- Copper(I) and Copper(II) Complexes of a New Tetradentate Chelating Ligand Containing Imidazole and Thioether Groups. The X-ray Structure of Trigonal-Bipyramidal bromocopper(II) Bromide
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The synthesis and characterization of a new potentially tetradentate chelating imidazole-thioether ligand 1,6-bis(N-benzylimidazol-2-yl)-2,5-dithiahexane, CH2SCH2>2, BBIDH, and some of its CuI, CuII, and ZnII complexes are described.X-ray crystal structure determination showed that the CuII atom in Br*xsolvent is in a trigonal-bipyramidal coordination geometry with two axial imidazole N donor atoms (Cu-N = 1.93(2) and 1.94(2) Angstroem) and two thioether S atoms and a Br- ion in equatorial plane (Cu-S = 2.565(6) and 2.470(6) Angstroem, Cu-Br = 2.417(3) Angstroem).The compounds crystallizes in space group P1/ with a = 8.397(2), b = 11.415(2), and c = 18.016(2) Angstroem, α = 103.74(1), β = 94.49(2), and δ = 100.48(2) deg, and Z = 2.Intensities of 3982 unique reflections (θ 2?(I) to a final R value of 0.071.From ESR and visible spectra, it was inferred that other solid CuII compounds also have a trigonal-bipyramidal coordination geometry, with H2O as the fifth ligand if no halogenide ions are available.The spectra of solutions of the CuII compounds indicate a change in coordination geometry.In I(BBIDH)>+, the Cu atom is probably linearly coordinated by two N atoms.The ZnCl2 adduct is a nonelectrolyte.The coordination chemistry of this imidazole-thioether ligand is in this respect not different from its earlier reported benzimidazole-containing analogon, (C7H5N2CH2SCH2)2, justifying the use of benzimidazole derivatives in model systems for the coordination of Cu in copper proteins.
- Birker, Paul J. M. W. L.,Godefroi, Eric F.,Helder, Janneke,Reedijk, Jan
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p. 7556 - 7560
(2007/10/02)
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