二氧化硅负载胂钯(0)配合物催化酰氯和芳基碘与四苯硼化钠的苯基化反应

氯丙基三乙氧基硅烷依次与气相法二氧化硅、二苯胂钾、氯化钯作用, 再用水合肼还原, 合成了二氧化硅负载的胂钯(0)配合物. 该配合物是酰氯及芳基碘化物与四苯硼化钠苯基化反应的有效催化剂, 为苯基酮及不对称联苯的合成提供了简便且实用的新方法.     

聚-ω-(甲硒基)十一烷基硅氧烷钯(0)配合物的合成与催化性能

ω-氯代十一烷基三乙氧基硅烷依次用气相法二氧化硅固载、与甲硒基钠和氯化钯作用, 再用水合肼还原, 合成了气相法二氧化硅负载的聚-ω-(甲硒基)十一烷基硅氧烷钯(0)配合物. 该钯(0)配合物对丙烯腈和丙烯酸与芳基碘的Heck芳基化反应具有很高的催化活性, 为各种肉桂腈和肉桂酸的立体选择合成提供了方便实用的新途径.     

HYDROFORMYLATION OF MMA CATALYZED BY SILICA-SUPPORTED POLY-γ-AMINO PROPYLSILOXANE-Rh-Co BIMETALLIC COMPLEX

A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed that the catalyst could catalyze the reaction in95.6% conversion with 92.8% selectivity for the normal aldehyde, methyl β-formylisobu-tyrate. Such catalyst also showed high stability during the reaction and could be used repeat-edly.     

Preparation of palladium clusters protected by silica-supported,crosslinking, partially phosphorylated poly(vinyl alcohol) and their catalytic activity

The palladium cluster protected by silica-supported, crosslinking, partially phosphorylated poly(vinyl alcohol) (P-PVA) was prepared from a crosslinking P-PVA–Pd(II) complex by reduction in alcohol. The P-PVA–Pd complex and the palladium cluster protected by P-PVA were analyzed by electron spectroscopy, X-ray photoelectron spectrometry and transmission electron microscopy. The complex formation between the Pd(II) ion and phosphoric acid groups in P-PVA was important in the formation of a fine palladium cluster. Palladium clusters protected by silica-supported crosslinking P-PVA were used as catalysts for the hydrogenation of nitrobenzene or acrylic acid at 30°C under atmospheric pressure. The palladium cluster protected by crosslinking P-PVA supported on silica was the most active catalyst, was stable and had no by-products, compared with the palladium cluster protected by silica-supported noncrosslinking P-PVA or PVA.     

Catalytic Synthesis of 2-Methyl-1,4-Naphthoquinone (Vitamin K3) Over Silica-Supported Aminomethyl Phosphine-Ru(II), Pd(II), and Co(II) Complexes

Ru(II), Pd(II), and Co(II) complexes of the free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl)aminopropyltriethoxysilane [(EtO)₃Si(CH₂)₃ N(CH₂PPh₂)₂] (DIPAPTES), and its SiO₂-DIPAPES have been synthesized under a nitrogen atmosphere using Schlenk techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to give 2-methyl-1,4-naphthoquinone (vitamin K₃, menadione, 2MNQ) in the presence of hydrogen peroxide as a clean and cheap oxidant. The catalytic synthesis of vitamin K₃ was investigated using both homogeneous catalysis with free complexes and heterogeneous catalysis with silica-supported complexes. [(DIPAPTES)PdCl₂] and its silica-supported form showed the best catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphtoquinone compared to the other metal complexes. 2MNQ yield reached 52.26% with the 2MN conversion of 90.52% using complex [(DIPAPTES)PdCl₂] and 58.59% with the 2MN conversion of 99.56% using the silica supported [SiO₂(DIPAPES)PdCl₂] complex for 1 h. Recycling was investigated for the silica-supported Pd(II) complex and compared with the classical production of vitamin K₃.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Catalytic behavior of a silica-supported polystannazane-copper complex for the oxidation of methanol to formaldehyde at mild reaction conditions

A very cheap catalyst, a silica-supported polystannazane-copper complex (abbreviated as SiO₂ Sn N Cu) was prepared by the reaction of the silica-supported polystannazane ligand with CuCl₂ in ethanol. The results showed that SiO₂ Sn N Cu can catalyze the oxidation of methanol to formaldehyde in high yield at mild conditions, i.e. at 40°C and 1 atm of oxygen. The catalyst could be recovered and could catalyze the reaction repeatedly.     

Irreversible Dissociation of <Emphasis Type="Italic">Tris-</Emphasis>2,2′-Bipyridyl-iron(II) Complex in TEOS-Derived Acidic Silica Sol

Irreversible dissociation of tris-2,2′-bipyridine iron(II) (Fe(II)-bpy) to completion in acidic silica sol was elucidated in an attempt to designing silica-supported complex compounds. Liberated Fe(II) was oxidized to form tetrahedral [FeCl₄]⁻ ion, preventing regeneration back to Fe(II)-bpy. Change in the rate of dissociation was also discussed by taking competitive coordination of Cl and H₂O with Fe(II) into account.     

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.     

Carbonyl allylation of aldehydes catalyzed by a silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex

A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The palladium(0) complex has been found to catalyze the allylation of aldehydes via the formation of π-allylpalladium complexes, using allylic chlorides as allylating agent and SnCl₂ as reducing agent. This polymeric palladium complex can be recovered and reused.     

Syntheses and characterization of alkylzirconium complexes containing two silanolato ligands with a bowl-shaped framework

The reaction of a bowl-type silanol with tetrabenzylzirconium yielded a dibenzylbis(silanolato)zirconium complex selectively, which is an intriguing species in connection to the chemistry of silica-supported ZrR₄ olefin polymerization catalysts. Treatment of this neutral complex with B(C₆F₅)₃ afforded the corresponding cationic monobenzyl complex, presenting the first example of a cationic zirconium complex containing a silanolato ligand. The structures of both complexes have been characterized by X-ray crystallography.     

Convenient Deoxygenation of Aromatic Ketones by Silica-Supported Chitosan Schiff Base Palladium Catalyst

Abstract

A novel and effective catalytic system, silica-supported chitosan Schiff base palladium complex (SiO₂–CS–Schiff base–Pd) was described for catalytic hydrogenation of aromatic ketones to corresponding hydrocarbons at ambient temperature and normal pressure of H₂.     

Isdmerization of Olefins Catalyzed by Silica-Polyalumazine-Palladium Complexes

A silica-supported polyalumazane-palladium complex (abbreviated Al-N-Pd) has been found to be an effective isomerization catalyst for olefins. It can catalyze pentene-1 to pentene-2 in 72% yield and hexene-1 to hexene-2 and hexene-3 in yields of 88 and 12%, respectively, at 0°C and under atmospheric pressure. In investigating the solvent effects on the isomerization of hexene-1 catalyzed by Al-N-Pd, it was found that alcohol probably plays a role as promoter. Kinetic studies on the isomerization of hexene-1 indicate that the rate equation is r = kC^pd C ^hexene-1, where k = 0.82 ± 0.07 (mol Pd-min)^?1. Al-N-Pd is very stable in air and relatively stable during the reaction. The turnover numbers in the isomerization of hexene-1 amount to above 1 000. These results show that the inorganic polymer-supported metal complex Al-N-Pd is more active, selective, and stable than other catalysts for isomerization of α-olefins.     

Heterogeneous synergistic catalysis by a palladium complex and an amine on a silica surface for acceleration of the tsuji-trost reaction

The cooperative surface-catalysis strategy of a Br?nsted acid and an organic base can be extended to a metal complex and organic base pair. A silica-supported diaminopalladium complex and a tertiary amine were prepared and characterized. The Pd-catalyzed Tsuji-Trost reaction was enhanced significantly by the presence of the tertiary amine on the same silica surface as the Pd complex.     

Oxygenation of Isopropanol and Ethanol Catalyzed by a Silica-Supported Polysilazane-Platinum Complex

A new inorganic polymer-platinum complex, silica-supported polysilizane-platinum complex, has been prepared and found capable of catalyzing the oxygenation of both isopropanol to acetone and of ethanol to acetaldehyde in high yield (90%) at room temperature under atmospheric oxygen pressure. This inorganic polymer complex is very stable and can be reused several times without any appreciable change in catalytic activity.     

用X-射线光电子能谱(XPS)研究聚-γ-二苯基膦丙基硅氧烷-铂络合物的结构及其催化活性

本文用X-射线光电子能谱(XPS)研究了聚-γ-二苯基膦丙基硅氧烷-铂络合物,证明了这一催化剂是络合物,提出了它的可能结构,探讨了催化剂制备中不同的P/Pt克分子比及其所催化体系的酸碱度对它的活性的影响。由不同条件下催化剂中两个分离的Cl_(2P)光电子峰强度得出:适当的P/Pt克分子比和HCl加入催化体系所导致的活性提高是由于络合物中反映H_2PtCl_6分子络合特征程度的增加。     

A STUDY OF SILICA-SUPPORTED CROSS-LINKED POLY (MALEIC ACID-CO-STYRENE)-PLATINUM COMPLEX IN THE HYDROGENATION OF p-CRESOL

A silica-supported cross-linked poly(maleic acid -co- styrene)-platinum complex (PMS-Pt) has been prepared and found to be active in the hydrogenation of p-cresol undermild conditions (303-323K, 1.01×10~5Pa). In this hydrogenation system water servesas a solvent and p-cresol can be converted to 4-methylcyclohexanol quantitatively via4-methylcyclohexanone as intermediate.     

Ultrasound-Assisted Selective Deprotection of Terminal Acetonides Catalyzed by Silica-Supported Boron Trifluoride

An efficient and convenient method for the selective cleavage of terminal acetonides is described. Treatment of terminal acetonides in the presence of a wide range of functional groups with silica-supported boron trifluoride as a catalyst furnished the corresponding diols in 82–95% yield under ultrasound irradiation conditions. The acid-labile p-methoxybenzyl group as a protecting group remained intact under the conditions employed to the present deprotection condition.     

非贵金属Fe催化剂体系催化硝基苯还原羰化反应

SiO₂负载天然生物高分子材料壳聚糖(简写为CS),再络合FeCl₃,所得催化剂SiO₂-CS-FeCl₃,利用高分子载体对催化活性物种的保护和Fe-Ni双金属协同效应,在催化硝基苯及其衍生物的还原羰化反应中表现出了较高的催化活性和选择性.     

二氧化硅-聚-γ-巯丙基硅氧烷-铂络合物对不饱和化合物的硅氢加成的催化活性和稳定性

<正> 文献指出带有二苯膦、二甲基胺或氰基基团的聚苯乙烯、聚烯丙基氯和聚甲基丙烯酸酯的铂或铑的络合物可用来作为烯烃的非均相硅氢加成催化剂。我们曾经发现二氧化硅-聚-γ-氨丙基硅氧烷-铂络合物(简称为Si-NH_2-Pt)也是一种对烯烃的硅氢加成具有高活性及选择性的催化剂。     

A Mo(VI) alkylidyne complex with polyhedral oligomeric silsesquioxane ligands: homogeneous analogue of a silica-supported alkyne metathesis catalyst

A highly active alkyne metathesis catalyst is realized by replacing the amide ligands of a molybdenum(VI) trisamide alkylidyne complex with silanol groups from incompletely condensed POSS (polyhedral oligomeric silsesquioxane) ligands. This catalyst serves as an effective homogeneous mimic of an amorphous silica-supported catalyst. Reactivities of various catalytic mixtures are reported along with an X-ray structure of the aniline-coordinated amidodisiloxymolybdenum(VI) alkylidyne complex.