Dichlororuthenium complexes

In this section, we will review the nature and chemical reactivities of several kinds of ruthenium complexes under the following headings ruthenium carbonyl complexes, dichlororuthenium complexes, chlorohydrido complexes, dihydridoruthenium complexes, ruthenium complexes with chiral ligands, ruthenium complexes with cyclopentadienyl ligands, and ruthenium arene/diene complexes. 

To further expand the scope of Ru-arene catalyst precursors in olefin metathesis, we have investigated the replacement of phosphine ligands by NHC species, either preformed or generated in situ, in monometallic dichlororuthenium complexes of the [RuCl2(p-cymene)(L)] type/ In this contribution, we summarize the main results that were obtained with both imidazole- or triazole-based ancillary ligands for the ROMP of cyclooctene. 

One of the earliest reports of enantioselective transfer hydrogenation was by Alper et al., who used chiral Schiff bases and a dichlororuthenium(II)benzene complex employing the IPA system [5]. In another report, Lemaire et al. utilized... 

The dichlororuthenium arene dimers are conveniently prepared by refluxing ethanolic ruthenium trichloride in the appropriate cyclohexadiene [19]. The di-chloro(pentamethylcyclopentadienyl) rhodium dimer is prepared by refluxing Dewar benzene and rhodium trichloride, whilst the dichloro(pentamethylcyclo-pentadienyl)iridium dimer is prepared by reaction of the cyclopentadiene with iridium trichloride [20]. Alternatively, the complexes can be purchased from most precious-metal suppliers. It should be noted that these ruthenium, rhodium and iridium arenes are all fine, dusty, solids and are potential respiratory sensitizers. Hence, the materials should be handled with great care, especially when weighing or charging operations are being carried out. Appropriate protective clothing and air extraction facilities should be used at all times. 

A chiral dichlororuthenium(IV) complex of a Z)4-symmetric porphyrin, [Ru (Z)4-por )(Cl)2], has been prepared by heating [Ru (Z>4-por )(CO)(MeOH)] in CCI4. The complex is characterized by NMR (paramagnetically shifted pyrrolic protons at = 52.3 ppm), FAB-MS, and magnetic susceptibility measurement (/.teff= 3.1/.tB). It is a very active catalyst for enantioselective alkene epoxidations using 2,6-dichloropyridine A-oxide as the terminal oxidant, with a turnover number of up to 2000 the ee of the epoxides is 50-80%. The complex can be incorporated into sol-gel and turnovers of over 10" can be achieved." ... 

When butadiene is treated with RuCls in 2-methoxyethanol at 100°C, yellow-brown crystals of composition (C4H8)3RuCl2 are obtained 381). Crystal structural analysis has identified 381, 382] the complex as (2,6,10-dodecatriene-l,12-diyl)dichlororuthenium (146), analogous to the nickel complex (194) suggested 608) as the catalytic intermediate in the nickel-catalyzed cyclic trimerization of butadiene. In this complex, the ruthenium atom has a trigonal-bipyramidal configuration with the... 

N16CI2F24P4RU3C68H52 3H2O, Ruthenium(II), bis (bipyridine)[2,3-bis(2-pyridylpyra-zine)]- dichlororuthenium(II), tetrakis-(hexafluorophosphate), trihydrate, 33 15 N18CU5EUO24C45H55, Europium, 15-metalla-crown-5 complex, 33 69... 

Two novel complexes have been reported as aetive catalysts for both inter-and intra-molecular C( p )-H aminations of hydrocarbons. While perfluorinated dichlororuthenium(IV) porphyrin (171) proved efifieient using phosphoryl azides as... 

Zhang, J. and Che, C. (2005). Dichlororuthenium(IV) Complex of Meso-tetrakis(2,6-dichlorophenyl)porphyrin Active and Robust Catalyst for Highly Selective Oxidation of Arenes, Unsaturated Steroids, and Electron-deficient AUcenes by Using 2,6-Dichloropyridine N-Oxide, Chem. Eur. J., 11, pp. 3899-3914. 

Bis(dimethylphenylphosphine)(ethylene)(carbonyl)dichlororuthenium is the first example of a six-co-ordinate complex containing ethylene as a ligand which has been studied by X-ray crystallography (18). The ethylenic double bond is closely parallel to the Ru—P bonds the Ru—C(ethylene) distance is 2.214(4) A and C=C is 1.376(10) A. The analysis indicates that the ethylene is possibly non-planar with the hydrogen atoms bent away from the metal. 

---