Stabilized Palladium Nanoparticles from Bis-(N-benzoylthiourea) Derived-PdII Complexes as Efficient Catalysts for Sustainable Cross-Coupling Reactions in Water

Stable palladium (II) complexes, incorporating a double (N-benzoylthiourea) arrangement bonded to a complex heterocyclic scaffold, are used as precursors of catalytic species able to promote Suzuki-Miyaura, Mizoroki-Heck, Hiyama, Buchwald-Hartwig, Hirao and Sonogashira-Hagihara cross-coupling transformations in water. These sustainable processes are chemoselective and very versatile. The nanoparticles responsible for these catalytic reactions were analyzed and studied. Their usefulness is demonstrated after several tests and analyses. The heterogeneous character of this species in water was also confirmed.

First Reusable Catalyst for the Reductive Coupling Reaction of Organohalides with Aldehydes

In this study, we simulate the reductive coupling (Barbier-Grignard-type) reaction of organohalides with aldehydes using a new reusable catalyst. In this regard, bimetallic alloys of NiCo encapsulated in melamine-based dendrimers (MBD) immobilized on magnetic nanoparticles symbolized as γ-Fe2O3-MBD/NiCo were designed and synthesized. The structure and properties of the catalyst were studied by a variety of techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy-dispersive spectrometry (EDS) mapping, and inductively coupled plasma (ICP). The presence of NiCo nanoalloys was confirmed by XRD and XPS analysis, TEM images, and EDS mapping. Various secondary alcohols were produced in good to high yields by reductive coupling of different types of aldehydes and organohalides in the presence of HCO2K as a nonmetallic reducing agent in aqueous media catalyzed by γ-Fe2O3-MBD/NiCo. In these reactions, the high catalytic performance of γ-Fe2O3-MBD/NiCo was achieved in comparison to monometallic counterparts due to the synergistic cooperative effect of Co and Ni in the NiCo nanoalloys. Magnetic and hydrophilic properties of the catalyst facilitate the catalyst recyclability for seven runs. The reusability of γ-Fe2O3-MBD/NiCo, use of water as an environmentally friendly solvent, ease of processing, and absence of metal additives make this process an excellent choice for the reductive coupling reaction to produce secondary alcohols from aldehydes. This is the first report on these kinds of reactions using a reusable catalyst.

Cobalt isatin-Schiff-base derivative of MOF as a heterogeneous multifunctional bio-photocatalyst for sunlight-induced tandem air oxidation condensation process

A sunlight-induced tandem air oxidation-condensation of alcohols with ortho-substituted anilines or malononitrile for the efficient synthesis of benz-imidazoles/-oxazoles/-thiazoles, or benzylidene malononitrile catalyzed by Co-isatin-Schiff-base-MIL-101(Fe) as a heterogeneous multifunctional bio-photocatalyst is reported. In these reactions, Co-isatin-Schiff-base-MIL-101(Fe) acts both as a photocatalyst, and a Lewis acid to catalyze the reaction of the in-situ formed aldehydes with o-substituted anilines or malononitrile. A significant decrease in the band gap energy and an increase in the characteristic emission of MIL-101(Fe) after functionalization with cobalt Schiff-base according to the DRS analysis and fluorescence spectrophotometry, respectively, indicate that the photocatalytic effectiveness of the catalyst is associated primarily to the synergetic influence of Fe-O cluster and Co-Schiff-base. EPR results obviously pointed out that Co-isatin-Schiff-base-MIL-101(Fe) is capable of creating ¹O₂ and O₂^⋅- as active oxygen species under visible light irradiation. Using an inexpensive catalyst, sunlight irradiation, air as a cost-effective and abundant oxidant, and a low amount of the catalyst with recoverability and durability in ethanol as a green solvent, make this methodology as an environmentally friendly process with energy-saving organic synthetic strategies. Furthermore, Co-isatin-Schiff-base-MIL-101(Fe) displays excellent photocatalytic antibacterial activity under sunlight irradiation against E. coli, S. aureus and S. pyogenes. Based on our knowledge, this is the first report of using a bio-photocatalyst for the synthesis of the target molecules.

Solar light induced photocatalytic degradation of tetracycline in the presence of ZnO/NiFe2O4/Co3O4 as a new and highly efficient magnetically separable photocatalyst

In this study, a new solar light-driven magnetic heterogeneous photocatalyst, denoted as ZnO/NiFe₂O₄/Co₃O₄, is successfully prepared. FT-IR, XPS, XRD, VSM, DRS, FESEM, TEM, EDS, elemental mapping, and ICP analysis are accomplished for full characterization of this catalyst. FESEM and TEM analyses of the photocatalyt clearly affirm the formation of a hexagonal structure of ZnO (25–40 nm) and the cubic structure of NiFe₂O₄ and Co₃O₄ (10–25 nm). Furthermore, the HRTEM images of the photocatalyst verify some key lattice fringes related to the photocatalyt structure. These data are in very good agreement with XRD analysis results. According to the ICP analysis, the molar ratio of ZnO/NiFe₂O₄/Co₃O₄ composite is obtained to be 1:0.75:0.5. Moreover, magnetization measurements reveals that the ZnO/NiFe₂O₄/Co₃O₄ has a superparamagnetic behavior with saturation magnetization of 32.38 emu/g. UV-vis DRS analysis indicates that the photocatalyst has a boosted and strong light response. ZnO/NiFe₂O₄/Co₃O₄, with band gap energy of about 2.65 eV [estimated according to the Tauc plot of (αhν)²vs. hν], exhibits strong potential towards the efficacious degradation of tetracycline (TC) by natural solar light. It is supposed that the synergistic optical effects between ZnO, NiFe₂O₄, and Co₃O₄ species is responsible for the increased photocatalytic performance of this photocatalyst under the optimal conditions (photocatalyst dosage = 0.02 g L⁻¹, TC concentration = 30 mg L⁻¹, pH = 9, irradiation time = 20 min, and TC degradation efficiency = 98%). The kinetic study of this degradation process is evaluated and it is well-matched with the pseudo-first-order kinetics. Based on the radical quenching tests, it can be perceived that ^•O₂⁻ species and holes are the major contributors in such a process, whereas the ^•OH radicals identify to have no major participation. The application of this methodology is implemented in a facile and low-cost photocatalytic approach to easily degrade TC by using a very low amount of the photocatalyst under natural sunlight source in an air atmosphere. The convenient magnetic isolation and reuse of the photocatalyst, and almost complete mineralization of TC (based on TOC analysis), are surveyed too, which further highlights the operational application of the current method. Notably, this method has the preferred performance among the very few methods reported for the photocatalytic degradation of TC under natural sunlight. It is assumed that the achievements of this photocatalytic method have opened an avenue for sustainable environmental remediation of a broad range of contaminants.

ZnCo2O4/g-C3N4/Cu nanocomposite as a new efficient and recyclable heterogeneous photocatalyst with enhanced photocatalytic activity towards the metronidazole degradation under the solar light irradiation

In this study, ZnCo₂O₄/g-C₃N₄/Cu is synthesized as a new and highly effectual solar light-driven heterogeneous photocatalyst. The prepared photocatalyst is characterized using FT-IR, XRD, XPS, DRS, FESEM, TEM, EDS, and elemental mapping techniques. The performance of ZnCo₂O₄/g-C₃N₄/Cu is studied towards the metronidazole (MNZ) degradation under solar light irradiation. The kinetics of MNZ degradation and efficacy of the operational parameters comprising the initial MNZ amount (10-30 mg L^-1), photocatalyst dosage (0.005-0.05 g L^-1), pH (3-11), and contact time (5-30 min) on the MNZ degradation process are investigated. Surprisingly, the ZnCo₂O₄/g-C₃N₄/Cu nanocomposite presents a privileged photocatalytic performance towards the MNZ degradation under solar light irradiation. The enhanced photocatalytic activity of this photocatalyst can be ascribed to the synergistic optical effects of ZnCo₂O₄, g-C₃N₄, and Cu. The value of band gap energy for ZnCo₂O₄/g-C₃N₄/Cu is estimated to be 2.3 eV based on the Tauc plot of (αhν)² vs. hν. The radical quenching experiments confirm that the superoxide radicals and holes are the principal active species in the photocatalytic degradation of MNZ, whereas the hydroxyl radicals have no major role in such degradation. The as-prepared photocatalyst is simply isolated and recycled for at least eight runs without noticeable loss of the efficiency. Using the natural sunlight source, applying a very low amount of the photocatalyst, neutrality of the reaction medium, short reaction time, high efficiency of the degradation procedure, utilizing air as the oxidant, low operational costs, and easy to recover and reuse of the photocatalyst are the significant highlights of the present method. It is supposed that the current investigation can be a step forward in the representation of an efficacious photocatalytic system in the treatment of a wide range of contaminated aquatic environments.

A novel base-metal multifunctional catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes by a multicomponent tandem oxidation process

A novel base-metal multifunctional nanomagnetic catalyst is prepared by the immobilization of tungstate anions onto γ-Fe₂O₃ supported with imidazolium moieties. The (γ-Fe₂O₃-Im-Py)₂WO₄ was fully characterized using FT-IR, XPS, TEM, FESEM, ICP, TGA, VSM and XRD and used as a multifunctional heterogeneous catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes via a multicomponent tandem oxidation process starting from alcohols under solvent-free conditions. During this process, tungstate catalyzes the oxidation of a wide range of alcohols in the presence of TBHP as a clean source. The in-situ formed aldehydes are condensed with malononitrile and β-dicarbonyl compounds/naphthols/4-hydroxycumarin through promotion by pyridine and imidazolium moieties of the catalyst. By this method, a variety of 2-amino-3-cyano-4H-chromenes are generated in good to high yields from alcohols as inexpensive and easily available starting materials. The catalyst is recovered easily by the aid of an external magnetic field and reused in five successive runs with insignificant decreasing activity.

Photocatalytic Homocoupling Transformations

Homocoupling reactions promoted by photocatalysts are not very abundant in the literature. However, the products generated from such processes are very interesting. In this review, we highlight the most relevant reports concerning photocatalyzed dimerizations covering the literature until the middle of 2020. Reactions will be classified according to the type of starting material employed, with an emphasis being placed on the corresponding mechanism.

1 Introduction

2 Arenes and Heteroarenes

3 Alkenes

4 Alkanes

5 Alkynes

6 Aldehydes, Ketones, Alcohols, Amines and Imines

7 Carboxylic Acids

8 Nitro Compounds

9 Conclusions

A new nanomagnetic Pd-Co bimetallic alloy as catalyst in the Mizoroki-Heck and Buchwald-Hartwig amination reactions in aqueous media

A Pd-Co bimetallic alloy encapsulated in melamine-based dendrimer supported on magnetic nanoparticles denoted as γ-Fe2O3@MBD/Pd-Co was synthesized by a facile co-complexation-reduction method and characterized sufficiently. The catalytic evaluation of γ-Fe2O3@MBD/Pd-Co showed promising results in the Mizoroki-Heck and Buchwald-Hartwig amination reactions of various iodo-, bromo- and challenging chloroarenes in aqueous media. The synergetic cooperative effect of both Pd and Co and dispersion of the catalyst in water due to the encapsulation of γ-Fe2O3 by melamine-based dendrimer lead to high catalytic performance compared with the monometallic counterparts. The dispersion of the magnetic catalyst also facilitates the recovery and reuse of the catalyst by ten consecutive extraction and final magnetic isolation with no loss of catalytic activity, keeping its structure unaltered.

Fe-MIL-101 modified by isatin-Schiff-base-Co: a heterogeneous catalyst for C–C, C–O, C–N, and C–P cross coupling reactions

Fe-MIL-101-isatin-Schiff-base-Co was synthesized and applied as a catalyst for Ullmann-type, Buchwald–Hartwig, Hirao, Hiyama and Mizoroki–Heck cross-coupling reactions of aryl halides.

Tandem imine formation via auto-hydrogen transfer from alcohols to nitro compounds catalyzed by a nanomagnetically recyclable copper catalyst under solvent-free conditions

A direct imination reaction was developed by tandem reaction of alcohols and nitro compounds in the presence of Cu-isatin Schiff base-γ-Fe₂O₃ as a nanomagnetically recyclable catalyst under solvent-free conditions. By this method, various imines were prepared in good to high yields from one-pot reaction of various alcohols (primary aromatic and aliphatic) and nitro compounds (aromatic and aliphatic) via an auto-hydrogen transfer reaction. Use of an inexpensive and easily reusable catalyst, without requiring any additives or excess amounts of benzyl alcohol as the reaction solvent are the other advantages of this method. This catalytic system has the merits of cost effectiveness, environmental benignity, excellent recyclability and good reproducibility.

A direct imination reaction was developed by tandem reaction of alcohols and nitro compounds in the presence of Cu-isatin Schiff base-γ-Fe₂O₃ as a nanomagnetically recyclable catalyst.

Photocatalytic degradation of model pharmaceutical pollutant by novel magnetic TiO2@ZnFe2O4/Pd nanocomposite with enhanced photocatalytic activity and stability under solar light irradiation

In the last decades, the use of magnetic nanocomposites as a catalyst was considered for removal of organic pollutants due to its easy separation. Therefore, initially, TiO₂@ZnFe₂O₄/Pd nanocomposite was prepared and then used in the photodegradation of diclofenac under direct solar irradiation in the batch and continuous systems. The structure, morphology and other specifications of produced nanocatalyst were determined via XRD, VSM, FESEM/EDX, FTIR, GTA, UV-Vis, Zeta potential, XPS and ICP-OES. The effective factors on diclofenac removal via nanophotocatalyst viz. pH, catalyst concentration, initial concentration of diclofenac, and flow rate and column length on diclofenac photodegradation were studied. Based on the results, the optimal rate for pH, catalyst concentration, and initial concentration of diclofenac was 4, 0.03 g/l and 10 mg/l respectively. Pd-coated TiO₂@ZnFe₂O₄ magnetic photocatalyst had higher photocatalytic activity in diclofenac photodegradation in relation to ZnFe₂O₄ and TiO₂@ZnFe₂O₄ under solar light irradiation. The findings showed that after five recycles, the photocatalytic efficiency did not show much reduction i.e. the removal efficiency from 86.1% in the first cycle reduced only to 71.38% in the last cycle. Likewise, in this study, with flow rate reduction and column length increase diclofenac degradation rate increased.

New Nanomagnetic Heterogeneous Cobalt Catalyst for the Synthesis of Aryl Nitriles and Biaryls

Cobalt nanoparticles immobilized on magnetic chitosan (Fe3O4@CS-Co) have been prepared. They were identified using various techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy analysis and applied efficiently as a cobalt catalyst in the cyanation and fluoride-/palladium-free Hiyama reactions of different types of aryl halides employing K4[Fe(CN)6]·3H2O and triethoxyphenylsilane, respectively. After each reaction, the catalyst was isolated and reused for the second run. The catalytic activity of the catalyst was not lost apparently even after five runs. No considerable changes in its chemical structure and morphology were observed. It is worth to note that in this paper, the cobalt catalyst has been used for the first time for the cyanation of aryl halides.

g-C3N4/γ-Fe2O3/TiO2/Pd: a new magnetically separable photocatalyst for visible-light-driven fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature

g-C₃N₄/γ-Fe₂O₃/TiO₂/Pd is developed as a new magnetically separable photocatalyst for efficient fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature under visible light irradiation.

Trend of fatal poisoning at national and provincial levels in Iran from 1990 to 2015

OBJECTIVES

Comprehensive and up-to-date data on fatal injury trends are critical to identify challenges and plan priority setting. This study provides a comprehensive assessment of poisoning mortality trends across Iran.

STUDY DESIGN

The data were gathered from various resources, including death registration systems, cemetery databases of Tehran and Esfahan, the Demographic and Health Survey of 2000, and three rounds of national population and housing censuses.

METHODS

After addressing incompleteness for child and adult death data separately and using a spatio-temporal model and Gaussian process regression, the level and trend of child and adult mortality were estimated. For estimating cause-specific mortality, the cause fraction was calculated and applied to the level and trend of death.

RESULTS

From 1990 to 2015, 40,586 deaths due to poisoning were estimated across the country. The poisoning-related age-standardized death rate per 100,000 was estimated to have changed from 3.08 (95% uncertainty interval [UI]: 2.32-4.11) in 1990 to 0.96 (95% UI: 0.73-1.25) in 2015, and the male/female ratio was 1.35 during 25 years of study with an annual percentage change of -5.4% and -4.0% for women and men, respectively. The annual mortality rate was higher among children younger than 5 years and the elderly population (≥70 years) in the study period.

CONCLUSIONS

This study showed that mortality from poisoning declined in Iran over the period from 1990 to 2015 and varied by province. Understanding the reasons for the differences of poisoning mortality by province will help in developing and implementing measures to reduce this burden in Iran.

A new bifunctional heterogeneous nanocatalyst for one-pot reduction-Schiff base condensation and reduction–carbonylation of nitroarenes

In this work, synthesis of Pd–NHC-γ-Fe₂O₃-n-butyl-SO₃H and its activity as a bifunctional heterogeneous nanocatalyst containing Pd–NHC and acidic functional groups, are described. This newly synthesized nanomagnetic catalyst is fully characterized by different methods such as FT-IR, XPS, TEM, VSM, ICP and TG analysis. At first, the catalytic activity of Pd–NHC-γ-Fe₂O₃-n-butyl-SO₃H is evaluated for the reduction of nitroarenes in aqueous media using NaBH₄ as a clean source of hydrogen generation at ambient temperature. Using the promising results obtained from the nitroarene reduction, this catalytic system is used for two one-pot protocols including reduction-Schiff base condensation and reduction–carbonylation of various nitroarenes. In these reactions the in situ formed amines are further reacted with aldehydes to yield imines or carbonylated to amides. The desired products are obtained in good to high yields in the presence of Pd–NHC-γ-Fe₂O₃-n-butyl-SO₃H as a bifunctional catalyst. The catalyst is reused with the aid of a magnetic bar for up to six consecutive cycles without any drastic loss of its catalytic activity.

This paper presents synthesis of Pd–NHC-γ-Fe₂O₃-n-butyl-SO₃H and its activity as bifunctional heterogeneous nanocatalyst containing Pd–NHC and acidic functional groups.

Application of magnetic ionomer for development of very fast and highly efficient uptake of triazo dye Direct Blue 71 form different water samples

This research focuses on removing Direct Blue 71 (DB 71) from aqueous solution in an efficient and very fast route by ionic liquid mediated γ-Fe₂O₃ magnetic ionomer. 2-hydroxyethylammonium sulphonate immobilized on γ-Fe₂O₃ nanoparticles (γ-Fe₂O₃-2-HEAS) was used for this purpose. The influence of shaking time, medium pH, the concentration of sorbent and NaNO₃ on removal was evaluated to greatly influence removal extent. The optimal removal conditions were determined by response surface methodology based on the four-variable central composite design to obtain maximum removal efficiency and determine the significance and interaction effect of the variables on the removal of target triazo dye. The results have shown that an amount of 98.2% as % removal under the optimum conditions. The adsorption kinetics and isotherms were well fitted to a pseudo-second order model and Freundlich model, respectively. Based on these models, the maximum dye adsorption capacity (Q_m) of 47.60mgg^-1 was obtained. Finally, the proposed nano-adsorbent was applied satisfactorily for removal of target triazo dye from different water samples.

P-arylation of aryl halides by an environmentally compatible method

In this paper, palladium–DABCO complex supported on magnetic nanoparticles was successfully used as a new magnetically recoverable heterogeneous catalyst for the synthesis of arylphosphonates via P-arylation of different types of aryl halides (aryl iodides/bromides/chlorides and benzene boronic acid/sulfonate), with phosphite esters (triethyl/triphenyl/tri-iso-propyl/diethyl/diphenyl/di-iso-propyl phosphite) in neat water without using any additive. The heterogeneous catalyst was easily isolated from the reaction mixture by an external magnet and reused five times without significant degradation in its activity.

Ionic liquids grafted onto graphene oxide as a new multifunctional heterogeneous catalyst and its application in the one-pot multi-component synthesis of hexahydroquinolines

The synergistic effect of ionic liquids and carboxylic acids in the reaction mechanism improved the catalytic activity of supported ILs.

Correction: Pd complex of an NNN pincer ligand supported on γ-Fe2O3@SiO2 magnetic nanoparticles: a new catalyst for Heck, Suzuki and Sonogashira coupling reactions

Correction for ‘Pd complex of an NNN pincer ligand supported on γ-Fe₂O₃@SiO₂ magnetic nanoparticles: a new catalyst for Heck, Suzuki and Sonogashira coupling reactions’ by Sara Sobhani et al., New J. Chem., 2015, 39, 7076–7085.

Synthesis of arylphosphonates catalyzed by Pd-imino-Py-γ-Fe2O3 as a new magnetically recyclable heterogeneous catalyst in pure water without requiring any additive

Arylphosphonates were synthesized in the presence of Pd-imino-Py-γ-Fe₂O₃ in pure water without using any additive.

Pd complex of an NNN pincer ligand supported on γ-Fe2O3@SiO2 magnetic nanoparticles: a new catalyst for Heck, Suzuki and Sonogashira coupling reactions

Pd-BIP-γ-Fe₂O₃@SiO₂ was used successfully as an air- and moisture-stable magnetically recyclable catalyst for Heck, Suzuki and Sonogashira coupling reactions.

A Pd complex of a NNN pincer ligand supported on γ-Fe2O3@SiO2 as the first magnetically recoverable heterogeneous catalyst for C–P bond forming reactions

A Pd complex of the NNN pincer ligand supported on γ-Fe₂O₃@SiO₂ was used as a new catalyst for a phosphonation reaction.

Pyridine-grafted graphene oxide: a reusable acid–base bifunctional catalyst for the one-pot synthesis of β-phosphonomalonates via a cascade Knoevenagel–phospha Michael addition reaction in water

Py–GO as a new acid–base bifunctional catalyst was synthesized and employed for the one-pot synthesis of β-phosphonomalonates in water.

Running with a minimalist shoe increases plantar pressure in the forefoot region of healthy female runners

OBJECTIVES

Minimalist running shoes have been proposed as an alternative to barefoot running. However, several studies have reported cases of forefoot stress fractures after switching from standard to minimalist shoes. Therefore, the aim of the current study was to investigate the differences in plantar pressure in the forefoot region between running with a minimalist shoe and running with a standard shoe in healthy female runners during overground running.

DESIGN

Randomized crossover design.

METHODS

In-shoe plantar pressure measurements were recorded from eighteen healthy female runners. Peak pressure, maximum mean pressure, pressure time integral and instant of peak pressure were assessed for seven foot areas. Force time integral, stride time, stance time, swing time, shoe comfort and landing type were assessed for both shoe types. A linear mixed model was used to analyze the data.

RESULTS

Peak pressure and maximum mean pressure were higher in the medial forefoot (respectively 13.5% and 7.46%), central forefoot (respectively 37.5% and 29.2%) and lateral forefoot (respectively 37.9% and 20.4%) for the minimalist shoe condition. Stance time was reduced with 3.81%. No relevant differences in shoe comfort or landing strategy were found.

CONCLUSIONS

Running with a minimalist shoe increased plantar pressure without a change in landing pattern. This increased pressure in the forefoot region might play a role in the occurrence of metatarsal stress fractures in runners who switched to minimalist shoes and warrants a cautious approach to transitioning to minimalist shoe use.

Lanthanum(iii) triflate supported on nanomagnetic γ-Fe2O3: a new magnetically recyclable heterogeneous Lewis acid for the one-pot synthesis of β-phosphonomalonates

A new magnetically recyclable heterogeneous Lewis acid was synthesized and used for the one-pot synthesis of β-phosphonomalonates.

2-Hydroxyethylammonium acetate as a reusable and cost-effective ionic liquid for the efficient synthesis of bis(pyrazolyl)methanes and 2-pyrazolyl-1-nitroalkanes

A new and convenient method for the synthesis of bis(pyrazolyl)methanes by one-pot tandem Knoevenagel–Michael reaction of 3-methyl-1-phenyl-5-pyrazolone with aryl, heteroaryl, or alkyl aldehydes in the presence of 2-hydroxyethylammonium acetate (2-HEAA) as a task-specific ionic liquid is described. This method was also successfully applied for the synthesis of 2-pyrazolyl-1-nitroalkanes by Michael addition of 3-methyl-1-phenyl-5-pyrazolone with β-nitrostyrenes in short reaction times. The present protocol offers several advantages such as using a reusable and cost-effective ionic liquid, an environmentally benign reaction media, being amenable to scale-up and good to high yields of the products.

Sulfonated multiwalled carbon nanotubes (MWCNTs) as a new, efficient, and recyclable heterogeneous nanocatalyst for the synthesis of amines

Sulfonated multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition (CVD) as a new and facile one-pot method using acetylene (as the CNT precursor), thiophene (as the sulfur precursor), and ferrocene (for in situ liberation of metal nanoparticles as the CNT nanocatalyst). A low catalytic amount of the resulting sulfonated MWCNTs with a turnover number (TON) up to 980 and a turnover frequency (TOF) up to 11 160 h–1 was utilized as a new and recyclable heterogeneous nanocatalyst for the efficient one-pot synthesis of various amines (secondary and tertiary) by direct reductive amination of aldehydes and ketones using NaBH4. The catalyst was easily isolated from the reaction mixture by simple filtration and reused at least five times without significant degradation in activity.

Epidemiology of ankle and foot overuse injuries in sports: A systematic review

Studies regarding ankle and foot overuse injuries are quite diverse in research methodology, data reporting, and outcomes. The aims of this systematic review were to analyze the methodology of published studies regarding ankle and foot overuse injuries in different sports disciplines and to summarize epidemiological data of ankle and foot overuse injuries. Four electronic databases, PubMed (MEDLINE), EMBASE, CINAHL, and SPORTDiscus(®) were systematically searched up to June 2011. A total of 89 articles on 23 sports disciplines were included in this review. Soccer, running, and gymnastics were the most frequently studied sports. Achilles tendinopathy, plantar fasciitis, and stress fracture were the most frequently studied injuries. Study design and reporting methods were heterogeneous. Most studies suffered from a weak methodology and poor reporting. The most common weaknesses were lack of a clear case definition, describing assessment procedures and reporting sample characteristics. Due to methodological heterogeneity of studies, inter-sports and intra-sports comparisons and meta-analysis were not possible. Methodology of most studies on incidence and prevalence of ankle and foot overuse injuries is insufficient. Based on the results, we recommend authors to clearly define cases, describe assessment procedures and report sample characteristics adequately.

Efficient synthesis of 2-indolyl-1-nitroalkanes catalyzed by tetramethyl-tetra-3,4-pyridinoporphyrazinato copper(II) methyl sulfate

A new method for the synthesis of 2-indolyl-1-nitroalkanes from indoles and β-nitrostyrene via Michael addition catalyzed by [ Cu (3,4-tmtppa)] (MeSO4)4 as a reusable catalyst under solvent-free conditions is described. This method has been also successfully applied for Michael addition of 3-methyl-1-phenyl-5-pyrazolone with β-nitrostyrenes.

Formylation of amines and alcohols using aminopropylated mesoporous SBA-15 silica (APMS) as an efficient and recyclable catalyst

Aminopropylated mesoporous SBA-15 silica (APMS) is introduced as a new, recyclable and efficient catalyst for the formylation of a variety of amines and alcohols by using readily available formic acid under solvent-free conditions.

Efficient synthesis of secondary and primary dialkyl α-aminophosphonates catalyzed by tetramethyl-tetra-3,4-pyridinoporphyrazinato copper(II) methyl sulfate under solvent-free conditions

An efficient method for the synthesis of secondary and primary dialkyl α-aminophosphonates under solvent-free conditions by one-pot reaction of aldehydes/ketones, amines/ammonium acetate and trialkyl/diethyl phosphite in the presence of a low catalytic amount of [ Cu (3,4-tmtppa)]( MeSO 4)4(0.16 mol%) as a highly stable and reusable catalyst, is described. By this method, aromatic, aliphatic, cyclic and heterocyclic aldehydes, hindered and cage ketones are converted into their corresponding α-aminophosphonates in good to excellent yields.