Copper(I) salt/PEG‐400 catalysis in one‐pot direct synthesis of 1‐aryl‐1H‐indazoles from 2‐bromobenzaldehydes and arylhydrazines

2‐Bromobenzaldehydes are condensed and cyclized with arylhydrazines (or their hydrochlorides) in PEG‐400 at 110 °C in the presence of a catalytic amount of a copper(I) salt along with a base to give 1‐aryl‐1H‐indazoles in high yields. Copyright © 2013 John Wiley & Sons, Ltd.     

Ruthenium carbonyl complexes in catalytic epoxidation of olefins co‐catalyzed by isobutyl‐aldehyde

The present work shows the catalytic activity of a series of carbonyl ruthenium complexes in the epoxidation of olefins co‐catalyzed by isobutyl‐aldehyde. The complexes display catalytic activity in the epoxidation of the cyclohexene with high selectivity. Copyright © 2006 John Wiley & Sons, Ltd.     

One‐step synthesis of Pt@three‐dimensional graphene composite hydrogel: an efficient recyclable catalyst for reduction of 4‐nitrophenol

A Pt@three‐dimensional graphene (Pt@3DG) composite hydrogel with a unique porous nanostructure was prepared and used as an efficient, recyclable and robust catalyst for the reduction of 4‐nitrophenol to 4‐aminophenol under mild conditions. The influence of graphene architecture on catalytic activities was comparatively investigated by loading the same amount of Pt on reduced graphene oxide. Pt@3DG exhibits a very high catalytic activity owing to the three‐dimensional macroporous framework with high specific surface area, numerous activation sites and efficient transport pathways. Moreover, catalyst separation can be easily achieved by simple filtration, and the catalyst can be reused for at least five runs, maintaining its high catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

PEG‐4000‐promoted palladium‐catalyzed N‐allylation in water: aminonaphthalene as an example

An environmentally friendly, efficient catalytic process using palladium associated with ligands in a PEG4000–water system leading to N‐allylation was described in this study. PEG‐4000 was found to improve the palladium‐catalyzed allylic amination of allylic acetates with aminonaphthalenes and gave overall good to high yields of the corresponding N‐allylic aminonaphthalenes. Copyright © 2012 John Wiley & Sons, Ltd.     

Silane‐bridged diphosphine ligand for palladium‐catalyzed ethylene oligomerization

In this study, bis(diphenylphosphinemethyl)dimethyl silane ( L1 ) and its palladium(II) halide complex, L1 /PdCl₂ ( C1 ), were synthesized and characterized. Single‐crystal X‐ray analysis of the complex revealed bidentate coordination at the Pd center. In combination with methylaluminoxane (MAO) as co‐catalyst, C1 exhibited excellent catalytic activity and selectivity for ethylene dimerization toward butene. The maximum catalytic activity obtained from the C1 /MAO system for ethylene dimerization to yield butenes was 7.33 × 10⁵ g/(mol_Pd · h). The selectivity toward butene remained stable and high (> 96%) over the various conditions.     

Dehydrogenation of Propane to Propylene in the Presence of CO2 over Steaming‐treated HZSM‐5 Supported ZnO

Dehydrogenation of propane to propylene over zinc oxide catalysts supported on steaming‐treated HZSM‐5 in the presence of CO₂ has been investigated. The highest catalytic performance can be achieved on the 5%ZnO/HZSM‐5(650) catalyst with the HZSM‐5 support steaming at 650°C, which allows the maximum propylene yields of 29.7% and 20.3% at the initial and steady states, respectively, in the catalytic dehydrogenation of propane at 600°C. The superior catalytic performance of this catalyst can be attributed to high dispersion of ZnO and appropriate Br?nsted acidity of the HZSM‐5(650) support. The catalytic stability is enhanced by the addition of CO₂ to the feed gas due to the suppression of coke formation.     

Half‐titanocene complexes bearing dianionic 6‐benzimidazolylpyridyl‐2‐carboximidate ligands: Synthesis,characterization, and their ethylene polymerization

6‐Benzimidazolylpyridyl‐2‐carboximidic half‐titanocene complexes, Cp′TiLCl (Cp′ = C₅H₅, MeC₅H₄, C₅Me₅, L = 6‐benzimidazolylpyridine‐2‐carboxylimidic, C1–C13 ), were synthesized and characterized along with single‐crystal X‐ray diffraction. The half‐titanocene chlorides containing substituted cyclopentadienyl groups, especially pentamethylcyclopentadienyl groups were more stable, while those without substituents on the cyclopentadienyl groups were easily transformed into their dimeric oxo‐bridged complexes, (CpTiL)₂O ( C14 and C15 ). In the presence of excessive amounts of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all half‐titanocene complexes showed high catalytic activities for ethylene polymerization. The substituents on the Cp groups affected the catalytic behaviors of the complexes significantly, with less substituents favoring increased activities and higher molecular weights of the resultant polyethylenes. Effects of reaction conditions on catalytic behaviors were systematically investigated with catalytic systems of mononuclear C1 and dimeric C14 . With C1 /MAO, large MAO amount significantly increases the catalytic activity, while the temperature only has a slight effect on the productivity. In the case of C14 /MAO catalytic system, temperature above 60 °C and Al/Ti value higher than 5000 were necessary to observe good catalytic activities. In both systems, higher reaction temperature and low cocatalyst amount gave the polyethylenes with higher molecular weights. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3396–3410, 2008     

Base‐amplifying silicone resins with photobase‐generating side chains and their application to negative‐working photoresists

To accomplish high photosensitivity of resist systems including photobase generators, we have proposed the concept of base‐proliferation reactions that generate base molecules in a nonlinear manner by the action of a catalytic amount of base; however, excessive diffusion of generated base molecules is still a problem. We have designed novel functional silicone resins bearing both base‐amplifying units and photobase‐generating units, and synthesized resins with various composition ratios. The synthesized resins are decomposed autocatalytically after UV irradiation and subsequent heating at 100 °C, which indicates progression of base‐proliferation reactions. High photosensitivity (8.1 mJ cm^?2) was recorded, and it was found that the photosensitivity is about 490 times enhanced by replacing a base‐catalytic reaction system with the base‐proliferation reaction system. Furthermore, a 4 × 10 µm line‐and‐space pattern has been successfully fabricated using the silicone resin. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1205–1212     

Bis(2‐(6‐methylpyridin‐2‐yl)‐benzimidazolyl)titanium dichloride and titanium bis(6‐benzimidazolylpyridine‐2‐carboxylimidate): Synthesis,characterization, and their catalytic behaviors for ethylene polymerization

A series of 6‐(benzimidazol‐2‐yl)‐N‐organylpyridine‐2‐carboxamide were synthesized and transformed into 6‐benzimidazolylpyridine‐2‐carboxylimidate as dianionic tridentate ligands. Bis(2‐(6‐methylpyridin‐2‐yl)‐benzimidazolyl)titanium dichloride ( C1 ) and titanium bis(6‐benzimidazolylpyridine‐2‐carboxylimidate) ( C2 – C8 ) were synthesized in acceptable yields. These complexes were systematically characterized by elemental and NMR analyses. Crystallographic analysis revealed the distorted octahedral geometry around titanium in both complexes C1 and C4 . Using MAO as cocatalyst, all complexes exhibited from good to high catalytic activities for ethylene polymerization. The neutral bis(6‐benzimidazolylpyridine‐2‐carboxylimidate)titanium ( C2 – C8 ) showed high catalytic activities and good stability for prolonged reaction time and elevated reaction temperature; however, C1 showed a short lifetime in catalysis as being observed at very low activity after 5 min. The elevated reaction temperature enhanced the productivity of polyethylenes with low molecular weights, whereas the reaction with higher ethylene pressure resulted in better catalytic activity and resultant polyethylenes with higher molecular weights. At higher ratio of MAO to titanium precursor, the catalytic system generated better activity with producing polyethylenes with lower molecular weights. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3411–3423, 2008     

In(OTf)3催化下水相合成2-(3,4,5-三甲氧基苯基)-5-[(5-烷硫基-1,3,4-噁二唑-2-基)硫甲基]-1,3,4-噻二唑类衍生物

以2-巯基-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑为原料,经醚化、酰肼化、闭环、硫醚化四步反应合成了10个2-(3,4,5-三甲氧基苯基)-5-[(5-烷硫基-1,3,4-噁二唑-2-基)硫甲基]- 1,3,4-噻二唑类衍生物。通过元素分析、IR、MS、1H NMR和 13C NMR对目标化合物进行了表征。采用In(OTf)3催化下40 oC水相合成目标化合物,具有反应条件温和、合成收率高、催化剂可循环使用等特点。     

Iron‐ and Bismuth‐Catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media

We have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral Fe^II and Bi^III complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (?78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water‐compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1 , which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a Fe^II or Bi^III metal salt, a chiral ligand ( L1 ), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo‐ and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the Fe^II and Bi^III centers and the effect of additives on the chiral catalysis. Notably, both Brønsted acids and bases worked as efficient additives in the Fe^II‐catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems.     

Hiyama cross‐coupling reaction catalyzed by a palladium salt of 1‐benzyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride under microwave irradiation

An efficient catalytic system using 1‐benzyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride ((BeDABCO)₂Pd₂Cl₆) was developed for the Hiyama cross‐coupling reaction of various aryl halides with triethoxy(phenyl)silane. The substituted biaryls were produced in excellent yields in short reaction times using a catalytic amount of this catalyst in NMP at 100 °C. Copyright © 2014 John Wiley & Sons, Ltd.     

Asymmetric Hydroalkoxylation of Non‐Activated Alkenes: Titanium‐Catalyzed Cycloisomerization of Allylphenols at High Temperatures

The asymmetric catalytic addition of alcohols (phenols) to non‐activated alkenes has been realized through the cycloisomerization of 2‐allylphenols to 2‐methyl‐2,3‐dihydrobenzofurans (2‐methylcoumarans). The reaction was catalyzed by a chiral titanium–carboxylate complex at uncommonly high temperatures for asymmetric catalytic reactions. The catalyst was generated by mixing titanium isopropoxide, the chiral ligand (aS)‐1‐(2‐methoxy‐1‐naphthyl)‐2‐naphthoic acid or its derivatives, and a co‐catalytic amount of water in a ratio of 1:1:1 (5 mol % each). This homogeneous thermal catalysis (HOT‐CAT) gave various (S)‐2‐methylcoumarans with yields of up to 90 % and in up to 85 % ee at 240 °C, and in 87 % ee at 220 °C.     

β‐cyclodextrin‐capped palladium nanoparticle‐catalyzed ligand‐free Suzuki and Heck couplings in low‐melting β‐cyclodextrin/NMU mixtures

Low‐melting β‐cyclodextrin/N‐methylurea (NMU) mixture, an efficient catalytic system for ligand‐free Suzuki and Heck couplings in the presence of fresh native β‐CD‐capped Pd⁰ nanoparticles, has been successfully reported. This natural and convenient system can be performed in air and could afford the corresponding cross‐coupled products in good to excellent isolated yields after a simple workup under every low Pd loading (0.05 mol%). Remarkably, the catalytic system can be recycled and reused without loss of catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Ethylene polymerization with long‐lifetime monopendant thienyl‐substituted group 4 metallocenes

A series of group 4 metallocenes (RCp)[Cp―(bridge)―(2‐C₄H₃S)]MCl₂ [M = Ti ( C1 , C2 , C3 , C4 ); M = Zr ( C5 , C6 , C7 , C8 )] bearing a pendant thiophene group on a cyclopentadienyl ring have been synthesized, characterized and tested as catalyst precursors for ethylene polymerization. The molecular structures of representative titanocenes C2 and C4 were confirmed by single‐crystal X‐ray diffraction and revealed that both complexes exist in an expected coordination environment for a monomeric bent metallocene. No intramolecular coordination between the thiophene group and the titanium center could be observed in the solid state. Upon activation by methylaluminoxane (MAO), titanocenes C1 , C2 , C3 , C4 showed moderate catalytic activities and produced high‐ or ultra‐high‐molecular‐weight polyethylene (M_v 70.5–227.1 × 10⁴ g mol^?1). Titanocene C3 is more active and long‐lived, with a lifetime of nearly 9 h at 30 °C. At elevated temperatures of 80–110 °C, zirconocenes C5 , C6 , C7 , C8 displayed high catalytic activities (up to 27.6 × 10⁵ g PE (mol Zr)^?1 h^?1), giving high‐molecular‐weight polyethylene (M_v 11.2–53.7 × 10⁴ g mol^?1). Even at 80 °C, a long lifetime of at least 2 h was observed for the C8/MAO catalyst system. Copyright © 2014 John Wiley & Sons, Ltd.     

Green conditions for the Suzuki reaction using microwave irradiation and a new HNT‐supported ionic liquid‐like phase (HNT‐SILLP) catalyst

A new catalytic system based on modified halloysite nanotubes was employed in the Suzuki reaction under microwave irradiation. A set of solvents, times and bases was screened and the best experimental conditions were obtained when the reactions were carried out for 10 min in water–ethanol at 120 °C in presence of K₂CO₃ as base. Good recyclability was observed. The new catalytic system was employed using either 1 mol% or 0.1 mol%. The palladium catalyst displayed good activity, allowing the synthesis of several biphenyl compounds in high yield working with only 0.1 mol% palladium loading. The application of microwave irradiation decreased the reaction time and also improved conversion with respect to traditional heating. Copyright © 2014 John Wiley & Sons, Ltd.     

Palladium‐catalyzed three‐component cyclization of 2‐bromocyclohex‐1‐enecarboxylic acids with carbon monoxide and arylhydrazines leading to 2‐anilinohydroisoindoline‐1,3‐diones

2‐Bromocyclohex‐1‐enecarboxylic acids are carbonylatively cyclized with arylhydrazines or their hydrochlorides in tetrahydrofuran at 120 °C under carbon monoxide pressure in the presence of a catalytic amount of PdCl₂ and 1,3‐bis(diphenylphosphino)propane along with Et₃N to give 2‐anilinohydroisoindoline‐1,3‐diones. Copyright © 2015 John Wiley & Sons, Ltd.     

Hydrogenation of aldehydes catalyzed by kieselguhr‐supported carboxymethylcellulose‐nickel complex

A new kieselguhr‐supported carboxymethylcellulose‐nickel complex (Kie‐CMC‐Ni) has been prepared by a simple method, which has been found to catalyze the hydrogenation of benzaldehyde, valeraldehyde and isobutyraldehyde to the corresponding alcohols in high yield (100, 92 and 86% respectively). The catalyst could be reused without obvious loss of its catalytic activity. Copyright © 2004 John Wiley & Sons, Ltd.     

ε‐Caprolactone polymerization under air by the biocatalyst: Magnesium 2,6‐di‐tert‐butyl‐4‐methylphenoxide

This study investigated the synthesis of the biocatalyst, magnesium 2,6‐di‐tert‐butyl‐4‐methylphenoxide (Mg(BHT)₂) complex, and the ring‐opening polymerization (ROP) of ε‐caprolactone (CL). The complex demonstrates high catalytic activity and controllable of molecular weight for the ROP of CL in tetrahydrofuran at room temperature, even when polymerization was performed under air. Before this study, the polymerization of CL had never been performed using a magnesium catalyst under air at room temperature. Various forms of alcohols with different purposes were also used as initiators with Mg(BHT)₂. The results show that the magnesium complex acts as a perfect catalyst because of its high catalytic activity and control ability without any cytotoxicity in the polymerization of CL, making it suitable for biomedical applications. In addition, nanoparticle formation, cytotoxicity, and phototoxicity of tri‐2‐hydroxyethyl ester [Ce6‐(CH₂CH₂OPCL)₃] were also studied in this article and Ce6‐(CH₂CH₂OPCL)₃ formed nanoparticle can act as a nanophotosensitizer for photodynamic therapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

1d‐3,4‐Di‐O‐(di­phenyl­methylphos­pho­nio)‐1,2,5,6‐tetra‐O‐methyl‐chiro‐inositol diiodide

The title compound, 3,4,5,6‐tetra­methoxy­cyclo­hexane‐1,2‐diyl­dioxy­bis­(methyl­di­phenyl­phospho­nium) diiodide, C₃₆­H₄₄­O₆­P₂²⁺·­2I^?, was prepared from a New Zealand natural product, d ‐chiro‐inositol, in order to develop new catalytic metal complexes. The inositol ring retains its usual chair conformation with only minor perturbations caused by the bound di­phenyl­methyl­phosphines. Crystal‐packing forces are provided by C—H?I cation–anion interactions.