CATALYTIC BEHAVIOR OF A SILICA-SUPPORTED POLYTITAZANE-PLATINUM COMPLEX FOR THE HYDROGENATION OF PHENOL

A new kind of inorganic polymer, viz, silica-supported polytitazane (Ti-N), and its platinum complex (Ti-N-Pt) were prepared. Cyclohexanone can be obtained in a maximum yield of about 62.2% in the hydrogenation of phenol over Ti-N-Pt at room temperature under atmospheric pressure. The effects of mole ratio of N/Pt in the complex, concentration of the catalyst and reaction temperature on the catalytic activity and selectivity have been studied. The complex can be reused several times without loss in its catalytic activity.

π-π Stacking, Hydrogen Bonding and Magnetic Coupling Mechanism on a Mono-nuclear Cu^Ⅱ Complex

A new mono-nuclear CuII complex [Cu（DPP）（DP）Br]（ClO4）H2O （DPP = 2-（3,5- dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole） has been syn- thesized with 2-（3,5-dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline and 3,5-dimethyl-1H-pyrazole as ligands, and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic system, space group P21/c with a = 13.765（2）, b = 17.044（3）, c = 10.9044（16）, β= 97.112（2）°, V = 2538.5（6）3, Z = 4, C22H24BrClCuN6O5, Mr = 631.37, Dc = 1.652 g/cm3, F（000） = 1276 and μ= 2.585 mm-1. In the crystal, DPP functions as a tridentate ligand and CuII ions assume a distorted square pyramidal geometry with Br atom lying on the apex, and at the same time, there is π-π stacking between adjacent complexes, which deals with two 1,10-phenanthroline plane rings. In addition to the π-π stacking, there are C-H···Br non-classic hydrogen bonds between adjacent complexes. The theoretical calculations reveal that the π-π stacking and C-H···Br non-classic hydrogen bond result in a weak anti-ferromagnetic interaction with 2J = -5.34 cm-1 and a weak ferromagnetic 2J = 5.92 cm-1, respectively. The magnetic coupling sign from the π-π stacking could be explained with McConnell I spin-polarization mechanism.

Catalytic Hydrogenation over Palladium Complex of Molecular Complex of Poly(4-vinylpyridine) with Acetic Acid

The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the corresponding palladium complex of poly(4 vinylpyridine). In the presence of a strong inorganic alkali, especially potassium hydroxide, the catalytic activity is greatly improved. The suitable hydrogenation condition for PVP/HAc Pd is to use 0 1 mol/L ethanol solution of potassium hydroxide as the hydrogenation medium and the hydrogenation is carried out at 45 ℃.

Hydrogenation of SBS Catalyzed by Immobilized Ru-TPPTS Complex in Polyether Molten Salt

Catalytic hydrogenation of SBS was performed for the first time in polyether molten salt with Ru/TPPTS complex as catalyst. Experimental results showed that the hydrogenation degree can be enhanced significantly by the addition of triphenylphosphine (TPP). When the molar ratio of TPP, TPPTS and Ru is 2:5:1, 89% hydrogenation degree can be achieved after 12 h under reaction conditions of 5.0 MPa and 150°C. The ionic liquid containing catalyst can be reused three times without obvious changes in the catalytic selectivity and activity.

A DFT Investigation on Hydrogen Adsorption Based on Alkali-metal Organic Complexes

Using density functional theory calculation based on the B3LYP method,we have studied the interactions of H2 molecules with alkali-metal organic complexes C6H6-nLin（n = 1～3）,C6H5Na and C6H5K.A significant part of the electronic charge of M s orbital（Li 2s,Na 3s,K 4s） is donated to phenyl and is accommodated by H2 bonding orbital.For all the complexes considered,each bonded alkali-metal atom can adsorb up to five H2 in molecular form with the mean binding energy of 0.59,0.55 and 0.56 eV/H2 molecule for C6H6-nLin（n = 1～3）,C6H5Na and C6H5K,respectively.The kinetic stability of these hydrogen-covered organometallic complexes is discussed in terms of energy gap between HOMO and LUMO.It is remarkable that these alkali-metal organic complexes can store up to 23.80 wt% hydrogen.Therefore,the complexes studied may be used as hydrogen storage materials.

Layered Lanthanum Complex with 3-Nitrophthalic Acid Assembled via Hydrogen Bonds-Synthesis, Structure and Characterization of [LaL(HL)(H_2O)_3]_2·2H_2O (H_2L=3-NO_2C_6H_3(CO_2H)_2)

A new dinuclear centrosymmetric complex [LaL（HL）（H2O）3]2（2H2O （H2L = 3-nitrophthalic acid, NPA） was synthesized in water/ethanol solution and characterized by X-ray diffraction, IR spectrum and TGA-DTA. The complex crystallizes in triclinic system, space group P1^- with a = 8.1549（16）, b = 8.8856（18）, c = 15.277（3）A,α= 100.93（3）,α= 90.81（3）, γ= 104.56（3）°, V = 1049.8（4）A^3, Z = 1,μ= 2.125 mm^-1, Dc=1.994 g/cm^3, R = 0.0259 and wR = 0.0679. Two 3-nitrophthalates（2-） coordinate with the La3＋ ions in a bridging mode, and two monohydrogen- 3-nitrophthates（1-） and three waters in terminal ways, respectively. Each La^3＋ ion is nine-coordinated to exhibit a distorted tricapped trigonal prism coordination polyhedron. Both the coordinated and crystal waters are involved in the inter- and intramolecular hydrogen bonds. The dinuclear units are linked into a 2D network structure in the ab plane via intermolecular hydrogen bonds along the axes a and b. Two crystal waters fill each rhombic pore of the network. The networks are further packed along the c axis forming a layered supramolecular structure through the C-H…O weak forces between the adjacent sheets. TGA analysis shows the complex undergoes the loss of waters of crystallization and coordination and the decomposition of ligands sequentially.

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Complex aluminum hydrides have been widely studied as potential hydrogen storage materials but also,for some time now, for electrochemical applications. This review summarizes the crystal structures of alkali and alkaline earth aluminum hydrides and correlates structure properties with physical and chemical properties of the hydride compounds. The crystal structures of the alkali metal aluminum hydrides change significantly during the stepwise dehydrogenation. The general pathway follows a transformation of structures built of isolated [AlH4]- tetrahedra to structures built of isolated [Al H6]3- octahedra.The crystal structure relations in the group of alkaline earth metal aluminum hydrides are much more complicated than those of the alkali metal aluminum hydrides. The structures of the alkaline earth metal aluminum hydrides consist of isolated tetrahedra but the intermediate structures exhibit chains of cornershared octahedra. The coordination numbers within the alkali metal group increase with cation sizes which goes along with an increase of the decomposition temperatures of the primary hydrides. Alkaline earth metal hydrides have higher coordination numbers but decompose at slightly lower temperatures than their alkali metal counterparts. The decomposition pathways of alkaline metal aluminum hydrides have not been studied in all cases and require future research.

Novel Chiral PNNP-Ru Complexes:Synthesis and Application in Asymmetric Transfer Hydrogenation of Ketones

The efficient catalytic systems generated in situ from RuCl2（PPh3）3 and chiral ligands N,N-bis[2-（di-o-tolylphosphino）-benzyl]cyclohexane-1,2-diamine（2） were employed for asymmetric transfer hydrogenation of aromatic ketones, giving the corresponding optically active alcohols with high activities（up to 99% conversion） and excellent enantioselectivities（up to 96% e.e.） under mild conditions. The chiral ruthenium（Ⅱ） complex （R,R）-3 has been prepared and characterized by NMR and X-ray crystallography.

Baeyer-Villiger oxidation of ketones with hydrogen peroxide catalyzed by Sn-aniline complex

Sn-aniline complex was prepared by a simple procedure. Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.

Supramolecular Formation via Hydrogen Bonding in Copper and Nickel Complexes with 2-Hydroxynicotinic Acid

Two complexes, Cu（HnicO）2 1 and Ni（HnicO）2（H2O）2 2 （H2nicO = 2-hydroxynicolinic acid）, were synthesized by hydrothermal reactions and structurally characterized. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 8.314（7）, b = 6.275（4）, c = 11.283（7）A, β = 98.32（3）°, V = 582.5（7）A^3, Z = 2, Mr = 339.74, Dc = 1.937 g/cm3, F（000） = 342, μ = 1.908 mm^-1, S = 1.097, the final R = 0.0284 mad wR = 0.0781 for 1177 observed reflections with Ⅰ 〉 2σ（Ⅰ）. Complex 2 crystallizes in monoclinic, space group P21/c, with a = 7.438（5）, b = 12.22（1）, c = 7.537（5）A,β = 100.07（3）°, V= 674.3（8）A3, Z = 2, Mr = 370.95, Dc = 1.827 g/cm^3, F（000） = 380, = 1.487 mm^-1, S = 1.041, the final R = 0.0335 and wR = 0.0779 for 1202 observed reflections with I 〉 2σ（Ⅰ）. There are extended 3D framework structures in complexes 1 and 2 due to the N-H…O and C-H…O hydrogen bonds. The copper atom in 1 has square planar coordination, while the nickel atom in 2 adopts octahedral coordination geometry. The TG curve shows that complex 2 is stable in solid state to 150 ℃.

Synthesis, Crystal Structure and Hydrogenation Catalysis of a CF_3-BINAP(O)-Rh-COD Complex

The complex [（CF3-BINAP（O））Rh（COD）][ClO4]·Et2O （2, CFa-BINAP（O） = 2- {bis[3,5-bis（trifluoromethyl）phenyl]phosphino } -2 ＇- {bis [3,5-bis（trifluoromethyl）phenyl]phosphinyl } -1,1、-binaphthyl, COD = 1,5-cyclooctadiene） was obtained directly from the reaction of CF3- BINAP（O） ligand with [Rh（COD）][C104]. Complex 2 has been characterized by single-crystal X-ray diffraction. The crystal adopts space group P21/n with a = 19.0727（4）, b = 15.6275（4）, c = 22.3039（6） A, fl = 112.3570（10）°, V= 6148.2（3） A3, Z = 4, Dc = 1.693 g/cm3, F（000） = 3144, μ（MoKa） = 0.500 mm-1, the final R = 0.0947 and wR = 0.2501. Structural studies reveal that Rh（I） is coordinated by one oxygen and one phosphorus in the same ligand. Asymmetric hydrogenation of acetami- docinnamic acid with compound 2 was also evaluated.

Supramolecular Sheet Co(Ⅱ) Complex Assembled by Hydrogen Bond

The title complex, [ [ Co （Py） 2 （H20） 2 （ NO3 ）2 ] ] n （ 1 ） was synthesized by liquid/liquid diffusion method at room temperature. The complex crystallizes in monoclinic, space group P2 （1）/C, with a = 0.8775（6）nm, b=1.171 5（8）nm, c=0.7518（5）nm, V=0.739 3（9）nm3, C10H14CoN4O8, Mr= 377.18, Dc=1.694g/cm^3, μ=1.210mm^-1, F（000）=386, Z=2, the final R=0.0229 and wR= 0.066 1 for 3 137 observed reflections （I〉2σ（I））. In the structure of 1, the center atom of cobalt revealed a centrosymmetric, six-coordinate structure, with two Py ligands, two monodentate nitrate groups and two water molecules. It is notable that a series of hydrogen bonds （O-H…O） formed two kinds of rings exist in the structure, which linked neighboring six-coordinate polymer into a two-dimensional H-bonding network, and then assembled into a three-dimensional supramolecular architecture through electrostatic and hydrophobic interaction. In the structure, supramolecular sheet was observed, which contains alte .rnative organic and inorganic layers.

SYNTHESIS AND CHARACTERIZATION OF A SILICA-SUPPORTED CARBOXYMETHYLCELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATI0N OF AR0MATICS

A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.

Modification of Metal Complex on the StereoselectiveHydrogenation of 2,3-Butanedione

The modification of some metal complexes on Pt/Al2O3 clusters leads to remarkable increases in both the activity and the selectivity for meso-2,3-butanediol in the stereoselectivity hydrogenation of 2,3-butanedione.

HYDROGENATION OF PHENOL AND CRESOLS CATALYZED BY CHITOSAN SUPPORTED PALLADIUM COMPLEX AT MILD CONDITIONS

A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70 degrees C and 1.01325 x 10(5) Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->o- The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.

Enantioselective Transfer Hydrogenation of Aromatic Ketones Catalyzed by New Diaminodiphosphine Ru(Ⅱ) Complexes

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CARBONACEOUS PRODUCTS OF POLYMER-PALLADIUM COMPLEXES AS CATALYSTS FOR THE HYDROGENATION OF METHYL ACRYLATE

Many catalysts were pcrpared by carbonization of ion exchange resin-PdCl_2 complexes at high temperature in nitrogen, hydrogen atmosphere. The rates for the hydrogenation of methyl acrylate and the amounts of Pd elution of the carbonaceous products were measured and compared with those of commercial Pd/C catalyst. It indicates that the carbonaceous products are less active than Pd/C. However, the leaching of Pd from carbonaceous products is very small and much less than that from Pd/C.

Kinetics and Stoichiometry of the Reduction of Hydrogen Peroxide by an Aminocarboxylactocobaltate(II) Complex in Aqueous Medium

The kinetics and stoichiometry of the reduction of H2O2 by an aminocaboxylactocobaltate(II) complex (hereafter[CoHEDTAOH2]-) in aqueous medium have been studied under the following conditions: T = 29℃ ± 1℃, Ionic Strength, I = 0.50 mol dm-3 (NaClO4), [H+] = 1 × 10-3 mol dm-3. The ratio from the stoichiometric study conforms to the equation 2[CoHEDTAOH2]- + H2O2 + 2H+ → 2 [CoHEDTAOH2] + 2H2O. The rate of reaction varied linearly to the first power of the concentrations of the reductant and oxidant and displayed inverse dependence on acid concentration. The plot of acid dependent rate constant versus [H+]-1 was linear with zero intercept. The [CoHEDTAOH2]- - H2O2 reaction was insensitive to the change in ionic strength of the medium suggesting interaction of charged and uncharged species at the activated complex. The Michaelis-Menten plot of was linear without intercept which suggested absence of intermediate complex. Evidences in this paper showed that the reaction occurred through the outer-sphere mechanism.

Asymmetric hydrogenation of aromatic ketones using new chiral-bridged diphosphine/diamine-Ru(Ⅱ) complexes

A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.

Hydrogenation of Toluidines Catalyzed by Silica-supported Carboxymethylcellulose-platinum Complex

The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields, respectively, at 30 ℃ and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.