96-41-3Relevant academic research and scientific papers
Ruthenium(II) Complexes with New Tridentate Ligands containing P, N, O Donor Atoms: Highly Efficient Catalysts for Transfer Hydrogenation of Ketones by Propan-2-ol
Yang, Hong,Alvarez, Marie,Lugan, Noel,Mathieu, Rene
, p. 1721 - 1722 (1995)
The complexes in which L is a tridentate ligand with P, N and O donor atoms are very efficient catalysts for the transfer hydrogenation of cyclic ketones and acetophenone (turnover -1) in basic media; when L is optically active, no significant e.e. is observed.
Thermodynamic properties, conformational composition, and phase transitions of cyclopentanol
Kabo, G. J.,Diky, V.V.,Kozyro, A. A.,Krasulin, A. P.,Sevruk, V. M.
, p. 953 - 968 (1995)
Thermodynamic properties of cyclopentanol were studied.The molar heat capacity of c-C5H9OH(cr and l) in the temperature range T = 5.4 K to 303.0 K was measured by vacuum adiabatic calorimetry.Three solid-to-solid transitions were found: at T = 176 K with ΔtrsHm = (57 +/- 5) J*mol-1; at T = 202.6 K with ΔtrsHm = (3366 +/- 14) J*mol-1, and at T = 234 K with ΔtrsHm = (55 +/- 6) J*mol-1.The fusion temperature of c-C5H9OH is 255.6 K, and ΔfusHm = (1227 +/- 5) J*mol-1.Basic thermodynamic functions at T = 298.15 K in the liquid state are Cs,m = (182.48 +/- 0.73) J*K-1*mol-1, Sm = (204.14 +/- 0.90) J*K-1*mol-1, and Φm = (96.98 +/- 0.40) J*K-1*mol-1.The enthalpy of vaporization was measured with a heat-conducting microcalorimeter: ΔvapHm(298.15 K) = (57.05 +/- 0.65) kJ*mol-1.Using these and literature data, the standard molar entropy of c-C5H9OH(g) was determined: S0m(g, 340 K) = (362.9 +/- 2.4) J*K-1*mol-1.Conformational analysis was made by the molecular-mechanics method, and statistical calculations of standard molar thermodynamic functions in the ideal-gas state were carried out on the basis of molecular parameters and conformational properties.The calculated entropy value at T = 340 K was put into agreement with the experimental one by adjusting the pseudorotational moment of inertia.The standard molar entropy and molar heat capacity of c-C5H9OH in the ideal-gas state at T = 298.15 K are 347.91 J*K-1*mol-1 and 105.43 J*K-1*mol-1, respectively.Thermodynamic analysis of phase transitions in the condensed state was made.It was shown that pseudorotation in the plastic crystal state of c-C5H9OH is significantly hindered.Thermodynamic quantities allowed us to propose the absence of a non-equilibrium mixture of conformers at T -> 0.An anomalously low entropy difference between liquid and rigid crystal of cyclopentanol in comparison with other cyclopentane derivatives shows a relatively high ordering in the liquid.
Catalytic hydroprocessing of furfural to cyclopentanol over Ni/CNTs catalysts: Model reaction for upgrading of bio-oil
Zhou, Minghao,Zhu, Hongyan,Niu, Lei,Xiao, Guomin,Xiao, Rui
, p. 235 - 241 (2014)
A series of nickel-based catalysts with HNO3- pretreated CNTs as support (x% Ni/CNTs, x represents the Ni loading amount) were synthesized using impregnation method, which were successfully applied for the upgrading of model compound (furfural) in bio-oil. Effects of nickel loading amount, reaction temperature, reaction time and hydrogen pressure on conversion of furfural as well as selectivity for cyclopentanol were investigated systematically. The conversion of furfural over 30 wt% Ni/CNTs was up to 96.5 % with a yield of 83.6 % toward cyclopentanol, when the reaction was carried out at 140 °C with a initial H2 pressure of 5.0 MPa. The features of the Ni/ CNTs catalysts were investigated via XRD, XPS, TEM. Springer Science+Business Media New York 2013.
An efficient method for the catalytic aerobic oxidation of cycloalkanes using 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI)
Guha, Samar K.,Ishii, Yasutaka
, p. 327 - 335 (2021/12/13)
N-Hydroxyphthalimide (NHPI) is known to be an effective catalyst for the oxidation of hydrocarbons. The catalytic activity of NHPI derivatives is generally increased by introducing an electron-withdrawing group on the benzene ring. In a previous report, two NHPI derivatives containing fluorinated alkyl chain were prepared and their catalytic activity was investigated in the oxidation of cycloalkanes. It was found that the fluorinated NHPI derivatives showed better yields for the oxidation reaction. As a continuation of our work with fluorinated NHPI derivatives, our next aim was to investigate the catalytic activity of the NHPI derivatives by introducing fluorine atoms in the benzene ring of NHPI. In the present research, 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI) is prepared and its catalytic activity has been investigated in the oxidation of two different cycloalkanes for the first time. It has been found that F4-NHPI showed higher catalytic efficiency compared with that of the parent NHPI catalyst in the present reactions. The presence of a fluorinated solvent and an additive was also found to accelerate the oxidation.
Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
Topf, Christoph,Vielhaber, Thomas
, (2021/07/10)
We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
Ruthenium-p-cymene Complex Side-Wall Covalently Bonded to Carbon Nanotubes as Efficient Hybrid Transfer Hydrogenation Catalyst
Blanco, Matías,Cembellín, Sara,Agnoli, Stefano,Alemán, José
, p. 5156 - 5165 (2021/11/05)
A half-sandwich ruthenium-p-cymene organometallic complex has been immobilized at Single Walled Carbon Nanotubes (SWNT) sidewalls through a stepwise covalent chemistry protocol. The introduction of amino groups by means of diazonium-chemistry protocols leads the grafting at the outer walls of the nanotubes. This hybrid material is active in the transfer hydrogenation of ketones to yield alcohols, using as hydrogen source 2-propanol. SWNT?NH2?Ru presents a broad scope, performing the reaction under aerobic conditions and can be recycled over 9 consecutive reaction runs without losing activity or leaching ruthenium out. Comparison of the activity with related homogeneous catalysts reveals an improved performance due to the covalent bond between the metal and the material, achieving turnover frequencies as high as 192774 h?1.
Synthesis, crystal and structural characterization, Hirshfeld surface analysis and DFT calculations of three symmetrical and asymmetrical phosphonium salts
Delaram, Behnaz,Gholizadeh, Mostafa,Makari, Faezeh,Nokhbeh, Seyed Reza,Salimi, Alireza
, (2021/07/01)
Three stable phosphonium salts of 1,4-butanediylebis(triphenylphosphonium) dibromide I, butane-4?bromo-1-(triphenylphosphonium) bromide II and 1,3-propanediylbis(triphenylphosphonium) tetrahydroborate III were synthesized and structurally characterized. Single crystal X-ray diffraction analysis, spectroscopic methods and thermal analysis methods were used for the characterization of titled compounds. Crystallographic data showed that compound I crystallized in the triclinic crystal system with Pī space group and compound II crystallized in the monoclinic crystal system with P21/c space group. The crystal packing structures of I and II were stabilized by various intermolecular interactions, especially of C–H···π contacts. The molecular Hirshfeld surface analysis and 2D fingerprint revealed that the C···H contacts have 24.3% and 18.4% contributions in the crystal packings of compounds I and II, respectively. In addition, the H···Br (28.5%) contact has a considerable contribution to the crystal architecture of compound II. Theoretical studies were performed by DFT method to investigate the structural properties of the titled compounds. The isotopic ratio of boron in tetrahydroborate anion of compound III calculated by 1H NMR spectroscopy. The isotopic ratio for 10B/11B was 19.099 / 80.900%. Reduction of some carbonyl compounds to corresponding alcohols was performed by compound III and the optimum conditions were determined.
Synthesis of new rhodium(III) complex by benzylic C[sbnd]S bond cleavage of thioether containing NNS donor Schiff base ligand: Investigation of catalytic activity towards transfer hydrogenation of ketones
Biswas, Sujan,Das, Akash,Kumar Manna, Chandan,Kumar Mondal, Tapan,Naskar, Rahul
, (2020/11/04)
A new rhodium(III)-triphenylphosphine mixed ligand complex, [Rh(PPh3)(L)Cl2] (1) is synthesized by benzylic C[sbnd]S bond cleavage of L-CH2Ph ligand (where, L-CH2Ph = 2-(benzylthio)-N-(pyridin-2-ylmethylene)aniline). The complex is thoroughly characterized by several spectroscopic techniques. Geometry of the complex is confirmed by single crystal X-ray crystallography. Electronic structure, redox properties, absorption and emission properties of the complex were studied. DFT and TDDFT calculations were carried out to interpret the electronic structure and absorption properties of the complex respectively. The synthesized Rh(III) complex was tested as catalyst towards transfer hydrogenation reaction of ketones in iPrOH and an excellent catalytic conversion was observed under mild conditions.
Pincerlike molybdenum complex and preparation method thereof, catalytic composition and application thereof, and alcohol preparation method
-
Paragraph 0134-0140, (2021/08/11)
The invention discloses a clamp-type molybdenum complex, a preparation method, a corresponding catalyst composition and application. The method comprises the steps: obtaining 9 molybdenum complexes with different structures through coordination reaction of 2-(substituent ethyl)-(5, 6, 7, 8-tetrahydroquinolyl) amine and a corresponding carbonyl molybdenum metal precursor; and catalyzing a ketone compound transfer hydrogenation reaction through a molybdenum complex to generate 40 alcohol compounds. The preparation method of the molybdenum complex is simple, high in yield and good in stability. For a transfer hydrogenation reaction of ketone, the molybdenum-based catalytic system has high catalytic activity and small molybdenum loading capacity, is used for production of aromatic and aliphatic alcohols, and has the advantages of simple method, small environmental pollution and high yield.
Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
supporting information, p. 2108 - 2114 (2021/02/06)
Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
