Structures, preparation and catalytic activity of ruthenium cyclopentadienyl complexes based on pyridyl-phosphine ligand

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

“…As aldehydes show ah igherr eduction potential than ketones, [33] ah igher substrate concentration could be employedi nT H, which is as ignificant advantage for industrial applications.H owever, by increasingt he concentration of b from 0.1 to 1 m (b/5 = 10 000, 5mol %K 2 CO 3 )t he conversion decreasedf rom 69 to 33 %( 16 h) with the formation of 37, 27, and 22 %o fa lcohol at 0.1, 0.2, and 1 m,r espectively.C omplexes 4-9 efficiently catalyzed the chemoselective TH of 4-(dimethylamino)benzaldehyde c (0.1 m)t oa lcohol. With 4 at S/ C = 5000 and 10 000, 4-(dimethylamino)benzyl alcoholw as attained in 94 and 97 %( 1.5 and 3h,r espectively;e ntries 14 and 15), whereas 99 %c onversion was achieved at ar emarkably high S/C = 100 000 in 20 hw ith 5 with no erosion of the selectivity (entries [16][17][18][19][20][21]. Without aR uc atalyst andi nt he presence of K 2 CO 3 ,n or eduction occurred (entry 27).…”

“…In addition to Ir complexes, the Ru Noyori system [(arene)RuCl(TsDpen)] (Tsdpen= N ‐( p ‐toluenesulfonyl)‐1,2‐diphenylethylenediamine), [CpRu(PPh 3 )(PN)] (PN=diphenyl‐2‐pyridylphosphine), [RuH 2 (PPh 3 ) 4 ], [RuCl 2 (PTA) 4 ] (PTA=1,3,5‐triaza‐7‐phosphaadamantane), [RuCl 2 ( m tppms) 2 ] 2 (mtppms=sodium 3‐diphenylphosphinobenzenesulfonate), [RuCl 2 (PO) 2 ] (PO=(2‐methoxyethyl)diphenylphosphine), [RuCl 2 (POP)(dmso)] (POP=xantphos), [RuCl 2 (PPh 3 )(NNN)] (NNN=2‐(benzoimidazol‐2‐yl)‐6‐(3,5‐dimethylpyrazol‐1‐yl)pyridine), [RuCl(PPh 3 ) 2 (MeCN) 3 ][BPh 4 ], [RuCl 2 (CO) 2 (PS)] (PS=bis(2‐diphenylphosphanylphenyl)ether monosulfide and 9,9‐dimethyl‐4,5‐bis(diphenylphosphanyl)xanthene monosulfide), and Ru cluster carbonyl derivatives catalyze the aldehyde TH using 2‐propanol or formates as hydrogen donors that work at relatively low S/C (100–1000). Complexes 2 and 3 were active in the TH of aldehydes with NaO i Pr and K 2 CO 3 as the base.…”

ChemInform Abstract: Synthesis and Characterization of Rhodium(I) Complexes with P—N Donor Ligands and Their Catalytic Application in Transfer Hydrogenation of Carbonyl Group.

“…From Table , it can be seen that with any particular catalyst, there is an overall decrease in percentage conversion from ketone to alcohol when going from acetophenone to benzophenone through p ‐hydroxyacetophenone. The ketonic group of acetophenone is more reactive than that of p ‐hydroxyacetophenone and benzophenone because of the mesomeric effect in the latter, which tends to decrease electrophilicity of the carbonyl carbon in the corresponding ketones . Moreover, the lower conversion to alcohols from ketones with bulky substituents might be due to steric hindrance caused by the bulky phenyl rings of the ligand about the central metal ions during substrate binding .…”

Synthesis and characterization of ruthenium(II) complexes based on diphenyl-2-pyridylphosphine and their applications in transfer hydrogenation of ketones

“…Ru(II) complexes are generally employed as the most useful catalysts for such reactions [3,[28][29][30][31][32][33]. To develop and explore hydrogen transfer catalysts in the present study, we choose PPh 2 Py as a versatile ligand which may bind the metal center in a monodentate, chelating or bridging mode depending upon requirements at the reaction center [34][35][36][37][38][39]. In its chelating coordination mode it forms four membered rings which are strained, relatively unstable and plays a vital role in catalysis [40][41][42][43][44].…”