Carbonyl complexes of ruthenium

Dr. Halpern I don t know whether this is relevant to the first reaction or not, but we have also been struggling with the study of various reactions of ruthenium chlorides including ruthenium(II) chloride for a long time. Among the reactions studied is the formation of olefin and carbonyl complexes of ruthenium(II). These form readily in aqueous solution, and are fairly stable. James and Kemp, working on these systems in my laboratory have studied in some detail the kinetics of the reactions ... 

Synthesis of Ru3(CO)i2 using atmospheric pressure CO involves first treating RuCl3 xH20 with CO in refluxing 2-ethoxyethanol to give a halo-carbonyl complex of ruthenium, which is then reduced by Zn to the product (75-80% yield). ... 

Robinson SD, Wilkinson G (1966) New diene and carbonyl complexes of ruthenium. J Chem Soc A 300-301... 

These concepts are not restricted solely to Ru(bpy)3 but similar correlations are found in study of the quenching rate constants of para-substituted tetra-phenylporphorin carbonyl complexes of ruthenium(II), and of Cifbpy) (Chapter 2)019)... 

Rillema DP, Nagle JK, Barringer LFJ, Meyer TJ (1981) Redox properties of metalloporphyrin excited states, lifetimes, and related properties of a series of para-substimted tetraphenylporphine carbonyl complexes of ruthenium(II). J Am Chem Soc 103 56-62... 

Carbonyl derivatives of ruthenium sulphoxide complexes have been made [113]. 

Carbonyl and alkene complexes of ruthenium have been previously reviewed. The syntheses of [Ru(CO)(NH3)5]2+ are summarized in Scheme 3. The dependence of vc=0 upon counterion and upon solvent has been discussed. 88 The Mossbauer spectrum of [Ru(CO)(NH3)5 2+ has been reported.27 120 The replacement of HzO by isn in /razw-[Ru(L)(NH3)4(OH2)]2+ has been assessed, the lability increasing in the order L = CO = N2 < isn < py < imid (N bound) az NH3 < OH- < CN-< SO2- < imid (C bound).189 For n acid ligands good correlation between specific rate and k-l/2 values for the ruthenium(II)/(III) couple was observed.189... 

Although a whole series of carbonyl complexes of other transition metals (Fe, Mo, W, Ni) could only be used in stoichiometric Pauson-Khand reactions [11], two Japanese laboratories have since independently reported efficient ruthenium-catalyzed (intramolecular) reactions. The desired cy-clopentenones are formed in good to excellent yields in dimethylacetamide [12] or dioxane [13] in the presence of 2 mol% of [Ru3(CO),2] at 140-160 °C and 10-13 atm CO pressure. 

Osmium forms a wide variety of alkyl and aryl complexes including homoleptic alkyl and aryl complexes and many complexes with ancillary carbonyl (see Carbonyl Complexes of the Transition Metals), cyclopentadienyl (see Cyclopenta-dienyl), arene (see Arene Complexes), and alkene ligands (see Alkene Complexes). It forms stronger bonds to carbon and other ligands than do the lighter elements of the triad. Because of this, most reactions of alkyl and aryl osmium complexes are slower than the reactions of the corresponding ruthenium complexes. However, because osmium is more stable in higher oxidation states, the oxidative addition (see Oxidative Addition) of C-H bonds is favored for osmium complexes. The rate of oxidative addition reactions decreases in the order Os > Ru Fe. 

Recent literature describes the synthesis of vinyl esters in the presence of platinum metal complexes. Complexes which have proven particularly suitable in this context are those of ruthenium (eq. (15)), such as, for example, cyclooc-tadienylruthenium halides [36], ruthenium carbonyl complexes, and ruthenium acetate complexes [37]. A characteristic feature of these is their high selectivity with regard to acetylene, so that the production of acetylene polymers is reduced. 

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