Rh/DNA Nanoparticles, Synthesis, Characterization and Catalytic Activity in “On Water” Asymmetric Hydroformylation Reaction

Abstract

DNA-stabilized Rh NPs were synthesized by the chemical reduction of Rh(acac)(CO) 2 (acac = acetylacetonate) in water at 80 8C. The obtained nanoparticles, Rh/DNA, were characterized by various spectroscopic and microscopic methods, such as IR, UV-Vis, XRD (X-ray diffraction), ICP-AES (Inductively coupled plasma atomic emission spectroscopy), EDX (Energy-dispersive X-ray spectroscopy analysis), TEM (Transmission electron microscopy), and SEM (Scanning electron microscopy) analyses. Their catalytic activity was successfully investigated in the "on water" hydroformylation of styrene. The conversion of styrene and chemoselectivity towards aldehydes were 100%. A high iso/n ratio was also obtained, up to 6.1 and 16.7 with PPh 3 (triphenylphosphine) and (R)-BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) ligands respectively. In the hydroformylation of vinyl acetate with Rh/DNA, performed in the presence of a chiral BINAP ligand "on water", high enantioselectivity was obtained, up to 49% ee. These results were significantly better than when utilizing Rh(acac)(CO) 2 as a catalyst under the same conditions. dd, 24.5 ppm, J Rh-P 129.6 Hz, J P-P 44.2 Hz; dd, 45.4 ppm, J Rh-P 161.1 Hz d, 36.3 ppm, J Rh-P 176.7 Hz d, 49 ppm, J Rh-P 176.7 Hz Rh(acac)(CO) 2 + BINAP + H 2 /CO + vinyl acetate (on water, Figure S10) d, 46.6 ppm, J Rh-P 172.6 Hz d, 53.1 ppm, J Rh-P 168.4 Hz Rh(acac)(CO) 2 + BINAP + H 2 /CO + vinyl acetate (in C 6 D 6 , Figure S27) 1) dd, 24.5 ppm, J Rh-P 141.2 Hz, J P-P 42 Hz; dd, 48.4 ppm, J Rh-P 152.2 Hz; 2) dd, 37.5 ppm, J P-P 32.3, J Rh-P 75.3 Hz m, 33.7 ppm, J Rh-P 68.7 Hz d, 36.6 ppm, J Rh-P 137.6 Rh/DNA + BINAP + H 2 /CO + vinyl acetate (Figure S8) 1) dd, 23.3 ppm, J Rh-P 134.5 Hz, J P-P 44.9 Hz; dd, 43.9 ppm, J Rh-P 155.6 Hz; 2) dd, 39.7 ppm, J P-P 44.9, J Rh-P 144.8 Hz m, 35.3 ppm, J Rh-P 75.3 Hz m, 12.2 ppm, J Rh-P 215.8 Hz d, 25.1 ppm, J Rh-P 139.2 Hz d, 28.9 ppm, J Rh-P 85 Hz m, 35.3 ppm, J Rh-P 75 Hz a experimental details are presented in supplementary material. Signals originated from BINAPO and BINAPO 2 were observed ca. 30 ppm and ca. À15 ppm. [77]

Valorisation of biobased olefins via Rh-catalyzed transfer hydroformylation and isomerization using formaldehyde as a CO/H2 surrogate

“…A triplet of doublet centered at δ −8.74 ppm was observed in the 1 H-NMR spectrum. This hydride species was also confirmed by comparison with the values reported in the literature, 25 and also in an additional experiment when the mixture of [Rh(acac)(CO) 2 ], ( S )-BINAP and formaldehyde was investigated by 31 P and 1 H-NMR (Table 2, entry 4). On the other hand, the 31 P-NMR experiments, from the mixture of [Rh(acac)(CO) 2 ], PPh 3 and formaldehyde (Table 2, entry 5), showed two doublets at δ 40.5 ppm ( J Rh–P = 154 Hz) and at δ 31.8 ppm ( J Rh–P = 134 Hz) which were assigned to the hydride species in equilibrium [(RhH(CO)PPh 3 ) 3 ] and [(RhH(CO)PPh 3 ) 2 ], respectively.…”

Synthesis, Structural Characterization, and Hydroformylation Activity of Rhodium(I) Complexes with a Polar Phosphinoferrocene Sulfonate Ligand

“…As expected, iso -aldehyde (2-acetoxypropanal ( P1 )) was the main product, and acetic acid ( P2 ) and propanal ( P3 ), resulting from the decomposition of 3-acetoxypropanal (linear aldehyde), were also detected (Scheme ). Notably, 3-acetoxypropanal itself was not observed in the reaction mixture …”

Merging Chiral Diamine and Ni/SiO2 for Heterogeneous Asymmetric 1,4-Addition Reactions

“…Supported metal nanoparticles (NPs) are an important type of heterogeneous catalysts in industry for a wide range of reactions, including oxidation, reduction, and cross-coupling. , The merging of supported metal NPs and chiral ligands will provide a new design principle for the preparation of chiral heterogeneous catalysts. Chiral tartaric acid modified Raney Ni was first proposed for the asymmetric hydrogenation of β-keto esters with high enantioselectivity. , Later, the cinchonidine modified Pt/C first reported by Orito and co-workers showed high enantioselectivity and activity in the asymmetric hydrogenation of α-keto esters, , and cinchona alkaloid modified Pd NPs have been successfully used for the asymmetric hydrogenation of unsaturated acids. − Although other metal NPs modified with chiral ligands have been used in asymmetric hydrogenation/hydroformylation, − examples with high enantioselectivity are still limited.…”