77520-51-5

Upstream product

• 16592-00-0 [Ru(CO)3(tricyclohexylphosphine)2] 
• 1333-74-0 hydrogen 
• 124-41-4 sodium methylate 
• 7291-22-7 perdeuteriopyridine 
• 1333-74-0 parahydrogen 
• 201230-82-2 carbon monoxide 
• 187793-40-4 [RuH2[(η(2)-HSiMe2)2O](PCy3)2] 
• 237437-61-5 [RuH2[(η(2)-HSiPh2)2O](PCy3)2] 
• 112320-11-3 RuH₂(H₂)2(tricyclohexylphosphine)2 
• 1111-72-4 carbon dioxide 
• 25015-63-8 4,4,5,5-tetramethyl-[1,3,2]-dioxaboralane 

Relevant academic research and scientific papers

Trapping formaldehyde in the homogeneous catalytic reduction of carbon dioxide

Formaldehyde detectives: Evidence for the production of formaldehyde during a ruthenium-catalyzed CO2 reduction process, and for its involvement in the formation of the resulting C2 compound, is disclosed. Ultimately, formaldehyde can be recovered by methanol trapping. HBPin=pinacolborane. Copyright

Reactions of Grubbs catalysts with excess methoxide: Formation of novel methoxyhydride complexes

On exposure to NaOMe (≥3 equiv) in CH2Cl2-MeOH at 23 °C, the first-generation Grubbs catalyst RuCl2(PCy 3)2(=CHPh) (1a) is immediately transformed into the six-coordinate methoxyhydride complexes RuH(OMe)(CO)2(PCy 3)2 (4a) and RuH(OMe)(CO)(H2)(PCy 3)2 (5a). Complex 5a can be recycled into 4a under conditions conducive to removal of H2. The second-generation catalyst RuCl2(IMes)(PCy3)(=CHPh) (1b; IMes = N,N′- bis(mesityl)imidazol-2-ylidene) reacts more slowly, requiring several hours even at 20 equiv of NaOMe, and terminates at five-coordinate RuH(OMe)(CO)(IMes) (PCy3) (3b). Experiments in the presence of added PCy3 reveal that consumption of 1a, but not 1b, proceeds via the four-coordinate intermediate formed by equilibrium loss of phosphine, a function of the lability of the PCy3 ligand at ambient temperatures. The poor accessibility of such an intermediate for 1b at 23 °C retards salt metathesis and inhibits further reaction of 3b. For the bis(PCy3) analogue 3a, fast transformation into 4a is proposed to involve reversible loss of PCy 3, coordination of methanol, σ-metathesis of methanol at the hydride site to liberate H2, and β-elimination/decarbonylation of bound methoxide. Competitive uptake of H2 by 3a yields six-coordinate 5a (the dihydrogen adduct of 3a). Independent routes to RuH(OMe)(CO)2(L)(PCy3) (4a/b; a, L = PCy3; b, L = IMes) were developed: these involved sequential transformation of RuHCl(CO)(L)(PCy3) (2a/b) into the bis-carbonyl adducts RuHCl(CO)2(L)(PCy3) (7a/b) under CO, conversion of 7a/b into the more reactive triflates RuH(OTf)(CO)2(L)(PCy3) (8a/b), and reaction of 8a/b with equimolar NaOMe. Dihydride 6b was also prepared, by reaction of 8b with NaH.

A combined parahydrogen and theoretical study of H2 activation by 16-electron d8 ruthenium(0) complexes and their subsequent catalytic behaviour

The photochemical reaction of Ru(CO)3(L)2, where L = PPh3, PMe3, PCy3 and P(p-tolyl)3 with parahydrogen (p-H2) has been studied by in-situ NMR spectroscopy and shown to result in two competing processes. The first of these involves loss of CO and results in the formation of the cis-cis-trans-L isomer of Ru(CO)2(L)2(H)2, while in the second, a single photon induces loss of both CO and L and leads to the formation of cis-cis-cis Ru(CO)2(L)2(H)2 and Ru(CO)2(L) (solvent)(H)2 where solvent = toluene, THF and pyridine (py). In the case of L = PPh3, cis-cis-trans-L Ru(CO)2(L) 2(H)2 is shown to be an effective hydrogenation catalyst with rate limiting phosphine dissociation proceeding at a rate of 2.2 s -1 in pyridine at 355 K. Theoretical calculations and experimental observations show that H2 addition to the Ru(CO)2(L) 2 proceeds to form cis-cis-trans-L Ru(CO)2(L) 2(H)2 as the major product via addition over the π-accepting OC-Ru-CO axis.

Redistribution at silicon by ruthenium complexes. Bonding mode of the bridging silanes in Ru2H4(μ-η2:η2:η2 :η2-SiH4)(PCy3)4 and Ru2H2(μ-η2:η2- H2Si(OMe)2)3(PCy3)2

The bis(dihydrogen) complex RuH2(η2-H2)2 (PCy3)2 (1) reacts with 2 equiv. of H2SiMePh to produce a mixture of Ru2H4 (μ-η2:η2:η2:η2- SiH4)(PCy3)4 (2) and RuH2(η2-H2)(η2- HSiPh3)(PCy3)2 (4) together with HSiMePh2, HSiMe2Ph and traces of HMe2SiSiMe2H as a result of redistribution at silicon. The bridging SiH4 ligand in 2 is coordinated to the two ruthenium via four σ-Si-H bonds in agreement with NMR, X-ray data (on 2, and 2′ the analogous PiPr3 complex) and DFT calculations. Each interaction involves σ-donation to a ruthenium and back-bonding from the other ruthenium. Elimination of SiH4 and formation of RuH2(CO)2(PCy3)2 (5), RuH2(tBuNC)2(PCy3)2 (6) or RuH(η2-H2)Cl(PCy3)2 (7) were observed upon the reaction of 2 with CO, tBuNC, CH2Cl2, respectively. No reaction occurred in the presence of H2, but H/D exchange was observed under D2 atmosphere. Another redistribution reaction at silicon can be obtained by adding 4 equiv. of HSi(OMe)3 to 2 to produce Si(OMe)4 and Ru2H2(μ-η2:η2- H2Si(OMe)2)3(PCy3)2 (3) displaying three bridging (μ-η2:η2 alkoxysilane) ligands. Complex 3 is characterized by multinuclear NMR spectroscopies and by a crystal structure. DFT calculations show that the model complex Ru2H2(μ-η2:η2- H2Si(OR)2)3(PR3)2 (R = H, Me) is a minimum on the potential energy surface, and support the dihydride formulation with three bridging H2Si(OMe)2 ligands coordinated to the two ruthenium through σ-Si-H bonds.

Preparation and characterization of ruthenium(II) monophosphaferrocene complexes. Reactivity, dynamic solution behavior, and X-ray structure of [RuH2(η2-H2)(PCy3) 2(2-phenyl-3,4-dimethylphosphaferrocene)]

The bis(dihydrogen) complex RuH2(H2)2(PCy3)2 (1) reacts with 2-phenyl-3,4-dimethylphosphaferrocene (L1) to give RuH2(H2)(PCY3)2(L1) (2). This dihydride-dihydrogen complex has been characterized by X-ray crystallography and variable-temperature 1H and 31p NMR spectroscopy. The exchange between the dihydrogen ligand and the two hydrides is characterized by a ΔG of 46.2 kJ/mol at 263 K. H/D exchange is readily observed when heating a C7D8 solution of 2 (JH-D = 30 Hz). The H2 ligand in 2 can be displaced by ethylene or carbon monoxide leading to the corresponding ethylene or carbonyl complexes. The reaction of 1 with 2 equiv of 3,4-dimethylphosphaferrocene (L2) yields the dihydride complex RuH2(PCy3)2(L2)2 (5).

Ruthenium complexes containing two Ru-(η2-Si-H) bonds: Synthesis, spectroscopic properties, structural data, theoretical calculations, and reactivity studies

The bis(dihydrogen) complex RuH2(H2)2(PCy3)2 (1) reacts with the disilanes (R2SiH)2X to produce the dihydride complexes [RuH2{(η2-HSiR2)2X}(PCy 3)2] (with R = Me and X = O (2a), C6H4 (3), (CH2)2 (4), (CH2)3 (5), OSiMe2O (6)) and R = Ph, X = O (2b)). In these complexes, the bis(silane) ligand is coordinated to ruthenium via two σ-Si-H bonds, as shown by NMR, IR, and X-ray data and by theoretical calculations. 3, 4, and 6 were characterized by X-ray diffraction. In the free disilanes the Si-H bond distances and the JSi-H values are around 1.49 A and 200 Hz, respectively, whereas in the new complexes the values are in the range 1.73-1.98 A and 22-82 Hz, respectively for the σ-Si-H bonds. The importance of nonbonding H...Si interactions, which control the observed cis geometry of the two bulky PCy3 ligands, is highlighted by X-ray data and theoretical calculations. The series of bis(silane) model complexes, RuH2{(η2-HSiR2) 2X}(PR′3)2, with X = (CH)2, C6H4, (CH2)n, O, and OSiH2O, and with R and R′ = H or Me, was investigated by density functional theory (DFT) by means of two hybrid functional B3LYP and B3PW91. In the case of X = C6H4 three isomers were studied, the most stable of which has C2v symmetry and whose structure closely resembles the X-ray structure of 3. Calculated binding energies for the bis(silane) ligand to the RuH2(PH3)2 fragment vary from 130 to 192 kJ/mol, showing that in the more stable complexes, the Si-H bonds are bound more strongly than dihydrogen. The dynamic behavior of these complexes has been studied by variable temperature 1H and 31P{1H} NMR spectroscopy and exchange between the two types of hydrogen is characterized by barriers of 47.5 to 68.4 kJ/mol. The effect of the bridging group X between the 2 silicons is illustrated by reactions of compounds 2-6 with H2, CO, tBuNC. 3 is by far the most stable complex as no reaction occurred even in the presence of CO, whereas elimination of the corresponding disilane and formation of RuH2(H2)2-(PCy3)2, RuH2(CO)2(PCy3)2, or RuH2(tBuNC)2(PCy3)2 were observed in the case of 2 and 4-6. The mixed phosphine complexes [RuH2{(η2-HSiMe2)2X}(PCy 3)(PR3)] 3R-6R (with R = Ph and R = pyl) have been isolated in good yields (80-85%) and fully characterized by the addition of 1 equiv of the desired phosphine to 3-6. In the case of 4Ph, an X-ray determination was obtained. In the case of 2, elimination of the disiloxane was always observed. Addition of 1 equiv of a disilane to Ru(COD)(COT) in the presence of 2 equiv of the desired phosphine under an H2 atmosphere produces the complexes [RuH2{(η2-HSiMe2)2X}(PR 3)2] (X = C6H4, R = Ph (3Ph2) and R = pyl (3pyl2); X = (CH2)2, R = Ph, 4Ph2; R = pyl, 4pyl2). 4Ph2 was also characterized by an X-ray structure determination.