Hydrogenation of m-xylene catalyzed by a silica-supported polysilazane–platinum complex

A new kind of inorganic polymer, silica-supported polysilazane (Si–N), and its platinum complex (Si–N–Pt) were prepared and characterized by X-ray photoelectron spectroscopy. It was found that Si–N–Pt can catalyze hydrogenation of m-xylene under mild conditions (30–50°C, 1 atm). The products of the reaction were cis- and trans-1,3-dimethylcyclohexane. The formation of trans-1,3-dimethylcyclohexane may be adequately explained according to the “roll-over” model. The stereoselectivity was influenced by temperature and catalyst concentration, the proportion of the cis isomer decreasing with an increase in each of the two factors. The effects of other reaction parameters, such as the N/Pt mole ratio in the complex, solvents and reaction time, etc., on the hydrogenation of m-xylene were also studied. The Si–N–Pt catalyst is very stable in reaction and turnover numbers amount to 520 in 70 hr.     

Preparation of silica-supported polysulfoalumoxane–platinum complexes and their catalytic activity in the hydrogenation of aromatics

A novel inorganic polymer, silica-supported polysulfoalumoxane, has been prepared and used as a support for preparing a silica-supported polysulfoalumoxane–platinum complex. It has been used as a catalyst for the hydrogenation of aromatics under mild conditions. The effects of several reaction parameters such as metal loading, temperature and solvents on the hydrogenation of methyl benzoate have been studied. The catalyst showed high activity and selectivity.     

Aerobic epoxidation of olefins catalyzed by MgO–polysilazane–metal complexes

Co, Fe, Ni and Cu complexes of MgO‐supported polysilazane were prepared and found to be able to catalyze the aerobic epoxidation of long‐chain olefins to give corresponding epoxy‐alkanes in the presence of an aldehyde (as reductant) under mild conditions. When the Co complex catalyst was used for the aerobic oxidation of 1‐octene to give 1,2‐epoxy‐hexane, the yield and selectivity could achieve 92% and 100% respectively at 70 °C and under 1‐atm of O₂. The catalyst was very stable, and could be reused several times without any appreciable change in catalytic activity. Copyright © 1999 John Wiley & Sons, Ltd.     

Direct hydrogenation of nitroaromatics and one-pot amidation with carboxylic acids over platinum nanowires

A novel ultrathin platinum nanowire with uniform length and a diameter of 1.5 nm was synthesized by acidic etching of FePt nanowire in methanol. This nanowire was characterized by high‐resolution transmission electron microscopy (HRTEM). X‐ray diffraction (XRD) data indicated that the main plane is (111). The ability of this nanowire to catalyze the heterogeneous hydrogenation of nitroaromatics to give the corresponding amines has been investigated. The catalyst showed satisfactory activity in various solvents under mild conditions and showed excellent stability. The catalytic performance was also evaluated in the one‐pot reduction of nitroaromatics and amidation with carboxylic acids under a hydrogen atmosphere at 100 °C. These methods for the hydrogenation of nitroaromatics and the direct amidation of nitroaromatics with carboxylic acids are simple, economical, and environmentally benign, and have practical advantages for the synthesis of amines and amides without the production of toxic byproducts.     

A novel fumed silica-supported nitrogenous platinum complex as a highly efficient catalyst for the hydrosilylation of olefins with triethoxysilane

A novel fumed silica-supported nitrogenous platinum complex was conveniently prepared from cheap γ-aminopropyltriethoxysilane via immobilization on fumed silica in toluene, followed by a reaction with hexachloroplatinic acid. The title complex was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the complex is an efficient and stable catalyst for the hydrosilylation of olefins with triethoxysilane. The title platinum complex could be separated by simple filtration and reused several times without any appreciable loss in the catalytic activity.     

Oxidation of benzyl alcohol with dioxygen catalyzed by an inorganic polymer–platinum complex

An inorganic polymer–platinum complex, magnesiasupported polytitanzane–platinum complex (MgO Ti N Pt), was prepared and used to catalyze the oxygenation of benzyl alcohol. It was found that this kind of catalyst has great activity and stability in the reaction. The objective product (benzaldehyde) was obtained in 100% yield in 6 hr under a moderate reaction temperature and atmospheric oxygen pressure. This inorganic polymer complex was also very stable during the reaction.     

Asymmetric hydrogenation of salicyl alcohol catalyzed by methylsulfo–sodium carboxymethylcellulose–Pt complex

A new chiral polymer–metal complex, methylsulfo–sodium carboxymethyl–cellulose–Pt complex (MS‐NaCMC‐Pt), has been prepared by the reaction of sodium carboxymethylcellulose with methylsulfonyl chloride and H₂PtCl₆·6H₂, which was found to be able to catalyze the asymmetric hydrogenation of salicyl alcohol to give (1S,2S)‐2‐(hydroxymethyl)‐cyclohexanol at 28 °C and under 1 atm H₂, in > 90% product and optical yields, respectively. The catalyst could be reused many times without any remarkable changes in optical catalytic activity. Copyright © 2000 John Wiley & Sons, Ltd.     

Oxygenation of 3-pentanol to 3-pentanone catalyzed by polymer–platinum complex

A new inorganic polymer–platinum complex, silicasupported polysilazane–platinum complex, has been prepared and found to be capable of catalyzing the oxygenation of 3-pentanol to 3-pentanone in 100% yield at moderate temperature and under atmospheric oxygen pressure. Water is the best solvent for this reaction. This inorganic polymer complex is very stable in the reaction and can be reused several times without any appreciable change in catalytic activity.     

Synthesis of a fumed silica-supported poly-3-(2-aminoethylamino)propylsiloxane platinum complex and its catalytic behavior in the hydrosilylation of olefins with triethoxysilane

A novel fumed silica-supported bidentate nitrogen platinum complex was conveniently prepared from N-(2-aminoethyl)-3-aminopropyltriethoxysilane via immobilization on fumed silica followed by a reaction with hexachloroplatinic acid. The title complex was systematically characterized and analyzed by Fourier Transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and specific surface area analysis (BET). The resulting title complex was found to be efficient and stable in catalyzing the hydrosilylation reaction of olefins with triethoxysilane. Furthermore, the polymeric platinum complex could be separated by simple filtration and reused four times without any appreciable loss of catalytic activity.     

Oxidation of methanol catalyzed by silica-supported polystannazane–copper complex

Silica-supported polystannazane–copper complex has been prepared and used as a catalyst for the oxidation of methanol. The results showed that the catalyst could catalyze the oxidation of methanol to formaldehyde at a high yield and selectivity at 30°C and under 1 atm mild conditions. The N/Cu mole ratio in the complex, temperature and the amount of NaOH additive had much influence on the catalytic activity. The complex was stable during the reaction and could be used repeatedly.     

Catalytic behavior of silica‐supported chitosan‐platinum‐iron complex for asymmetric hydrogenation of ketones

Silica‐supported chitosan‐platinum‐iron complex (SiO₂‐CS‐Pt‐Fe) is prepared by a simple method from silica, chitosan, H₂PtCl₆ · 6H₂O and FeCl₃. It has been found to be an effective chiral catalyst for the asymmetric hydrogenation of 2‐hexanone to give (S)‐(+)‐2‐hexanol and methyl acetoacetate to give methyl‐(S)‐(+)‐3‐hydroxybutyrate in 85.4 and 75.0% optical yields, respectively, if a proper content of Pt and Fe in SiO₂‐CS‐Pt‐Fe complex and appropriate reaction conditions are selected at room temperature and under 1 atm H₂. The catalyst could be reused several times without any remarkable change in optical catalytic activity. Copyright © 2004 John Wiley & Sons, Ltd.     

Catalytic synthesis of 3-glycidoxypropyltriethoxysilane over silica-supported chitosan-platinum complex

An efficient and cost-effective method for the synthesis of 3-glycidoxypropyltriethoxysilane from the hydrosilylation reaction of allyl glycidyl ether with triethoxysilane using a silica-supported chitosan-platinum complex as catalyst is described for the first time. By an orthogonal experimental design method, the optimum parameters for the process were determined. The product yield can reach 78.9%, and the catalyst can be recovered and reused six times without noticeable loss of activity.     

丙氨酸铂配合物的合成与表征

顺铂、卡铂等铂配合物目前已经应用于卵巢癌、睾丸癌等肿瘤疾患的治疗,然而这类药物在低剂量下也存在严重的毒副作用,同时还存在溶解性差、不稳定等缺点[1,2,3].寻找高效、低毒的新一代铂类抗癌药物是医药领域的迫切任务.     

Catalytic behaviors of magnesia-supported polytitanazane–platinum complex on the oxygenation of 3-heptanol

A kind of inorganic polymer–platinum complex, magnesia-supported polytitanazane–platinum complex (MgO-Ti-N–Pt), was prepared and used to catlayze the oxygenation of 3-heptanol. It was found that this kind of catalyst was very active and stable in the reaction. The objective product (3-heptanone) was obtained near 100% yield in 40 hr under moderate reaction temperature and atmospheric oxygen pressure.     

Asymmetric transfer hydrogenation catalyzed by a novel planar chiral N‐heterocyclic carbene–rhodium(I) complex

A novel chelated ferrocene‐based planar chiral N‐heterocyclic carbene‐Rh(I) complex was synthesized by a simple method. It was applied to the asymmetric transfer hydrogenation of prochiral ketones. Enantioselectivities of up to 67% ee were observed. Copyright © 2009 John Wiley & Sons, Ltd.     

High-selectivity hydrogenation of cinnamaldehyde over platinum supported on aluminosilicates

This work studies liquid-phase hydrogenation of cinnamaldehyde to cinnamylalcohol over Pt/K-10 and ion-exchanged Pt/Na-Y. The experiments show the highest selectivity of 78% for Pt/K-10 and 92% for the Pt/Na-Y. By careful analysis, characterisation and changing reaction conditions it was attempted to cover key parameters possibly responsible for the high selectivity. The parameters are described and discussed in detail.     

Hydrogenation of norbornene catalyzed by magnesium oxide-supported polyalumazane–platinum complexes

A magnesium oxide-supported polyalumazane–platinum complex was synthesized and characterized by X-ray photoelectron spectroscopy (XPS) and its performance toward the hydrogenation of norbornene. XPS data indicated that a large amount of platinum existed in a zero-valent state. The catalyst showed high performance for the hydrogenation of norbornene. Its performance depended on the type of the support, the platinum loading and the reaction temperature. With 0.1544 mmol/g platinum loading at 25°C, the hydrogenation of norbornene to norbornane was completed within 2 min. Also, the turnover number of the catalyst reached 11,000 within 280 min.     

Ru–η6‐benzene–phosphine complex‐catalyzed transfer hydrogenation of ketones

Three Ru–η⁶‐benzene–phosphine complexes bearing tri‐(p‐methoxyphenyl)phosphine, triphenylphosphine and tri‐(p‐trifluoromethylphenyl)phosphine were synthesized and characterized by ³¹P{¹H} NMR, ¹H NMR, ¹³C{¹H} NMR and elemental analyses. Complex 1 was further identified by X‐ray crystallography. These complexes exhibit good to excellent activities for the transfer hydrogenation of ketones in refluxing 2‐propanol, and the highest turnover frequency (TOF) is up to 5940 h⁻¹. The effect of electronic factors of these complexes on the transfer hydrogenation of ketones reveals that the catalytic activity is promoted by electron‐donating phosphine and the catalyst stability is improved by electron‐withdrawing phosphine. Copyright © 2011 John Wiley & Sons, Ltd.     

Hydrogenation of aldehydes and ketones catalyzed by a polysulfosiloxane–platinum complex

An acidic inorganic polymer, polysulfosiloxane, has been prepared and used as ligand for preparing a polysulfosiloxane–platinum complex. It has been found that such a complex could catalyze the hydrogenation of aldehydes and ketones to alcohols, giving as much as 100% yield at room temperature and under atmospheric pressure. Temperature, S/Pt molar ratio in the complex and solvents greatly influenced the reaction. This complex was very stable and could be used several times without any change in catalytic activity.