Iron dioxygen carriers

R Volume 2,1993,292 pp. 109.50/ 70.00 ISBN 1-55938-272-4 CONTENTS Introduction, Robert W. Hay. Dynamics of Iron (II) and Cobalt (II) Dioxygen Carriers, P. Richard Warburton and Daryle H. Busch. Homodinuclear Metallobiosites, David... 

Figure 52 Some synthetic iron(II) porphyrins which function as models for dioxygen carriers...

Nature sometimes solves identical problems with apparently quite different solutions. Important examples of such a convergent evolution at the molecular level are the functional parallels between iron and copper centers in bioinorganic chemistry. The dioxygen-carrier proteins of different organisms may, for instance, be based on mononuclear iron tetrap5rrrole complexes or in contrast may involve dinuclear copper sites 10). S5mthetic chemistry can even go a step fiuther and try to mimic basic... 

REVERSIBLE COBALT(II) AND IRON(II) DIOXYGEN CARRIERS OF TOTALLY SYNTHETIC LACUNAR CYCLIDENE COMPLEXES ... 

The iron(II) complex XIII crystallizes as the bis(hexafluorophosphate) salt with acetonitrile as the fifth, axial, ligand. This composition appears to be dictated largely by the relative solubilities of the salts of the possible anions in the mixed solvent. Most of the iron(II) lacunar complexes crystallize as the chloride hexafluorophosphate mixed salts, in which the chloride occupies the axial site. The complex is high spin and Five coordinate in the solid state and in coordinating solvents. In N-methylimidazole at 20 °C the title complex binds dioxygen reversibly with = 0.0012 torr . In 3 1 1 acetone-N-methylimidazole-water the half-life toward irreversible auto-xidation is 24h at room temperature. This complex constitutes the First example of a nonporphyrin iron(II) complex that can act as a dioxygen carrier at room temperature. ... 

In 1973, Baldwin and Huff [31] reported the synthesis of the iron(n) octaazamacrocycle (2) (Figure 2), the first nonporphyrin model which acts as a reversible dioxygen carrier at relatively low temperature. The sterically hindered substituents form a cavity in which the dioxygen is fixed and retard p-0x0 dimer formation. 

Sauer-Masarwa, A., N. Herron, C.M. Fendrick, and D.H. Busch (1993). Kinetics and intermediates in the autoxidation of synthetic, non-porphyrin iron(II) dioxygen carriers. Inorg. Chem. 32, 1086-1094. 

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