Ruthenium complexes thermolysis

Ruthenium complex 33 has been prepared by thermolysis as shown in Scheme 1 for early transition metals [25]. However, this procedure is not applicable to nickel, platinum and palladium complexes because they undergo reductive elimination, rather than beta elimination. Complexes 31 and 32 have been prepared by sodium amalgam reduction of the corresponding a-complex 37, as shown in Scheme 6 [6,7,24]. 

Thermolysis of ruthenium carbene complexes leads to intramolecular r/> -bcnzylic C-H functionalization in the presence of a hydrogen-accepting olefin (Equation (35)).44,44a. 

Thermolysis of RuPh2(TPP) at 100 °C for 30 h in benzene produces a phenyl-ruthenium(III) complex, RuPh(TPP) [155] (see Table 2). In contrast to RuPh2(P) and FePh(P) [222] no N-arylation occurred on oxidation of the five-coordinate RuPh(P) [306]. 

Thermolysis of ruthenium vinyl complexes also promotes intramolecular orthometallation [Eq. (112)]. However, performing the reaction in the... 

The abnormal carbene complex 27 (bonded through C3) is formed from the reaction between M3(CO)i2 (M = Ru, Os) and the bulky NHC ImAd2 (l,3-di(adamantyl)imidazol-2-ylidene) the reaction with the ruthenium precursor occurs readily in thf at room temperature, whereas the osmium reaction requires heating at 70 °C. Thermolysis of 27 affords 28.30... 

Ruthenium clusters with even higher nuclearity have also been isolated. When (1) is refluxed in ethanol for 18h, the hexaruthenium hydrido complexes [HRu6(CO)i8] (18) and [H2Ruio(CO)25] (19) are produced, along with metallic ruthenium (equation 8). The dihydride complex (19) represents the first noncarbido decaruthenium cluster. A trianion with 11 ruthenium centers (20) is synthesized by thermolysis of (1) in undried acetonitrile (equation 9), and... 

Certain transition-metal salts were also found to catalyze the apparent 1,6-ECRC. For example, thermolysis of silyl ether 74 (R1 = R2 = H) in toluene solution at 110°C (7 d) affords only a modest yield of enone 76. Attempts to cyclize the potassium enolate corresponding to 74 were also unsuccessful. However, treatment of 74 with substoichiometric amounts of a palladium(II) complex, bis(trifurany]phosphane)palladium dichloride [Pd(PFu3)2Cl ], in toluene (110 °C, 72 h) affords enone 76 in 84% yield. Substitution at R1 is detrimental, but butyl and phenyl substituents at R2 afford -substituted 76 in comparable yields. (Triphenylphos-phane)ruthenium dichloride [Ru(PPh3)Cl2] can be used in place of the palladium salt. 

Ruthenium (IV [RUCI4L] has been reported to be the product of the oxidation of LH[RuCl4L] with CI2 or Ce" in HN03, " while thermolysis of (phenH2)[RuClj] yields [RuCl4phen]." The magnetic properties of these complexes have been reported. "" ... 

Another important mechanistic issue is the thermal decomposition of ruthenium alkylidene catalysts. To understand the decomposition pathways available in these systems, the thermolysis of two ruthenium alkylidene complexes, the propylidene (PCy3)2(Cl)2Ru=CHEt (3) and the methyhdene (PCy3)2(Cl)2Ru=CH2 (4), was examined in detail [93]. These two compounds were chosen because a variety of alkylidenes [as modeled by the propylidene (3)] and the methyhdene (4) are key intermediates in a range of olefin metathesis reachons with terminal alkenes. The studies revealed that the thermal decomposihon of the propylidene... 

---