Three polymeric iron(II)-tetraoxime chelates of the formula CH3C(NOH)C(NOH)-R-C(NOH)C(NOH)-CH3, where R: C6H4-O-C6H4, C6H4-C6H4, and 2,6-pyridyl, are characterized and compared with monomeric α-dioxime analogues. Analytical data indicate that in the solid state these Fe-N4 type chelates do not coordinate an axial base. Axial substitution takes place only upon dissolution into pyridine or similar basic solvents. The resemblance between the substituted polymer chelates and the monomeric dimethylglyoxime compounds, as far as their electronic spectra are concerned, is discussed. While the solid state polymers are all paramagnetic with moments 2.0–2.5 B.M., ESR data show that in solution a conversion into a diamagnetic species takes place. A strong absorption band due to the O–N stretching vibration appears at about 1650 cm−1 upon complexing of the nitrogen atoms. The paramagnetism and the reflectance spectra of the solid state samples are related to their structure.
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