The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Chemistry of ruthenium(II) monohydride and dihydride complexes containing pyridyl donor ligands including catalytic ketone H2-hydrogenation.

In this study we determine the changes to the properties of dihydride catalysts for ketone H2-hydrogenation by successively replacing the amine donors in the known dach complex RuH2(PPh3)2(dach) (2a), dach = 1,2-(R,R)-diaminocyclohexane, with one pyridyl group in the corresponding 2-(aminomethyl)pyridine (ampy) complexes RuH2(PPh3)2(ampy) (2b) and with two pyridyl groups in the complexes RuH2(PPh3)2(bipy) (2c) and RuH2(PPh3)2(phen) (2d). The ruthenium monohydride complex, (OC-6-54)-RuHCl(PPh3)2(ampy), (1b with Cl trans to H) was prepared by the addition of 1 equiv of ampy to RuHCl(PPh3)3 in THF. Treatment of the monohydride complex with K[BH(sec-Bu)3] in THF or KOtBu/H2 in toluene resulted in the formation of a mixture of at least two isomers of the highly reactive, air-sensitive ruthenium dihydride complex 2b. One is the cis dihydride (OC-6-14)-2b or more simply c,t-2b with trans PPh3 groups and another is the cis dihydride c,c-2b (OC-6-42) that has PPh3 trans to H and PPh3 trans to N(pyridyl). The isomer c,c-2b slowly converts to c,t-2b in solution. The reaction of 1b with KOtBu under Ar results in the formation of a mixture that includes a complex with an imino ligand HN=CH-2-py while the same reaction under H2 leads to c,c-2b and then c,t-2b. The dach complex c,t-2a, reacts with ampy, 2,2'-bipyridine (bipy), and 1,10-phenanthroline (phen) in refluxing THF to form the substituted cis-dihydride complexes c,t-2b, (OC-6-13)-RuH2(PPh3)2(bipy) (c,t-2c with trans PPh3 groups) and (OC-6-13)-RuH2(PPh3)2(phen), c,t-2d, respectively. The dihydrides containing amino groups and cis-PPh3 groups, i.e., c,c-2a or c,c-2b, are active precatalysts for the H2-hydrogenation of acetophenone (neat or in benzene) under mild reaction conditions, whereas those with trans-PPh3 groups, c,t-2a and c,t-2b are much less active. The combination of ampy complex 1b and KOtBu also provides a catalyst in benzene that is more active than the corresponding dach system. The complexes without amino groups c,t-2c and c,t-2d are air-stable and inactive as hydrogenation catalysts under comparable conditions. The mechanism of hydrogenation of ketones catalyzed by isomers of 2a,b is thought to be similar and to proceed via a trans-dihydride complex, t,c-2a or t,c-2b, and an amido complex, neither of which are directly observed for the ampy complexes. The dihydride complex c,t-2b reacts with formic acid to give (OC-6-45)-RuH(OCHO)(PPh3)2(ampy), 3b, with formate trans to hydride. The structures of 1b, c,t-2b, c,t-2c, and 3b have been determined by single-crystal X-ray diffraction.[1]


  1. Chemistry of ruthenium(II) monohydride and dihydride complexes containing pyridyl donor ligands including catalytic ketone H2-hydrogenation. Abdur-Rashid, K., Abbel, R., Hadzovic, A., Lough, A.J., Morris, R.H. Inorganic chemistry. (2005) [Pubmed]
WikiGenes - Universities