Synthesis and crystal structure of a dinuclear praseodymium nitrate complex

Dinuclear supramolecular complex of praseodymium nitrate with an unsymmetrical tipodal ligand benzyl-N,N-bis[(2′-benzylaminoformyl)phenoxyl)ethyl]-amine (L), have been prepared. The X-ray single-crystal diffraction analysis indicates that this complex was crystallized in the monoclinic system, space group P2₁/c with parameters a = 16.736(3), b = 14.042(3), c = 19.782(4) Å, β = 101.823°, V = 4550.50(16) ų, Z = 4. The structure was refined to the final R ₁ = 0.0473. The complex units are linked by the intermolecular hydrogen bonds to form a three-dimensional (3D) netlike supramolecuar structure.     

Crystal and molecular structure of a new gadolinium nitrate complex with furancarboxylic acid and dipyridyl

The gadolinium nitrato complex with α-furancarboxylic acid (FA) and 2,2′-dipyridyl (Dipy) has been synthesized. According to X-ray diffraction results, the complex is composed of the [Gd(FA)₂(NO₃)(Dipy)]₂ dimers. The crystals are triclinic: a = 9.942(2) Å, b = 10.231(2) Å, c = 11.037(2) Å, α = 85.50(3)°, β = 75.71(3)°, γ = 69.82(3)°, Z = 1. Two gadolinium atoms are linked by four carboxylate groups of furancarboxylic acid molecules. Each gadolinium atom is coordinated to seven oxygen atoms (five belonging to the FA carboxyl groups and two belonging to the bidentate nitrate group) and to two nitrogen atoms (from Dipy).     

Specific features of the structure of coordination polymers of silver with ditopic nitrogen-containing ligands

Chemistry of coordination polymers and metal-supramolecular ensembles attracts attention due to their structural diversity and potential physical and chemical properties. In this article, the works on the synthesis and structure of coordination polymers of silver published by the authors and coworkers are briefly reviewed and compared with literature data on the structure of coordination polymers of silver published in the recent five years.     

三硝酸根.四(二甲亚砜)合镨的晶体结构

“镧系收缩”与配位构型间的关系是当前结构化学中颇感兴趣的一个课题。近来,关于稀土金属的各种盐类与二甲亚砜配合物的研究日益增多。这类配合物具有催化和发光性能,已引起广泛重视。本文发表的三硝酸根·四(二甲亚砜)合镨[Pr(NO_3)_3(DMSO)_4](1)晶体结构是这类稀土配合物结构的又一研究。     

Specific features of the structure of germanium(IV) complexes with polybasic acids

The specific features revealed in the structure of germanium(IV) compounds with ligands in the form of anions of polybasic acids (monoamine, diamine, and triamine complexones, i.e., hydroxyethylidene-diphosphonic and carboxylic acids) have been considered. The influence of the individuality of specific acids on the structure type (mononuclear, binuclear, trinuclear, hexanuclear, polynuclear), the coordination mode of monodentate ligands and donor atoms of polydentate ligands (terminal, bridging, chelating, chelating-bridging), and variants of the coordination of polydentate ligands, i.e., anions of polybasic acids, with metal atoms (germanium, rare-earth elements, copper, barium), as well as on the dependence of the Ge-O bond length on the individual nature of ligands (OH, H₂O, O(oxo)) and donor atoms of polydentate ligands α- and β-O(carb), O(hydr), O(P)] and their function in the structure (terminal, bridging, chelating, chelating-bridging), has been analyzed using 28 homometallic and heterometallic complexes as an example.     

The special features of the crystal structure and properties of oxides with mixed conductivity based on lanthanum gallate

The paper presents a review of works on the synthesis, structural composition effects, phase transitions, and electrical conductivity properties of multicomponent solid solutions based on heterosubstituted lanthanum gallate (La,A)(Ga,M)O_{3 ? y} . High-temperature phase transitions and structural and charge ordering effects were studied. The presence of iron cations in different valence states was proved; the relative contents of these cations depended on the x parameter and nonstoichiometry parameter y of the base composition. For M = Fe, antiferromagnetic ordering was observed; its temperature interval was determined by the concentration of iron cations in the high-spin state. The total conductivity was found to increase as the concentration of transition metal cations grew because of an increase in the electronic conductivity component. The data on structural parameters and dc and ac conductivity substantiated the conclusion that the highest ionic conductivity and permeability to oxygen were characteristic of iron-containing oxides. The results obtained are evidence that crystal chemical factors play a determining role in the formation of the ion-conducting properties of anion-deficient perovskite-like oxides.     

Synthesis and structure of complex compounds of lanthanum,europium, and scandium iodides with antipyrine

Synthesis and X-ray single-crystal diffraction study of antipyrine complexes of lanthanum, europium, and scandium iodides were performed. In all compounds, the inner coordination sphere of the complex cation is an octahedron formed by antipyrine molecules coordinated through the oxygen atoms of the C=O groups.     

Specific features of photoconductivity in a polymer composite with a heterometallic Copper(II)/Vanadium(V) complex

The dark conductivity and the photoconductive properties of polymer film composites based on polyvinyl butyral doped with various amounts of the heterometallic complex (H₃O)₂(H₂en)[Cu(en)₂(H₂O)₂][V₁₀O₂₈] · 3H₂O (where en is ethylenediamine) have been studied. It has been found that the activation energy of photocurrent in the films increases with an increase in applied electric field strength. An increase in the applied electric field strength has been assumed to result in the release of charge carriers from deeper energy traps that can occur in the heterometallic complex.     

硝酸铕与含氮冠醚配合物的电子结构和化学键

本文用XPS和INDO方法研究了硝酸铕与含氮冠醚配合物[Eu(NO3)2(2,2)]NO3的电子结构, 结合能和电荷分布数据指出, 在配位原子中, 电负性低的氮原子N1s结合能的化学位移比电负性高的氧原子O1s的大。在配合物中, 氮原子转移至中心金属离子上的电荷比氧原子转移的多。铕与含氮冠醚配合物的化学键具有一定程度的共价性, 电负性低的氮原子与铕的配位键(N→Eu)的共价性比电负性高的氧原子的配位键(O→Eu)的大。     

Protonation of a lanthanum phosphide-alkyl occurs at the P-La not the C-La bond: isolation of a cationic lanthanum alkyl complex

Protonation of the heteroleptic, cyclometalated lanthanum phosphide complex [((Me3Si)2CH)(C6H4-2-CH2NMe2)P]La(THF)[P(C6H4-2-CH2NMe2)(CH(SiMe3)(SiMe2CH2))] with [Et3NH][BPh4] yields the cationic alkyllanthanum complex [(THF)4La[P(C6H4-2-CH2NMe2)(CH(SiMe3)(SiMe2CH2))]][BPh4].     

Crystal structure of a calcium(II) complex with pyrazine-2,3-dicarboxylate,nitrate and water ligands

The structure of catena-[tris(aquo-O)(nitrato-O,O′)(µ-hydrogen pyrazine-2,3-dicarboxylato-O,N–O′,N′)calcium(II)][tetra(aquo-O)(μ-hydrogen pyrazine-2,3-dicarboxylato-O,N–O′,N′) calcium(I)] nitrate, {Ca[H(2,3-PZDC)](H₃O)₃(NO₃)}{Ca[H(2,3-PZDC)](H₂O)₄}⁺ (NO₃)^?, is composed of molecular ribbons in which calcium atoms are bridged by both N,O-bonding moieties of singly deprotonated ligand molecules. The hydrogen atom donated by one carboxylic group is linked by a short intramolecular hydrogen bond of 2.37 Å to an oxygen atom of the second carboxylic group of the same ligand. Two crystallographically independent Ca(II) ions exhibit different coordination modes. One is coordinated by two bonding moieties of the bridging ligand molecules, three water oxygen atoms and two oxygen atoms of a nitrate ligand. The other calcium ion is chelated by two bonding moieties donated by the bridging ligand molecules and four water oxygen atoms, forming a positively charged assembly with a nitrate anion located nearby. The coordination polyhedron of the first calcium ion is a strongly deformed bicapped pentagonal bipyramid with nine-coordinated atoms; the second calcium ion is also in a strongly deformed pentagonal bipyramid with one apex on one side of the equatorial plane and two apices on the other. Coordinated water oxygen atoms act as donors in a hydrogen-bond network.     

Iron-dextran complex: geometrical structure and magneto-optical features

Molecular mass of the iron-dextran complex (M(w)=1133 kDa), diameter of its particles (～8.3 nm) and the content of iron ions in the complex core (N(Fe)=6360) were determined by static light scattering, measurements of refractive index increment and the Cotton-Mouton effect in solution. The known number of iron ions permitted the calculation of the permanent magnetic dipole moment value to be μ(Fe)=3.17×10(-18) erg Oe(-1) and the determination of anisotropy of linear magneto-optical polarizabilities components as Δχ=9.2×10(-21) cm(3). Knowing both values and the value of the mean linear optical polarizability α=7.3×10(-20) cm(3), it was possible to show that the total measured CM effect was due to the reorientation of the permanent and the induced magnetic dipole moments of the complex. Analysis of the measured magneto-optical birefringence indicated very small optical anisotropy of linear optical polarizability components, κ(α), which suggested a homogeneous structure of particles of spherical symmetry.     

Specific features of tetrahydrofuran copolymerization with lactones

Mechanistic features of the cationic copolymerization of lactones with cyclic ethers are studied for β-propiolactone (PL) with tetrahydrofuran (THF) and ?-caprolactone (CL) with THF. It is shown that, in the PL-THF system at [THF]₀ > [THF]_e, the copolymer is considerably enriched with the more basic THF whereas at [THF]₀ < [THF]_e anomalous enrichment of the copolymer with the less basic PL is observed. The mechanism of this phenomenon, which is applicable to many other cases and causes the formation of block copolymers from some heterocyclic monomers, is considered. At concentrations below equilibrium, THF is incorporated in the copolymer as pairs of units due to the effect of the penultimate unit on the thermodynamics of its addition.