- Impregnated Type Sorbents for Pb2+ Recovery from Neutral and Acidic Solutions
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Abstract: Synthetically convenient method for preparing phosphoryl podand 1,8-bis[2-(diphenylphosphorylmethyl)phenoxy]-3,6-dioxaoctane (L) has been developed. Recovery of Pb2+ with impregnated type sorbents was studied, the sorbents contain iso
- Bezhin,Dovhyi,Lyapunov, A. Yu.,Baulin,Baulin,Tsivadze, A. Yu.
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- Complexation of phosphoryl-containing mono-, bi- and tri-podands with alkali cations in acetonitrile. Structure of the complexes and binding selectivity
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We present experimental and theoretical studies on new ionophores (L) which possess a high complexation ability for Li+or Na+cations. Four tri-podands(R1-O-C2H4-)3N[R 1 = -CH2-P(O)Ph2(P1), -C2H4-P(O)Ph2 (P2), -o-C6H4P(O)Ph2 (P3) and -o-C6H4-CH2-P(O)Ph2 (P4)], one bi-podand (R2-O-C2H4-)2N-CH3 [R2 = -o-C6H4-CH2-P(O)Ph2 (P5)] and one mono-podand [R2-O-(CH2-CH2-O)3R2 (P6)] containing phosphine oxide terminal groups have been synthesised. Stability constants, enthalpies and entropies of their complexation with lithium, sodium and potassium thiocyanates have been determined in acetonitrile at 298 K by a calorimetric titration technique. We find that tri-podands form a variety of complexes [(M+)3L, (M+)2L, M+L and M+L2)], whereas the bi- and mono-podand form only M+L complexes with Li+ and Na+, and M+L and M+L2 complexes with K+. Formation of poly-nuclear (M+)nL complexes of tri-podands in solution has been confirmed by electro-spray mass spectrometry. At relatively small concentrations of the ligand (CL0)S P1 binds Na+ much better than Li+, whereas P4 and P5 display a remarkable Li+/Na+ selectivity; at large CL0 the complexation selectivity decreases. X-Ray diffraction studies performed on monocrystals of complexes of NaNCS with tri-podands P2 and P3 show that Na+ is encapsulated inside a 'basket-like' pseudocavity, coordinating all donor atoms of the tri-podand. Molecular dynamics simulations on P2, P3 and P4 and on their 1:1 complexes with M+ in acetonitrile solution suggest that the structures of M+L complexes in solution are similar to those found for P2 and P3 complexes in the solid state.
- Solov'ev, Vitaly P.,Baulin, Vladimir E.,Strakhova, Nadezhda N.,Kazachenko, Vladimir P.,Belsky, Vitaly K.,Varnek, Alexandre A.,Volkova, Tatiana A.,Wipff, Georges
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p. 1489 - 1498
(2007/10/03)
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- IR study of polymorphic modifications of 1,8-bis-3,6-dioxaoctane
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Phosphoryl-containing podand 1,8-bis-3,6-dioxaoctane exists in two crystaline polymorphic modifications with melting points of 131.5-133 and 112-113 deg C, which are distinguished, according to IR spectral data, by the presence of mechanical interaction of the same groups of atoms of different molecules and by conformations of the OCH2CH2O ethylene glycol fragments.
- Baulin, V. E.,Solotnov, A. F.,Tsvetkov, E. N.
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p. 337 - 339
(2007/10/03)
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- PHOSPHORUS-CONTAINING PODANDS. 4. EFFECT OF POLYETHER CHAIN LENGTH OF OLIGOETHYLENE GLYCOL BIS(ORTHO-DIPHENYLPHOSPHINYLMETHYL)PHENYL ETHERS ON THEIR COMPLEX-FORMING AND SELECTIVE PROPERTIES WITH RESPECT TO ALKALI METAL CATIONS
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Alkylation of o-(diphenylphosphinylmethyl)phenol by oligoethylene glycol ditosylates leads to a series of acyclic polyether complexing agents (podands) with phosphinylmethylphenyl terminal groups.A conductometric method in tetrahydrofuran-chloroform (4:1 by volume) has been used to determine the stability constants of the pobands with alkali metal 2,4-dinitrophenoxides.Several of the prepared ligands exhibited a high Li/Na, Na/K, and Li/K selectivity.For lithium and sodium cations, the curve of complex-forming ability against the overall number of donor centers in the structure of the podand has a maximum for the case of tetraethylene glycol bis(o-diphenylphosphinylmethyl)phenyl ether.For lithium cations, this compound surpasses the crown ethers in terms of its effectiveness and is the most powerful of the phosphoryl-containing complexing agents.For potassium, rubidium, and cesium cations, the complex-forming ability increases with increase in the number of oxygen donor centers in the polyether chain of the ligand.
- Evreinov,V. I.,Baulin, V. E.,Vostroknutova, Z. N.,Bondarenko, N. A.,Syundyukova, V. Kh.,Tsvetkov, E. N.
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p. 1828 - 1834
(2007/10/02)
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