12184-84-8Relevant academic research and scientific papers
Protonation studies of the new iron carbonyl cyanide trans-[Fe(CO) 3(CN)2]2-: Implications with respect to hydrogenases
Kayal, Ajay,Rauchfuss, Thomas B.
, p. 5046 - 5048 (2003)
The new iron carbonyl cyanide trans-[Fe(CN)2(CO) 3]2-, [2]2-, forms in high yield via photosubstitution of Fe(CO)5 with 2 equiv of Et4NCN. Protonation of [2]2- generated [HFe(CN)
Oxidative Addition of the Carbon-Hydrogen Bond Is Not the Rate-Determining Step in the Remote Functionalization of Nitriles by Bare Fe(I) Ions
Czekay, Gregor,Drewello, Thomas,Schwarz, Helmut
, p. 4561 - 4563 (1989)
The study of D-labeled 5-cyanononane isotopomers in the gas phase provides evidence that the Fe+-mediated remote functionalization of nitriles, resulting in the regiospecific generation of H2 and C2H4 from the ω and (ω - 1) position of the alkyl chain, can be described as follows: (i) Oxidative addition of a methyl C-H bond is not rate limiting.For the generation of C2H(4-x)Dx it is the elimination of the olefin which is associated with kinetic isotope effects comparable to the ones reported earlier for other systems. (ii) The generation of H(2-x)Dx is affected bytwo isotope effects.One concerns the β-hydrogen transfer (kH/kD = 1.59) and the other the reductive elimination of hydrogen (kH2/kHD = 1.70 and kHD/kD2 = 1.44).
The decomposition pathways for LiBD4-MgD2 multicomponent systems investigated by in situ neutron diffraction
Price,Grant,Telepeni,Yu,Walker
, p. 559 - 564 (2009)
Complex hydride-binary hydride multicomponent hydrogen storage systems offer great potential for practical hydrogen stores because their dehydrogenation thermodynamics can be tailored through a destabilisation mechanism whilst maintaining a high hydrogen
Distributions of hydrogen and strains in LaNi5 and LaNi4.75Sn0.25
Fultz,Witham,Udovic
, p. 165 - 175 (2002)
Hydrogen distributions and internal strains that accompany hydriding of binary LaNi5 were compared to those of the ternary alloy LaNi4.75Sn0.25, which is known to have a cycle life superior to that of LaNi5 in electrochemical cells and in gas storage applications. X-ray diffractometry shows that the unit cell volume of the hydride phase changes more continuously with hydrogen concentration in LaNi4.75Sn0.25 than in binary LaNi5. Gas-phase isotherms show that the Sn atoms make significant changes to the local chemical potential of hydrogen atoms. Using generic hydrogen-solute interactions in Monte Carlo simulations and physical arguments, it is shown that normal coarsening of hydride zones will be altered, or even arrested, by hydrogen-solute interactions. Small-angle neutron scattering shows that the distribution of deuterium in partially-deuterated LaNi4.75Sn0.25 is more homogeneous than in partially-deuterated LaNi5, at least on the spatial scales around 100 ?. It is suggested that the more homogeneous deuterium distribution in LaNi4.75Sn0.25 suppresses the strain gradients that cause decrepitation of the metal hydride.
The Mechanism of the Photocatalytic Dehydrogenation of Methanol
Ohno, Masayuki,Uzawa, Hisaji,Miyazaki, Teruhisa,Tarama, Kimio
, p. 779 - 782 (1987)
We have studied on the mechanism of the photocatalytic dehydrogenation of methanol over Pt/TiO2.D2 was only evolved from CH3OD, and D2, HD, and H2 were detected in the evolved gas in the case of the mixed sample of CH3OD and CH3OH.These results show that
Visible-light-driven hydrogen evolution from water using a noble-metal-free polyoxometalate catalyst
Lv, Hongjin,Song, Jie,Zhu, Haiming,Geletii, Yurii V.,Bacsa, John,Zhao, Chongchao,Lian, Tianquan,Musaev, Djamaladdin G.,Hill, Craig L.
, p. 48 - 54 (2013)
In an effort to address the need to develop hydrolytically more stable, molecular water reduction catalysts (WRCs) amenable to in-depth investigation, we report here one prototype: a tetra-manganese-containing V-centered polyoxotungstate, Na10[Mn4(H2O) 2(VW9O34)2] (1). The electronic structure of 1 was elucidated using the DFT approach. Complex 1 is readily prepared by a one-pot procedure in aqueous solution and catalyzes the reduction of water using visible light irradiation (λ = 455 nm) with [Ru(bpy) 3]2+ and triethanolamine (TEOA) as a photosensitizer and sacrificial electron donor, respectively. Upon irradiation, the excited state [Ru(bpy)3]2+* is oxidatively quenched by 1, as confirmed by steady-state and time-resolved fluorescence decay studies, to form [Ru(bpy)3]3+ and a reduced form of the catalyst. The [Ru(bpy)3]2+ is rapidly regenerated by reaction with TEOA. The reduced form of the catalyst, 1, reacts with water to generate hydrogen. Isotope labeling experiments demonstrate that the hydrogen comes from water. The stability of the catalyst was assessed using different spectroscopic methods. A mechanism based on experimental results is proposed.
A Dawson-type dirhenium(V)-oxido-bridged polyoxotungstate: X-ray crystal structure and hydrogen evolution from water vapor under visible light irradiation
Kato, Chika Nozaki,Hara, Kazunobu,Hatano, Ayumi,Goto, Kazuhiro,Kuribayashi, Tomonori,Hayashi, Kunihiko,Shinohara, Akira,Kataoka, Yusuke,Mori, Wasuke,Nomiya, Kenji
, p. 3134 - 3141 (2008)
The synthesis and crystal structure of a Dawson-type dirhenium(V)-oxido- bridged polyoxotungstate are described. The potassium salt K 14[O{ReV(OH)(a2-P2W 17O61)}2]·21H2O (K-1) was obtained as analytically pure, homogeneous, black-purple crystals by the reaction of a monolacunary Dawson polyoxotungstate with [ReIVCl 6]2- in water, followed by crystallization from an aqueous HCl solution in the dark. Single-crystal X-ray structure analysis revealed that the dimeric dirhenium(V)-oxido-bridged structure has overall C2h symmetry. Characterization of K-1 was also accomplished by elemental analysis, TG/DTA, and FTIR, UV/Vis absorption, ESR, and solution 31P NMR spectroscopy. Furthermore, the black-purple compound K-1 was grafted onto a TiO2 surface by electrostatic binding to give TiO2 with a cationic quaternary ammonium moiety (1-grafted TiO2). Elemental analysis of 1-grafted TiO2 indicated that the seven potassium counterions of K-1 were ion-exchanged with seven cationic ammonium moieties to form {TiO2}5500[≡Si(CH2) 3N(CH3)3Cl]7[≡Si(CH 2)3-N+(CH3)3] 7(K7[O{Re(OH)(a2-P2W 17O61)}2]7-) and seven molecules of KCl. The diffuse reflectance (DR) UV/Vis spectrum of 1-grafted TiO2 exhibited two sharp bands at 496 nm and 751 nm due to the ReV→ WVI intervalence charge transfer (IVCT) band and the d-d band of the rhenium(V) atom, respectively, in the visible light region, which suggested that polyoxoanion 1 was isolated on the TiO2 surface. With 1-grafted TiO2, hydrogen evolution from water vapor under irradiation with visible light (>400 nm and >420 nm) was achieved. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Design considerations for chiral frustrated Lewis pairs: B/N FLPs derived from 3,5-bicyclic aryl piperidines
Lam, Jolie,Sampaolesi, Susanna,LaFortune, James H. W.,Coe, Jotham W.,Stephan, Douglas W.
, p. 133 - 141 (2019)
Herein, 3,5-bicyclic aryl piperidines are derivatized to generate chiral B/N FLPs. Initially, the twofold symmetric amine C6H2F2(C5H8NiPr) 1 was converted in a series of synthetic steps to the styrene-derivative C6HF2(C5H8NiPr)(CH═CH2) 4. Efforts to hydroborate the vinyl fragment proved challenging as a result of the strongly basic nitrogen, although the species C6HF2(C5H8N(H)iPr)(CH2CH2B(OH)(C6F5)2) 5 was crystallographically characterized. Modification of the system was achieved by conversion of the amine C6H2F2(C5H8NH) 6 to C6HF2(C5H8NPh)(CH═CH2) 9. Hydroboration of 9 with 9-BBN or HB(C6F5)2 gave C6HF2(C5H8NPh)(CH2CH2BBN) 10 or C6HF2(C5H8NPh)(CH2CH2B(C6F5)2) 11, respectively. The latter species was derivatized by complexation of PPh3 to give C6HF2(C5H8NPh)(CH2CH2B(C6F5)2)(PPh3) 12. The Lewis acidities of 10 and 11 were assessed by the Gutman-Beckett test and by computations of the FIA and GEI. While 10 did not effect HD scrambling or hydrogenation of N-phenylbenzylimine, 11 was effective in HD scrambling. Despite this, no reduction of N-t-butylbenzylimine or N-phenylbenzylimine was achieved. These data demonstrate that 10 lacks the threshold combination of Lewis acidity and basicity to activate H2, while 11 lacks the steric demands about boron to preclude classical Lewis acid-base bond formation with imine substrates.
NMR STUDIES ON HxTaS2 AND DxTaS2.
Kleinberg,Jacobson,Silbernagel,Halbert
, p. 1541 - 1546 (1980)
It is shown that the NMR properties of hydrogen and deuterium introduced into tantalum disulfide are very much the same as those of the Group VB transition metal hydrides and deuterides. The electric field gradient and s-wave electron spin density are app
A structural effect in direct reactions: Kinetics of D abstraction from Pt(110) 1×2 surfaces with gaseous H atoms
Biederer, Th.,Kammler, Th.,Kueppers
, p. 15 - 20 (1998)
Deuterium-covered Pt(110) surfaces were subjected to a flux of thermal H atoms at 100 K. The rates of product formation, HD and D2, were measured simultaneously with H atom exposure as a function of D coverage. D2 as a product and the kinetics of HD formation contradict the operation of Eley-Rideal type mechanisms in these reactions. More appropriate seems the assumption that a hot-atom type mechanism operates in abstraction of adsorbed D by gaseous H. The H/D abstraction kinetics at Pt(110) surfaces are completely different from that observed previously at Pt(111) surfaces. This structural effect puts a further question mark on the validity of the Eley-Rideal mechanisms in abstraction reactions and is interpreted in the present work as a consequence of the interrelation between a hot-atom mechanism and the surface structure of the reconstructed substrate.
