Structural and physical characterization of (nitrato)iron(III) porphyrinates [Fe(por)(NO 3)] – Variable coordination of nitrate

Abstract

We report the X-ray crystal structures of two different iron(III) porphyrinates: [Fe(OEP)(NO 3)] and [Fe(TPP)(NO 3)]. The first complex has the nitrate ion coordinated by a single oxygen atom while the second derivative has the nitrate coordinated in a symmetric bidentate fashion. This latter structure is a redetermination that shows some differences from an earlier structure; the difference appears to be the result of an unrecognized nitrate ion disorder in the earlier structure determination. Changes in physical properties of three species [Fe(TPivP)(NO 3)], [Fe(OEP)(NO 3)], and [Fe-(TPP)-(NO 3)] as a function of coordination mode were examined by Mössbauer and EPR spectroscopies; EPR spectra appear to be most sensitive to the change in coordination mode.