Iridium complexes sulfides

Desulfurization of thiophene by iridium complexes has been further investigated by Jones and coworkers using the diiridium complex [Cp IrH3]2(45). Thermal reaction of this bimetallic compound with thiophene in the presence of tert-butyl-ethylene leads directly to a product (46) in which both of the C-S bonds have been broken, leaving sulfide and butadiene ligands bridging the two iridium centers (Scheme 14). When d4-thiophene is used in this reaction, a d4-butadiene ligand is... 

A Cr(VI) sulfoxide complex has been postulated after interaction of [CrOjtClj] with MejSO (385), but the complex was uncharacterized as it was excessively unstable. It was observed that hydrolysis of the product led to the formation of dimethyl sulfone. The action of hydrogen peroxide on mesityl ferrocencyl sulfide in basic media yields both mesityl ferrocenyl sulfoxide (21%) and the corresponding sulfone (62%) via a reaction similar to the Smiles rearrangement (165). Catalytic air oxidation of sulfoxides by rhodium and iridium complexes has been observed. Rhodium(III) and iridium(III) chlorides are catalyst percursors for this reaction, but ruthenium(III), osmium(III), and palladium(II) chlorides are not (273). The metal complex and sulfoxide are dissolved in hot propan-2-ol/water (9 1) and the solution purged with air to achieve oxidation. The metal is recovered as a noncrystalline, but still catalytically active, material after reaction (272). The most active precursor was [IrHClj(S-Me2SO)3], and it was observed that alkyl sulfoxides oxidize more readily than aryl sulfoxides, while thioethers are not oxidized as complex formation occurs. 

Trinuclear and Larger Clusters - Addition of sodium sulfide to [Cp M(MeCN)3] yields sulfido-capped [Cp 3M3(p -S)2l (M=Rh,Ir), the iridium complex also being isolated from... 

In order to get a catalytic cycle it is necessary that the metal sulfide intermediate can react with hydrogen to form the reduced metal complex (or compound) and H2S. For highly electropositive metals (non-noble metals) this is not possible for thermodynamic reasons. The co-ordination chemistry and the oxidative addition reactions that were reported mainly involved metals such as ruthenium, iridium, platinum, and rhodium. 

Hydrogen sulfide, 4-methylbenzenethiol and 4-methylbenzene-1,2-dithiol add to trans-[Ir(Cl)(CO)(PPh3)2] to yield the iridium(III) complex lr(H)(Cl)(CO)(PPh3)2(SR)], wherein SR is SH, SC6H4Me or SC6H3MeSH, respectively. Spectroscopic data are consistent with the structure (160) with CO and SR groups trans to each other.372... 

Class I. ELEMENTS. A. Metals. Cubic copper, silver, gold, iron, platinum, iridium. - Tetragonal tin. - Rhombohedral and Hexagonal arsenic, antimony, bismuth, tellurium, (Os, Ir). - B. Metalloids. Cubic diamond. - Hexagonal graphite. - Orthorhombic sulfur, iodine. - Monoclinic sulfur, selenium. - Class II. SULFIDES. - Class HI. HALIDES. -Class IV. OXIDES, divided into SIMPLE OXIDES and COMPLEX OXIDES, such as CARBONATES, PHOSPHATES, SILICATES, BORATES and SULFATES. 

Iridium(III) compounds are generally more stable than those of iridium(lV), and iridium(III) coordination compounds include some of the most stable complexes known. On treatment with diethyl sulfide, iridium (IV) chloride loses chlorine, and the thio ether coordinates with the resulting iridium(III) chloride to form a mixture of stable, nonelectrolytic isomers of formula [Ir (C2H6)2S sCls]. The reaction is strongly dependent on the solvent it is accelerated in ethanol or acetone but inhibited completely in chloroform or benzene. Even in the presence of aqua regia, the same isomers are obtained—an indication of the extraordinary stability of iridium (III) complexes. 

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