Behaviour of triphenylphosphine-substituted ruthenium carbonyl carboxylates with hydrogen

Frediani, Piero; Faggi, Cristina; Papaleo, S.; Salvini, Antonella; Bianchi, Mario; Piacenti, Franco; Ianelli, S.; Nardelli, M.

doi:10.1016/s0022-328x(96)06668-5

Cited by 23 publications

(20 citation statements)

References 31 publications

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“…The catalysts RuH 2 (CO) 2 (P n Bu 3 ) 2 (1) [3], RuH 2 (CO) 2 (PPh 3 ) 2 (2) [5] and RuH 2 (PPh 3 ) 4 (3) [6] have been prepared according to the procedure described in the literature and their spectroscopic characteristics were in agreement with the reported data.…”

Section: Resultssupporting

confidence: 53%

“…The species (4) and (5) are not present in the solid state. The spectroscopic characteristics of the species present in solution are in agreement with the data reported in the literature [3,5,6].…”

Section: Resultsmentioning

confidence: 99%

“…In a first step, 1,2,3,4-tetrahydroquinoline (1,2,3,4-THQ) and 5,6,7,8-tetrahydroquinoline (5,6,7, are formed and in a second step decahydroquinoline (DHQ) (Scheme 1) is formed. Other intermediates were not evidenced in the reaction medium.…”

Section: Resultsmentioning

confidence: 99%

“…Kinetic analysis of the data reported in Table 1 (entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], following the procedure reported by Frediani et al [8], shows a first partial order with respect to reaction time with all the catalysts tested. The kinetic rates (K c ) are in the following order: (3) ) (2) @ (1) (14.60, 6.37 and 6.36 · 10 À6 s À1 , respectively) ( Table 2).…”

Section: Reaction Timementioning

confidence: 99%

“…The complex (3) hydrogenates IQ with a lower catalytic activity than Q: the conversion is 36.3% (entry 43) but surprisingly an opposite selectivity is obtained since the reaction gives exclusively 5,6,7,8-tetrahydroquinoline (5,6,7,. Pyridine (PY) and 2-methylpyridine (MPY) are also hydrogenated in the presence of RuH 2 (PPh 3 ) 4 (3) ( Table 8) (Scheme 4).…”

Section: Influence Of An Acid or A Basic Mediamentioning

confidence: 99%

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Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Frediani

Pistolesi

Frediani

et al. 2006

Inorganica Chimica Acta

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The catalytic activity of the dihydride ruthenium complexes, RuH 2 (CO) 2 (P n Bu 3 ) 2 , RuH 2 (CO) 2 (PPh 3 ) 2 and RuH 2 (PPh 3 ) 4 , in the hydrogenation of nitrogen containing heterocycles has been tested by analyzing the influence of reaction parameters such as temperature, hydrogen pressure, catalyst concentration, on the rate and regioselectivity of the reaction.RuH 2 (PPh 3 ) 4 shows a better catalytic activity with an 86.7% conversion of quinoline after 24 h at 100°C under a hydrogen pressure of 25 bar, while RuH 2 (CO) 2 (PPh 3 ) 2 and RuH 2 (CO) 2 (P n Bu 3 ) 2 in the same conditions give a conversion of 37.1% and 35.6%, respectively. These results are confirmed by the reaction rate of the hydrogenation of quinoline, since the K c in the presence of RuH 2 (PPh 3 ) 4 (1.46 · 10 À5 s À1 ) is higher than others (6.37 · 10 À6 s À1 for RuH 2 (CO) 2 (PPh 3 ) 2 and 6.36 · 10 À6 s À1 for RuH 2 (CO) 2 (P n Bu 3 ) 2 ).Noteworthy is the selectivity of these catalytic systems in the hydrogenation of quinoline: in all tests the three catalysts lead to 1,2,3,4-tetrahydroquinoline as the major product, furthermore this compound is the only formed in the presence of RuH 2 (CO) 2 (PPh 3 ) 2 . The selectivity is affected by the presence of an acid (CH 3 COOH) or a base (N n Bu 3 ) in the reaction media.The complex RuH 2 (PPh 3 ) 4 is catalytically active, even if in a minor extent, in the hydrogenation of isoquinoline, pyridine and 2-methylpyridine.The basicity of the substrate and steric hindrance around the nitrogen atom show a great influence on the conversion. The results obtained suggest that the catalytic system activates a heterocyclic ring through the coordination of the heteroatom to the metal centre of the complexes.

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Section: Resultssupporting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Reaction Timementioning

confidence: 99%

Section: Influence Of An Acid or A Basic Mediamentioning

confidence: 99%

See 3 more Smart Citations

Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Frediani

Pistolesi

Frediani

et al. 2006

Inorganica Chimica Acta

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Homogeneous hydrogenation of ketones in the presence of H ₂ Ru(CO) ₂ (PPh ₃ ) ₂

Salvini

Frediani

Gallerini

2000

Applied Organom Chemis

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The hydrogenation of ketones to alcohols in the presence of a hydrido ruthenium triphenylphosphine complex, H 2 Ru(CO) 2 (PPh 3 ) 2 , has been investigated. Acetophenone was hydrogenated at 120°C with a conversion of 69% after 24 h. The yield is 85% working at 140°C. A kinetic investigation of the reaction was also performed: the reaction is first order with respect to the hydrogen pressure, substrate and catalyst concentration. The rate of hydrogenation depends on the nature of the substrate: steric and electronic effects have a strong influence on the hydrogenation of ketones. 2,2,2-Trifluoroacetophenone is almost completely hydrogenated at 120°C after 3 h. A mechanism has been tentatively suggested for the hydrogenation of ketones in which the coordination of the substrate to the metal is followed by its insertion into the ruthenium-hydrido bond with formation of the corresponding alkoxide. This complex reacts with hydrogen, restoring the catalyst and forming the alcohol. We have also tested the activity of this catalyst in the hydrogenation of an a,bunsaturated ketone (trans-4-phenylbut-3-en-2-one). The C=C double bond is preferentially hydrogenated with a high chemoselectivity (92.4% at 100°C). The data collected on the hydrogenation of trans-4-phenylbut-3-en-2-one suggest a different mechanism in which the ratedetermining step is the interaction between the C=C double bond of the ketone with the metalhydrido bond. Experimental evidence is reported to support this different hypothesis.

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Mononuclear Ru/Os Compounds without Hydrocarbon Ligands

Whittlesey

2007

Comprehensive Organometallic Chemistry III

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Behaviour of triphenylphosphine-substituted ruthenium carbonyl carboxylates with hydrogen

Cited by 23 publications

References 31 publications

Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Homogeneous hydrogenation of ketones in the presence of H ₂ Ru(CO) ₂ (PPh ₃ ) ₂

Mononuclear Ru/Os Compounds without Hydrocarbon Ligands

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Behaviour of triphenylphosphine-substituted ruthenium carbonyl carboxylates with hydrogen

Cited by 23 publications

References 31 publications

Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Homogeneous hydrogenation of ketones in the presence of H 2 Ru(CO) 2 (PPh 3 ) 2

Mononuclear Ru/Os Compounds without Hydrocarbon Ligands

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Homogeneous hydrogenation of ketones in the presence of H ₂ Ru(CO) ₂ (PPh ₃ ) ₂