Chloro(N-p-nitrobenzoylimido-meso-tetraphenylporphyrinato)iron(iii): a high-spin complexDedicated to Professor Rob Dunbar (Case Western Reserve University) on the occasion of his 60th birthday.
Chen, Ching-Huei; Lee, Yu-Yi; Liau, Bing-Chuang; Elango, Shanmugham; Chen, Jyh-Horung; Hsieh, Hsi-Ying; Liao, Feng-Ling; Wang, Sue-Lein; Hwang, Lian-Pin; Chen Ching-Huei; Department of Chemistry, National Chung-Hsing University; Lee Yu-Yi; Department of Chemistry, National Chung-Hsing University; Liau Bing-Chuang; Department of Chemistry, National Chung-Hsing University; Elango Shanmugham; Department of Chemistry, National Chung-Hsing University; Chen Jyh-Horung; Department of Chemistry, National Chung-Hsing University; Hsieh Hsi-Ying; Chung Hwa College of Medical Technology; Liao Feng-Ling; Department of Chemistry, National Tsing-Hua University; Wang Sue-Lein; Department of Chemistry, National Tsing-Hua University; Hwang Lian-Pin; Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences
Журнал:
Journal of the Chemical Society, Dalton Transactions
Дата:
2002
Аннотация:
The crystal structures of diamagnetic (methanol)(N-p-nitrobenzoylimido-meso-tetraphenylporphyrinato)zinc(ii) methanol solvate Zn(N-p-NCOC6H4NO2-tpp)(MeOH)·MeOH [or 4(MeOH)·MeOH] and paramagnetic chloro(N-p-nitrobenzoylimido-meso-tetraphenylporphyrinato)iron(iii) Fe(N-p-NCOC6H4NO2-tpp)Cl (5), were determined. Both are pentacoordinate complexes where the p-nitrobenzoylimido (NNB) moiety is inserted into a zincâ pyrrole (or ironâ pyrrole) bond. The coordination geometry of the zinc (or iron) center is best described as a distorted trigonal bipyramid with the N(2), N(5), and O(4) [or N(2), N(5), and Cl(1)] atoms lying in the equatorial plane. The plane of the three pyrrole nitrogen atoms [i.e., N(1), N(2) and N(3)] strongly bonded to Zn<sup>2+</sup> in 4(MeOH)·MeOH (or Fe<sup>3+</sup> in 5) is adopted as a reference plane, 3N. The porphyrin ring is severely distorted and the pyrrole ring N(4) is bonded to the NNB ligand making a dihedral angle of 30.0° (or 27.8°) with the 3N plane for 4(MeOH)·MeOH (or 5). Solid state magnetic susceptibility and the effective magnetic moment data were measured for 5 from 300 to 5 K. In the higher temperature range (T > 50 K), the effective magnetic moment is constant and is equal to 5.87 μB. This μeff value confirms that there is a high-spin ferric (S = 5/2) state for the iron atom in 5. The g values of 9.5 ± 0.4, 4.2 and 1.1 measured from X-band EPR spectra were also consistent with a high-spin ferric iron in 5. The magnitude of zero field splitting, D, and the rhombicity parameter, λ (= E/D), in 5 were determined approximately as 0.79 cm<sup>â 1</sup> and 0.29, respectively, by EPR spectroscopy and paramagnetic susceptibility measurements.
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