/03)
Different alkylated hydroxybenzylamines and their hydrogen chloride salts were synthesized. The rate constants of their reactions with peroxide radicals k1 and the stoichiometric factors of inhibition f were measured in the initiated oxidation of cumene and methyl oleate. Copyright
Heterocyclic Spirocyclohexadienones from Substituted Phenols
Moehrle, H.,Schake, D.
, p. 1859 - 1868 (2007/10/03)
Mannich bases were prepared from substituted phenols with aliphatic amines and formaldehyde.Amine exchange with N-methyl-2-naphthylamine followed by a Hofmann Martius rearrangement gave rise to o,o'-amino-hydroxy-diphenylmethane derivatives.Under cyclization conditions some of these compounds produced spirocyclohexadienones, which are the ipso analogs to the hypothetic intermediates postulated in the aminomethylation mechanism of phenols. - Keywords: Mannich Reaction; Phenol Dienone Tautomerism; Hofmann Martius Rearrangement
