Supported organometallic complexes part 39: cationic diamine(ether–phosphine)ruthenium(II) complexes as precursors for the hydrogenation of trans-4-phenyl-3-butene-2-one

Treatment of RuCl2(η1-Ph2PCH2CH2OCH3)2(diamine) (1L1–1L7) with one equivalent of AgX (X=OTf, BF4) in CH2Cl2 results in the formation of the monocationic ruthenium(II) complexes [RuCl(η1-Ph2PCH2CH2OCH3)(η2-Ph2PCH2CH2OCH3)(diamine)]+X− (2L1–2L7). These complexes were characterized by NMR, and mass spectroscopy as well as by elemental analyses, 2L1 additionally by an X-ray structural analysis. Complex 2L1 crystallizes in the monoclinic space group C2/c with Z=8. The monocationic and neutral complexes were applied as catalysts in the selective hydrogenation of trans-4-phenyl-3-butene-2-one. With the exception of 1L3/1L7 and 2L3/2L7 all catalysts showed high activities and selectivities toward the hydrogenation of the carbonyl group under mild conditions. However, the activity of the cationic catalysts is only half of that of their neutral congeners.