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  • Author: K. G. Keramidas x
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Abstract

The title compound is orthorhombic, with space group B2mb and Z = 4. The cell dimensions are a = 8.66036(1) Å, b = 14.51489(5) Å and c = 13.25635(6) Å. A total of 1626 independent reflections were measured with a SYNTEX P21 automatic diffractometer using Mo radiation. The structure was refined by a full-matrix least-squares procedure to a conventional R = 0.055 for the 1556 unique reflections. The co-ordination around the central copper atom is octahedral with the copper atom 0.78(4) Å above the equatorial plane of the four nitrogen atoms of the ligand molecule. The Cu – N equatorial plane bond lengths are 1.975 and 2.031 Å. The remaining positions of the co-ordination octahedron are occupied by a fluorine atom of one of the fluorophosphate groups and an oxygen of a water molecule. The Cu – F and Cu – O bond lengths are 2.7371 Å and 2.3968 Å respectively.

Abstract

The title compound, Cu[C6H18N4](PF6)2, is orthorhombic, with space group B2mb and Z = 4. The cell dimensions are: a = 7.362(1) Å, b = 14.708(5) Å and c = 15.551(6) Å. A total of 1623 independent reflections were measured with a SYNTEX P21 automatic diffractometer using Mo radiation. The structure was refined by full-matrix least-squares to a conventional R factor 0.0693 for 1560 unique reflections. The co-ordination around the central copper atom is octahedral with the copper atom 0.096(18) Å below the equatorial plane of the four nitrogen atoms of the ligand molecule. The Cu – N equatorial plane bond lengths have a mean value of 1.9815 Å. The remaining positions of the co-ordination octahedron are occupied by two fluorine atoms of the fluorophosphate groups. The Cu – F bonds have lengths of 2.5901 Å and 2.6014 Å.

Abstract

The crystal structure of BiOCl has been redetermined with 3570 observed reflections of which 174 were unique measured on a computer controlled Philips PW 1100 single crystal diffractometer. The structure belongs to the tetragonal space group P4/nmm and the cell constants, obtained by a least-squares calculation from direct θ-value measurements on the diffractometer, are a = 3.8870(5) and c = 7.3540(5) Å.

The positional and thermal parameters, with anisotropic temperature factors, were refined by full-matrix least-squares calculations to a final R = 9.17%.

Each Bi atom is eight-coordinated by 4 O and 4 Cl atoms at distances of 2.316 Å and 3.059 Å respectively thus forming a decahedron. The faces of the decahedron are 2 rectangles (O–O–O–O and Cl–Cl–Cl–Cl) with sides 3.487 Å and 8 isosceles triangles (four O–Cl–O and four Cl–O–Cl) with sides O–Cl 3.249 Å and O–O or Cl–Cl 3.487 Å.

The decahedra are linked to each other by a common O–Cl edge along the a and b axes in infinite layers.

Abstract

The title compound is monoclinic, space group P21/c, Z = 4. Cell dimensions are a = 12.644(2) Å, b = 14.905(3) Å, c = 17.945(3) Å and β = 95.68°(14). A total of 5829 reflections were measured with a PC-computer-controlled PHILIPS PW1100 automatic diffractometer using MoKα radiation. The structure was refined by full-matrix least squares to a conventional R = 0.0668 for 4359 observed reflections. The charge of the [Ni(enR)2tfac]+ entity is counterbalanced electro-statically by the perchlorate anion. The nickel(II) ion is six-coordinated and it is positioned at the centre of a nearly regular octahedron. The best (equatorial) plane encompasses the β-dionato metallocyclic ring and one nitrogen of each of the bidentate diamino ligands. The other donor atoms occupy the remaining apical positions and are equidistant from the metal centre. The Ni–O bond lengths are virtually identical (average Ni–O 2.006 Å) despite the proximity of the strongly electron-attracting trifluoromethyl group to one of the oxygens. The 1,2-diamine forms five-membered chelate rings, adopts the gauche conformation and the meso form in accordance with the appearance of a double band in the infrared absorption spectrum attributable to the N–H stretching vibrations. The N–C distances connecting the phenyl groups are on average shorter by 0.05 Å than those within the chelate rings. The perchlorate group, [ClO4], exhibits a distorted tetrahedral structure that causes splitting in the relevant infrared absorption band at ∼ 1900 cm−1.

Abstract

The compound [Cu(CN-acac)Me2en(Br)] (Me2en denotes N,N-dimethyl-1,2-diaminoethane) was prepared and investigated by means of structural (X-Ray diffraction) and spectroscopic (IR and electronic) measurements. The compound crystallizes in the monoclinic space group P21/c with a = 5.959(1) Å, b = 7.465(2) Å, c = 19.338(3) Å, β = 90.89(2)° and Z = 4. The structure consists of discrete [Cu(CN-acac)Me2en(Br)] monomeric units, in which copper is five-coordinated. The 1,2-diamine adopts the gauche conformation with a torsional angle of 51.31°, coordinates as bidentate ligand through the nitrogen atoms, and attains the λ configuration. The anion of the 3-cyano-2,4-pentanedione, CN-acac, is bonded through the oxygen atoms and the six-membered metallocyclic ring exhibits a semi chair conformation. The nitrogen and oxygen donor atoms form a square plane. Copper is also bonded to the bromine atom and a distorted square pyramidal structure around copper exists. The inequalities in the Cu–N distances suggest a second-order Jahn-Teller deformation while the elongation of the Cu–Br bonds implicates d-s orbital mixing. The ligand field excitation energy is appreciably lower than that observed in the [Cu(CN-acac)Me2en]+ entity. The principal stretching vibrations are assigned and discussed in the light of the structure.

Abstract

The monoclinic structure of the dark green title compound, [Ni(hfac)2ΦenΦ], was elucidated employing a PHILIPS PW1100 PC-computer controlled automatic diffractometer using MoKα radiation. The space group is A2/n, Z = 4, and cell dimensions a = 13.932 Å, b = 10.222 Å, c = 19.958 Å, and β = 93.34°. A total of 2105 reflections were measured and the structure was refined by full-matrix least-squares to a conventional R = 0.076 for all observed reflections with I > 2σ(I). The nickel(II) ion is six-coordinated and is positioned at the centre of an almost regular octahedron. The best (equatorial) plane encompasses the nitrogens of the diamine ligand and one carbonyl oxygen atom of each β-dionato metallocyclic ring. The other oxygen donor atoms occupy the remaining apical positions and are equidistant from the metal centre. The Ni – N distances are imperceptibly longer than the Ni – O ones. In the five-membered chelate ring the 1,2-diamine adopts the gauche conformation with the phenyl groups.

Abstract

The title compound, C10H19N3O2Cu, is monoclinic, space group P21/n, Z = 2. Cell dimensions are a = 7.6071(6) Å, b = 20.623(1) Å, c = 7.9777(7) Å and β = 101.7359(7)°. A total of 3510 reflections were measured with an Enraf Nonius CAD-4 automatic diffractometer using CuKα radiation. The structure was refined by full-matrix least squares to a conventional R = 0.047 for 2957 unique reflections. The coordination around the central copper atom is octahedral with the copper atom on the equatorial plane of four nitrogen atoms. The Cu–N bond lengths have a mean value of 2.0646 Å. The two remaining apices of the octahedron are occupied by two nitrogen atoms of the β-dione groups at distances Cu–N = 2.5143 Å.