Ruthenium and osmium complexes containing 2-(aminomethyl)pyridine (Ampy)-based ligands in catalysis

Transfer Hydrogenation and Hydrogenation of Commercial‐Grade Aldehydes to Primary Alcohols Catalyzed by 2‐(Aminomethyl)pyridine and Pincer Benzo[h]quinoline Ruthenium Complexes

“…With complex 5 (S/C = 20 000),9 8% of alcohol is obtained in 16 h( entry 8), whereas less basic 6 was less active than 4 and 5 and afforded 60 %o f alcohol (entry 9). Interestingly,w ithc omplex 4 and under 5atm of H 2 ,t he electron-richa ldehyde c is reduced quantitatively and chemoselectively to 4-(dimethylamino)benzyl alcohol (> 97 %) at high S/C = 10 000-40 000 in 1-22 h( entries [10][11][12].…”

“…[9] In the last decade, we developedh ighly active and productive Ru and Os cata-lysts, whichh ave substituted 2-(aminomethyl)pyridine ligands, for the TH and HY of carbonyl compounds, and progress in this area has been reviewed recently. [10] The commercially available cis-[RuCl 2 (ampy)(PP)] [ampy = 2-(aminomethyl)pyridine; 1: PP = 1,4-bis(diphenylphosphino)butane (dppb), [11] 2:P P = 1,1'ferrocenediyl-bis(diphenylphosphine) (dppf)] [12] and pincer [RuCl(CNN)(dppb)] (HCNN = 6-(p-tolyl)-2-aminomethylpyridine; 3) [13] are practical catalysts fork etone reduction and other organic transformations, which include the dehydrogenation, deuteration, and isomerization of alcohols ( Figure 1). [12,14] Conversely,f or the reduction of simple aldehydest op rimary alcohols, NaBH 4 remains the preferred reagent in industry.…”

Iron Group Hydrides in Noyori Bifunctional Catalysis

“…Similarly we found that the complexes RuH 2 (bipyridine)(PPh 3 ) 2 and RuH 2 (phenanthroline)(PPh 3 ) 2 that do not contain NH groups were inactive while RuH 2 (AMPY)(PPh 3 ) 2 , AMPY = 2‐methylaminopyridine, was even more active than the DACH system 39. The flat backbone of the AMPY ligand appears to be responsible for the high activity of other catalysts with this ligand that are effective, for example, in the AH of hindered tert‐ butyl ketones61 and the transfer hydrogenation of ketones 24…”

“…The mechanism was proposed to involve ruthenium‐ligand bifunctional catalysis15 where a ruthenium hydride and amine proton smoothly transfer a dihydrogen equivalent to a ketone or imine (Figure , M = Ru). This concept has been applied widely in catalysis and extended to several transition metals and the work has been reviewed by our group16–19 and others 20–27…”

Synthesis, Spectral and Electrochemical Properties and DFT Studies of Two Complexes of Ruthenium with Bis-2,3-(2-Pyridyl)Pyrazine and 4-Picoline

“…To interact with this ligand (L, I), [Ru(dmso) 4 Cl 2 ] has been chosen because of its demonstrated ability to accommodate heterocyclic neutral ligands via displacement of the coordinated moities [19][20][21] . It may be worth mentioning here that ruthenium chemistry is also important [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] largely due to their interesting redox 35 , catalytic 22,24,30,38,41 , photophysical/photochemical 37 and biological properties 23,33,40 . The primary objective of the present study has been to synthesize mixed-ligand complexes of ruthenium incorporating ligand I and find out the coordination mode of ligand I in them.…”