Iron complexes heteronuclear

Fe—Fe bond can be assigned structures 201 or 202 based on spectral data. The other product of this reaction is 193 (R = r-Bu), however, it is produced in minor amounts. Complexes 199 (R = R = r-Bu, R = Ph, R = r-Bu) were obtained. Reaction of 146 (M = Mo, R = Ph, R = R = Ft, R = r" = Me) with (benzyli-deneacetone)iron carbonyl gives rise to the bimetallic complex 200 (M = Mo), which reacts further with the free phosphole to form the bimetallic heteronuclear sandwich 203. The preferable coordination of the molybdenum atom to the dienic system of the second phosphole nucleus is rather unusual. The molybdenum atom is believed to have a greater tendency to coordinate via the trivalent phosphorus atom than via the dienic system. 

Electric fleld gradient, 22 214-218 Electroabsorption spectroscopy, 41 279 class II mixed-valence complexes, 41 289, 291, 294-297 [j(jl-pyz)]=+, 41 294, 296 Electrocatalytic reduction, nickel(n) macro-cyclic complexes, 44 119-121 Electrochemical interconversions, heteronuclear gold cluster compounds, 39 338-339 Electrochemical oxidation, of iron triazenide complexes, 30 21 Electrochemical properties fullerene adducts, 44 19-21, 33-34 nickeljll) macrocyclic complexes, 44 112-113... 

The oxidation of [Cr(SH)(H20)5]2+ by I2 or Fe3+ under aerobic conditions in acid solutions gives the disulfido-bridged complexes [(H20)5CrS2Cr(H20)5]4+ and [(H20)sCr(S2H)Fe-(H20)5]4+ respectively (Scheme 100).967,968 The latter complex can also be obtained by substitution of chromium(III) in the former complex by iron(II) under acid conditions. The product distribution in the iron(UI) oxidation of [Cr(SH)(H20)5]2+ is pH dependent and at 298 K, pH = 1 the heteronuclear dimer [(H20)5Cr(S2H)Fe(H20)5]4+ constitutes over 80% of the product mixture. The rate of this reaction shows a [H+] 1 dependence, an observation consistent with [CrS(H20)5]+ being the kinetically active species. 

Homobinuclear macrobicyclic copper, cobalt, and iron(II) complexes and a heteronuclear iron(II)/cobalt(II) clathrochelate of the [MiM2(trom)] type arise from interaction of a sodium complex of trom ligand with the corresponding metal salts. 

The heteronuclear mixed-valence complexes 16b,c were obtained from H2L 15, triethylamine, and iron(III) chloride in the presence of an excess of cobalt(II) chloride or copper(II) chloride. In neutral 16b,c iron is present only in the oxidation state 3 , as unambiguously confirmed by Mossbauer spectroscopy, which reveals only one quadruple doublet. Cyclic voltammetric investigation of the redox-active metal centers of neutral 16b shows a reversible three-potential one-electron transfer process. The half-wave potentials of -660 and -1310 mV correspond to the redox processes [(Fe )2Co"OLf ] [Fe Fe Co OLf ]" [(Fe")2Co"OLf ] , whereas... 

Heteronuclear shift correlation is not restricted to and P alone. P-detected experiments permit ready observation of rare nuclei, such as and Fe, which are normally difficult to observe. This approach has been used with success for the observation of organometallic phosphorus tungs-ten(iv), rhodium(i), iron(O), iron(n), and nickel(O) complexes. Indirect observation of insensitive spin 1/2 nuclei offers tremendous gains in sensitivity over direct observation. 

To assess the suitability of metal cyanide complexes as active precursors for supported catalysts, a series of homo- and heteronuclear cyanide complexes has been precipitated in the presence of alumina, titania, and silica supports. To establish the distribution of the insoluble cyanide complexes on the support, the catalyst precursors were investigated by transmission electron microscopy. Conversion of the cyanide precursors into oxidic or metallic catalysts can be performed by thermal treatments in oxygen, argon, and hydrogen, respectively. Detailed results of the thermal treatment of a copper-iron cyanide precursor on alumina are presented. Oxidation of the cyanide precursors to highly dispersed oxides calls for treatment at relatively low temperatures, viz., about 573 K. The resulting oxide can subsequently be reduced smoothly to the corresponding (bi)metallic supported catalyst. 

The reaction of the iron-carbene complex [[Bu C CC(OEt)=)Fe(CO)4] with 1,3-cyclohexadiene afforded223 (32), which was characterised by X-ray diffraction. The addition of the anionic derivatives of i-(diphenylmethane)-il-fluorene- and ii-(9,10-dihydroanthracene)-bis tricarbonylchromium to the hydrocarbon moiety (alkene, benzene, cyclohexadienyl, cycloheptadienyl and cycloheptatrienyl) in various cationic compounds of manganese, rhenium, iron, chromium, molybdenum, tungsten and cobalt was reported224 to provide a new route to hydrocarbon-bridged heteronuclear species such as (33). 

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