Synthesis and Relation Between Magnetic and Structural Properties of a Series of Monomeric and Dimeric Nickel(II) Complexes
Crystal and molecular structures of bis(2,2′-biquinolyl)di-μ-chloro-dinickel(II)
A series of nickel(II) complexes has been synthesized with halogen and substituted phenanthroline or bipyridyl ligands. The relation between the magnetic and structural properties of the complexes has been investigated, and the crystal and molecular structures of five of them have been determined by single-crystal x-ray diffraction, using counter methods. It appears that the chloro complexes form only dimeric antiferromagnetic molecules containing five-coordinated nickel(II) atoms and that the bromo complexes can form either dimeric antiferromagnetic or pseudotetrahedral, monomeric normal paramagnetic molecules, while the iodo complexes appear to form four-coordinated paramagnetic monomers. Steric factors can weaken the bridging bonds between the halves of the dimeric molecules or prevent the dimerization which results from a drive to attain five-coordination about the nickel(II) atom. The ligand environment about the nickel atom is distorted tetrahedral in the monomeric complexes and may be regarded as either distorted square pyramidal or distorted trigonal bipyramidal in the dimers. Crystal data for bis(2,2′-biquinolyl)di-μ-chloro-dinickel(II), [Ni(biq)Cl2]2: Ni2Cl4N4C36H24, space group P1, Z = 1, a = 9.521 (4) Å, b = 9.570 (3) Å, c = 11.226 (3) Å, α = 95.23 (3)°, β = 117.43 (4)°, γ = 112.73 (3)°, V = 791 Å3, R = 2.6%, 1977 reflections. Crystal data for (2,2′-biquinolyl)dibromonickel(II), Ni(biq)Br2: NiBr2N2C18H12, space group P21/c, Z = 4, a = 7.929 (3) Å, b = 12.432 (6) Å, c = 17.158 (6) Å, β = 102.90 (3)°, V = 1649 Å3, R = 3.1%, 1621 reflections. Crystal data for (2,9-dimethyl-1,10-phenanthroline)di-μ-chloro-dinickel(II), [Ni(dmp)Cl2]2: Ni2Cl4N4C28H24, space group P1, Z = 1, a = 9.090 (1) Å, b = 9.287 (2) Å, c = 10.327 (2) Å, α = 100.28 (2)°, β = 113.19 (1)°, γ = 111.24 (2)°, V = 692 Å3, R = 3.6%, 2083 reflections. Crystal data for (2,9-dimethyl-1,10-phenanthroline)-di-μ-bromo-dinickel(II), [Ni(dmp)Br2]2: Ni2Br4N4C28H24, space group P1, Z = 1, a = 7.891 (2) Å, b = 10.259 (3) Å, c = 10.319 (4) Å, α = 100.48 (3)°, β = 116.49 (2)°, γ = 99.56 (1)°, V = 706 Å3, R = 4.2%, 2244 reflections. Crystal data for (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)diiodonickel(II), Ni(bc)I2: NiI2N2C26H20, space group P21/c, Z = 4, a = 12.873 (6) Å, b = 23.248 (7) Å, c = 8.310 (5) Å, β = 101.56 (4)°, V = 2436 Å3, R = 3.8%, 2270 reflections.
R. J. Butcher and E. Sinn, "Synthesis and Relation Between Magnetic and Structural Properties of a Series of Monomeric and Dimeric Nickel(II) Complexes," Inorganic Chemistry, American Chemical Society (ACS), Jan 1977.
The definitive version is available at http://dx.doi.org/10.1021/ic50175a037
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© 1977 American Chemical Society (ACS), All rights reserved.