Classical and non-classical phosphine-Ru(II)-hydrides in aqueous solutions: many, various, and useful
| Autor: | Ferenc Joó, Henrietta Győrváriné Horváth, Imre Szatmári, Gábor Papp, Ágnes Kathó, Gábor Laurenczy |
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| Rok vydání: | 2013 |
| Předmět: |
Aqueous solution
Denticity Atmospheric pressure 010405 organic chemistry Chemistry Hydride Inorganic chemistry Pressure dependence 010402 general chemistry 01 natural sciences 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound Természettudományok Triphenylphosphine Kémiai tudományok Phosphine |
| Zdroj: | DALTON TRANSACTIONS |
| DOI: | 10.1039/c2dt31793a |
| Popis: | Hydrogenation of the water-soluble [{RuCl(2)(mtppms)(2)}(2)] (mtppms = monosulfonated triphenylphosphine) was studied in aqueous solutions in the presence of excess mtppms both with H(2) and with aqueous HCOONa. Depending on the reductant, the pH and H(2) pressure altogether nine hydride species were identified. In acidic solutions at 1 bar H(2) pressure the known [RuHCl(mtppms)(3)] (1) and [{RuHCl(mtppms)(2)}(2)] (3) were formed, however, elevated pressure led to the formation of trans-[RuH(2)(mtppms)(4)] (11). In basic solutions at atmospheric pressure cis-fac-[RuH(2)(H(2)O)(mtppms)(3)] (12) was observed which was readily replaced by [RuH(2)(η(2)-H(2))(mtppms)(3)] (13) at higher H(2) pressures. 13 is the first water-soluble and stable η(2)-H(2) Ru(II)-complex stabilized only by monodentate phosphine ligands. [RuHBr(mtppms)(3)] (9) and [RuHI(mtppms)(3)] (10) were obtained analogously to 1. In concentrated aqueous HCOONa solutions (often used in H-transfer hydrogenations) the major species was trans-[RuH(2)(HCOO)(mtppms)](-) (14) while in dilute solutions trans-[RuH(2)(H(2)O)(mtppms)(3)] (15) could be observed. Formation of these various hydride species offers an explanation for the earlier observed pH and pressure dependence of the rates and selectivities in hydrogenation of unsaturated aldehydes catalyzed by [{RuCl(2)(mtppms)(2)}(2)] + mtppms. |
| Databáze: | OpenAIRE |
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