Alexey A. Vinogradov

Branched alkylphosphinic and disubstituted phosphinic and phosphonic acids: effective synthesis based on α-olefin dimers and applications in lanthanide extraction and separation

A number of mono-alkylphosphinic acids RCH2CH2CH(R)CH2P(O)(H)OH 8–12 were obtained via interaction of α-olefin vinylidene dimers RCH2CH2C(R)CH2 3–7 (R = n-butyl, 3, 8; isobutyl, 4, 9; n-octyl, 5, 10; isopropyl, 6, 11; cyclohexyl, 7, 12) with H3PO2 in an isopropanol medium at 90 °C. Hydrophosphinylation of 3 by 8 or PhPO2H2 at 140 °C resulted in disubstituted acids 13 and 14. Alkyl-methylphosphinic acids 15–19 and functionalized alkylphosphinic acids 20–22 have been synthesized via interaction of silyl ethers of mono-alkylphosphinic acids 8–12 with MeI, (2-chloromethyl)pyridine, acrylic acid or acrylamide. Non-catalytic hydroalumination of 3 with subsequent interaction with PCl3 and oxidation with SO2Cl2 led to the phosphonic acid anhydride, which was further used to obtain alkylphosphonic acids 23 and 24. It has been found that phosphinic acids 8–12 surpass di(2-ethylhexyl)phosphoric acid (extractant P204) in non-selective Ln3+ extractability (Ln = La, Pr, Nd, Dy and Lu). Significantly higher selectivity for heavy lanthanide extraction (Ln = Dy, Lu), compared to that of P204, is achieved by using a minimal excess of disubstituted phosphinic acids 13–24. Acid 13, which contains two branched substituents, demonstrated unique selectivity in the extraction of Lu in the presence of the other lanthanides. Dialkylphosphinic acids 16–18 and alkylarylphosphinic acid 14 possess a significant potential for the Pr/Nd pair separation. Taking into account the availability of 8–24 and the structural variability of the initial α-olefin dimers 3–7, the newly obtained compounds represent a promising group of rare-earth element extractants.

An efficient route for design of luminescent composite materials based on polyethylene containing europium dibenzoylmethanate

Luminescent composite materials based on linear polyethylene doped by a well dispersed tetrakis dibenzoylmethanate europium complex have been developed. The anion of the latter serves as an efficient light harvesting antenna and possesses the desired photophysical properties. The targeted modification of the Eu complex, namely introduction of a long hydrocarbon chain into the tetraalkylammonium cation [RNEt3]+, has ensured the compatibility of the complex with the polyethylene matrix. The [RNEt3]+ cation has been obtained by using long-chained 1-iodoalkanes synthesized via the Nd-catalyzed ethylene oligomerization process. The photophysical properties and the homogeneity of the obtained composites have been controlled by optical spectroscopy, luminescence intensity mapping as well as scanning electron microscopy.

Non-traditional Ziegler-Natta catalysis in a-olefin transformations: reaction mechanisms and product design

Abstract This paper describes our recent results in the field of zirconocene-catalyzed α-oltfin transformations, and focuses on questions regarding the reaction mechanism, rational design of zirconocene pre-catalysts, as well as prospective uses of α-olefin products. It has been determined that a wide range of α-olefin-based products, namely vinylidene dimers, oligomers and polymers, can be prepared via catalysis by zirconocene dichlorides, activated by a minimal (10–20 eq.) amount of MAO. We assumed that in the presence of minimal quantities of MAO, various types of zirconocene catalysts form different types of catalytic particles. In the case of bis-cyclopentadienyl complexes, the reactive center is formed under the influence of R2AlCl, which makes the chain termination via β-hydride elimination significantly easier, with α-olefin dimers being formed as the primary product. Bis-indenyl complexes and their heteroanalogues, form stable cationic catalytic particles and effectively catalyze the polymerization. Mono-indenyl and mono-substituted bis-cyclopentadienyl-ansa complexes catalyze α-olefin oligomerization. Effective catalysts of dimerization, oligomerization and polymerization of α-olefins in the presence of minimal MAO quantities are proposed. Prospects of using α-olefin dimers, oligomers and polymers in the synthesis of branched hydrocarbon functional derivatives (dimers), high quality, low viscosity motor oils (oligomers), and thickeners and absorbents (polymers) are examined.

Spontaneous Association of the Terbium Cyclopentadienyl Complexes under Controlled Hydrolysis

Controlled hydrolysis of the terbium cyclopentadienyl complexes results in the formation of the heteroligand tetranuclear terbium complex [{Tb(η5-C5H5)}3{Tb(THF)3}(μ3-Cl)(μ2-Cl)6(μ4-O)] (I), the recrystallization of which from tetrahydrofuran (THF) gives solvatomorph I · 0.5THF (Ia). According to the X-ray structure analysis data (CIF files CCDC 1569329 (I) and 1569330 (Ia)), the complexes are tetrahedral with the μ4-bridging O2– anion at the center of the tetrahedron. The cyclopentadienyl ligand in complex I is shown to act as an “antenna” providing luminescence of the complex.

(2R,3R)-1,4-Dioxa­spiro­[4.4]nonane-2,3-di­carb­oxy­lic and (2R,3R)-1,4-dioxa­spiro­[4.5]decane-2,3-di­carb­oxy­lic acids

The title compounds, (CH2)nC3H2O(COOH)2 (n = 4, 5), display intermolecular hydrogen bonding, forming a two-dimensional framework.

Crystal structure of (2,2′-bi­pyridine-κ2N,N′)-trans-bis­(tert-butyl­dimethyl­sil­yloxy)-cis-dioxidomolybdenum(VI)

In the title compound, [(tBuSiMe2O)2MoO2(2,2′-bipyridine)], the MoVI atom has a distorted octahedral environment with the siloxy substituents occupying the trans positions.

Crosslinked α-olefin-diene copolymers prepared using a metallocene catalyst deposited on the surface of SiO2-modified Fe3O4: Ferromagnetic oil sponges

The structure of zirconocene is determined experimentally. Zirconocene is found to catalyze effectively the copolymerization of α-olefins with nonconjugated dienes in the presence of minimal amounts of methylalumoxane as an organoaluminum activator. On the basis of a highly ferromagnetic carrier (a product of the reaction between Fe3O4 microparticles and Si(OEt)4), a deposited zirconocene catalyst is obtained. Using the latter, copolymers of α-olefins (1-hexene, 1-octene, and 1-decene) with 1,7-octadiene and 1,4- di(3-butenyl)benzene are synthesized. The obtained ferromagnetic copolymers demonstrate properties of effective absorbents of hydrocarbons, namely, oil sponges. A copolymer of 1-octene and 1,4-di(3-butenyl) benzene is found to possess the maximum adsorption capacity (up to 8) in the studied series.