Complexation of 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Mg2+, Ca2+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+ ions in aqueous solution

In a search for environmental-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of 3-hydroxy-2,2′-iminodisuccinic acid with Mg²⁺, Ca²⁺, Mn²⁺, Fe³⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ ions in aqueous 0.1 mol L^?1 NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML ^{n ?4} complexes.     

Crystal structure of salts of the trans-[Rh(NH3)2(NO2)4]− anion with K+, Cs+, Ag+, and (CH3)4N+ cations

Complex rhodium(III) salts with the composition trans-M[Rh(NH₃)₂(NO₂)₄], where M = K⁺, Cs⁺, Ag⁺, and N(CH₃) ₄ ⁺ , are prepared and characterized. The molecular and crystal structures are determined by X-ray crystallography.     

Complexation of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd2+, Hg2+, and Pb2+ in aqueous solution

In a search for environmentally friendly metal-chelating ligands for industrial applications, the protonation and complex formation equilibria of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd²⁺, Hg²⁺, and Pb²⁺ in aqueous 0.1?mol?L^?1 NaNO₃ solution were studied at 25°C by potentiometric titration. Models for complexation and stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML^2? complexes.     

Étude structurale comparée des chromates: M(I)M(III)(CrO4)2; M(I) = Li+, Na+, K+, Rb+, Cs+, NH4+, Ag+ et Tl+; M(III) = Al3+, Fe3+, Cr3+, Tl3+ et Bi3+

Among compounds of formula type M(I)M(III)(CrO₄)₂, the structures of trivalent bismuth compounds are always different from the others, because the surrounding of bismuth is never well-defined. Besides, nearly all these compounds have two-dimensional structures with the exception of Tl(I)Tl(III)(CrO₄)₂ which is three-dimensional. This structural type can exist only when the ionic radius of the monovalent cation has a value near that of O²⁻ ion (1.40 Å), as for Rb⁺, NH₄⁺ and Tl⁺.     

Synthesis and cyclization of N-(9-alkylcarbazol-3-yl)-β-alanines

The reaction of 3-amino-9-alkylcarbazoles with acrylic and itaconic acids yields N-substituted amino acids, which were converted into derivatives of 4-carboxy-2-pyrrolidinone and dihydropyrimidinedione.Kaunas Technological University 3028 Kaunas, LithuaniaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1637–1640, November–December, 1999.     

Synthetic Mucin Fragments: Methyl-3-O-(2-Acetamido-2-Deoxy-4-O- and 6-O-β-D-Galactopyranosyl-β-D-Glucopyranosyl)-β-D-Galactopyranoside and Methyl 3-O-(2-Acetamido-2-Deoxy-4-O- and 3-O-Methyl-β-D-Glucopyranosyl-3-D-Galactopyranoside

Abstract

Glycosylation of methyl 3-O-(2-acetamido-3, 6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (2) with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (1), catalyzed by mercuric cyanide, afforded a trisaccharide derivative, which was not separated, but directly O-deacetylated to give methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-β-D-galactopyranosyl-β-D-giucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (8). Hydrogenolysls of the benzyl groups of 8 then furnished the title trisaccharide (9). A similar pflyccsylation of methyl 3-O-(2-acetamido-3-O-acetyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl- β-D-galactopyranoside (obtained by acetylation of 4, followed by hydrolysis of the benzylidene acetal group) with bromide 1 gave a tribenzyl trisaccharide, which, on catalytic hydrogenolysls, furnished the isomeric trisaccharide (12). Methylation of 4 and 2 with methyl iodide-silver oxide in 1:1 dichloro-methane-N, N-dimethylformamide gave the 3-O- and 4-O-monomethyl ethers (13) and (15), respectively. Hydrogenolysis of the benzyl groups of 13 and 15 then provided the title monomethylated disaechartdes (15) and (16), respectively. The structures of trisacchacides 9 and 12, and disaccharides 14 and 16 were all established by ¹³C MMR spectroscopy.     

STRUCTURE OF TRISUBSTITUTED TUNGSTOSILICATE ANION [A-β-SiW_9Al_3(H_2O)_2O_36(μ_3-O2/2)]_2~14-

<正> Crystal of H14C[A-β-SiW9Al3(H2O)2O36(μ3-O2/2)]2 ·8H2O belongs to monoclinic system, space group P2/m. with a= 1 7. 525(6), b=14.348(3). c= 21. 669(8) A , β=113. 12(8)°, V = 5011 (3) A3,Z = 2. Dc = 3. 254 g. cm-3, A (MoKα) = 0. 70169 A , μ=223. 21 cm-1, F(000) = 4614, T = 298K. R=0. 066 for 3010 unique reflections [I≥5σ(I) ]. The crystal consists of water molecules, protons (or H3O+ ) and dimeric anions [A-β-SiW9Al3 (H2O)2O36(μ3-O2/2)D214.the half of which has a SiO1 tetrahedron in the center, a W3O13 group, two W2Al(H2O) O12 groups and a W2AlO13 group around the SiO4.     

Acetate-Functionalized Zirconium-Substituted Tungstogermanate, [Zr4O2(OH)2(CH3COO)2(α-GeW10O37)2]12−

The two acetate-functionalized zirconium(IV)-substituted tungstogermanates, Na₈K₄[Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂] · 33H₂O and Na₈Cs₄[Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂] · 32H₂O, were synthesized by the reaction of ZrOCl₂ with [A-α-GeW₉O₃₄]¹⁰⁻ in pH = 4.8 buffer and their structures were determined by single-crystal X-ray analysis. Both of them contain a centrosymmetric polyanion [Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂]¹²⁻ consisting of two {α-GeW₁₀O₃₇} units sandwiching an inorganic–organic hybrid {Zr₄O₂(OH)₂(CH₃COO)₂} cluster. The polyanion contains a mixing of seven- and eight-coordinate Zr centres. The two compounds were also characterized by elemental analysis, IR spectroscopy, UV–vis and TG–DSC analysis.     

Synthesis and Crystal Structure of[Co3(CO)9(μ3-C)C(O)OCH2]2

The title compound [Co3(CO)9(μ3-C)C(O)OCH2]2 was synthesized by the reaction of [Cl3CC(O)OCH2]2 with Co2(CO)8 at 40～50 ℃. Crystal data: C24H4O22Co6, Mr=997.88, monoclinic, space group P21/n(#14), a=9.330(2), b=15.197(4), c=11.783(4), β=91.16(2)°, V=1670.4(7) 3, Z=2, Dc=1.984 g/cm3, μ(MoKα)=30.01 cm-1, F(000)=972.00, T=293K, final R=0.045, Rw=0.051 for 1936 observed reflections with I＞2σ(I). The structure contains two centrosymmetric dimeric molecules in a unit cell, each of which has two tetrahedral skeletons (CCo3) connected through a C(O)OCH3CH2OC(O) bridge.     

Study of the state of uranoarsenates MII(AsUO6)2·nH2O(MII = Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+) in aqueous solutions

State of uranoarsenates M^II(AsUO₆)₂·nH₂O (M^II = Mn, Co, Ni, Cu, Zn, Cd, Pb) in aqueous solutions in a wide range of acidity (pH 0?C14) was studied. Acid-base boundaries of existence of the compounds were estimated, products of conversion were identified, and solubility of M^II(AsUO₆)₂·nH₂O was determined. On the basis of the obtained data the solubility products and Gibbs functions of formation of uranoarsenates, and the solubility curves were calculated, phase diagrams of uranium(VI) and arsenic(V) in solutions and in equilibrium solid phases were constructed with the use of the equilibrium thermodynamics technique.     

多孔磁体甲酸盐[M3(HCOO)6](M=Mn2+,Fe2+,Co2+,Ni2+,Fe2+/Zn2+)的研究

综述了近年来我们在多孔磁体甲酸盐系列[M3(HCOO)6](M=Mn2 ,Fe2 ,Co2 ,Ni2 ,Fe2 /Zn2 )获得的研究结果.这些多孔磁体可以在常温下用温和的溶液化学方法制备获得,它们的结构是以MM4四面体为节点的金刚石多孔骨架,呈现了很好的热稳定性、多孔性、广谱的客体包合性能和稳定性.由于客体的包合对多孔磁性骨架的结构参数产生影响以及客体和骨架之间的弱氢键相互作用,这些多孔磁体表现了丰富的和客体调控的磁性质.混合金属的多孔磁体[FexZn3-x(HCOO)6]表现了随着Zn2 的含量增加而发生的由三维磁有序到自旋玻璃、再到超顺磁体、最后到顺磁体的渐次转变.     

Structures, energetics, and aromaticities of the tetrasilacyclobutadiene dianion and related compounds: (Si4H4)(2-), (Si4H4)(2-)·2Li+, [Si4(SiH3)4](2-)·2Li+, [Si4(SiH3)4](2-)·2Na+, and [Si4(SiH3)4](2-)·2K+

In light of the important recent synthesis of a stable tetrasilacyclobutadiene dianion compound by Sekiguchi and co-workers and the absence of theoretical studies, ab initio methods have been used to investigate this dianion and a number of related species. These theoretical methods predict multiple minima for each compound, and most minima contain folded and bicyclic silicon rings. For (Si(4)H(4))(2-), (Si(4)H(4))(2-)·2Li(+), [Si(4)(SiH(3))(4)](2-)·2Li(+), [Si(4)(SiH(3))(4)](2-)·2Na(+), and [Si(4)(SiH(3))(4)](2-)·2K(+), respectively, the energetically lowest-lying structures are designated A-3 (C(2v) symmetry), B-8 (C(1) symmetry), C-1 (C(2) symmetry), D-1 (C(2) symmetry), and E-1 (C(2h) symmetry). None of these structures satisfies both the ring planarity and the cyclic bond equalization criteria of aromaticity. However, all of the representative NICS values of these lowest-lying structures are negative, indicating some aromatic character. Especially, structures C-1 and D-1 of C(2) symmetry effectively satisfy the criteria of aromaticity due to the slightly trapezoidal silicon rings, which are nearly planar with nearly equal bond lengths. SiH(3) substitution for hydrogen in (Si(4)H(4))(2-)·2Li(+) significantly reduces the degree of aromaticity, as reflected in the substantially smaller NICS absolute values for [Si(4)(SiH(3))(4)](2-)·2Li(+) than those of (Si(4)H(4))(2-) and (Si(4)H(4))(2-)·2Li(+). The aromaticity is further weakened in [Si(4)(SiH(3))(4)](2-)·2Na(+) and [Si(4)(SiH(3))(4)](2-)·2K(+) by replacing lithium with the sodium and potassium cations.     

Design and synthesis of trans-3-aminopyran-2-carboxylic acid (APyC) and α/β-peptides with 9/11-helix

A new β-amino acid, trans-3-aminopyran-2-carboxylic acid (APyC), was designed and synthesized from (R)-glyceraldehyde derivative and used in the synthesis of α/β-peptides in a 1 : 1 alternating pattern with d-Ala. The presence of oxygen atom at the Cβ(2)-position in APyC was envisaged to provide opportunity for additional interaction. These hybrid peptides have shown the presence of 9/11-helix through extensive NMR and MD studies. The amide protons of d-Ala, in addition to participating in 9-mr H-bonding with CO of succeeding β-residue, were also involved in additional electrostatic interaction with pyran ring oxygen of preceding β-residue, which facilitated further stabilization to the 9/11-mixed helix. The study thus results in a new 'motif' for a 9/11-helix, and the first example from a cyclic β-amino acid.     

Effect of Na+, Li+, Pb2+, Ba2+, Si2+, and Ca2+ cations on force constants of W-O and Mo-O bonds of WO4 2− and MoO4 2− anions in melts

By a matrix method of successive approximations, using perturbation theory, the complete set of force constants has been calculated for the free anions WO,^2– and MoO₄ ^2– and for systems MEO₄ ^2–(M = Na₂ ⁺, Li₂ ⁺, Pb²⁺,Sr²⁺, Ca²⁺; E = W, Mo) on the basis of known frequencies of IR and Raman spectra of the corresponding individual melts. Analysis of the results indicates an increase in the force constants of E-O bond stretching and the bending force constants for AD- and MoO₄ ^2– with increasing specific charge of the cation in a field of singly or doubly charged cations.Deceased.Poltava Engineering Construction Institute. Institute of General and Inorganic Chemistry, Academy of Sciences of the Ukrainian SSSR, Kiev. Translated from Teoreticheskuya i ÉksperimentaI'naya Khimiya, No. 1, pp. 120–123, January–February, 1991. Original article submitted January 12, 1989.     

The antimony(III)-bridged heteropolyanion sandwich dimers [Sb(II3(A-α-XW9O34)2]11- (X = SiIV, GeIV and C-shaped double-sandwich [SbIII6O2(PW6O26)(A-α-PW9O34)2]15-

Interaction of potassium antimony(iii) tartrate hydrate K(2)(SbC(4)H(2)O(6))(2)·3H(2)O with the trilacunary Keggin derivatives [A-α-XW(9)O(34)](10-) (X = Si(IV), Ge(IV)) and [A-α-PW(9)O(34)](9-) in aqueous acidic medium (pH 4.8) resulted in three novel polyanions, [Sb(3)(A-α-XW(9)O(34))(2)](11-) (X = Si(IV) (1), Ge(IV) (2)) and [Sb(6)O(2)(A-PW(6)O(26))(A-α-PW(9)O(34))(2)](15-) (3), which were isolated as the hydrated potassium salts K(11)[Sb(3)(A-α-XW(9)O(34))(2)]·31H(2)O (X = Si(IV) (K-1), Ge(IV) (K-2)) and the mixed potassium-sodium salt K(14)Na[Sb(6)O(2)(A-PW(6)O(26))(A-α-PW(9)O(34))(2)]·61H(2)O (KNa-3) salts, respectively, and characterized by single-crystal X-ray diffraction, IR spectroscopy, as well as elemental and thermogravimetric analyses. The Sb(III)-containing polyanions 1-3 possess unique structural features, as they represent the first examples of sandwich-type POMs with trigonal-pyramidal Sb(III)O(3) linkers. The stability of 1-3 in aqueous media was investigated by multinuclear ((183)W, (31)P) NMR and UV-Vis spectroscopy.     

Synthesis and Crystal Structure of 〔Co_3(CO)_9(μ_3-C)C(O)OCH_2〕_2

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