The influence of ionic liquid's nature on free radical polymerization of vinyl monomers and ionic conductivity of the obtained polymeric materials

Various 1,3‐dialkylimidazolium and tetraalkylphosphonium ionic liquids (ILs), including novel ones, have been studied as reaction media for free radical polymerization of methyl methacrylate (MMA), acrylonitrile (AN) and 1‐vinyl‐3‐ethylimidazolium salts (ViEtIm⁺)Y^?. The influence of IL's nature upon the polymer formulation was investigated. The use of different ionic liquids allows not only to obtain the polymers with high molecular weight (PMMA, up to 5,770,000 g/mol; PAN, up to 735,000 g/mol and poly[(ViEtIm⁺)Y^?], up to 1,130,000 g/mol) in high yields, but also to control the polymerization rate and molecular mass. The physicochemical characteristics, including mechanical properties, thermal stability and heat‐resistance of the obtained polymers were studied in order to compare with those of polymers prepared in a traditional media. It was found that elongation, tensile modulus and strength of PAN, which was synthesized in ionic liquid, are reliatively higher. The influence of IL's nature upon their ionic conductivity and the formation of conductive polymers from molten‐salt‐type vinyl monomers was investigated. Molecular design of the polymers simultaneously with the influence of IL's nature in order to achieve higher ionic conductivity is discussed. Flexible, transparent polymer films, obtained in different ways, show relatively high ionic conductivity (of about 10^?5 S cm^?1 at 20°C). Copyright © 2006 John Wiley & Sons, Ltd.     

Complexes of αω-bis(3,3-dialkyldiaziridin-1-yl)alkanes and their bis(2-arylcarbamoyl) derivatives with cadmium and nickel salts

Complexes of αω-bis(3,3-dialkyldiaziridin-1-yl)alkanes and their bis(2-arylcarbamoyl) derivatives with Cd²⁺ and Ni²⁺ salts were synthesized. The X-ray diffraction study showed that only one molecule of the starting bis-diaziridine is involved in the complexation. The Cd²⁺ complexes have octahedral geometry. The Ni²⁺ complexes are either square-planar or octahedral. One of the octahedral Ni²⁺ complexes crystallizes in the chiral space group P2₁. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 53–59, January, 2008.     

4-(1-Alkylbenzimidazol-2-ylazo)-2-pyrazolin-5-ones: specific features of prototropic tautomerism

Quantum chemical calculations, ¹H and ¹³C NMR, and X-ray studies showed that, in contrast to 4-arylazo-2-pyrazolin-5-ones, 4-(1-alkylbenzimidazol-2-ylazo)-2-pyrazoline-5-ones mainly exist in the condensed phase as unusual ketoazine tautomers of high polarity, while the ketohydrazone tautomer stabilized by intramolecular hydrogen bond apparently predominates in the gas phase. According to calculations, various types of tautomerism are possible for 4-(benzimidazol-2-ylazo)-2-pyrazolin-5-ones, including mono- and bimolecular 1,3-, 1,5-, and 1,7-prototropic migrations proceeding by the single- and double-proton transfer mechanism with low activation energies (ΔE ^≠ ≈ 2–14 kcal mol⁻¹). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1467–1478, July, 2008.     

Synthesis and condensation reactions of the boron difluoride complex with 3-acetyl-4-hydroxy-1-methyl-2-quinolone

A reaction of 3-acetyl-4-hydroxy-1-methyl-2-quinolone with boron trifluoride etherate gave its boron difluoride complex. Condensation of this complex with various carbonyl compounds afforded new 2-quinolone derivatives (polymethine and styryl dyes) that intensely absorb in the visible region of the spectrum and show effective fluorescence. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1701–1706, August, 2008.     

Thermal arene exchange in the naphthalene complex [CpRu(η<Superscript>6</Superscript>-C<Subscript>10</Subscript>H<Subscript>8</Subscript>)]<Superscript>+</Superscript>

Naphthalene in the [CpRu(⁶−C₁₀H₈)]⁺ complex (1) is substituted for other arenes under reflux in 1,2-dichloroethane to form the [CpRu(⁶-arene)]⁺ cations (arene = C₆H₆, 1,2-C₆H₄Me₂, 1,2,4,5-C₆H₂Me₄, or C₆Me₆) in 70–80% yields. The reaction is accelerated in the presence of a catalytic amount of acetonitrile. The structure of [1]PF₆ was established by X-ray diffraction.     

Two isostructural carboranes: 3‐phenyl‐1,2‐dicarba‐closo‐dodecaborane(12) and 1‐phenyl‐1,7‐dicarba‐closo‐dodecaborane(12)

Two phenyl‐substituted carboranes, 3‐phenyl‐1,2‐dicarba‐closo‐dodecaborane(12), C₈H₁₆B₁₀, (I), and 1‐phenyl‐1,7‐dicarba‐closo‐dodecaborane(12), C₈H₁₆B₁₀, (II), were found to be isostructural. Comparison of the bond angles at the ipso‐C atoms of the phenyl substituent for (I) and (II) [117.71 (3) and 118.45 (10)°, respectively] indicates that electron donation of the carborane cage for B‐ and C‐substituted carboranes is different.     

Synthesis of new acyclic aminophosphites and their chelate complexes with rhodium(i) and palladium(ii)

New acyclic aminophosphites (RO)₂POCH₂CH₂NMe₂ (PN) (R=Et, Prⁱ, or adamantyl) characterized by various steric requirements of the phosphorus center were synthesized. The reactions of the aminophosphites with Pd(COD)Cl₂ (COD is 1,5-cyclooctadiene) and [Rh(CO)₂Cl]₂ afforded the stable chelate mononuclear complexes PdCl₂(PN) and RhClCO(PN), respectively. The structures of the resulting compounds were established by¹H,¹³C, and³¹P NMR and IR spectroscopy, X-ray diffraction analysis, laser and plasma desorption mass spectrometry, X-ray photoelectron spectroscopy, and sedimentation analysis.     

Bispidine Platform as a Tool for Studying Amide Configuration Stability

In this work, the solution conformations of seventeen 3,7-diacyl bispidines were studied by means of NMR spectroscopy including VT NMR experiments. The acyl groups included alkyl, alkenyl, aryl, hetaryl, and ferrocene moieties. The presence of syn/anti-isomers and their ratios were estimated, and some reasons explaining experimental facts were formulated. In particular, all aliphatic and heterocyclic units in the acylic R(CO) fragments led to an increased content of the syn-form in DMSO-d₆ solutions. In contrast, only the anti-form was detected in DMSO-d₆ and CDCl₃ in the case when R = Ph, ferrocenyl, (R)-myrtenyl. In the case of a chiral compound derived from the natural terpene myrtene, a new dynamic process was found in addition to the expected inversion around the amide N-C(O) bond. Here, rotation around the CO-C=C bond in the acylic R fragment was detected, and its energy was estimated. For this compound, ΔG for amide N-C(O) inversion was found to be equal to 15.0 ± 0.2 kcal/mol, and for the rotation around the N(CO)–C^2′ bond, it was equal to 15.6 ± 0.3 kcal/mol. NMR analysis of the chiral bispidine-based bis-amide was conducted for the first time. Two X-ray structures are reported. For the first time, the unique syn-form was found in the crystal of an acyclic bispidine-based bis-amide. Quantum chemical calculations revealed the unexpected mechanism for amide bond inversion. It was found that the reaction does not proceed as direct N-C(O) bond inversion in the double-chair (CC) conformation but rather requires the conformational transformation into the chair–boat (CB) form first. The amide bond inversion in the latter requires less energy than in the CC form.     

First Trifluoromethylated Phenanthrolinediamides: Synthesis,Structure, Stereodynamics and Complexation with Ln(III)

The first examples of 1,10-phenanthroline-2,9-diamides bearing CF₃-groups on the side amide substituents were synthesized. Due to stereoisomerism and amide rotation, such complexes have complicated behavior in solutions. Using advanced NMR techniques and X-ray analysis, their structures were completely elucidated. The possibility of the formation of complex compounds with lanthanoids nitrates was shown, and the constants of their stability are quantified. The results obtained are explained in terms of quantum-chemical calculations.