Abstract
The title complex, [Fe(C64H64N8O4)(C9H8N2)2](CF3O3S)·2C6H5Cl, has an unusual relative orientation of the two planar axial ligands [dihedral angle between the two imidazole planes = 46.55 (9)°]. The average equatorial Fe—N bond length is 1.974 (3) Å; the axial distances are 1.9628 (19) and 1.9932 (19) Å. The porphyrin core displays modest ruffling. Disorder is modeled for three of the tert-butyl groups of the pickets. In the crystal, a modest π–π interaction exists between adjacent phenyl rings related by an inversion center, and hydrogen bonds connect the trifluoromethanesulfonate oxygen atoms to the amide groups of the picket substituents.
Highlights
The title complex, [Fe(C64H64N8O4)(C9H8N2)2](CF3O3S)Á2C6H5Cl, has an unusual relative orientation of the two planar axial ligands [dihedral angle between the two imidazole planes = 46.55 (9)]
A modest – interaction exists between adjacent phenyl rings related by an inversion center, and hydrogen bonds connect the trifluoromethanesulfonate oxygen atoms to the amide groups of the picket substituents
The relative orientation of the two planar axial ligands has been suggested as a structural feature capable of modulating redox potentials (Walker, 2004)
Summary
A widespread function of heme proteins in biology is that of electron transfer. One common class of electron-transfer proteins are those in which the central iron of the porphyrin is further coordinated by two axial histidine (imidazole) ligands (Scheidt et al, 1987; Safo et al, 1997). The average Fe-to-porphyrin-nitrogen bond length is 1.974 (3) A , a value that is on the low side compared to other six-coordinate low-spin iron(III) porphyrinates. This low value can be expected given that the porphyrin core displays modest ruffling, with the average observed displacement of the methine carbon atoms of 0.29 (8) Afrom the mean plane of the 24-atom core. A recent review (Scheidt, 2012) has provided structural details for these, including values for the relative orientation angle between the planar ligands and the dihedral angle between the ligand plane and the closest iron to porphinato nitrogen vector (see Table 6 of the review)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
