The factors stabilizing square-planar geometries in σ-bonding amine adducts: crystal and molecular structure of bis(N-tosyl-β-alaninato)bis(piperidine)copper(II)

1987 ◽  
Vol 138 (2) ◽  
pp. 127-130 ◽  
Author(s):  
L. Menabue ◽  
M. Saladini ◽  
L.P. Battaglia ◽  
A.Bonamartini Corradi
1984 ◽  
Vol 37 (7) ◽  
pp. 1395 ◽  
Author(s):  
BF Hoskins ◽  
IAS Mcdonald

The crystal and molecular structure of the 1-propylimidazolate bridged binuclear complex, LPd2(primid) has been determined by single-crystal X-ray diffraction techniques at 20�C; disordered ethanol molecules are also present in the lattice. The quinquedentate ligand L3- is formally the trianion α,α'-{(2-mercapto-4-methylbenzene-1,3-diyl)di(methylidyne)di(azino)bis(cyclohexane-methanol)ato(3 -). Crystals of LPd2 (primid) are triclinic, P1, with a 7.078(2), b l3.615(3), c 17365(3) �, α 78.52(2), β 80.21(2) and γ 83.83(2)�. The structure was solved by conventional Fourier methods and refined by full-matrix least-squares procedures to convergence with R and Rw 0.053 obtained for the 4133 statistically significant structure amplitudes. The ligand sidearms are essentially equivalent with both palladium centres displaying similar distorted square-planar geometries, the separation being 3.605 �. The propylimidazolate bridging group is comfortably accommodated within the binuclear framework and displays a geometry typical of metal complexes of imidazole and its derivatives. Coordination to the palladium centres occurs through C4 and N3, a bridging mode not previously characterized by X-ray crystallography, and one which illustrates the remarkable stability and flexibility of the binuclear LPd2+ core.


1965 ◽  
Vol 19 ◽  
pp. 2361-2368 ◽  
Author(s):  
Olav Foss ◽  
Kjartan Marøy ◽  
Steinar Husebye ◽  
Svein Solheimsnes ◽  
Brita Swan ◽  
...  

1969 ◽  
Vol 23 ◽  
pp. 3206-3216 ◽  
Author(s):  
Kjell Åse ◽  
Georg Lundgren ◽  
Wanda Mark ◽  
Hans Lundström ◽  
Gunner Borch ◽  
...  

1983 ◽  
Vol 61 (7) ◽  
pp. 1651-1658 ◽  
Author(s):  
Raymond M. Morrison ◽  
Robert C. Thompson ◽  
James Trotter

Reaction of aqueous solutions containing CO2+ or Ni2+ and PF6−, or AsF6− with excess 3-methylpyridine yields crystals of compounds of composition M(H2O)2(3mpy)6(EF6)2. Blue crystals of diaquohexakis(3-methylpyridine)nickel(II) hexafluorophosphate, C36H46F12NiN6O2P2, are monoclinic, a = 10.497(1), b = 20.074(3), c = 21.836(5) Å, β = 103.93(2)°, Z = 4, space group Cc. The structure was determined with MoKα CAD4 diffractometer data by direct methods, and refined by full-matrix least-squares procedures to R = 0.048 for 2723 reflections with I ≥ 3σ(I). The structure consists of {Ni(3mpy)4[(OH2)(3mpy)]2}2+ cations and PF6− anions. The cation contains a NiN4O2 chromophore with water molecules occupying trans positions of a distorted octahedron about nickel. One additional 3-methylpyridine molecule is H-bonded to each of the water molecules with [Formula: see text] distances of 2.717(11) and 2.719(11) Å. Weak interaction of each water molecule via its second hydrogen atom with a PF6− ion is indicated by the positioning of the anions. The [Formula: see text] distances are 2.958(11) and 2.959(11) Å. Two other complexes of this type, where M is Ni and E is As and where M is Co and E is P, are reported here and on the basis of spectroscopic and magnetic studies are assigned structures similar to the Ni/P complex.Decomposition of the aquo complexes under mild conditions yields compounds of composition M(3mpy)4(EF6)2. Ni(3mpy)4(PF6)2 is assigned a square planar structure with weakly interacting PF6−, anions in axial positions. Both Co(3mpy)4(EF6)2 complexes, where E is P or As, have tetrahedral [Co(3mpy)4]2+ cations and non-coordinated anions.


2017 ◽  
Vol 73 (8) ◽  
pp. 1148-1150
Author(s):  
Shravan Kumar Ellandula ◽  
Cosmos Opoku Amoako ◽  
Joel T. Mague ◽  
Perumalreddy Chandrasekaran

The unsymmetrical α-diimine ligand N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline, [ArN=C(Me)—(Et)C=NAr] [Ar = 2,6-(iPr)2C6H3], (I), and the corresponding palladium complex, cis-(N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline)dichloridopalladium(II) 1,2-dichloroethane monosolvate, [PdCl2(C29H42N2)]·C2H4Cl2 or cis[PdCl2{I}], (II), have been synthesized and characterized. The crystal and molecular structure of the palladium(II) complex have been established by single-crystal X-ray diffraction. The compound crystallized along with a 1,2-dichloroethane solvent of crystallization. The coordination plane of the PdII atom shows a slight tetrahedral distortion from square-planar, as indicated by the dihedral angle between the PdCl2 and PdN2 planes of 4.19 (8)°. The chelate ring is folded along the N...N vector by 7.1 (1)°.


1976 ◽  
Vol 54 (8) ◽  
pp. 1309-1316 ◽  
Author(s):  
Norman Camerman ◽  
Arthur Camerman ◽  
Bibudhendra Sarkar

Glycylglycyl-L-histidine-N-methyl amide is a copper-binding tripeptide designed and synthesized to mimic the copper-transport site of human albumin. Reddish-purple crystals of the copper-tripeptide amide complex (Cu–GGHa), grown at physiological pH, are triclinic, with cell dimensions a = 9.990, b = 9.986, c = 7.682 Å, α = 107.40, β = 91.72, γ = 96.49°, space group P1, Z = two units of Cu–GGHa and two water molecules per cell. The structure was solved by interpretation of a Cu–phased Fourier map containing a great deal of false symmetry, after multiple attempts with direct phasing methods failed. Refinement proceeded to R = 0.036. The conformations of the two Cu–GGHa units are virtually identical. Each copper is tetradentate chelated by the amino terminal nitrogen, the next two peptide nitrogens, and a histidyl nitrogen of a single tripeptide molecule in a mildly distorted square planar arrangement. The Cu…N distances range between 1.90–2.05 Å, with N…Cu…N angles of 165 and 176°. An oxygen atom provides a fifth position weaker interaction in each case, with Cu…O distances of 2.61 and 2.88 Å.


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