Title

Aggregation Properties of Nitroporphyrins: Comparisons between Solid-State and Solution Structures

Document Type

Article

Publication Date

1-1-1993

Abstract

Previous NMR spectroscopic studies on the aggregation properties of metalloporphyrins suggested that monosubstituted octaethylporphyrin (OEP) derivatives with substituents capable of inducing charge polarization form tail-to-tail type dimers in solution. Such dimers have implications as model compounds for the photosynthetic reaction center. Crystallographic studies on a series of 5-NO2-OEP compounds show that the zinc(II) complexes can indeed form dimers of the proposed type in the solid state. A four-coordinated planar zinc(II) 5-nitrooctaethylporphyrin and the corresponding methanol complex showed strong aggregation in the solid state. The pyridine complex and the free-base porphyrin showed no strong aggregation. Crystal data: 5-NO2-OEP (7), C36H45N5O2, Mr = 579.8, triclinic, P1̄, a = 9.374(3) Å, b = 13.794(6) Å, c = 14.221(4) Å, α = 104.69(3)°, β = 106.39(2)°, γ = 104.57(3)°, V= 1599.7(10) Å3, Z = 2, Dx = 1.204 Mg·m−3, λ(Mo Ka) = 0.710 73 Å,µ = 0.080 mm−1, 130 K, R = 0.078 for 3328 reflections with F > 3.5σ(F); Zn(5-NO2-OEP)(C5H5N) (9-C5H5N), C41H48N6O2Zn, Mr = 722.6, triclinic, P1̄, a = 9.942(3) Å, b = 10.722(4) Å, c = 17.744(5) Å α = 81.74(3)°, β = 78.67(3)°, γ = 83.99(3)°, V = 1829.5(8) Å3, Z = 2, Dx = 1.32 Mg·m−3, λ(Mo Kα) = 0.710 73 Å µ = 0.731 mm−1, 293 K, R = 0.063 for 5161 reflections with F > 3σ(F); Zn(5-NO2-OEP) (9), C36H43N5O2Zn, Mr = 643.15, monoclinic, P21/c, a = 9.721(3) Å b = 21.807(6) Å, c = 15.378(4) Å, ² = 102.99(2)°, V = 3176.6 Å, Z = 4, Dx = 1.322 Mg·m−3, λ(Cu Kα) = 1.541 84 Å µ = 0.138 mm−1, 293 K, R = 0.067 for 3017 reflections with F > 3σ(F); Zn(5-NO2-OEP)(CH3OH) (9-CH3OH), C37H47N5O3Zn, M, = 675.2, monoclinic, P21/c, a = 10.540(8) Å b = 14.240(12) Å c = 23.625(16) Å, β = 101.39(5)°, K= 3476(4) Å3 Z = 4, Dx = 1.290 Mg·m−3, λ(Mo Kα) = 0.710 73 Å, µ = 0.749 mm−1, 130 K, R = 0.106 for 3894 reflections with F > 4σ(F). © 1993, American Chemical Society. All rights reserved.

Publication Source (Journal or Book title)

Inorganic Chemistry

First Page

3134

Last Page

3142

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