Structural investigations of the dipyrromethene complexes of calcium(II), nickel(II) and copper(II)

Eric T. Clarke, Philip J. Squattrito, Philip R. Rudolf, Ramunas Z. Motekaitis, Arthur E. Martell, Abraham Clearfield

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Structures of complexes formed between calcium(II), nickel(II) and copper(II) and the ligand, 3,3′,4,4′-tetrachloro-5,5′-dicarbethoxy-2,2′-dipyrromethene have been determined. The Ni(II) and Cu(II) ions are six-coordinate, with a distorted octahedral configuration consisting of the four pyrrole nitrogen atoms and two oxygen atoms of the ligand. The Ca(II) ion is eight-coordinate with a distorted dodecahedral geometry involving four pyrrole nitrogen atoms and the four carbonyl oxygen atoms of the carbethoxy groups. For each metal complex, oxygen coordination results in distortion away from the tetrahedral conformation of the ligand nitrogen donors. The Ca(II) chelate is monoclinic, space group P21/n, Z = 4, a = 11.381(2), b = 24.916(4), c = 13.410(2) Å, β = 94.31(1)°, V = 3792(1) Å3. The Ni(II) and Cu(II) complexes are isostructural, triclinic, space group P1, Z = 2. For the Ni(II) chelate, a = 12.574(4), b = 14.608(3), c = 10.634(2) Å, α = 96.42(2), β = 100.05(2), γ = 108.89(2)°, V = 1789.6(8) Å3. For the Cu(II) chelate, a = 12.522(5), b = 14.493(6), c = 10.704(6) Å, α = 96.50(5), β = 100.86(2), γ = 108.44(1)°, V = 1778.41(6) Å3. The structures were solved by direct methods and refined by least-squares techniques to R = 0.043 (2531 independent reflections) for the Ca(II) chelate; R = 0.044 (3149 independent reflections) for the Ni(II) chelate; and R = 0.067 (2468 independent reflections) for the Cu(II) chelate.

Original languageEnglish
Pages (from-to)221-231
Number of pages11
JournalInorganica Chimica Acta
Issue number2
StatePublished - Dec 15 1989


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