Structural Systematics of Lanthanide(III) Picrate Solvates: Hexamethylphosphoramide and Octamethylpyrophosphoramide Adducts

2020 ◽  
Vol 73 (6) ◽  
pp. 477
Author(s):  
Eric J. Chan ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
Allan H. White
Keyword(s):  
Metal Ion ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Heavier Lanthanides ◽  
Bidentate Chelate ◽  
Trigonal Prismatic Coordination ◽  
Lighter Lanthanides ◽  
Trigonal Prismatic ◽  
Isolated Species

Crystalline products of the reactions of lanthanide picrates, Ln(pic)3 (pic=2,4,6-trinitrophenoxide), with hexamethylphosphoramide (hmpa) and octamethylpyrophosphoramide (ompa) have been characterised by single-crystal X-ray diffraction studies. With hmpa and lighter lanthanides (La, Sm, Eu), isomorphous species (monoclinic, P21/c, Z 4) of stoichiometry [Ln(pic)3(hmpa)3]·0.5H2O, have been defined where the molecular units in the lattice contain 9-coordinate Ln with tricapped trigonal-prismatic coordination geometry. The picrate ligands are bidentate through phenoxide-O and 2-nitro-O, with the latter occupying the capping positions, while the hmpa ligands are singly O-bound to one trigonal face. Heavier lanthanides (Gd, Lu) and Y have been found to give isomorphous (monoclinic, P21/n, Z 4) species of stoichiometry [Ln(pic)3(hmpa)2], with 8-coordinate Ln of an irregular geometry best considered as close to that of a bicapped trigonal-prism. The picrate ligands chelate in the same manner as in the lighter Ln complexes but with one spanning a trigonal edge, and the hmpa-O donors occuping two apices of the other trigonal face. The ligand ompa has been found to act as a bidentate chelate in all isolated species, displacing one picrate from the metal ion coordination sphere to give ionic complexes. For La, Nd, and Gd, isomorphous (monoclinic, P21/n, Z 4) complexes of stoichiometry [Ln(pic)2(ompa)2(OH2)](pic)·0.5H2O containing 9-coordinate, tricapped trigonal-prismatic Ln with a single aqua ligand have been defined, while for Er, Yb, Lu, and Y, both the coordinated and lattice water molecules are lost in isomorphous (monoclininc, P21/c, Z 8) 8-coordinate, square-antiprismatic species of stoichiometry [Ln(pic)2(ompa)2](pic). For Er, further polymorphs, one monoclinic, P21/c, and the other triclinic, , have also been characterised.

scholarly journals Poly[diaqua(μ5-1H-imidazole-4,5-dicarboxylato)(μ4-1H-imidazole-4,5-dicarboxylato)trisilver(I)ytterbium(III)]

2012 ◽  
Vol 68 (8) ◽  
pp. m1073-m1074
Author(s):  
Si-Ming Zhu
Keyword(s):  
Hydrogen Bonding ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
Coordination Geometry ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Hydrogen Bonding Interactions ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

The asymmetric unit of the title compound, [Ag3Yb(C5HN2O4)2(H2O)2]n, contains three AgIions, one YbIIIion, two imidazole-4,5-dicarboxylate ligands and two coordinating water molecules. The YbIIIatom is eight-coordinated, in a bicapped trigonal prismatic coordination geometry, by six O atoms from three imidazole-4,5-dicarboxylate ligands and two coordinating water molecules. The two-coordinated AgIions exhibit three types of coordination environments. One AgIatom is bonded to two N atoms from two different imidazole-4,5-dicarboxylate ligands. The other two AgIatoms are each coordinated by one O atom and one N atom from two different imidazole-4,5-dicarboxylate ligands. These metal coordination units are connected by bridging imidazole-4,5-dicarboxylate ligands, generating a two-dimensional heterometallic layer. These layers are stacked along theaaxisviaO—H...O hydrogen-bonding interactions to generate a three-dimensional framework.

Crystal Structure of Calcium Picrate Pentahydrate: A New Eight-Coordinate Stereochemistry for [M(bidentate)2(unidentate)4]

1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Title Compound ◽  
Lattice Site ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Triangular Face ◽  
X Ray

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.

Polypyridines, Picrates, Lanthanides: A Plethora of Stacks?

2020 ◽  
Vol 73 (6) ◽  
pp. 529
Author(s):  
Eric J. Chan ◽  
Simon A. Cotton ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
...  
Keyword(s):  
Nitro Group ◽  
The Other ◽  
Molar Ratio ◽  
Lanthanide Ion ◽  
X Ray ◽  
The Third ◽  
Group Oxygen ◽  
Structure Determinations ◽  
Lighter Lanthanides ◽  
Trigonal Prismatic

Reactions of the lanthanide(iii) picrates (picrate=2,4,6-trinitrophenoxide=pic) with 1,10-phenanthroline (phen) and 2,2′:6′,2′′-terpyridine (terpy) in a 1:2 molar ratio have provided crystals suitable for X-ray structure determinations in instances predominantly involving the lighter lanthanides. In all, the aza-aromatic ligands chelate the lanthanide ion, none being found as ‘free’ ligands within the lattice. The complexes of 1,10-phenanthroline have been characterised in two forms, one unsolvated (Ln=La, Sm, Eu; monoclinic, C2/c, Z 8), one an acetonitrile monosolvate (Ln=Gd; monoclinic, P21/a, Z 4), the latter being the only previously known form (with Ln=La). In both forms, the LnIII is nine-coordinate, in an approximately tricapped trigonal-prismatic environment, with two picrate ligands chelating through phenoxide and 2-nitro group oxygen atoms, the third being bound through phenoxide-O only. The 2,2′:6′,2′′-terpyridine complexes, all acetonitrile monosolvates defined for Ln=La, Gd, Er, and Y (monoclinic, C2/c, Z 4), are ionic, one picrate having been displaced from the primary coordination sphere. For Ln=La, the two bound picrates are again chelating, making the LaIII 10-coordinate in a distorted bicapped square-antiprismatic environment but in the other species they are bound through phenoxide-O only, making the LnIII ions eight-coordinate in a distorted square-antiprismatic environment. Stacked arrays of the ligands can be found in both series of complexes, with intramolecular picrate–picrate and picrate–aza-aromatic stacks being prominent features.

Poly[diaquadi-μ6-succinato-μ5-succinato-dierbium(III)]

2006 ◽  
Vol 62 (4) ◽  
pp. m738-m740 ◽  
Author(s):  
Gui-Ying Dong ◽  
Guang-Hua Cui ◽  
Jin Lin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Coordination Environment ◽  
Trigonal Prismatic Coordination ◽  
Coordinated Water ◽  
Trigonal Prismatic

In the title compound, [Er2(C4H4O4)3(H2O)2] n , the asymmetric unit consists of two ErIII cations, three succinate anions and two coordinated water molecules. Both ErIII ions are in a tricapped trigonal–prismatic coordination environment. The Er atoms are bridged into a three-dimensional framework by succinate anions, which exhibit anti and gauche conformations with different coordination modes. The crystal structure is stabilized by O—H...O hydrogen bonds [O...O = 2.715 (8)–2.936 (8) Å].

Structural and spectroscopic studies of dipotassium 3,3,3′,3′-tetramethylcystinate trihydrate, K2[C10H18N2O4S2]3H2O

1984 ◽  
Vol 62 (6) ◽  
pp. 1127-1133 ◽  
Author(s):  
Romolo Faggiani ◽  
Helen Elaine Howard-Lock ◽  
Colin James Lyne Lock ◽  
Maria Lurdes Martins ◽  
Philip Stuart Smalley
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Spectroscopic Studies ◽  
The Other ◽  
Ionic Interactions ◽  
Water Molecules ◽  
Torsional Angle ◽  
X Ray Diffraction ◽  
Standard Methods ◽  
X Ray

The compound dipotassium 3,3,3′,3′-tetramethylcystinate trihydrate, K2[C10H18O4N2S2]3H2O, has been prepared and characterized by single crystal X-ray diffraction. Crystals were monoclinic, P21a = 6.160(1), b = 26.473(8), c = 6.193(1) Å, β = 113.94(1)°, with two formula units in the unit cell. Intensities were measured on a Syntex P21, diffractometer with use of MoKα radiation. The structure was solved by standard methods and refined to R1 = 0.0469, R2 = 0.0472 based on 2303 independent observed reflections. The C—S bonds (1.877(6), 1.891(6) Å) are longer than in many similar compounds although the S—S bond (2.040(2) Å) is not. The C—S—S—C torsional angle (108.7(3)°) is larger than normal in dithiol compounds. Other distances and angles are normal. Two types of potassium coordination are present, one a distorted octahedron, the other a distorted trigonal prism. In addition to the ionic interactions, hydrogen bonds involving the water molecules are important in stabilizing the structure.

scholarly journals Caesium propanoate monohydrate

2020 ◽  
Vol 76 (8) ◽  
pp. 1307-1310 ◽  
Author(s):  
Erika Samolová ◽  
Jan Fábry
Keyword(s):  
Hydrogen Bonds ◽  
General Position ◽  
Repeat Unit ◽  
Unit Cell ◽  
The Other ◽  
Water Molecules ◽  
Special Position ◽  
Space Group ◽  
Trigonal Prismatic ◽  
Oxygen Atoms

Caesium propanoate monohydrate, Cs+·C3H5O2 −·H2O, is composed of two symmetry-independent Cs+ cations, which are situated on the special position 4e of space group P\overline421 m, one symmetry-independent propanoate molecule in a general position and a pair of water molecules also situated on special position 4e. Two pairs of these symmetry-independent cations, four propanoate molecules and two pairs of symmetry-independent water molecules form a repeat unit. These units form columns that are directed along the c axis and possess symmetry mm2. There are four such columns passing through each unit cell. Each column is interconnected to its neighbours by four bifurcated three-centred Ow—H...Op (w = water, p = propanoate) hydrogen bonds of moderate strength. There are also four intramolecular Ow—H...Op hydrogen bonds of moderate strength within each column. One Cs+ cation is coordinated by six oxygen atoms (two water and four carboxylate) in a trigonal–prismatic geometry, while the other Cs+ cation is coordinated by four water and four carboxylate O atoms in a tetragonal–prismatic arrangement.

Crystal structure of praseodymium sulphate octahydrate

1981 ◽  
Vol 155 (3-4) ◽  
Author(s):  
I. S. Ahmed Farag ◽  
M. A. El-Kordy ◽  
N. A. Ahmed
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Bridging Ligand ◽  
Dimensional Network ◽  
Anisotropic Temperature ◽  
Temperature Factors

AbstractThe crystals of PrThe crystal structure has been determined from three-dimensional single-crystal X-ray diffraction data and refined by the least-squares method, using anisotropic temperature factors, to a discrepancy index ofThe molecules are arranged in layers forming a three-dimensional network. Each Pr atom is coordinated with eight oxygen atoms, four of which are related to sulphate groups, the other four are to water molecules. The sulphate ion, located at the twofold axis, behaves as a bidentate bridging ligand connecting two Pr atoms. The other sulphate ion acts as a threefold bridging ligand between three neighbouring Pr atoms.

scholarly journals Equiatomic iron-based tetrelides TFeSi and TFeGe (T = Zr, Nb, Hf, Ta) – A 57Fe Mössbauer-spectroscopic study

2019 ◽  
Vol 74 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Sebastian Stein ◽  
Theresa Block ◽  
Steffen Klenner ◽  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Room Temperature ◽  
Structural Motif ◽  
Clear Correlation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Structural Distortions ◽  
Trigonal Prismatic Coordination ◽  
The Common ◽  
Trigonal Prismatic

AbstractThe equiatomic iron-silicides TFeSi as well as the corresponding germanides TFeGe with the electron-poor 4d and 5d transition metals (T=Zr, Nb, Hf, Ta) have been synthesized from the elements by arc-melting. All samples were characterized through their lattice parameters using powder X-ray diffraction (Guinier technique). Four structures were refined from single-crystal X-ray diffractometer data: a=640.16(3), b=393.45(5), c=718.42(6) pm, Pnma, 390 F2 values, 20 parameters, wR2=0.0294 for ZrFeSi (TiNiSi type), a=719.63(11), b=1119.27(7), c=649.29(7) pm, Ima2, 1103 F2 values, 54 parameters, wR2=0.0555 for NbFeGe (TiFeSi type), a=655.96(7), c=372.54(4) pm, P6̅2m, 251 F2 values, 15 parameters, wR2=0.0260 for HfFeGe (ZrNiAl type) and a=624.10(3), b=378.10(6), c=725.25(7) pm, Pnma, 369 F2 values, 20 parameters, wR2=0.0513 for TaFeGe (TiNiSi type). The common structural motif of the four different structures is the slightly distorted tetrahedral tetrel (tr) coordination of the iron atoms and a trigonal prismatic coordination of iron by T=Zr, Nb, Hf, Ta. Three compounds were characterized as Pauli-paramagnetic by measuring their susceptibility. The measurement of the electrical resistivity of NbFeSi characterises this compound as a good metal. Furthermore, 57Fe Mössbauer spectra of all compounds could be obtained at room temperature, revealing a clear correlation between the structural distortions and the quadrupole splitting parameters.

The Relationship Between Octahedral and Trigonal-Prismatic Coordination in Bis Tridentate Complexes of TiIV and VIV

1988 ◽  
Vol 41 (4) ◽  
pp. 453 ◽  
Author(s):  
AA Diamantis ◽  
M Manikas ◽  
MA Salam ◽  
MR Snow ◽  
ERT Tiekink
Keyword(s):  
Tridentate Ligand ◽  
Vanadium Complexes ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Titanium Complexes ◽  
Tridentate Ligands ◽  
Space Group ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

The crystal structures of two vanadium complexes V( aabh )2 (1) and V( aasalh )2 (2) and of two titanium complexes Ti( aabh )2 (3) and Ti( babh )2 (4), where aabh is the dinegative, tridentate ligand pentane-2,4-dione benzoylhydrazonato (2-), aasalh is pentane-2,4-dione salicyloylhydrazonato (2-) and babh is 4-phenylbutane-2,4-dione benzoylhydrazonato (2-), were determined by X-ray diffraction methods. Crystals of (1) are monoclinic, space group P21/c, a 8.906(3), b 11.840(2), c 22.450(6)Ǻ, β 97.72(3)°, V 2345.8 and Z 4; those of (2) are triclinic, space group Pī , a 9.802(4), b 10.205(3), c 13.688(6)Ǻ, α 100.56(3),β 94.07(4),γ 112.89(3)°, V 1224.6 Ǻ3 and Z 2; those of (3) are monoclinic, space group C2/c, a 18.543(4), b 10.269(4), c 12.589(4)Ǻ, β 106.80(2)°, V 2294.9 Ǻ3 and Z 4; and those of (4) are monoclinic, space group P21/n, a 10.923(4), b 19.139(3), c 14.610(5)Ǻ, β 94.54(3)°, V 3044.7 Ǻ3 and Z 4. The structures were refined by a full-matrix least-squares procedure in each case to final values of R 0.102, 0.044, 0.049 and 0.058 for the structures (1), (2), (3) and (4), respectively, and values of Rw 0.099, 0.049, 0.053 and 0.065 for 1735, 3405, 1185 and 2911 statistically significant reflections, respectively. In the vanadium complexes the coordination geometry is approximately trigonal prismatic, whereas in each of the titanium complexes the two tridentate ligands are in a meridional arrangement with an approximately octahedral coordination. The stabilization of vanadium(IV) in the absence of the oxo function and the role of the metals in producing different coordination geometries are discussed.

scholarly journals Crystal structure of K3EuSi2O7

2021 ◽  
pp. 26-26
Author(s):  
Sabina Kovac ◽  
Predrag Dabic ◽  
Aleksandar Kremenovic
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
X Ray Diffraction ◽  
Coordination Environment ◽  
Distorted Octahedral ◽  
Earth Cation ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic ◽  
The Eu

As a part of the research of the flux technique for growing alkali rare-earth elements (REE) containing silicates, tripotassium europium disilicate, K3EuSi2O7, has been synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in the space group P63/mcm. In the crystal structure of the title compound, one part of the Eu cations are in a slightly distorted octahedral coordination and the other part are in an ideal trigonal prismatic coordination environment. The disilicate Si2O7 groups connect four EuO6 octahedra and one EuO6 trigonal prism. Three differently coordinated potassium cations are located between them. Silicates containing the larger rare earth elements usually crystallize in a structure that contains the rare-earth cation in both a slightly distorted octahedral and an ideal trigonal prismatic coordination environment.

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