The structure determination of a binuclear copper(II) complex of aTetra-Schiff base macrocycle

1976 ◽  
Vol 29 (3) ◽  
pp. 515 ◽  
Author(s):  
BF Hoskins ◽  
NJ McLeod ◽  
HA Schaap
Keyword(s):  
Schiff Base ◽  
Least Squares Method ◽  
Condensation Product ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Binuclear Copper ◽  
Apical Position ◽  
X Ray ◽  
Space Groups

The structure of the complex Lcu2Cl2,6H2O (where LH2 is the tetra-Schiff base macrocycle formed as the condensation product of propane-1,3-diamine and 2-hydroxy-5-methylisophthal- aldehyde in the mole ratio 2: 2) was determined by single-crystal X-ray diffraction methods. The crystals are monoclinic, a 7.720(1), b 17.079(1), c 11.171(1) � and β 91.50(1)�, with two molecules per unit cell. It has proved difficult to resolve the ambiguity between the three possible space groups (C2, Cm, and C2/m) and the initial model has been refined in each using a full-matrix least-squares method. The space group C2/m seems the most likely and the structure is described in it; R 0.049 for the 1369 independent reflections measured using counter methods. The structure analysis has confirmed the anticipated cyclic structure of the ligand with the two copper atoms held together in a binuclear arrangement by the planar N4O2 donor set; the Cu.. .Cu distance is 3.133(1)�. Each copper atom has a distorted square-pyramidal environment with the apical position of each being occupied by a chlorine atom; the two chlorine atoms are on the opposite sides of the macrocycle. The water molecules are not coordinated, but form an extensive system of hydrogen bonding throughout the crystal with discrete binuclear molecules of the LCu2Cl2 complex.

Etude structurale par diffraction des RX et spectroscopie IR des hydrates 10 et 8.4 Å de kaolinite

1999 ◽  
Vol 32 (5) ◽  
pp. 968-976 ◽  
Author(s):  
S. Jemai ◽  
A. Ben Haj Amara ◽  
J. Ben Brahim ◽  
A. Plançon
Keyword(s):  
Water Molecule ◽  
Octahedral Site ◽  
Ammonium Fluoride ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Tetrahedral Sheet ◽  
X Ray ◽  
Octahedral Sites ◽  
Sheet Structure

Two hydrated kaolinites, characterized by 10 and 8.4 Å basal distances, were synthesized by treating the kaolinite KGa-1 with dimethyl sulfoxide (DMSO) and ammonium fluoride (NH4F). The X-ray diffraction study was based on a comparison between the experimental and calculated profiles. This study was conducted in two steps: firstly, the study of the 00lreflections enabled the determination of the stacking mode alongc*, the number of water molecules and their positions along the normal to the plane of the sheet structure; secondly, the study of thehkbands, withhand/ork≠ 0, enabled the determination of the stacking mode and the positions of the water molecules in the (a,b) plane. The 10 Å hydrated kaolinite is characterized by two water molecules per Al2Si2O5(OH)4unit, situated at 3 and 3.4 Å from the hydroxyl surface, over the octahedral sites. Two adjacent layers are translated with respect to each other, withT11= −0.38a− 0.37b+ 10n. The 8.4 Å hydrated kaolinite is characterized by one water molecule per Al2Si2O5(OH)4unit, situated at 2.4 Å from the hydroxyl surface and inserted between the vacant octahedral site and the ditrigonal cavity of the tetrahedral sheet. The corresponding interlayer shift isT11= −0.355a+ 0.35b+ 8.4n.

scholarly journals Calcioferrite with composition (Ca3.94Sr0.06)Mg1.01(Fe2.93Al1.07)(PO4)6(OH)4·12H2O

2014 ◽  
Vol 70 (3) ◽  
pp. i16-i17
Author(s):  
Barbara Lafuente ◽  
Robert T. Downs ◽  
Hexiong Yang ◽  
Robert A. Jenkins
Keyword(s):  
Single Crystal ◽  
Water Molecules ◽  
Site Symmetry ◽  
Natural Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Small Crystals ◽  
Hydrated Calcium

Calcioferrite, ideally Ca4MgFe3+4(PO4)6(OH)4·12H2O (tetracalcium magnesium tetrairon(III) hexakis-phosphate tetrahydroxide dodecahydrate), is a member of the calcioferrite group of hydrated calcium phosphate minerals with the general formula Ca4AB4(PO4)6(OH)4·12H2O, whereA= Mg, Fe2+, Mn2+andB= Al, Fe3+. Calcioferrite and the other three known members of the group, montgomeryite (A= Mg,B= Al), kingsmountite (A= Fe2+,B= Al), and zodacite (A= Mn2+,B= Fe3+), usually occur as very small crystals, making their structure refinements by conventional single-crystal X-ray diffraction challenging. This study presents the first structure determination of calcioferrite with composition (Ca3.94Sr0.06)Mg1.01(Fe2.93Al1.07)(PO4)6(OH)4·12H2O based on single-crystal X-ray diffraction data collected from a natural sample from the Moculta quarry in Angaston, Australia. Calcioferrite is isostructural with montgomeryite, the only member of the group with a reported structure. The calcioferrite structure is characterized by (Fe/Al)O6octahedra (site symmetries 2 and -1) sharing corners (OH) to form chains running parallel to [101]. These chains are linked together by PO4tetrahedra (site symmetries 2 and 1), forming [(Fe/Al)3(PO4)3(OH)2] layers stacking along [010], which are connected by (Ca/Sr)2+cations (site symmetry 2) and Mg2+cations (site symmetry 2; half-occupation). Hydrogen-bonding interactions involving the water molecules (one of which is equally disordered over two positions) and OH function are also present between these layers. The relatively weaker bonds between the layers account for the cleavage of the mineral parallel to (010).

An accurate determination of the crystal structure of triclinic potassium dichromate, K2Cr2O7

1968 ◽  
Vol 46 (6) ◽  
pp. 933-941 ◽  
Author(s):  
J. K. Brandon ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Potassium Dichromate ◽  
Accurate Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Cell Refinement ◽  
Final Agreement ◽  
Dichromate Ions

The crystal structure of triclinic potassium dichromate has been determined by single crystal X-ray diffraction. The cell constants are a = 13.367, b = 7.376, c = 7.445 Å, α = 90.75°, β = 96.21°, γ = 97.96° with four K2Cr2O7 units per cell. Refinement of 2600 reflections in both the space groups P1 and [Formula: see text] leads to the same structure. This is in agreement with the results of anomalous dispersion measurements, confirming that [Formula: see text] is the correct space group. The final agreement index, R, is 0.054. The two crystallographically independent dichromate ions are similar, deviating only slightly from C2v) symmetry. The Cr—O (terminal) distance is 1.63 Å, the Cr—O (bridging) distance is 1.79 Å and all angles at the chromium atoms are tetrahedral except for one of the O(bridging)—Cr—O(terminal) angles in each ion which is 106°. The angles at the bridging oxygen atoms are 124° and 128°. The geometry of the anion is compared with that found in a number of similar groups.

Crystal Structure of a Binuclear Copper(II) Complex with μ-Alkoxo and μ-Pyridonato Bridges. Effect of the Dihedral Angle on the Superexchange Interaction

1989 ◽  
Vol 44 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Yuzo Nishida ◽  
Miyuki Masumoto ◽  
Yutaka Mori
Keyword(s):  
Crystal Structure ◽  
Schiff Base ◽  
Dihedral Angle ◽  
Schiff Base Ligand ◽  
Superexchange Interaction ◽  
X Ray Diffraction ◽  
Binuclear Copper ◽  
Ferromagnetic Interaction ◽  
X Ray

The crystal structure of the binuclear copper(II) complex. [Cu2(L)(2-pyridonato)] was determined by X-ray diffraction, where H3(L) represents the Schiff base ligand derived from 1,3-diaminopropane-2-ol and acetylacetone. Two copper(II) ions are bridged by alkoxide and 2-pyridonate groups with a Cu-Cu separation of 3.249(2) Å . Ferromagnetic interaction is found to be operating in this complex, which is attributed to the small dihedral angle (121°) between the two planes containing the copper(II) ion.

Experimental determination of electrostatic properties of Na–X zeolite from high resolution X-ray diffraction

2014 ◽  
Vol 16 (24) ◽  
pp. 12228-12236 ◽  
Author(s):  
F. F. Porcher ◽  
M. Souhassou ◽  
C. E. P. Lecomte
Keyword(s):  
High Resolution ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Cation Site ◽  
X Ray ◽  
X Zeolite ◽  
Adsorption Of Water ◽  
Zeolite P ◽  
Resolution Single

High resolution single crystal X-ray diffraction is used to obtain the electron density and atomic charges in Na–X zeolite. The Coulomb potential and interaction energies are calculated for a given Na+ distribution and are discussed in connection with cation site affinities and adsorption of water molecules in the zeolite.

Structural Studies on Catalysts and Catalyst Precursors. II. The X-Ray Structure Determination of Chloro(Pentante-2,4-dithionato)(tributylphosphine)nickel(II), Ni(sacsac)(PBu3)Cl

1985 ◽  
Vol 38 (3) ◽  
pp. 369 ◽  
Author(s):  
KJ Cavell ◽  
DG Hay ◽  
AF Masters ◽  
GA Williams
Keyword(s):  
Structural Studies ◽  
Donor Atom ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Apical Position ◽  
X Ray ◽  
Butyl Group ◽  
Atom Bond

The preparation and characterization of Ni( sacsac )(PBu3) Cl by single crystal X-ray diffraction [refined to R 0.052, R? 0.042 with 1325 data having I ≥ 3σ(I)], are reported. The compound crystallizes as discrete molecules in the orthorhombic space group P bca, with a 15.526(4), b 15.774(4), c 18.377(8)Ǻ, U 4500.7 Ǻ3, and Z 8. The nickel-donor atom bond distances are Ni-S (trans Cl ) 2.097(3), Ni-S (trans P) 2.138(3), Ni- Cl 2.216(3) and Ni-P 2.237(3)Ǻ, with the ligands subtending angles S-Ni-S 98.6(1), S-Ni- Cl 85.4(1), S-Ni-P 89.5(1) and Cl -Ni-P 86.8(1). The coordination about the nickel(II) centre is planar; however, one butyl group of the phosphine is oriented so that a hydrogen is directed towards the apical position of the nickel. The structure is correlated with the N.M.R . spectra in both solid and solution phases and compared with the structures of related com- pounds. The Ni-S bonds are shown to be short and the Ni-P bond long relative to such dimensions in comparable compounds.

scholarly journals Syntheses, Characterization, and X-ray Crystal Structure of Binuclear Lanthanide Complexes Assembled with Schiff Base and Acetate

2021 ◽  
pp. 81-95
Author(s):  
Mbossé Ndiaye-Gueye ◽  
Amar Diop ◽  
Papa Aly Gaye ◽  
Ibrahima Elhadji Thiam ◽  
Farba Bouyagui Tamboura ◽  
...  
Keyword(s):  
Schiff Base ◽  
Intermolecular Hydrogen Bond ◽  
Methanol Solution ◽  
Tridentate Ligand ◽  
Water Molecules ◽  
Binuclear Complexes ◽  
Asymmetric Unit ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
X Ray

Herein we reported the binuclear complexes of the 1-(pyridin-2-yl)-2-(pyridin-2-ylmethylene)hydrazine ligand (HL) [Ln2(HL)2(CH3COO)6].n(H2O) (Ln = Y, Pr, Gd and Er). The binuclear complexes are characterized by IR and physical measurement. Spectroscopic evidence indicated that the Schiff base HL behave an N3 coordination tridentate ligand. The complexes are formulated as [{Ln(1-(pyridin-2-ylmethylidene-kN)-2-(pyridin-2-yl-kN)hydrazine-kN1)(h2-OOCH3)2}{h1:h2:m2-OOCH3}2{Ln(1-(pyridin-2-ylmethylidene-kN)-2-(pyridin-2-yl-kN)hydrazine-kN1))(h2-OOCH3)2}].n(H2O). The structure of the praseodymium complex was elucidated by X-ray diffraction analysis. Suitable crystals were grown by slow evaporation of methanol solution. The asymmetric unit of the compound contains two neutral ligand molecules, two Pr3+ ions, four acetate anions acting in h2-OOCH3 mode, two acetate anions acting in h1:h2:m2-OOCH3 mode, and three uncoordinated water molecules. The praseodymium atom is ten coordinated and the coordination sphere is best described as a distorted bicapped square antiprism. The PrIII···PrIII distance is 4.2777(6) Å and the bridging angle Pr—O—Pr and O—Pr—O are respectively 115.8(3)° and 64.2(3)°. The structure is consolidated by intra and intermolecular hydrogen bond.

scholarly journals Synthesis, Characterization and Crystal Structure of Samarium(III)-(E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine Complex

2021 ◽  
pp. 87-94
Keyword(s):  
Schiff Base ◽  
Chemical Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Form Hydrogen Bond ◽  
X Ray ◽  
Mass Spectral ◽  
Cell Parameters ◽  
Ft Ir ◽  
Coordination Water

Samarium-benzylidene Schiff base adduct with the formula [Sm(NO3)3(H2O)3].2L (L= (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl) methanimine) (1) has been prepared, with two water molecules bonded to the samarium center form hydrogen bond with three molecules of title Schiff base through nitrogen atoms of the triazole rings. The chemical structure was confirmed by means of single-crystal X-ray diffraction (scXRD), FT-IR, electrical conductivity, thermogravimetric analysis (TGA), mass spectrometry and elemental analysis. The title complex 1 crystallizes in the triclinic P-1 space group. The unit cell parameters are a = 10.4045(1) Å, b = 12.5403(1) Å, c = 12.5477(2) Å,  = 96.668(1)o,  = 110.810(1)o,  = 111.567(1)o, V = 1.788 Å3, Z = 2, Rgt(F) = 0.0223, wRref(F2) = 0.0576. The samarium ion is in a distorted capped square antiprism environment, coordinated by three bidentate nitrates and three coordination water molecules. The [Sm(H2O)3(NO3)3] complex and the (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine) moiety (L) are held together via hydrogen interactions to form a 2-D supramolecular framework. It is a non-electrolyte as indicated by its molar conductivity (ΛM= 10.1 S cm2 mol-1) in MeOH at 1.0 mM. The mass spectral results confirm the suggested structure of the investigated adduct.

Determination of crystal symmetry for Bi4Ti3O12-based ferroelectrics by using electron diffraction

2013 ◽  
Vol 46 (3) ◽  
pp. 798-800 ◽  
Author(s):  
Wanneng Ye ◽  
Chaojing Lu ◽  
Peng You ◽  
Kun Liang ◽  
Yichun Zhou
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Electron Diffraction Technique ◽  
Convergent Beam

In recent years, inconsistent space groups of monoclinicB1a1 and orthorhombicB2cbhave been reported for the room-temperature ferroelectric phases of both Bi4Ti3O12and lanthanide-substituted Bi4Ti3O12. In this article, the electron diffraction technique is employed to unambiguously clarify the crystal symmetries of ferroelectric Bi4Ti3O12and Bi3.15Nd0.85Ti3O12single crystals at room temperature. All the reflections observed from the two crystals match well with those derived fromB1a1, but the observed reflections 010, 030, {\overline 2}10 and {\overline 2}30 should be forbidden in the case ofB2cb. This fact indicates that both the ferroelectrics are of the space groupB1a1 rather thanB2cb, which is confirmed by convergent-beam electron diffraction observations. On the basis of the monoclinic space groupB1a1, the lattice parameters of both the ferroelectrics were calculated by the Rietveld refinement of powder X-ray diffraction data.

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