Design of scaffold-like metal-organic coordination polymers based on dinuclear zinc(<Emphasis Type="SmallCaps">II</Emphasis>) carboxylate complexes

Two new scaffold-like metal-organic coordination polymers, [Zn₂ndc₂bpe]·DMF and [Zn₂ndc₂dedpbp] ·4DMF (ndc is 2,6-naphthalenedicarboxylate, bpe is trans-bis(4-pyridyl)ethylene, and dedpbp is 4,4′-diethynyl-4″,4′″-dipyridylbiphenyl), were synthesized by heating stoichiometric amounts of zinc(II) nitrate, H₂ndc, and bpe or dedpbp in DMF. The structures of the polymers were established by X-ray diffraction. Coordination of linear dicarboxylate ligands to zinc cations gives rise to planar square-grid networks, and additional coordination of the bifunctional nitrogen-containing ligands results in the formation of scaffold-like triply interpenetrating structures with a primitive cubic topology. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 219–223, February, 2007.     

First crystalline palladium(<Emphasis Type="SmallCaps">II</Emphasis>) carboxylate complex with divalent 3d metal,PdCo(μ-OOCMe)<Subscript>4</Subscript>(NCMe): synthesis and structure

The first heterometallic palladium(II) acetate complex with divalent 3d metal, PdCo(μ-OOCMe)₄(NCMe)·3 MeCN, was synthesized and structurally characterized. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2149–2152, September, 2005.     

Studies on crystals of <Emphasis Type="SmallCaps">d</Emphasis>-, <Emphasis Type="SmallCaps">l</Emphasis>-, and <Emphasis Type="SmallCaps">dl</Emphasis>-alaninato nickel(II) complexes

An attempt to link the heat of reaction obtained from analysis of UV spectra, bond energies deduced from crystallographic data and calorimetric measurements of [bis(d-, l-, and dl-alaninato)diaqua] nickel(II) dihydrate complexes to theoretical values obtained from calculation is described. The heat of reaction, which includes energy of ligand exchange in addition to crystal field stabilization energy of the three complexes, was calculated from changes in spectral shifts, bond lengths, and free energy between nickel(II) ion and the d-, l-, and dl-alanine complexed nickel(II) ion in aqueous solution. These investigations were done by UV–visible spectroscopy, X-ray crystallography, and isothermal calorimetry. The results reveal that the experimental heat of reaction based on the three mentioned parameters is in good agreement with the theoretical value. The results are found to be of considerable interest in its linking of spectrochemical quantities with thermodynamic functions.     

Dinuclear copper(<Emphasis Type="SmallCaps">II</Emphasis>) complexes with an unsymmetrical exchange fragment

New dinuclear copper(II) complexes with azomethines and hydrazones, which were produced by condensation of substituted salicylaldehyde derivatives with 1,3-diaminopropan-2-ol or carbo(thiocarbo) hydrazide, were studied. The structures of the [Cu₂L(μ-CH₂ClCOO)(CH₃OH)]·(CH₃OH) (L = C₁₇H₁₅N₂O₃) and [Cu₂L²(Cl₃CCO)(CH₃OH)]·H₂O (L² = C₃₂H₄₂N₄O₃) complexes were established by X-ray diffraction. The magnetic properties of these complexes, including the influence of the nature of the substituents in the ligands on exchange interactions, were studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 592–596, March, 2005.     

Synthesis,structure, and properties of <Emphasis Type="Italic">N</Emphasis>-(nitramino)phthalimide

N-(Nitramino)phthalimide R₂N-NHNO₂ (R₂NH is phthalimide) was synthesized by nitration of N-aminophthalimide with nitronium tetrafluoroborate. The structure of this compound was established by X-ray diffraction and confirmed by ¹H, ¹³C, and ¹⁴N NMR spectroscopy. The methylation of this compound with diazomethane affords a mixture of N-methyl (R₂N-NMeNO₂) and O-methyl (R₂N-N=N(O)OMe) isomers. The latter compound contains the previously unknown high-nitrogen-oxygen fragment. The thermal decomposition of N-(nitramino)phthalimide in vacuo at 80–100 °C gives 2H-3,1-benzoxazine-2,4(1H)-dione (isatoic anhydride) as the major product. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 625–630, March, 2008.     

Synthesis,structure, and properties of sodium <Emphasis Type="Italic">cis</Emphasis>-tetraethylcyclotetrasiloxanolate and new mesomorphic <Emphasis Type="Italic">cis</Emphasis>-tetra[ethyl(trimethylsiloxy)]cyclotetrasiloxane

Hydrolytic condensation of ethyltriethoxysilane in the presence of NaOH (Si: NaOH = 1) gave crystal solvate of sodium cis-tetraethyltetrasiloxanolate {(Na⁺)₄[EtSi(O)O⁻]₄}·nL (1, L = EtOH, H₂O) in high yield. The molecular structure of compound 1 at L = EtOH, n = 8 was determined by X-ray diffraction analysis. The reaction of compound 1 with trimethylchlorosilane affords cis-tetra[ethyl(trimethylsiloxy)]cyclotetrasiloxane cis-[EtSi(O)OSiMe₃]₄, which is the first representative of the group of mesomorphic cyclotetrasiloxanes containing alkyl groups. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–79, January, 2007.     

Synthesis and some properties of neodymium(<Emphasis Type="SmallCaps">III</Emphasis>) and dysprosium(<Emphasis Type="SmallCaps">III</Emphasis>) iodide hydrides LnI<Subscript>2</Subscript>H

The iodide hydrides NdI₂H (1) and DyI₂H (2) were obtained by the reactions of diiodides NdI₂ (3) and DyI₂ (4) with hydrogen at atmospheric pressure and temperature of 120–200 °C. Hydrolysis of products 1 and 2 gives hydrogen in a high yield. The reactions of 1 with phenol and of 2 with isopropyl alcohol in THF afford the iodide phenoxide NdI₂(OPh)(THF)₄ and iodide isopropoxide DyI₂(OPrⁱ)(PrⁱOH)₃, respectively. The reaction of 2 with cyclopentadiene is accompanied by disproportionation and gives, besides dihydrogen, Cp₂DyI(THF)₂ and DyI₃(THF)₃. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1887–1889, October, 2007.     

X-ray structures of iron(III) and cobalt(III) complexes containing 2-<Emphasis Type="Italic">S</Emphasis>-methyl-6-methyl-4-formylpyrimidine-<Emphasis Type="Italic">N</Emphasis>(4)-ethylthiosemicarbazone

Iron(III) and cobalt(III) complexes of types [Fe(LEt)₂]ClO₄·3/2C₆H₆ (1) and [Co(LEt)₂]ClO₄·2CH₂Cl₂ (2) with a new pyrimidine-derived thiosemicarbazone ligand, 2-S-methyl-6-methyl-4-formylpyrimidine-N(4)-ethylt-hiosemicarbazone (HLEt), having N, N, S donor centers have been synthesized and characterized by X-ray crystallography. The structural study shows distorted octahedral geometry for both 1 and 2 with MN₄S₂ chromophores. The space group of 1 is C2/c (monoclinic) and that of 2 is P2₁2₁2₁ (orthorhombic). The electrochemical electron transfer study in MeCN solutions shows a one-electron reductive response presumably due to a metal(III)–metal(II) couple.     

Complexation of Cu(II) with <Emphasis Type="SmallCaps">L</Emphasis>- and <Emphasis Type="SmallCaps">DL</Emphasis>-threonine: An ESR study

Complexation of Cu(II) ions with L- and DL-threonine in aqueous solution was studied. Treatment of the ESR spectra of solutions containing Cu(II) and threonine in various ratios and having various pH, involving total line shape analysis, revealed formation of geometric isomers of the complex ions [Cu(thrH_–1)₂]^2– differing in the mutual arrangement of the N and O atoms in the equatorial plane; the complexation and isomerization equilibrium constants were determined.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1388–1391.Original Russian Text Copyright © 2004 by Statsenko, Bolotin, Panyushkin.This revised version was published online in April 2005 with a corrected cover date.     

Physico-chemical characterization of anhydrous <Emphasis Type="Italic">D</Emphasis>-mannitol

In this work the solid-state characterization of anhydrous D-mannitol has been performed: α and β modifications can be distinguished only by XRPD and FTIR as they show melting temperature and enthalpy that are the same within the standard deviation. The understanding of the thermal behaviour of the δ form (obtained by re-crystallization in acetone) has required XRPD experiments performed at variable temperature. This form during heating undergoes a solid phase transition to α modification. By cooling a melted sample, under a wide range of experimental conditions, a very fast crystallization occurs. Independently of the starting crystal form (β or δ form), the re-crystallization of D-mannitol from melt always leads to α form.     

Crystal Structure of a New Modification of <Emphasis Type="Italic">cis</Emphasis>-Bis(pivalyltrifluoroacetonato)copper(II)

Powder and single-crystal X-ray diffraction study of cis-bis(pivalyltrifluoro-acetonato)copper(II) has been performed (Bruker AXS P4 automatic diffractometer, MoK _β radiation, t = −25°C). Crystal data for C₁₆H₂₀CuF₆O₄: a= 9.980(7) Å, b = 19.236(13) Å, c = 20. 771(14) Å, space group Pbca, V = 3987(5) ų, Z = 8, d _calc = 1.512 g/cm³. The square-planar environment of the Cu atom (Cu-O_av 1.904 Å, =O-Cu-O_av 92.4°) is completed to bipyramidal by the atoms of the neighboring molecules, Cu...F 2.78 Å and Cu...C_γ 3.30 Å. The complex forms centrosymmetric pseudo dimers with Cu...Cu distances of 4.59 Å.Original Russian Text Copyright © 2004 by S. A. Gromilov, I. A. Baidina, P. A. Stabnikov, and G. V. Romanenko__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 893–898, September–October, 2004.     

Crystal and molecular structure of two polymorphic modifications of <Emphasis Type="Italic">bis</Emphasis>(2,3-pentamethylene-3,4-dihydroquinazolinium) tetrachlorozincate

An X-ray diffraction investigation of two polymorphic modifications of the zinc chloride complex of 2,3-pentamethylene-3,4-dihydroquinazoline hydrochloride, grown under different temperature conditions, has been carried out. The geometry of the molecular complex is analyzed.     

Copolymerization of the poly(<Emphasis Type="Italic">N,N</Emphasis>-dimethyl-<Emphasis Type="Italic">N,N</Emphasis>-diallylammonium chloride) macromonomer with acrylamide

Copolymers of the poly(N,N-dimethyl-N,N-diallylammonium chloride) macromonomer (1′) with acrylamide (2) with a high content of cationic groups (up to 50%) were synthesized. The relative activities r _1′ and r ₂ were calculated. The relative activities calculated by the Kelen—Tudos (r _1′ = 0.057±0.009, r ₂ = 1.57±0.12) and Feynman—Ross (r _1′ = 0.055±0.011, r ₂ = 1.58±0.14) methods are in accordance. The intrinsic viscosity and the yield of copolymers were found to decrease with an increase in the molar fraction of macromonomer 1′ in the monomer mixture. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 515–518, March, 2007.     

Shift of stereochemical nonrigidity from coordination units to polymethylene fragments in heterospin copper(<Emphasis Type="SmallCaps">II</Emphasis>) hexafluoroacetylacetonate complexes with nitronyl nitroxide biradicals

The reactions of bis(hexafluoroacetylacetonato)copper(II) [Cu(hfac)₂] with the nitronyl nitroxide biradicals bis[4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyrazol-1-yl]alkanes (L⁶, L¹⁰, and L¹²) produced the framework heterospin complex [Cu(hfac)₂]₂L⁶ and the layer-polymeric heterospin complexes [Cu(hfac)₂]₂L¹⁰ and {[Cu(hfac)₂]₂L¹²} [Cu(hfac)₂(PrⁱOH)₂], respectively. In the solid state of these compounds, the stereochemical nonrigidity is manifested as a deformation of the polymethylene fragments-(CH₂)_n-. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1732–1741, September, 2007.     

Synthesis of magnesium catecholate and <Emphasis Type="Italic">o</Emphasis>-semiquinone complexes by oxidation of the metal with 3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">o</Emphasis>-benzoquinone

Oxidation of amalgamated magnesium metal with 3,6-di-tert-butyl-o-benzoquinone (1) in different aprotic organic solvents afforded magnesium catecholate and bis-o-semiquinolate complexes. The catecholate derivatives of magnesium CatMgL₂ (Cat is the 3,6-di-tert-butyl-o-benzoquinone dianion, L = THF or Py) were synthesized in high yields in pyridine and tetrahydrofuran, respectively. The reactions in diethyl ether or dimethoxyethane produced hexacoordinated metal bis-o-semiquinolates SQ₂MgL_n (SQ is the 3,6-di-tert-butyl-o-benzoquinone radical anion, L = Et₂O, n = 2; L = DME, n = 1). The reaction with the use of toluene as the solvent gave a magnesium bis-o-semiquinolate complex containing the coordinated unreduced o-quinone molecule. The molecular structures of the [CatMgPy₂]₂ and SQ₂Mg·DME complexes were established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 92–98, January, 2007.     

The self-organization properties of <Emphasis Type="Italic">n</Emphasis>-dodecylammonium α-glutamate/<Emphasis Type="Italic">n</Emphasis>-C<Subscript>5</Subscript>H<Subscript>11</Subscript>OH/water system

A biocompatible surfactant-n-dodecylammonium α-glutamate (GDA) with biodegradable and biocompatible properties was synthesized, and the phase behavior and the structural properties of GDA/n-pentanol/water system was studied by small-angle X-ray diffraction, electron spin resonance, and freeze-fracture transmission electron microscopy (FF-TEM). In the ternary phase diagram of GDA/n-pentanol/water system, there exist three isotropic regions—O/W, bicontinuous, and W/O structures, and two anisotropic regions—hexagonal liquid crystal (HEX), and lamellar liquid crystal (LLC) regions. UV irradiation causes the decrease in the interlayer space, d, of lamellar liquid crystal and in the radius, r, of column aggregates of hexagonal liquid crystal, but it has little effect on the structure of O/W and W/O microemulsions.     

1,3-Dipolar cycloaddition reaction of heteroaromatic <Emphasis Type="Italic">N</Emphasis>-ylides with 3-[(<Emphasis Type="Italic">E</Emphasis>)-2-aryl(hetaryl)-2-oxoethylidene]indolin-2-ones

A series of 6a′,7′,8′,9′-tetrahydrospiro[indoline-3,7′-pyrrolo[1,2-a]quinoline]-2-one derivatives were synthesized by the 1,3-dipolar cycloaddition reaction. The regio-and stereoselectivity of the reaction were established by X-ray diffraction study. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2357–2361, October, 2005.     

Structure of the oxidative dimerization product of 4,6-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)pyrogallol

The structure of the oxidation product of 4,6-di(tert-butyl)pyrogallol, viz., 6,10a-dihydroxy-3,4a, 7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo[b,e][1,4]dioxine-1,2-dione, was established by X-ray diffraction. Dimerization of intermediate 3-hydroxy-4,6-di(tert-butyl)-1,2-benzoquinone occurs by the mechanism of Diels—Alder heterocyclization. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 267–271, February, 2007.     

The Effect of Molecular Structuring of an Incompatible Linear Polymer-Net Polymer System on Its Micro-Heterogeneity under the Effect of 3<Emphasis Type="Italic">d</Emphasis>-Metal Chelates

The influence of the nature of the central ion [Cu(2+), Cr(3+), Fe(3+)] of the chelate compound on the possibility of interaction of the metal-containing modifier with one or both of the components of the incompatible PU/PMMA system was studied by the ESR method. It was shown by low-angle X-ray diffraction that the change in the degree of microheterogeneity of the semi-IPN correlated with the characteristics of complex forming metal and the polymer matrix. __________ Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 41, No. 4, pp. 252–256, July–August, 2005.