Synthesis, crystal structure and magnetic properties of an octanuclear cerium(III) complex of pyridine-2,6-dicarboxylate

2019 ◽  
Vol 74 (3) ◽  
pp. 255-260
Author(s):  
Shahzad Sharif ◽  
Islam Ullah Khan ◽  
Onur Sahin ◽  
Nadia Jabeen ◽  
Saeed Ahmad ◽  
...  

AbstractAn octanuclear compound of cerium(III), [Ce8(Pydc)10(HPydc)4.22H2O].11H2O (1) (Pydc=pyridine-2,6-dicarboxylate anion) was prepared under mild solvothermal conditions and its crystal structure was determined by single-crystal X-ray diffraction. Three kinds of coordination environments are observed, which include: [Ce(Pydc)3], [Ce(Pydc)(H2O)4(O,O)], and [Ce(H2O)7(O,O)]. Each cerium atom in 1 is nine-coordinated but two different geometries are found. The Ce1 and Ce2 atoms exhibit a nearly tricapped trigonal prismatic CeN3O6 geometry, while Ce3 and Ce4 possess CeNO8 and CeO9 coordination polyhedra, which approximate to slightly distorted mono-capped square antiprisms having 12 triangular faces. The Pydc ligands adopt tri-, tetra-, and penta-coordination modes through tridentate chelating and, μ2 and μ3-bridging modes, respectively. The clusters are joined by O–H···O hydrogen bonds to generate 3D supramolecular network. Magnetic susceptibility measurements for 1 indicate that the χm values obey the Curie-Weiss law. The overall magnetic behavior is typical for the presence of antiferromagnetic exchange coupling interactions between the cerium(III) ions.

IUCrJ ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Andrey A. Zolotarev ◽  
Sergey V. Krivovichev ◽  
Fernando Cámara ◽  
Luca Bindi ◽  
Elena S. Zhitova ◽  
...  

The crystal structure of ilmajokite, a rare Na-K-Ba-Ce-titanosilicate from the Khibiny mountains, Kola peninsula, Russia, has been solved using single-crystal X-ray diffraction data. The crystal structure is based on a 3D titanosilicate framework consisting of trigonal prismatic titanosilicate (TPTS) clusters centered by Ce3+ in [9]-coordination. Four adjacent TPTS clusters are linked into four-membered rings within the (010) plane and connected via ribbons parallel to 101. The ribbons are organized into layers parallel to (010) and modulated along the a axis with a modulation wavelength of csinβ = 32.91 Å and an amplitude of ∼b/2 = 13.89 Å. The layers are linked by additional silicate tetrahedra. Na+, K+, Ba2+ and H2O groups occur in the framework cavities and have different occupancies and coordination environments. The crystal structure of ilmajokite can be separated into eight hierarchical levels: atoms, coordination polyhedra, TPTS clusters, rings, ribbons, layers, the framework and the whole structure. The information-based analysis allows estimation of the complexity of the structure as 8.468 bits per atom and 11990.129 bits per cell. According to this analysis, ilmajokite is the third-most complex mineral known to date after ewingite and morrisonite, and is the most complex mineral framework structure, comparable in complexity to paulingite-(Ca) (11 590.532 bits per cell).


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Runmei Ding ◽  
Zixin He ◽  
Meilin Wang ◽  
Danian Tian ◽  
Peipei Cen

AbstractBased on 2-(4-pyridyl)-terephthalate (H2pta) and oxalate ligands, two new lanthanide-containing coordination polymers (CPs), [Tb(pta)(C2O4)0.5(H2O)2)]·2H2O (1) and [Sm(pta)(C2O4)0.5(H2O)2)]·2H2O (2), have been synthesized under solvothermal conditions. The structures of both 1 and 2 have been determined by single-crystal X-ray diffraction. Infrared, elemental analysis, powder X-ray diffraction and thermogravimetric analysis data are also presented. The crystals of 1 and 2 exhibit isostructural layer-like networks, crystallizing in the triclinic space group P$‾{1}$. The layers are further stabilized and associated into 3D architectures through hydrogen bonding. Remarkably, the CPs 1 and 2 exhibit excellent water stability and remarkable thermostability with thermal decomposition temperatures of more than 420 °C.


2015 ◽  
Vol 70 (9) ◽  
pp. 631-636 ◽  
Author(s):  
Huaixian Liu ◽  
Lin Sun ◽  
Huiliang Zhou ◽  
Peipei Cen ◽  
Xiaoyong Jin ◽  
...  

AbstractStarting with 1H-3-phenyl-5-(pyridin-2-yl)-1,2,4-triazole (1-Hppt), a Co(III) complex, [Co(ppt)3] (1), has been synthesized by reaction with CoF3 under hydrothermal conditions and characterized by its infrared spectrum and elemental analysis. The structure was determined by single-crystal and powder X-ray diffraction. Density functional theory (DFT) was employed to determine the optimized geometry and preferred conformation of the free ligand. A supramolecular network is formed via π–π stacking interactions. The conformation and geometry of the ligands correspond with the calculated results.


2000 ◽  
Vol 55 (1) ◽  
pp. 60-64
Author(s):  
Melanie Pülm ◽  
Joachim Becht ◽  
Reinhold Tacke

The zwitterionic λ5Si-tetrafluorosilicates F4SiCH2NMe2H (1) and F4SiCH2NMe3 (2) behave as Lewis acids and react with [Me3NH]F (molar ratio 1:1) in aqueous solution to yield the ionic λ6Si-pentafluorosilicates [Me3NH][F5SiCH2NMe2H] (3) and [Me3NH][F5SiCH2NMe3] (4), respectively. These hexacoordinate silicon compounds contain singly charged λ6Si-silicate anions ([F5SiCH2NMe2H]- , [F5SiCH2NMe3]- ) with an SiF5C skeleton. Compounds 3 and 4 were isolated as the crystalline hydrates 3·H2O (yield 80%) and 4·H2O (yield 82%) which were structurally characterized by single-crystal X-ray diffraction. The Si-coordination polyhedra in the crystals of 3·H2O and 4·H2O are slightly distorted octahedra


2020 ◽  
Vol 105 (1) ◽  
pp. 132-135 ◽  
Author(s):  
Luca Bindi ◽  
Aleksandra Bendeliani ◽  
Andrey Bobrov ◽  
Ekaterina Matrosova ◽  
Tetsuo Irifune

Abstract The crystal structure and chemical composition of a crystal of Mg-bearing phase Egg with a general formula M1−x3+Mx2+SiO4H1+x (M3+ = Al, Cr; M2+ = Mg, Fe), where x = 0.35, produced by subsolidus reaction at 24 GPa and 1400 °C of components of subducted oceanic slabs (peridotite, basalt, and sediment), was analyzed by electron microprobe and single-crystal X-ray diffraction. Neglecting the enlarged unit cell and the consequent expansion of the coordination polyhedra (as expected for Mg substitution for Al), the compound was found to be topologically identical to phase Egg, AlSiO3OH, space group P21/n, with lattice parameters a = 7.2681(8), b = 4.3723(5), c = 7.1229(7) Å, β = 99.123(8)°, V = 223.49(4) Å3, and Z = 4. Bond-valence considerations lead to hypothesize the presence of hydroxyl groups only, thereby excluding the presence of the molecular water that would be present in the hypothetical end-member MgSiO3·H2O. We thus demonstrate that phase Egg, considered as one of the main players in the water cycle of the mantle, can incorporate large amounts of Mg in its structure and that there exists a solid solution with a new hypothetical MgSiH2O4 end-member, according to the substitution Al3+ ↔ Mg2+ + H+. The new hypothetical MgSiH2O4 end-member would be a polymorph of phase H, a leading candidate for delivering significant water into the deepest part of the lower mantle.


1998 ◽  
Vol 53 (10) ◽  
pp. 1144-1148 ◽  
Author(s):  
Frank Wendland ◽  
Christian Näther ◽  
Michael Schur ◽  
Wolfgang Bensch

AbstractThe title compound has been synthesized under solvothermal conditions by the reaction of elemental chromium, antimony and selenium in a solution of 40% 1,2-ethanediamine (en) in methanol. The crystal structure consists of tetrahedral SbSe43- anions which are connected by monoprotonated 1,2-ethanediamine (enH+) cations via N-H--Se hydrogen bonding. The enH+ cations are joined via strong N-H -N hydrogen bonds between the ammonium hydrogen and the amino nitrogen atom forming four distinct chains, each built up of three crystallographically independent enH+ cations. Two of these chains are running parallel to [100], the other two are parallel to [010]. Based on this arrangement different centrosymmetric or non-centrosymmetric hydrogen bonding patterns are possible, but only in one chain the sequence of NH2 and NH3+ groups was determined by X-ray diffraction


2014 ◽  
Vol 70 (8) ◽  
pp. i42-i42
Author(s):  
Volodymyr Levytskyy ◽  
Volodymyr Babizhetskyy ◽  
Bohdan Kotur ◽  
Volodymyr Smetana

The crystal structure of the title compound, Tb2Ni7, was redetermined from single-crystal X-ray diffraction data. In comparison with previous studies based on powder X-ray diffraction data [Lemaireet al.(1967).C. R. Acad. Sci. Ser. B,265, 1280–1282; Lemaire & Paccard (1969).Bull. Soc. Fr. Mineral. Cristallogr.92, 9–16; Buschow & van der Goot (1970).J. Less-Common Met.22, 419–428], the present redetermination affords refined coordinates and anisotropic displacement parameters for all atoms. A partial occupation for one Tb atom results in the non-stoichiometric composition Tb1.962 (4)Ni7. The title compound adopts the Ce2Ni7structure type and can also be derived from the CaCu5structure type as an intergrowth structure. The asymmetric unit contains two Tb sites (both site symmetries 3m.) and five Ni sites (.m.,mm2, 3m., 3m., -3m.). The two different coordination polyhedra of Tb are a Frank–Kasper polyhedron formed by four Tb and 12 Ni atoms and a pseudo Frank–Kasper polyhedron formed by two Tb and 18 Ni atoms. The four different coordination polyhedra of Ni are Frank–Kasper icosahedra formed by five Tb and seven Ni atoms, four Tb and eight Ni atoms, three Tb and nine Ni atoms, and six Tb and six Ni atoms, respectively.


2008 ◽  
Vol 72 (3) ◽  
pp. 771-783 ◽  
Author(s):  
L. Bindi ◽  
M. D. Welch ◽  
P. Bonazzi ◽  
G. Pratesi ◽  
S. Menchetti

AbstractThe crystal structure of seeligerite, Pb3IO4Cl3, from the San Rafael mine, Sierra Gorda, Chile, was solved in the space group Cmm2, and refined to R = 3.07%. The unit-cell parameters are: a = 7.971(2), b = 7.976(2), c = 27.341(5) Å, V = 1738.3(6) Å3 and Z = 8. The crystal structure consists of a stacking sequence along [001] of square-net layers of O atoms and square-net layers of Cl atoms with Pb+ and I+ cations located in the voids of the packing. As is typical of cations with a stereoactive lone-pair of electrons, Pb2+ and I5+ adopt strongly-asymmetrical configurations. Pb2+ cations occur in a variety of coordination polyhedra, ranging from anticubes and monocapped anticubes to pyramidal ‘one-sided’ coordinations. I5+ is coordinated by a square of four oxygen atoms: I1 and I3 exhibit a ‘one-sided’ coordination, whereas I2 has square-planar coordination.The TEM investigation has revealed additional superlattice reflections (which were not registered by X-ray diffraction (XRD)) in the hk0 diffraction pattern of seeligerite based upon a 0.158 Å-1 square net, which can be interpreted as arising from a 20-cation super-sheet motif (12.6 Å x 12.6 Å), likely related to a further level of Pb-I order superimposed upon the 8-site motif identified by XRD.


1988 ◽  
Vol 41 (2) ◽  
pp. 269 ◽  
Author(s):  
SF Colmanet ◽  
MF Mackay

After reaction of benzene-1,2-dithiol (bdtH2) with ammonium [99Tc] pertechnetate in aqueous alcohol, extraction of the reaction mixture with chloroform yielded wine-red crystals of the title compound, C24H16S8Tc2.CHCl3. The crystal structure of the binuclear complex has been determined by X-ray diffraction. Crystals are triclinic and belong to the space group Pī with a 8.534(1), b 8.842(2), c 11.192(3)Ǻ, α 107.02(2), β 98.13(1), γ 100.60(2)° with Z 1. Refinement on 1524 data measured with Cu Kα radiation converged at R 0.082. The complex has exact Ci point symmetry and pseudo-C2 symmetry. Each technetium atom is coordinated to a trigonal -prismatic array of six sulfur ligand atoms. These arrays are fused through a quadrilateral face defined by the four bridging sulfur atoms of two benzene-1,2- dithiolato ligands to give a Tc2S8 core of D2h pseudo-symmetry. As a Tc - Tc bond [bond length 2.591(3)Ǻ] passes through the mid point of the quadrilateral face, this novel geometry can be described in terms of capped trigonal prisms. The chloroform is disordered.


2011 ◽  
Vol 66 (11) ◽  
pp. 1122-1126 ◽  
Author(s):  
Mohammad Hakimi ◽  
Zahra Mardani ◽  
Keyvan Moeini ◽  
Mao Minoura ◽  
Heidar Raissi

The ligand, 2-(2-(pyridin-2-yl)oxazolidin-3-yl)-N-(pyridin-2-ylmethylene)ethanamine, POPME, was prepared via microwave-supported Schiff base and oxazolidination reactions. The cadmium iodide complex [Cd2(POPME)(μ-I)2I2] was prepared and identified by elemental analysis, IR, Raman and 1H and 13C NMR spectroscopy and single-crystal X-ray diffraction. In the crystal structure two Cd(II) ions with coordination numbers four and six are bridged by two iodide anions. Cd1 and Cd2 have distorted octahedral CdI2N4 and tetrahedral CdI4 geometries, respectively.Weak intermolecular hydrogen bonds H・ ・ ・I and H・ ・ ・O stabilize the supramolecular network


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