Iron model compounds

Trimethylphosphane complexes of nickel, cobalt and iron — model compounds for homogeneous catalysis. H. F. Klein, Angew. Chem., Int. Ed. Engl., 1980,19, 362-375 (108). 

Fe20(0Ac)2Cl2(bipy)2 successfully hydroxylates C6, C3, and C2 alkanes when tert-butyl hydrogen peroxide (TBHP) is used as the oxygen donor ([5] [TBHP]-.[substrate] = 1 150 1100) the observed reactivity is C6 > C3 > C2 (Table IV). This work represents the first report of the oxidation of a small molecular weight alkane (ethane) by a characterized iron model compound. Reactions of this complex with Zn dust and acetic acid under 1 atm of dioxygen with cyclohexane gave rise to only cyclohexanone (turnover number 2.5). The parent tetrameric compound, 6, was reported to be a more efficient catalyst. 

Figure 2 N-donor ligands used in nonheme di-iron model compounds and their abbreviations.

Figure 2. Separation of iron model compounds with Fe and B detection. Conditions Polar amino cyano column flow rate, 1 mL/min eluent, CHCls/0.5% CtHsOH. Key 1, triirondodecacarbonyl 2, (Cp)Fe(CO)J 3, acetyl ferrocene 4, iron clathro chelate 5, diacetyl ferrocene and 6, Fe[B(PZ)Jt, Iron compouruts are...

Attempts to elucidate the bonding have concentrated mainly on graphite-FeCla- This intercalate is especially suitable as a model compound, because the magnetic and Mossbauer properties of the iron nucleus constitute excellent probes for electronic structure and environment of the latter. 

Liu X, Ibrahim SK, Tard C, Pickett CJ. 2005. Iron-only hydrogenase Synthetic, structural and reactivity studies of model compounds. Coord Chem Rev 249 1641-1652. 

All but two of the known synthetic iron(IV)-oxo compounds are low-spin, 5=1 [202, 240]. The first example of an iron(IV)-oxo model compound with spin 5 = 2 was the quasioctahedral complex [(H20)5Fe =0] (5 = 0.38 mm s, A q = 0.33 mm s ) which was obtained by treating [Fe°(H20)6] with ozone in acidic aqueous solution [204]. The spin state of iron in this type of structure is determined by the energy gap between the d,2 y2 and the d y orbitals [241]. The weak water ligands induce a sufficiently small gap being less than the spin paring energy and stabilizing the HS state (Fig. 8.25, case a). 

These researchers also described [93] the design and synthesis of iron(II) porphyrin dendrimers with triethylene glycol monomethyl, ether surface groups (e.g., 31) which render them soluble in a wide range of organic solvents and water. The potential difference between the first (1 FeCl) and second generation (2 FeCl) Fe-porphryin dendrimers was found to increase more in water than in dichloromethane (0.42 vs 0.08 V). This remarkable potential difference between 2 FeCl and 1 FeCl in water was comparable with that found between cytochrome c and a similarly ligated, more solvent-exposed cytochrome c heme model compound. 

Le Pape, L., Lamotte, B., Mouesca, J.-M., and Rius, G. 1997. Paramagnetic states of four iron-four sulfur clusters. 1. EPR single-crystal study of 3+ and 1+ clusters of an asymmetric model compound and general model for the interpretation of the g-tensors of these two redox states. Journal of the American Chemical Society 119 9757-9770. 

IRON SEQUESTRATION BY SMALL MOLECULES THERMODYNAMIC AND KINETIC STUDIES OF NATURAL SIDEROPHORES AND SYNTHETIC MODEL COMPOUNDS... 

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