Ruthenium complexes carbonyl phosphines

Remarkably, the heterogenisadon process can confer dramatically enhanced activity on the metal complex. Thus, the dimolybdenum complex [Mo2(MeCN)8][BF4]-Si02 prepared by direct reaction of silica with the metal complex is unusual in its ability to catalyse the polymerisation of norbomene in the absence of an aluminium co-catalyst and at moderate temperatures.165 Sol-gel processing of the ruthenium complex m-Cl(H)Ru(CO)(P)3 (where P is a coordinated ether-phosphine) with tetraethoxysilane and [Al(0-i-Pr)3] gives a stable material with moderate surface area which is active in the hydrogenation of fraras-crotylaldehyde with reasonable chemoselectivity to the carbonyl reduced products, cis- and trans-crotyl alcohol.166... 

Ruthenium(IT), d A wide range of Ru complexes incorporating carbonyl, phosphine, ammine and heterocyclic ligands are known. Virtually all Ru complexes are octahedral and diamagnetic with a l2g configuration (unless steric constraints are present). Catalytic processes utilizing Ru" phosphine complexes, kinetic studies on substitution reactions of [Ru(NH3)5L] " and the photophysics and photochemistry of [Ru(bipy)j] and related systems have been areas of major advance in recent years. 

H, Hydrogen, molybdenum complex, 27 3 tungsten complex, 27 6, 7 H2AUF5OP5RUC73HJ0, Ruthenium(l+), carbonyl-di-p-hydrido-tris(triphenyl-phosphine)[(triphenylphos-phine)gold]-, hexafluorophos-phate(l-), 29 281... 

Ghosh P, Fagan PJ, Marshall WJ, Hauptman E, Bullock RM (2009) Synthesis of ruthenium carbonyl complexes with phosphine or substituted Cp ligands, and their activity in the catalytic deoxygenation of 1,2-propanediol. Inorg Chem 48 6490-6500... 

In order to explore the effect of the heteroatom in Fischer-carbene type ligands on the reactivity and thermal stability of ruthenium complexes, Grubbs et al. prepared and characterized a series of well-defined bis-phosphine 4-8, NHC imidazole (IMes) 9-12, and NHC imidazolidine (HglMes) 13 complexes (Figure 12.3) [17]. The exceptionally high stability of 8 at 55 C (20 days before half the complex was decomposed) could be explained by the chelation ofthe amide carbonyl to the ruthenium center. When tested in ROMP reactions, all Fischer carbene complexes demonstrated rapid and quantitative polymerization of norbornene (NBE) derivatives at room temperature, although the polymerization... 

Materials. The commercially available aldehydes were distilled prior to use and stored at 0°C under argon. The cyclohexene- and cyclopentene- aldehydes, and the indane aldehyde (see Table) were gifts from Professor E. Piers of this department. The Ru(TPP)(PPh3)2 complex (1) was prepared from Ru(TPP)(CO)(EtOH) and PPh3 (1,7), while Ru(TPP)(CO)(tBu2POH), was prepared from the carbonyl (ethanol) adduct by treatment with tBu2PCl (1). The phosphines were from Strem Chemicals, and the ruthenium was obtained as RuCl Ol O from Johnson, Matthey Limited. 

We do not know exactly where the hydrogen binds at the active site. We would not expect it to be detectable by X-ray diffraction, even at 0.1 nm resolution. EPR (Van der Zwaan et al. 1985), ENDOR (Fan et al. 1991b) and electron spin-echo envelope modulation (ESEEM) (Chapman et al. 1988) spectroscopy have detected hyperfine interactions with exchangeable hydrous in the NiC state of the [NiFe] hydrogenase, but have not so far located the hydron. It could bind to one or both metal ions, either as a hydride or H2 complex. Transition-metal chemistry provides many examples of hydrides and H2 complexes (see, for example. Bender et al. 1997). These are mostly with higher-mass elements such as osmium or ruthenium, but iron can form them too. In order to stabilize the compounds, carbonyl and phosphine ligands are commonly used (Section 6). 

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