Iron and Ruthenium Oxides

Thin films of the iron oxide system [Fe304](i )[Fe8/304](.,) reportedly are attractive materials for high-density magnetic recording [53, 54]. 

Iron(iii) oxide, a-Fe203, is used as a beam splitter and interference layer in optical devices [10]. a-lron(iii) oxide can be prepared by CVD using iron pentacarbonyl, Fe(CO)5 (10), as a precursor [55, 56]. The decomposition of ferrocene, Cp2Fe, (11) at 

Ruthenium dioxide, RuO, displays interesting physical properties such as a low resistivity and high thermodynamic stability [63]. Additionally, the compound exhibits excellent diffusion barrier properties [64] and is used in resistor applications [65]. Precursors for the deposition of RUO2 include ruthenium acetylacetonate, Ru3(CO)i2 (12) and RuCp2 (11) [63, 64]. However, only RuCp produces high quality RUO2 films [63]. 

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Stabilization of high iron and ruthenium oxidation states has been achieved with the N2H2S2—H2 ligand. The reaction according to Eq. 15 yields diamagnetic [Ru(PCy3)(N2S2)] which formally contains a Ru(IV) center (78). 

Figure 1. Comparison of iron and ruthenium oxidation in l,l -bis(diphenylphosphino)ferrocene-ruthenium(II) complexes (ESR spectra [44a] from electrolytically oxidized solutions of precursors [44b, c] in THE at 4 K) Oxidation of [Cp RuH(dppf), dppf= l,l -bis(diphenylphosphino)ferro-cene, and [(Cym)RuCl[dppf)](PF6), Cym = p-cymene, occurs at ruthenium for the former compound but yields a ferrocenium species for the latter.

For cobalt, iron, and ruthenium sarcophaginates, the Log kn values increase with an increase in the redox potentials. This is the case when the main factor affecting a variation in both values in the same direction is the electronic configuration. The increase in E values in a series of clathrochelates from cobalt to ruthenium is attributed to differences in spin states Is > hs for cobalt. Is > hs, Is for iron. Is > Is for ruthenium complexes. The increase in Logftii values correlates with ALFSE for +3 and +2 oxidation states. 

As compared with Fe(III) oxidants, other metal compounds are scarcely used for phenolic oxidation. Both iron and ruthenium are members of the same group of the Periodic... 

The organoiron, -ruthenium and -osmium complexes generally have oxidation states of -2 to +4, -2 to +4 and -2 to +2, respectively [1]. Organoosmium chemistry has received less attention than that of iron and ruthenium, because of the high price of Os metal. 

With the exception of a few rare examples from the chemistry of molybdenum, manganese, rhenium, iron, and ruthenium, chelate complexes of O-func-tionalized cyclopentadienyl ligands have only been reported in this category for the very oxophilic group 4 metals, preferentially in their highest and most Lewis acidic oxidation state. Linked alkoxo— or aryloxo—cyclopentadienyl and ether—cyclopentadienyl systems are almost equally abundant for these metals. 

S.-I. Murahashi, Y. Oda, and T. Naota, Iron- and ruthenium-catalyzed oxidations of... 

Phthalocyanine complexes within zeolites have also been prepared by the ship-in-a-bottle method (see Section 6.6), and have subsequently been investigated as selective oxidation catalysts, where their planar metal-N4 centres mimic the active sites of enzymes such as cytochrome P450, which is able to oxidize alkanes with molecular oxygen. Cobalt, iron and ruthenium phthalocyanines encapsulated within faujasitic zeolites are active for the oxidation of alkanes with oxygen sources such as iodosobenzene and hydroperoxides. Following a similar route, Balkus prepared Ru(II)-perchloro- and perfluorophthalocyanines inside zeolite X and used these composites for the selective catalytic oxidation of alkanes (tert-butylhydroperoxide). The introduction of fluorinated in place of non-fluorinated ligands increases the resistance of the complex to deactivation. 

The selective oxidation of sulfides to sulfoxides is an important reaction in biological systems, ft is a well-studied model reaction for oxo atom transfer and it is of importance for applications in pharmaceutical and preparative organic chemistry [1, 2, 60]. Iron- and ruthenium-based sulfoxidation catalysts have also been explored in the area of asymmetric synthesis and enantioselective catalysis... 

Other references in this section listed by title are the following Trans-chelating ligating ability of l,l -bis(diphenylselenophosphoryl)ferrocene (dpspf) towards silver(I). Crystal structure of [Ag(dpspf)]C104 Amine-oxide-mediated oxidative methanolysis of metal-metal bonds in [MM (CO)io] (M = Mn, Re M = Re) and [Os3(CO)i2] crystal structure of /ac-[Re OC(0)OMe (CO)3(r A dppf)] Iron versus ruthenium oxidation in l,T-bis(diphenylphosphino)ferro-cene-ruthenium(II) complexes EPR and spectroelectrochemical evidence. "... 

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