The crystal and molecular structure of N,N′-ethylenebis(benzoylacetoniminato)-nickel(II)

1981 ◽  
Vol 59 (18) ◽  
pp. 2766-2770 ◽  
Author(s):  
Vincenzo Malatesta ◽  
Angelo Mugnoli
Keyword(s):  
Oxygen Carriers ◽  
X Ray Diffraction ◽  
Chemical Models ◽  
Square Planar ◽  
Combined Use ◽  
Biological Interest ◽  
Cell Dimensions ◽  
Phenyl Rings ◽  
Relevant Point ◽  
Automatic Diffractometer

The crystal structure of N,N′-ethylenebis(benzoylacetoniminato)nickel(II), NiII(benacacen), has been determined by X-ray diffraction. Crystals are monoclinic and belong to the space group P21/n; the cell dimensions are a = 793(2), b = 7.910(1), c = 22.020(4) Å, β = 96.68(2)°. Intensity data were measured on a four-circle automatic diffractometer and the structure was solved by combined use of direct and Patterson methods. Full-matrix least-squares refinement converged at R = 0.032 for 3456 observed reflections. The geometry around the Ni atom is square planar; remarkable planarity extends to the whole ligand, aside from the rotation of the phenyl rings and the torsion along the dimethylene bond. Bond distances and bond angles are in agreement with corresponding values found for other Schiff-base type complexes. The packing of the molecules leaves empty channels running through the crystal, a relevant point in the study of chemical models for oxygen carriers of biological interest.

Thyroid Hormone Stereochemistry. II. Molecular Structure of Thyronine HCl Ethyl Ester Monohydrate

1974 ◽  
Vol 52 (17) ◽  
pp. 3042-3047 ◽  
Author(s):  
Arthur Camerman ◽  
Norman Camerman
Keyword(s):  
Ethyl Ester ◽  
Three Dimensional ◽  
Chloride Ion ◽  
Dimensional Structure ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Ether Linkage ◽  
Cell Dimensions ◽  
Phenyl Rings

The three-dimensional structure of L-thyronine, the non-iodinated physiologically inactive analog of thyroxine, has been determined by single crystal X-ray diffraction and compared to the active thyroid hormones. The compound crystallized as the monohydrate of thyronine hydrochloride ethyl ester in the monoclinic space group P21 with cell dimensions a = 10.502, b = 5.165, c = 17.940 Å, β = 109.74°. The structure was solved by Patterson methods to find the chloride ion and iterative Fourier maps to locate the rest of the atoms. Refinement was by anisotropic full-matrix least squares to convergence at R = 0.048.The two phenyl rings adopt a twisted orientation with respect to each other with angles of −37° and −67° between the plane of the inter-ring ether linkage and the planes of the α- and β-rings, respectively. This orientation differs considerably from that found in the iodinated thyronines. The conformation of the alanine side chain is remarkably similar to that of the alanine in the iodinated thyronines.

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate, [PtCl(PEt3)2(naph)]BF4, a complex containing a monodentate 1,8-naphthyridine ligand

1978 ◽  
Vol 56 (4) ◽  
pp. 450-455 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Keith R. Dixon ◽  
Masood A. Khan
Keyword(s):  
Crystal Structure ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Interatomic Distances ◽  
X Ray ◽  
Heterocyclic Ligand ◽  
Square Planar ◽  
Cell Dimensions ◽  
R Value

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate has been determined by single crystal X-ray diffraction and refined to an R-value of 0.063. The cell dimensions are a = 1.4246, b = 1.2676, c = 1.6530 nm, β = 115.66°. The space group is P21/c with 4 molecules per unit cell, and the measured density is 1.665 g cm−3. The structure is essentially a 4-coordinate square planar platinum(II) complex containing monodentate 1,8-naphthyridine. Interatomic distances to platinum are: Pt—Cl, 236.6(4); Pt—P(1), 225.4(4); Pt—P(2), 225.2(4); Pt—N(1), 208.3(11); and Pt—N(2), 304.5(14) pm. The structure is discussed in relation to variable temperature nmr studies of solutions, which indicate fluxional behaviour of the heterocyclic ligand.

The crystal structure of cis-chlorobis(triethylphosphine)phthalazineplatinum(II) tetrafluoroborate, [PtC](PEt3)2(phth)]BF4

1978 ◽  
Vol 56 (6) ◽  
pp. 878-883 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Keith R. Dixon
Keyword(s):  
Crystal Structure ◽  
Elevated Temperatures ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Dissociative Mechanism ◽  
Interatomic Distances ◽  
Heterocyclic Ligand ◽  
Square Planar ◽  
Cell Dimensions

The crystal structure of cis-chlorobis(triethylphosphine)phthalazineplatinum(II) tetrafluoroborate has been determinee by single crystal X-ray diffraction and refined to an R-value of 0.076 for 1935 reflections. The cell dimensions are a = 1315.7(2), b = 2462.7(4), c = 899.6(3) pm, β = 104.99(2)°. The space group is P21/c with 4 molecules per unit cell, ρo = 1.593, ρc = 1.613 g cm−3. The structure is a square planar 4-coordinate platinum(II) complex with an angle of 80.0° between the plane of the phthalazine molecule and that of the coordination. Interatomic distances to platinum are Pt—Cl, 235.4(9); Pt—P(1), 225.2(8); Pt—P(2), 226.9(8); Pt—N(1), 208(3); and Pt—N(2), 297(3) pm, the phthalazine ligand being monodentate. The structure is compared to previous results and discussed in relation to variable temperature nmr studies of solutions, which show that the heterocyclic ligand exchanges its point of attachment to and fro between N(1) and N(2) by a dissociative mechanism at elevated temperatures.

scholarly journals The Crystal and Molecular Structure of Diazido-2,2′-bipyridinecopper(II)

1974 ◽  
Vol 52 (17) ◽  
pp. 3125-3133 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Masood A. Khan
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Square Planar ◽  
Copper Coordination ◽  
Cell Dimensions ◽  
Coordinate Bond

The crystal and molecular structure of diazido-2,2′-bipyridinecopper(II), C10H8N2(N3)2Cu, is determined by single crystal X-ray diffraction, and refined to an R value of 0.067. The cell dimensions are a = 664.9(2), b = 843.3(1), c = 1082.0(2) pm, α = 86.99(2)°, β = 87.77(3)°, γ = 78.59(2)°. The space group is [Formula: see text] (No. 2) with 2 molecules per unit cell and the measured density is 1.71(2) g cm−3. The copper coordination is square planar with two additional longer bonds. The coordinate bond lengths in pm to the bipyridine ligand are: Cu—N(1), 201.6(6); Cu—N(2), 201.9(6). The coordinate bonds to the azido ligands are: Cu—N(3), 194.9(6); Cu—N(6), 196.6(6). The longer bonds are: Cu—N(3)″, 268.0(8), Cu—N(6)′ 268.2(8). The N—N bond lengths within each azido ligand are unequal: N(3)—N(4), 118.2(10); N(4)—N(5), 115.4(11); N(6)—N(7), 119.2(9); N(7)—N(8), 114.8(9). The angles at N(3) and N(6) are both 130° and at N(4) and N(7) the angles are both 175(1)°. Each azide takes part in asymmetric bridging through a single nitrogen atom. The results are compared with other structural studies on azido complexes and to a nitrate complex of Ag(II) which is structurally similar.

Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

1992 ◽  
Vol 50 (1) ◽  
pp. 36-37
Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler
Keyword(s):  
Single Phase ◽  
X Ray Diffraction ◽  
Rich Region ◽  
Average Cell ◽  
X Ray ◽  
Delta Phase ◽  
Cell Dimensions ◽  
Δ Phase ◽  
Morphological Differences ◽  
Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

Synthesis and Structure of a Clathrated Two-Dimensional Metal-Organic Framework: [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2·H2O (L = Bis(1-pyrazinylethylidene)hydrazine)

2008 ◽  
Vol 73 (1) ◽  
pp. 24-31
Author(s):  
Dayu Wu ◽  
Genhua Wu ◽  
Wei Huang ◽  
Zhuqing Wang
Keyword(s):  
Metal Organic Framework ◽  
Channel Structure ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Square Planar ◽  
Metal Organic ◽  
Aqueous Meoh ◽  
Organic Framework

The compound [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2 was obtained by the reaction of Cd(ClO4)2, bis(1-pyrazinylethylidene)hydrazine (L) and 4,4'-bipyridine in aqueous MeOH. Single-crystal X-ray diffraction has revealed its two-dimensional metal-organic framework. The 2-D layers superpose on each other, giving a channel structure. The square planar grids consist of two pairs of shared edges with Cd(II) ion and a 4,4'-bipyridine molecule each vertex and side, respectively. The square cavity has a dimension of 11.817 × 11.781 Å. Two guest molecules of bis(1-pyrazinylethylidene)hydrazine are clathrated in every hydrophobic host cavity, being further stabilized by π-π stacking and hydrogen bonding. The results suggest that the hydrazine molecules present in the network serve as structure-directing templates in the formation of crystal structures.

scholarly journals Synthesis, Characterization, and Non-Covalent Interactions of Palladium(II)-Amino Acid Complexes

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4331
Author(s):  
David B. Hobart ◽  
Michael A. G. Berg ◽  
Hannah M. Rogers ◽  
Joseph S. Merola
Keyword(s):  
Amino Acid ◽  
High Resolution Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Amino Acid Complexes ◽  
Acetone Water ◽  
Square Planar ◽  
Non Covalent Interactions ◽  
Covalent Interactions

The reaction of palladium(II) acetate with acyclic amino acids in acetone/water yields square planar bis-chelated palladium amino acid complexes that exhibit interesting non-covalent interactions. In all cases, complexes were examined by multiple spectroscopic techniques, especially HRMS (high resolution mass spectrometry), IR (infrared spectroscopy), and 1H NMR (nuclear magnetic resonance) spectroscopy. In some cases, suitable crystals for single crystal X-ray diffraction were able to be grown and the molecular structure was obtained. The molecular geometries of the products are discussed. Except for the alanine complex, all complexes incorporate water molecules into the extended lattice and exhibit N-H···O and/or O···(HOH)···O hydrogen bonding interactions. The non-covalent interactions are discussed in terms of the extended lattice structures exhibited by the structures.

Crystallization and preliminary X-ray diffraction studies of human catalase

1999 ◽  
Vol 55 (9) ◽  
pp. 1614-1615 ◽  
Author(s):  
R. A. P. Nagem ◽  
E. A. L. Martins ◽  
V. M. Gonçalves ◽  
R. Aparício ◽  
I. Polikarpov
Keyword(s):  
Search Model ◽  
Molecular Replacement ◽  
X Ray Diffraction ◽  
Beef Liver ◽  
X Ray ◽  
Diffusion Technique ◽  
Cell Dimensions ◽  
Synchrotron Radiation Diffraction ◽  
Replacement Solution ◽  
Unit Cell Dimensions

The enzyme catalase (H2O2–H2O2 oxidoreductase; E.C. 11.1.6) was purified from haemolysate of human placenta and crystallized using the vapour-diffusion technique. Synchrotron-radiation diffraction data have been collected to 1.76 Å resolution. The enzyme crystallized in the space group P212121, with unit-cell dimensions a = 83.6, b = 139.4, c = 227.5 Å. A molecular-replacement solution of the structure has been obtained using beef liver catalase (PDB code 4blc) as a search model.

The high-pressure cadmium borate Cd6B22O39·H2O

2015 ◽  
Vol 70 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Gerhard Sohr ◽  
Nina Ciaghi ◽  
Klaus Wurst ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Cell Dimensions ◽  
Temperature Experiment ◽  
Unit Cell Dimensions ◽  
Ir And Raman

AbstractSingle crystals of the hydrous cadmium borate Cd6B22O39·H2O were obtained through a high-pressure/high-temperature experiment at 4.7 GPa and 1000 °C using a Walker-type multianvil apparatus. CdO and partially hydrolyzed B2O3 were used as starting materials. A single crystal X-ray diffraction study has revealed that the structure of Cd6B22O39·H2O is similar to that of the type M6B22O39·H2O (M=Fe, Co). Layers of corner-sharing BO4 groups are interconnected by BO3 groups to form channels containing the metal cations, which are six- and eight-fold coordinated by oxygen atoms. The compound crystallizes in the space group Pnma (no. 62) [R1=0.0379, wR2=0.0552 (all data)] with the unit cell dimensions a=1837.79(5), b=777.92(2), c=819.08(3) pm, and V=1171.00(6) Å3. The IR and Raman spectra reflect the structural characteristics of Cd6B22O39·H2O.

Synthesis, structural and magnetic properties of macrocyclic aza-amido binuclear copper(II) complexes

1989 ◽  
Vol 67 (4) ◽  
pp. 662-670 ◽  
Author(s):  
Sanat K. Mandal ◽  
Laurence K. Thompson ◽  
Michael J. Newlands ◽  
Amal K. Biswas ◽  
Bibhutosh Adhikary ◽  
...  
Keyword(s):  
Variable Temperature ◽  
Complex Iii ◽  
Azomethine Nitrogen ◽  
X Ray Diffraction ◽  
Binuclear Copper ◽  
Magnetic Studies ◽  
Monoclinic System ◽  
Space Group ◽  
Pyramidal Geometry ◽  
Square Planar

Binuclear, antiferromagnetically coupled, macrocyclic copper(II) complexes, [Cu2(C28H32N4O4)]•H2O (II) and [Cu2(C36H32N4O4)]•CH3CN•H2O (III), involving asymmetric ligands with two deprotonated amide, two azomethine nitrogen, and two phenoxide donors at the binuclear centre, have been synthesized and characterized by single-crystal X-ray diffraction and variable temperature magnetic studies. Complex II crystallizes in the monoclinic system, space group P21/n, with a = 16.4854(9) Å, b = 7.6005(13) Å, c = 21.1617(11) Å, β = 104.090(5)°, Z = 4, Rf = 0.068 for 2062 significant reflections. The two copper(II) centres have square planar N2O2 donor sets with two phenoxide oxygen atoms bridging the copper centres with a copper–copper separation of 2.898(2) Å. A long copper–oxygen (amide) contact (2.808(10) Å) forms a weak dimer association. Complex III crystallizes in the triclinic system, space group [Formula: see text], with a = 8.7771(9) Å, b = 12.3983(16) Å, c = 15.7299(16) Å, α = 85.003(11)°, β = 84.574(8)°, γ = 76.838(10)°, Z = 2, Rf = 0.041 for 2966 significant reflections. The two copper(II) centres have distorted square-pyramidal geometry involving an N2O2 in plane donor set and two phenoxide oxygen bridges with a copper–copper separation of 3.018(1) Å. The fifth coordination site at each copper centre involves an amide oxygen from a neighbouring molecule (Cu(1)—O 2.371(4), Cu(2)—O 2.413(3) Å) in a staggered intermolecular array. Very strong antiferromagnetic exchange is observed in both cases (−2J = 689 ± 7 cm−1 (II), −2J = 816 ± 8 cm−1 (III)). Keywords: macrocycles, binuclear copper(II) complexes.

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