Coordination chemistry of dimethylgold(III) and methylmercury(II). Synthesis, 1H N.M.R. and structural studies of Poly(pyrazol-1-yl)borate complexes

1983 ◽  
Vol 36 (6) ◽  
pp. 1107 ◽  
Author(s):  
AJ Canty ◽  
NJ Minchin ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Coordination Chemistry ◽  
Variable Temperature ◽  
Gold Atom ◽  
Pyrazole Ring ◽  
Structural Studies ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Borate Complexes

Dimethylgold(III) and methylmercury(II) form complexes Me2AuL and MeHgL where L are poly-(pyrazol-1-yl)borate ligands [HB(pz)3]- and [B(pz)4]-. The structure of Me,Au{HB(pz)3} has been determined by single-crystal X-ray diffraction at 295 K and refined by least-squares methods to R 0.056 for 2194 independent 'observed' reflections. This complex has square-planar coordination for the gold atom involving two coordinated pyrazole rings and one uncoordinated ring, in contrast to the isoelectronic cation [Me2Au{(pz)3CH)]+ which has square planar coordination with a weak axial Au . .N interaction. Variable temperature 1H n.m.r. spectra in CD2Cl2 indicate presence of rapid equilibria between pyrazole ring environments at ambient temperature and, for the MeHgII complexes, down to -90�C. For the Me2AuIII complexes spectra at -90�C indicate presence of pyrazole ring environments in ratios 2 : 1 (L = [HB(pz)3]-) and 2 : 1 : 1 (L = [B(pz)4]-). Crystal data for Me2Au{HB(pz)3}: rhombohedral, space group R3c, a 17.98(1) �, α 117.98(5)�, Z 18.

Crystal data for ternary compounds of the system Cu–As2Se3

1987 ◽  
Vol 20 (4) ◽  
pp. 323-323
Author(s):  
C. A. Majid ◽  
M. A. Hussain
Keyword(s):  
Diffraction Data ◽  
Lattice Parameters ◽  
Structural Studies ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Ternary Compounds

Structural studies of polycrystalline CuAsSe2, Cu3AsSe4 and Cu3AsSe3 are reported. These were found to be cubic with space group Pm{\bar 3}m and lattice parameters as follows: (1) CuAsSe2: a = 5.513(4) Å, V = 167.47(1) Å3, Z = 2; Dm = 5.56(6), Dx = 5.88 g cm−3. (2) Cu3AsSe4: a = 5.530(5) Å; V = 169.11(2) Å3; Z = 1; Dm = 5.51(5), Dx = 5.75 g cm−3. (3) Cu3AsSe3: a = 5.758(9) Å, V = 190.87(3) Å3, Z = 1, Dm = 5.03(9), Dx = 4.45 g cm−3. X-ray diffraction data using a Rigaku DMAX-IIIA diffractometer and Cu Kα radiation.

Synthesis, Crystal Structure and Magnetic Properties of a (μ-Hydroxo)(μ-Pyrazolato) Dicopper(II) Complex

2000 ◽  
Vol 55 (9) ◽  
pp. 796-802 ◽  
Author(s):  
H. Kara ◽  
Y. Elerman ◽  
K. Prout
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Variable Temperature ◽  
Powdered Sample ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Present Complex ◽  
Square Planar ◽  
Super Exchange Interaction

Preparation and magnetic properties of a 3,5-dimethylpyrazolate bridged binuclear copper(II) complex [Cu2(L)(3 ,5 -pyz)] (L = 1,3-Bis(2-Hydroxy-5-Chlorosalicylideneamino)propan- 2-ol) is reported. The crystal structure determined by X-ray diffraction methods. (C22H20N4O3CI2CU2), triclinic, space group P1̄, a = 9.622(3), b = 10.921(2), c = 11.420(3) Å, α = 100.73(2), β = 94.04(2), Υ = 108.08(2)°, V = 1110.2(5) Å3, Z = 2. Two copper(II) ions in a square-planar coordination are bridged via alkoxide oxygen and 3,5-dimethyl pyrozolate nitrogen atoms to form a dinuclear unit. The metal coordination sphere is four-coordinate, planar with an N2O2 donor set. The dihedral angle between the two coordination planes is 166.83°. There are significant intermolecular interactions between neighbouring binuclear entities. The shortest intermolecular Cu (1) ... Cu(1)i distance is 3.383(1) Å and the Cu(1) - O ( 1)i distance is 2.666(3) Å (i = 1 -x, -y, 1 - z). The variable-temperature magnetic susceptibility measurement for a powdered sample of the complex was carried out in the temperature range 5 - 350 K and analysed to obtain values of the parameter J in the exchange Hamiltonian ℋ = -2JScu Scu; 2J = -164 cm-1. The magnetic moment at 300 K is about 2.42 μB, and 0.22 μB at 5 K. The weak antiferromagnetism of the present complex is reasonably explained in terms of the orbital countercomplementary effect based on Hoffmann's theory for super-exchange interaction

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.

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.

Synthesis and Structural Study of the Thermochromic Compounds Bis(2-amino-4-oxo-6-methylpyrimidinium) Tetrachlorocuprate(II) and Bis(2-amino-4-chloro-6-methylpyrimidinium) Hexachlorodicuprate(II)

1999 ◽  
Vol 54 (6) ◽  
pp. 718-724 ◽  
Author(s):  
Isabel Díaz ◽  
Vicente Fernández ◽  
Vitaly K. Belsky ◽  
Jose Luis Martínez
Keyword(s):  
Charge Transfer ◽  
Low Temperature ◽  
Magnetic Measurements ◽  
Variable Temperature ◽  
Major Change ◽  
Crystal Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar ◽  
Intermediate States

The compound bis(2-amino-4-oxo-6-methylpyrimidinium) tetrachlorocuprate(II) 1 contains CuCU42- square-planar anions, and bis(2-amino-4-chloro-6-methylpyrimidinium) hexachlorodicuprate( II) 2 quasi-planar CU2CI62- anions. Both compounds show thermochromic behaviour. This phenomenon has been studied by X-ray crystallography at variable temperature, with the result that no major change is observed in the geometry of the copper atom. Thus it is possible to assume some influence of the hydrogen bonds and o f the different geometries of intermediate states on the color of the compounds due to the modifications provoked in the L→M charge transfer and in the energy o f the metal d-d transitions. Magnetic measurements of the compounds give information on magneto-structural correlations. Compound 1 is ferromagnetic (Tc ≅ 20 K) due to the perpendicular arrangement of the square anions that allows exchange pathways only via Cu-Cl -Cu , H-bonding or cationic n electron interactions. Compound 2 shows a very complicated behavior at low temperature with local antiferromagnetic fluctuations. Crystal data: 1 C10H10N6O2Cl4Cu, triclinic, P1; 393(2) K: α = 11.053(2), b = 11.334(2), c =14.038(3) (Å), α = 95.76(3), β = 101.35(3), γ=90.15(3)(°) ; 293(2) K: a = 11.022(2), b = 11.289(2), c = 14.001(3) (Å), α = 95.86(2), β = 101.34(2), γ=90.09(3)(°) ; 155(2) K: a = 11.008(2), b = 11.231 (2), c = 13.967(3) (A), a = 95.86(2), β = 101.37(2), γ=89.99(2)(°) ; Z = 4. 2 (C5H7N3Cl3Cu)2 , monoclinic, P21/c; 293(2) K: a = 5.998(1), b =18.669(4), c = 9.466(2) (Å), β =100.93(3)(°) ; 150(2) K: a = 5.971(1), b = 18.655(4), c = 9.383(2) (Å), ß =101.64(1)(°);Z=4

Synthesis and structural studies of rhodium complexes of phosphorus—sulfur ligands

1986 ◽  
Vol 64 (9) ◽  
pp. 1870-1875 ◽  
Author(s):  
David G. Dick ◽  
Douglas W. Stephan
Keyword(s):  
Single Crystal ◽  
Planar Geometry ◽  
Methyl Groups ◽  
Rhodium Complexes ◽  
Coordination Geometry ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Square Planar

Rhodium complexes of the phosphorus—sulfur ligands, 2-diphenylphosphinoethyl methyl sulfide (MeSP), 1, and 2-diphenylphosphinothiophene (PTH), 2, have been prepared and studied by single crystal X-ray diffraction methods. [Rh(MeSP)2]BF4•H2O, 3, crystallizes in the space group P21/n with a = 16.939(6) Å, b = 17.152(5) Å, c = 12.049(9) Å, β = 106.50(4)°, and Z = 4. The MeSP ligands chelate to Rh yielding a distorted square-planar geometry. The disposition of the methyl groups on the cis sulfur atoms is transoid. Average Rh—P and Rh—S bond distances were found to be 2.225(3) and 2.347(3) Å, respectively. [Rh(PTH)2(COD)]BF4, 4, crystallizes in the space group Cc with a = 15.862(2) Å, b = 15.112(3) Å, c = 16.029(3) Å, β = 103.32(1)°, and Z = 4. The Rh atom in 4 also has essentially a square-planar coordination geometry. 2 does not chelate but rather is monohapto through phosphorus. Rh—P distances of 2.319(3) and 2.378(3) Å and Rh—C distances of 2.17(1), 2.22(1), 2.24(1), and 2.27(1) Å were found. The small variations in the Rh—P and Rh—C bonds distances appear to be a result of steric interactions between 2 and the COD ligand.

scholarly journals Synthesis, Structure, Magnetic and Catalytic Competency of a Tetradentate (NNOO) Schiff Base Mediated Dimeric Copper(II) Complex

2021 ◽  
Vol 33 (6) ◽  
pp. 1280-1286
Author(s):  
Habibar Chowdhury ◽  
Rajesh Bera ◽  
Chandan Adhikary
Keyword(s):  
Variable Temperature ◽  
Spectroscopic Studies ◽  
Planar Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Π Interactions ◽  
Tert Butyl Hydroperoxide ◽  
Square Planar ◽  
3D Network ◽  
Acetonitrile Medium

One dinuclear copper(II) complex {μ-[2,2′-{ethane-1,2-diylbis[(azanylylidene)methanylylidene]}- bis(phenolato)]}-{μ-[2,2′-{ethane-1,2-diylbis[(azanylylidene)methanylylidene]}bis(phenolato)]}- dicopper(II), [Cu2(salen)2] (1) [salen2− = [2,2′-{ethane-1,2-diylbis[(azanylylidene)methanylylidene]}- bis(phenolato)] has been isolated and characterized by X-ray diffraction analysis and spectroscopic studies. X-ray single crystal structure examination revealed that each Cu(II) center in the asymmetric unit of 1 adopts a distorted square planar geometry with a CuN2O2 chromophore, where two asymmetric units are attached through congregation of Salen involving Cu-O bond to form dinuclear molecular unit [Cu2(salen)2]. In crystalline state, these dinuclear entities in 1 are extended through C-H···π interactions and π···π interactions displaying a 3D network structure. The variable-temperature magnetic susceptibility measurement asserted a dominant antiferromagnetic interaction between the copper(II) centers through Cu-O-Cu linkage in 1 with J = -1.46 cm-1. The catalytic efficacy of complex 1 was studied in a series of solvents for the oxidation of styrene and cyclooctene using tert-butyl-hydroperoxide (TBHP) as an active oxidant under mild conditions. The catalytic reaction mixture has been analyzed by gas chromatography and it displayed that the yield of the epoxidation and its selectivity is optimum in acetonitrile medium.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

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.

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