Iron-porphyrin derivatives

Finally, we should note that a particularly important area of application where density functional techniques, in spite of the deficiencies noted above, are virtually without competition is provided by biochemically relevant molecules, such as enzymes or nucleic acids. The techniques discussed in this section are virtually the only quantum chemical methods which can be applied in this context due to their outstanding price/performance ratio. For example, the 13C and 15N chemical shifts in bacteriochlorophyll A have been studied by Facelli, 1998, and in another investigation the 57Fe, 13C and 170 shifts in iron porphyrin derivatives gave important clues as to the structural details of these species, as shown by McMahon et al 1998. 

Terphenyl ligands have also been utilized in the context of metalloporph-yrin chemistry. For example, the use of four Triph substituents at the periphery of manganese and iron porphyrin derivatives dramatically in-... 

These iron porphyrin derivatives selectively catalyzed cyclohexane hydroxidation, where (FeTNMCPP)Cl displayed the higher stability. Cyclooctane epoxidation on the same mimic proceeded with multiple oxidant addition. 

The significance of porphyrins can be interpreted from their involvement in the most important processes of natural life. For example, chlorophyll, the magnesium porphyrin derivative, is related to photosynthesis and hemoglobin, the iron porphyrin derivative existing in the blood... 

J. T. Groves, Y. Watanabe, Reactive iron porphyrin derivatives related to the catalytic cycles of cytochrome P-450 and peroxidase. Studies of the mechanism of oxygen activation, ]. Am. Chem. Soc. no (1988) 8443. 

A number of recent studies have demonstrated the importance of axial ligand orientations in fine-tuning the physical properties of iron porphyrinate derivatives. Properties affected include structure, spin state, EPR and redox potentials. A convenient measure of the orientation is the dihedral angle formed by the coordinate plane containing oppo-... 

Nasri H, Ellison MK et al (1997) Sharing the Jt-bonding. An iron porphyrin derivative with trans, x-accepting axial ligands. Synthesis, EPR and Mossbauer spectra, and molecular structure of two forms of the complex nitronitrosyl(a, a, a, a-tetrakis(o-pivalamidophenyl)-porphinato)ferrate(II). J Am Chem Soc 119 6274—6283... 

Rigid spirocyclic linking groups can be introduced between porphyrin subunits to provide significant steric restriction to prevent structural relaxation, which in turn helps promote fruitful catalytic properties in PIMs. Phthalocyanine network PIMs are important catalysts for example, iron-porphyrin derivatives can permit the catalysis of hydrocarbon hydroxylations and alkene epoxidations." ... 

In the example of Figure 20, the heme of cytochrome 562 of Escherichia coli is bound within a protein bundle by coordination of the heme s iron to a methionine and a histidine." Attachment of a modified heme (iron porphyrin derivative) to the protein s surface is performed via mutation of the histidine 63 to introduce a cysteine residue opposite to the heme pocket. The subsequent removal of the native heme leaves a protein receptor that can self-assemble by ligation of the pendant external heme in a neighboring heme pocket. The assemblies have some flexibility, as shown by the bends observed in AFM images of the polymers. The right amount of flexibility was important in obtaining a 100-mer that was approximately 350 nm long. 

Example 2 Synthesis of Block Copolymer-Linked Iron-Porphyrin Derivative (4) [14]... 

A sterically modified and amphiphilic iron-porphyrin derivative was synthesized to improve the compatibility of the iron-porphyrin with the phospholipid bilayer of the liposome. Structure (5) represents a lipid derivative of iron-porphyrin the iron-porphyrin has four alkanephosphocholine... 

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