Ruthenium RuCl -chloride

Anhydrous ruthenium(lll) chloride, RuCL, is made by direct chlorination of the metal at 700°C. Two aliotropic forms result. The trihydrate is made by evaporating an HQ solution of rulheinuiu(III) hydroxide to dryness or reducing ruthenium(VIII) oxide in a HQ solution. The tnhydrate, RuCk 3R>0, is the usual commercial form. Aqueous solutions of the tri-hydrate are a straw color in dilute solution and red-brown in concentrated solution. Ruthenium(lll) chloride in solution apparently forms a variety of aquo- and hydroxy complexes. The analogous bromide. RuBr3, is made by the same solution techniques as the chloride, using HBr instead of HQ. 

Stroganov und Ovtchinnikov (163) untersuchten 1957 die Struktur der Hochtemperaturmodifikation des Ruthenium(III)-chlorids, des a-RuCls. Sie ordneten diese dem CrCl3-Typ zu. Im Gegensatz dazu beschrieben... 

Ruthenium(IV) chloride has been detected in the vapour phase on heating RUCI3 and Clj between 400-800 C. It is the principal vapour phase species up to 853 C and it is reported that solid RUCI4 can be isolated by cooling the above vapour to liquid air temperatures. Above — 30 C, it decomposes to RUCI3 and Cl2. Note however that Fletcher and co-workers suggest that the above observations are compatible with oxochlorides such as [RU2OCI6] and are not, per se, evidence for the existence of RuCl,. 

Ruthenium(III) chloride (RuCls) [3H2O 13815-94-6 XH2O 14898-67-0 Anhydrous 10049-08-8] M 207.4 (anhydrous), 261.5 (3H2O), 3.11. The anhydrous salt exists in two forms. The a-form is produced by the... 

Binary Compounds. The mthenium fluorides are RuF [51621 -05-7] RuF [71500-16-8] tetrameric (RuF ) [14521 -18-7] (15), and RuF [13693-087-8]. The chlorides of mthenium are RUCI2 [13465-51-5] an insoluble RuCl [10049-08-8] which exists in an a- and p-form, mthenium trichloride ttihydrate [13815-94-6], RuCl3-3H2 0, and RuCl [13465-52-6]. Commercial RuCl3-3H2 0 has a variable composition, consisting of a mixture of chloro, 0x0, hydroxo, and often nitrosyl complexes. The overall mthenium oxidation state is closer to +4 than +3. It is a water-soluble source of mthenium, and is used widely as a starting material. Ruthenium forms bromides, RuBr2 [59201-36-4] and RuBr [14014-88-1], and an iodide, Rul [13896-65-6]. 

Ruthenium complexes have also been reported as active species for enan-tioselective Diels-Alder reactions. Faller et al. prepared a catalyst by treatment of (-)-[( ] -cymene)RuCl(L)]SbF6 with AgSbFe resulting in the formation of a dication by chloride abstraction [95]. The ligand was (-l-)-IndaBOx 69 (Scheme 36) and the corresponding complex allowed the condensation of methacrolein with cyclopentadiene in 95% conversion and 91% ee. As another example, Davies [96] prepared the complex [Ru(Fl20)L ( i -mes)] [SbFe]2 (with 70 as L in Scheme 36), and tested its activity in the same reaction leading to the expected product with similar activity and lower enan-tioselectivity (70%). 

Trust s group has shown that another selective reaction involving C—O bond formation followed by rearrangement and C—C bond formation occurred when Cp-containing ruthenium complexes were used as catalytic precursors. With RuCl(Cp)(PPh3)2 in the presence of NH4PF6, an additive known to facilitate chloride abstraction from the metal center, the addition of allylic alcohols to terminal alkynes afforded unsaturated ketones [46, 47]. It has been shown that the key steps are the... 

The formation of a ruthenium vinylidene is proposed as the key intermediate in the regioselective addition of hydrazine to terminal alkynes [55]. This reaction, which proceeds via addition of the primary amino group of a 1,1-disubstituted hydrazine followed by deamination, provides an unprecedented access to a variety of aromatic and aliphatic nitriles. The tris(pyrazolyl)borate complex RuCl(Tp)(PPh3)2 gave the best catalytic activity in the absence of any chloride abstractor (Scheme 10.17). 

The ability of the binuclear complex [Cp RuCl(p2-SR)2RuCl(Cp )] to generate cationic allenylidene complexes by activation of terminal prop-2-ynols in the presence of NH4BF4 as a chloride abstractor opens the way to a variety of catalytic transformations of propargylic alcohols involving nucleophilic addition at the Cy atom of the ruthenium allenylidene intermediate (Scheme 19). This leads to the formation of a functional ruthenium vinylidene species which tau-tomerizes into an -coordinated alkyne that is removed from the ruthenium centre in the presence of the substrate. 

Treatment of 1 with a variety of inorganic salts MX in polar solvents leads to the displacement of CP for X-. The reaction most likely involves predissociation of the chloride ion followed by attack of the exchanging anion X" at the coordinatively unsaturated ruthenium center [Eq. (31)]. Conductivity tests indicate that although (r -CsHsXPPl RuCl is a nonelectrolyte in acetone, appreciable ionic behavior develops in donor... 

Potassium Nitrosochlor-ruthenate or Potassium Ruthenium Ni-trosochloride, 2KC1. RuCl3. XO or K2RuClsNO, is obtained by direct precipitation of concentrated solutions of potassium chloride and ruthenium nitrosochloride it also results on evaporation of mixed dilute solutions of the two substances.3 It yields black orthorhombic crystals which dissolve in water to a reddish violet solution. The aqueous solution is stable, its electric conductivity showing no alteration whatever after standing for two weeks. Its solution apparently contains three ions,4 namely, K , K and RuCls.XO". 

The common starting material for nearly all preparations of ruthenium is a hydrated chloride (RuCb) of approximate composition RuCls 3H2O, containing 36-42% Ru. Although the material from most sources is not very pure, for example, containing nitrosyls from prior contact with nitric acid, the presence of impurities in most cases is not a serious problem and the yields of conversion of RuCb 3H2O can be nearly quantitative based on metal content. 

Ruthenium, in the presence of osmium, can be determined after reduction of RUO4 in 6-10 M HCl (RuCle complex) (Os does not interfere in the determination of Ru) [8]. Ruthenium can be determined also as various chloride complexes combined with SnCb ions [54,70]. Such a complex has been used for determining Ru in the presence of Os, by derivative spectrophotometry [71]. This method has also been used for determining Ru in the presence of Rh after the reaction with octadecyldithiocarbamate [72] and triazine derivatives (in picrate medium) [73]. Simultaneous determination of Ru and Os by derivative spectrophotometry can be performed after absorption of volatile RUO4 and OSO4 in water [7]. 

Oro and co-workers have shown that the one-pot reductive carbonylation of RuCls n-HjO with zinc, in the presence of a pyrazole derivative, yields dinuclear, pyrazolato-bridged, carbonyl complexes. To our knowledge, this was the first report on a facile, one-step synthesis of substituted carbonyl clusters, starting from ruthenium chloride. The one-pot synthetic route described here gives [PPN][HRu3(CO)n] in a yield of 83%, with respect to RUCI3 n-H20 as the starting material. 

Since its preparation, reactions of RuCl[k -HB(pz)3](PPh3)2 have been investigated in a number of papers. The lability of both the phosphines and the chloride hgand allow functional group transformations to be carried out in order to provide a wide range of ruthenium hydro-tris(pyrazol-l-yl)borate complexes. A straightforward preparation of the complex on a large scale (10 g) is described here. 

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