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Journal ArticleDOI

Efficient catalytic transfer hydrogenation reactions of carbonyl compounds by Ni(II)-diphosphine complexes

TL;DR: In this paper, the catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L2NiCl2] (where L2 = 1,1-bis(...
Abstract: The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L2NiCl2] (where L2 = 1,1-bis(...
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Journal ArticleDOI
TL;DR: In this paper, the authors provide an update on recent advances in homogeneous catalytic transfer hydrogenation reactions catalyzed by base-metal (Mn, Fe, Co and Ni) complexes.

17 citations

Journal ArticleDOI
TL;DR: In this article , a new Ni(II) complex, [Ni(L)2(H2O)2] (1) (HL = 6-phenylpyridine-2-carboxylic acid, NaOH and Ni(CH3COO)2), was synthesized using elemental analysis and single crystal X-ray diffraction.
Abstract: In ethanol-water (v:v = 1:1), a new Ni(II) complex, [Ni(L)2(H2O)2] (1) (HL = 6-phenylpyridine-2-carboxylic acid) was synthesized using 6-phenylpyridine-2-carboxylic acid, NaOH and Ni(CH3COO)2.4H2O. The structure of complex 1 has been determined by elemental analysis and single crystal X-ray diffraction. The single crystal analysis shows that complex 1 contains one Ni(II) ion, two L ligands and two coordinated water molecules. In 1, the Ni(II) ion is six-coordinated to two O atoms and two N atoms from L ligands and two O atoms from coordinated water molecules, respectively, which form a distorted octahedral coordination geometry. The whole unit of complex 1 is interconnected to each other through intermolecular N−H•••O hydrogen bonds involving oxygen atom of coordinated water molecule and the oxygen atoms of L ligand to form 1D molecular architecture. The catalytic activity of complex 1 for oxidation of benzyl alcohol with O2 was investigated. The complex 1 shows good catalytic performance for the oxidation of benzyl alcohol, the benzyl alcohol conversion, benzaldehyde selectivity, and benzaldehyde yield were 49.1%, 92.0%, and 45.2%, respectively, at 90 °C under 0.7 Mpa O2 for 2 h. Moreover, complex 1 could be recovered easily by centrifugation and used repetitively for at least four times. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

4 citations

Journal ArticleDOI
TL;DR: In this paper , the (R,R)-amido-ene(amido) nickel catalysts for asymmetric transfer hydrogenation (ATH) of ketone substrates are presented.
Abstract: Catalytic asymmetric transfer hydrogenation (ATH) reactions of ketones have become an important tool for producing enantiomerically pure alcohols that are widely used in the syntheses of bioactive compounds. However, the high toxicities and low abundances of traditionally employed precious metals serving as catalyst centers have impeded widespread application of precious metal-based catalysts in asymmetric synthesis. Development of catalysts from abundant and less toxic 3d metals is highly desirable but still challenging. We report herein the development of structurally well-defined (R,R)-amido-ene(amido) nickel catalysts for ATH of ketone substrates, facilitating access to a wide range of secondary (S)-configuration alcohols, many of which are synthetic building blocks of biologically relevant molecules, with up to 95% enantiomeric excess (e.e.) and broad scope of functional group tolerance. Catalytic intermediate isolation and density functional theory calculation ascribed the catalytic activity to stabilization of the electron-rich nickel center with the ene(amido) group via a π-backdonation interaction within the catalytic intermediates, while the stereoinduction mainly arises from a catalyst–substrate π–π interaction in the transition state for enantioselective hydride transfer.
References
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Journal ArticleDOI
TL;DR: It is argued that certain duties of patients counterbalance an otherwise unfair captivity of doctors as helpers and that vulnerability does not exclude obligation.
Abstract: There has been a shift from the general presumption that “doctor knows best” to a heightened respect for patient autonomy. Medical ethics remains one-sided, however. It tends (incorrectly) to interpret patient autonomy as mere participation in decisions, rather than a willingness to take the consequences. In this respect, medical ethics remains largely paternalistic, requiring doctors to protect patients from the consequences of their decisions. This is reflected in a one-sided account of duties in medical ethics. Medical ethics may exempt patients from obligations because they are the weaker or more vulnerable party in the doctor-patient relationship. We argue that vulnerability does not exclude obligation. We also look at others ways in which patients’ responsibilities flow from general ethics: for instance, from responsibilities to others and to the self, from duties of citizens, and from the responsibilities of those who solicit advice. Finally, we argue that certain duties of patients counterbalance an otherwise unfair captivity of doctors as helpers.

17,373 citations

Journal ArticleDOI
15 May 2014-Nature
TL;DR: Some of the most recent and significant developments in homogeneous nickel catalysis are discussed, with an emphasis on both synthetic outcome and mechanism.
Abstract: Tremendous advances have been made in nickel catalysis over the past decade Several key properties of nickel, such as facile oxidative addition and ready access to multiple oxidation states, have allowed the development of a broad range of innovative reactions In recent years, these properties have been increasingly understood and used to perform transformations long considered exceptionally challenging Here we discuss some of the most recent and significant developments in homogeneous nickel catalysis, with an emphasis on both synthetic outcome and mechanism

1,487 citations

Journal ArticleDOI

1,307 citations

BookDOI
30 Jul 1998

1,280 citations