Chloroaqua Complexes [M3S4(H2O)9?xClx](4?x)+ (M = Mo, W; x = 4, 6, 7) and Their Supramolecular Compounds with Cucur[8]uril

Compounds of trigonal cluster chloroaqua complexes with cucurbit[8]uril were synthesized by slowly evaporating HCl solutions of chalcogenides heterometallic cubane cluster complexes of molybdenum and tungsten with cucurbit[8]uril in air; the complexes were characterized by X-ray diffraction analysis: (H₃O)₈[Mo₃S₄(H₂O)_2.5Cl_6.5]₂Cl(PdCl₄)·(C₄₈H₄₈N₃₂O₁₆)· 29H₂O (a = 13.3183(17) Å, b = 13.7104(18) Å, c = 18.225(3) Å; α = 80.263(3)°, β = 77. 958(3)°, γ = 87.149(4)°, V = 3207.4(7) ų, space group P , Z = 1, ρ(calc) = 1.900 g/cm³), (H₃O)₄ [Mo₃S₄(H₂O)₃Cl₆]₂·(C₄₈H₄₈N₃₂O₁₆)₃·68H₂O (a = 21.413(6) Å, c = 49.832(10) Å; γ = 120°, V = 19788(8) ų, space group R , Z = 3, ρ(calc) = 1.695 g/cm³), (H₃O)₆ [Mo₃S₄(H₂O)₃Cl₆]₂Cl₂·(C₄₈H₄₈N₃₂O₁₆)·12H₂O (a = 15.881(2) Å, b = 17.191(2) Å, c = 23.276(4) Å; β = 98.865(15)°, V = 6278.7(15) ų, space group P2₁/c, Z = 2, ρ(calc) = 1.638 g/cm³), [W₃S₄(H₂O)₅Cl₄]₂·(C₄₈H₄₈N₃₂O₁₆)₃·35H₂O (a = 21.038(3) Å; α = 61.20(1)°, V = 6762.0(14) ų, space group R , Z = 1, ρ(calc) = 1.582 g/cm³). The [Mo₃S₄(H₂O)₃Cl₆]²⁻ anion complex was isolated as three geometrical isomers.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, H. G. Platas, F. M. Dolgushin, A. V. Gerasimenko, M. N. Sokolov, Z. A. Starikova, M. Yu. Antipin, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1049–1058, November–December, 2004.     

Inclusion of Two PhP(O)(OH) 2 Guest Molecules into the Cavity of Macrocyclic Cavidand Cucurbit[8]uril

A new inclusion compound which is a supramolecular adduct of cucurbit[8]uril with two guest molecules of phenylphosphonic acid, PhP(O)(OH)₂, included into the cavity as ``two guests in host'' is reported. The guests match both size and hydrophilicity/hydrophobicity requirements. Two phenyl groups of molecules of PhP(O)(OH)₂ are directed toward the center of the large hydrophobic cavity whereas the PO(OH)₂ groups are outward-looking and bound with each hydrophilic portal of cucurbit[8]uril by a short hydrogen bond.     

Currents of the second kind in quasielastic scattering ofv(\tilde v) by free polarized nucleons

Expressions are obtained for the cross sections for scattering of high-energy (E _v Mc², where M is the nucleon mass) neutrinos and antineutrinos by free polarized nucleons with currents of the second kind taken into account. The effect of the axial-tensor form factor F_T of these currents on the spin asymmetry coefficients A_L and A_S and on the charge asymmetry coefficient is considered. It is shown that experimental study of the energy dependence of these coefficients can improve the accuracy of the bounds on the form factor.Russian University of the Friendship of Nations. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 36–40, January, 1993.     

Synthesis and Crystal Structure of Supramolecular Adducts of Macrocyclic Cavitand Cucurbituril with Chromium(III) and Nickel(II) Aqua Complexes

Supramolecular compounds {[Cr(H₂O)₆](C₃₆H₃₆N₂₄O₁₂)}(NO₃)₃ · 13H₂O (I) and {[Ni(H₂O)₆]₂(C₃₆H₃₆N₂₄O₁₂)}(SO₄)₂ · 16H₂O (II) were obtained from aqueous solutions of chromium nitrate or nickel sulfate and the macrocyclic cavitand cucurbituril. According to X-ray diffraction analysis data, the cucurbituril molecule is closed from both sides by metal aqua complexes due to the formation of hydrogen bonding between the cucurbituril CO groups and aqua ligands. Compound I has a chain structure, while the structure of compound II is layered. Modes of cucurbituril coordination, depending on the size and charge of the metal cation, are discussed.     

Synthesis and structure of chiral coordination polymers of CoII, CuII, and MgII saccharates

Chiral metal-organic coordination polymers [Co₂(sacch)₂]·1/₂H₂O·CH₃OH (1), [Cu(sacch)(H₂O)₂]·3H₂O (2), and [Mg(H₂O)₃(sacch)] (3) (H₂sacch is d-saccharic acid) were synthesized from aqueous or water-methanol solutions of potassium hydrogen saccharate and a salt of the corresponding metal. The compositions and structures of the resulting compounds were determined by single-crystal X-ray diffraction and confirmed by X-ray powder diffraction, IR spectroscopy, thermogravimetry, and elemental analysis.     

Sorption of benzene vapors to flexible metal–organic framework [Zn2(bdc)2(dabco)]

The isotherms of benzene sorption by the metal–organic coordination polymer [Zn₂(bdc)₂(dabco)] were studied within the temperature range 25–90 °C at pressures up to 75 torr. The maximal benzene content in [Zn₂(bdc)₂(dabco)] at room temperature was demonstrated to correspond to the composition [Zn₂(bdc)₂(dabco)]·3.8C₆H₆. It was established that the process of benzene desorption from the substance under investigation occurs in three stages. (1) Evaporation of benzene from the phase of variable composition (phase C) with compression and distortion of the unit cell (the composition of the phase C varies from [Zn₂(bdc)₂(dabco)]·3.8C₆H₆ to [Zn₂(bdc)₂(dabco)]·3.2C₆H₆). (2) The transformation of the phase C into phase P. The phase P has the same unit cell geometry as that for the empty framework. The maximal benzene content is [Zn₂(bdc)₂(dabco)]·1.0C₆H₆. (3) Benzene evaporation from the phase P of variable composition. We studied the temperature dependences of the equilibrium vapor pressure of benzene for the samples with compositions [Zn₂(bdc)₂(dabco)]·3.0(3)C₆H₆ and [Zn₂(bdc)₂(dabco)]·2.0(3)C₆H₆ within the temperature range 290–370 K. The thermodynamic parameters of benzene vaporization were determined for the latter compound ( $ \Updelta {\text{H}}_{{{\text{av}} .}}^{o} = 49\left( 1 \right) \,{\text{kJ }}\left( {{\text{moleC}}_{6} {\text{H}}_{6} } \right)^{ - 1} $ ; $ \Updelta {\text{S}}_{{{\text{av}} .}}^{^\circ } = 100\left( 3 \right)\, {\text{J}}\left( {{\text{moleC}}_{6} {\text{H}}_{6} {\text{K}}} \right)^{ - 1} $ ; $ \Updelta {\text{G}}_{298}^{^\circ } = 19.0\left( 2 \right)\, {\text{kJ}}\left( {{\text{moleC}}_{6} {\text{H}}_{6} } \right)^{ - 1} $ ).     

A FOUR-NUCLEAR Ag(I) COMPLEX SUPPORTED BY A N,N′,N″,P-LIGAND: SYNTHESIS,CRYSTAL AND ELECTRONIC STRUCTURE

Journal of Structural Chemistry - A four-nuclear complex [Ag4(Lut3P)2(MeCN)2](BF4)4 is synthesized by treating tris[(6-methylpyridin-2-yl)methyl]phosphine (Lut3P) with AgBF4 in a MeCN solution. The...     

Cyanide Complexes Based on {Mo6I8}4+ and {W6I8}4+ Cluster Cores

Compounds based on new cyanide cluster anions [{Mo₆I₈}(CN)₆]^2–, trans-[{Mo₆I₈}(CN)₄(MeO)₂]^2– and trans-[{W₆I₈}(CN)₂(MeO)₄]²⁻ were synthesized using mechanochemical or solvothermal synthesis. The crystal and electronic structures as well as spectroscopic properties of the anions were investigated. It was found that the new compounds exhibit red luminescence upon excitation by UV light in the solid state and solutions, as other cluster complexes based on {Mo₆I₈}⁴⁺ and {W₆I₈}⁴⁺ cores do. The compounds can be recrystallized from aqueous methanol solutions; besides this, it was shown using NMR and UV-Vis spectroscopy that anions did not undergo hydrolysis in the solutions for a long time. These facts indicate that hydrolytic stabilization of {Mo₆I₈} and {W₆I₈} cluster cores can be achieved by coordination of cyanide ligands.     

Synthesis and crystal structure of new coordination polymers based on sodium aqua complexes and macrocyclic cavitand cucurbit[6]uril

The crystals of the compounds [Na₄(H₂O)₁₄CB[6]](bdc)₂ · 13H₂O (1) and [Na₆(H₂O)₁₉CB[6]]-(bdc)₃ ·15H₂O (2) were obtained by heating an aqueous solution of sodium terephthalate (Na₂bdc) and cucurbit[6]uril (CB[6]). According to the single-crystal X-ray diffraction data, the sodium aqua complexes and cucurbit[6]uril molecules form chains (in structure 1) and layered metal-organic frameworks (in structure 2). The structures of the sodium aqua complexes [Na₃(H₂O)₁₀]³⁺ in 1 and [Na₆(H₂O)₁₉]³⁺ in 2 have been previously unknown. When submitted to ultraviolet radiation, crystals of 1 and 2 exhibit luminescence with an emission maximum at 428 and 434 nm, respectively.

     

Metal-organic frameworks based on [Re6Se8(CN)6]4− cluster anions,Yb3+ cations,and thiophene-2,5-dicarboxylate linkers

Russian Chemical Bulletin - The reaction of [Re6Se8(CN)6]4? cluster anions with Ln3+ cations in the presence of thiophene-2,5-dicarboxylate anions in an aqueous solution was studied. Two new...