Ruthenium derivatives

Monosubstituted derivatives Ru6(CO)i6(L)C [ L = PPh3, P(p-FC6H4)3, AsPh3] have been obtained by boiling Ru6(CO)i7C in hexane with excess tertiary phosphines or arsines (85). 

---

Associated to copper(II) pre-catalysts, bis(oxazolines) also allowed the asymmetric Diels-Alder and hetero Diels-Alder transformations to be achieved in nearly quantitative yield and high diastereo- and enantioselectivities. Optically active sulfoximines, with their nitrogen-coordinating site located at close proximity to the stereogenic sulfur atom, have also proven their efficiency as copper ligands for these asymmetric cycloadditions. Other precursors for this Lewis acid-catalyzed transformation have been described (e.g., zinc salts, ruthenium derivatives, or rare earth complexes) which, when associated to bis(oxazolines), pyridine-oxazolines or pyridine-bis(oxazolines), led to efficient catalysts. 

Kinetic experiments were performed in other ruthenium-derivative proteins [115, 116, 117, 118], but it is difficult to compare their results with those previously reported as long as the temperature dependence of the rate has not been measured. 

In a sense, the comparative studies that were performed in the ruthenium derivatives of plastocyanin and azurin are also related to this kind of approach [152]. 

The nature of the bridging thiolate ligands or the replacement of a terminal chloride ligand by water did not have much effect on the catalytic activity, complexes 105b-d and 106a,b being also operative in these transformations. In contrast, conventional monometallic ruthenium derivatives, as well as diruthenium complexes having no Ru-Ru bond, did not work at all. 

The behavior of ruthenium derivative (333) resembles that of the iron analogue and reactions with some other electrophiles (CS2, PhNCO, tetracyanoethylene) was also studied <91JOM(406)123>. 

Much of the chemistry of metal-vinylidene complexes has been summarized in several reviews [11-14] and the following will merely summarize the main preparative methods and survey the reactions of many of the metal complexes so obtained. Complexes of most transition metals have been described, although most work has been developed using electron-rich ruthenium derivatives, which have been used in... 

None of the ruthenium complexes gave greater than trace amounts of disproportionation. Both of the nitrosyl-containing ruthenium derivatives showed some double-bond isomerization activity with 1-2% 1-pen-tene being observed. 

Ruthenium derivatives were found to be catalytically active in dehydrogenation of cyclic alkenes [333]. 

Surprisingly, RuX2PR3(r 6-arene) complexes did not promote the addition of ammonium N,N-dialkyl carbamates to alkenylacetylenes. However, this reaction was catalyzed by tr-allyl ruthenium derivatives such as [Ph(CH2) PPh2]Ru(r 3-CH2=C(Me)CH2)2 (n = 1-4), and yielded 0-l-(l,3-dienyl)carbamates (4—62% yield)... 

Activation of the triple bond of enynes with electrophilic metal derivatives, especially cationic gold complexes, platinum salts such as PtCl2, and ruthenium derivatives, has been reviewed.117 These catalysts make possible nucleophilic addition of the double... 

An interesting diruthenium compound (entry 33) has the structure shown in (XLVII) the ring is planar, bisected by a metal-metal bond, and the Si-Ru distances vary noticeably according to their bridging or terminal position and, in the former case, whether they are trans to carbonyl or silicon. The remaining ruthenium derivatives in entries... 

An attempt to achieve the complexation of the cyclophane iron complex 276 by treatment with the solvated (p-cymene)ruthenium derivative 7 results in disruption of the arene-iron bond and formation of the (p-cymene)[[22](l,4)cyclophane]ruthenium(II) salt 277 as the only-product (164) (Scheme 29, p. 224). 

The dehalogenation of arene ruthenium derivatives 299 and 300 with Co2(CO)s gives access to Ru—Co complexes stabilized by a phosphido bridge. Complexes 301 (40%) and 302 (30%) are isolated in both cases. In addition, complex 300 afforded the RuCo2 derivative 303 (10%) (170,171) [Eq. (39)]. 

The first use of ruthenium atoms in the synthesis of arene ruthenium derivatives was achieved in 1978 for the preparation of the thermally unstable bisbenzene ruthenium(O) complex 196a by condensation of ruthenium vapor with benzene (191). The more stable bisbenzene osmium(O) complex (322) has also been prepared in 15% yield by cocondensation of osmium atoms with benzene (192,193). 

Metathesis-curable compositions of polyethylene glycol monomers, (V), using ruthenium derivatives, (VI), were prepared by Angeletakis [5] and used as dental impression materials and orthodontic appliances. 

---