Cu@KCC-1-NH-CS2 as a new and highly efficient nanocatalyst for the synthesis of 2-amino-4H-chromene derivatives

In the present work, Cu@KCC-1-NH-CS₂ as a green, efficient, and reusable nano-reactor was designed and used for the one-pot, three-component synthesis of 2-amino-4H-chromene derivatives using the reaction of cyclic 1,3-diketones, arylglyoxals, and malononitrile, under reflux conditions in EtOH. Engineered nanocatalyst characterized using different methods including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), adsorption/desorption analysis (BET), and energy dispersive X-ray spectroscopy (EDS). According to the obtained results, presented protocol for the synthesis of 2-amino-4H-chromenes using Cu@KCC-1-NH-CS₂ gave the desired products in higher yields (89–98%) with short reaction times. Also, under mild reaction conditions this green nanocatalyst indicated recyclable behavior five times with minor reduce in its catalytic activity.     

Simultaneous fluorometry and phosphorometry of Langendorff perfused rat heart: ex vivo animal studies

Fluorescence imaging of intrinsic fluorophores of tissue is a powerful method to assess metabolic changes at the cellular and intracellular levels. At the same time, exogenous phosphorescent probes can be used to accurately measure intravascular tissue oxygenation. Heart failure is the leading cause of death in America. A rat heart can potentially model the human heart to study failures or other abnormalities optically. We report simultaneous fluorescence and phosphorescence measurements performed on a rat heart. We have used two different optical systems to acquire fluorescence signals of flavoprotein and nicotinamide adenine dinucleotide--the two intrinsic fluorophores of mitochondria--and the phosphorescence signal of an intravascular oxygen probe to extract intracellular and intravascular metabolism loads, respectively.     

Catalyst-free green synthesis of tetrahydro-benzo[b]pyrans in magnetized water: experimental aspects and molecular dynamics simulation

Research on Chemical Intermediates - In this work, magnetized water is applied as a green-promoting medium for the catalyst-free, one-pot, practical, efficient, and environmentally benign...     

Glycerol‐lactic acid star‐shaped oligomers as efficient biobased surface modifiers for improving superabsorbent polymer hydrogels

The glycerol‐lactic acid‐based star‐shaped modifier (SM) were synthesized and employed for surface modification of hygienic superabsorbent polymer (SAP) hydrogels for the first time. Surface crosslinking was carried out to increase the saline‐absorbency under load (AUL) and the swollen gel strength. The surface treatment process was analyzed employing free absorbency and AUL tests, salt sensitivity, attenuated total reflectance‐Fourier‐transform infrared spectroscopy (ATR‐FTIR), oscillatory rheometry, as well as scanning electron microscopy analysis. The effect of the branched architecture and the contents of SM on the properties of the modified SAPs were studied. The implementation of surface treatment leads to increase up to a 28% in the AUL of the modified SAP. Moreover, the loss modulus was surprisingly increased, while the storage modulus was enhanced (possibly due to the star architecture of oligomers). M_c and crosslink density values have been estimated based on modified rubber elasticity theory. Salt sensitivity factor (f) was calculated; the modified samples showed lower salt sensitivity in NaCl (f = 0.7) and CaCl₂ (f = 0.93–0.95) compared with the intact SAP (f = 0.84 for NaCl, and f = 0.95–0.97 for CaCl₂).     

Determination of copper ion by square wave anodic stripping voltammetry at antimony trioxide-modified carbon nanotube paste electrode

In this work, an antimony trioxide-modified multi-walled carbon nanotube paste electrode (Sb₂O₃/CNTPE) was employed for determination of Cu²⁺ ions by using square wave anodic stripping voltammetry (SWASV) in the presence of 8-hydroxy-7-iodo-5-quinoline sulfonic acid (HIQSA) as a chelating agent. The field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS) methods were applied to estimate the morphology and properties of the modified electrode. Measurements related to SWASV were taken in 0.6 M HCl at ?1.0 V versus Ag|AgCl|KCl (3 M) for 90 s (deposition step). After equilibrium time of 15 s, an ASV appeared at 0.0 V versus Ag|AgCl|KCl (3 M) (stripping step). The sensor depicted a fairly linear response for Cu²⁺ in the concentration range of 2–100 ppb with appropriate detection limit about 0.39 ppb and limit of quantification about 1.3 ppb. The stability of the modified electrode during 7 weeks and its behavior in the presence of some metal ions was evaluated. The practical applicability of the Sb₂O₃/CNTPE was established on the voltammetric determination of Cu²⁺ in tap water as a sample.     

Fe3O4@MCM-48–SO3H:合成苯并[f]色烯并[2,3-d]嘧啶酮的高效、可磁性分离纳米催化剂（英文）

Sulfonic acid groups were grafted onto three different types of synthesized magnetic nanoparticles, namely Fe3O4, Fe3O4@SiO2, and Fe3O4@MCM‐48. The sulfonic acid‐functionalized nanoparticles were evaluated as catalysts for the synthesis of 5‐aryl‐1H‐benzo[f]chromeno[2,3‐d]pyrimidine‐2,4(3H,5H)‐dione derivatives in terms of activity and recyclability. Their catalytic activities were compared with that of the homogeneous acid catalyst 1‐methylimidazolium hydrogen sulfate ([HMIm][HSO4]). The activity of Fe3O4@MCM‐48–SO3H was comparable to those of the other heter‐ogeneous and homogeneous catalysts.     

Synthesis and Cytotoxic Activity of Some Novel Dihyrobenzo[h]pyrano[3,2‐c]chromene Derivatives

Three‐component reaction of 4‐hydroxy‐2H‐benzo[h]chromen‐2‐one, aromatic aldehydes, and malononitrile in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) in ethanol at room temperature affords good yields of novel dihyrobenzo[h]pyrano[3,2‐c]chromene derivatives. The synthesized compounds examined by MTT assays for cytotoxic activity in two human cancer cell lines (MOLT‐4, HL‐60). Most of the evaluated compounds showed low inhibitory activity against tumor cell line at micromolar concentrations.     

Polar/nonpolar gas transfer through PEO-based copolymers membranes

Two PEG-based copolymers containing two different chain extenders, as hard segments, were synthesized by 4,4′-methylenediphenyl diisocyanate (MDI). The chain extenders were 1,4-butane diol (BDO) and 1,2-ethane diamine (EDA). The application of the polyurethane (PU) and poly(urethane-urea)s (PUU)s synthesized polymers, which were characterized by Fourier transform infrared spectrometer (FTIR), differential scanning calorimetry (DSC) and atomic Force Microscopy (AFM), in the gas permeability was investigated. The obtained results indicated that by replacing the urea linkage in the polymers, the microphase separation of hard and soft segments increased. The synthesized PEG-based copolymers were semi-crystalline at room temperature. According to the DSC results, the crystallinity of the synthesized polyurethanes decreased as temperature increased. In addition, a reduction in mean surface roughness could be seen based AMF information. The gas (carbon dioxide and methane) separation properties of the polymers revealed that by replacing the urea linkage, the diffusivity, permeability and selectivity of the gases increased slightly.

The solubility and diffusivity of gases indicated he solubility domination of gas transport in these membranes. However, the sorption coefficient (S) of a particular gas was surprisingly constant for the two synthesized polymers. The CO₂ permeability increased with increasing feed pressure, while CH₄ permeability remained almost constant at both temperatures of 25°C and 35°C. The increase in temperature led to an increase in the permeability of the gases and a decrease in the gas selectivity for the both synthesized polyurethanes.     

Direct Determination of Pyrethroids in Aqueous Samples by a Metal Organic Framework “MIL-101(Cr)” Sorbent for Solid-Phase Extraction and Thermal Desorption Coupled with GC-FID

Journal of Analytical Chemistry - In this study, an online solid-phase extraction-thermal desorption method coupled with gas chromatography-flame ionization detection was used to extract seven...     

Palladium nanoparticles immobilized on Schiff base‐functionalized mesoporous silica as a highly efficient and magnetically recoverable nanocatalyst for Heck coupling reaction

A new magnetically recoverable nanocatalyst was prepared by functionalization of mesoporous silica (SBA‐15) with a Schiff base ligand, and then immobilization of palladium nanoparticles on it using a simple procedure. This heterogeneous catalyst was fully characterized using appropriate analyses and its catalytic efficiency was investigated in Heck reaction using iodo‐, bromo‐ and chlorobenzene derivatives and styrene, with the aim of synthesizing stilbene derivatives, a class of compounds with a variety of pharmacological properties. Some of the characteristics of this nanocatalyst include good dispersion of palladium nanoparticles on the SBA‐15 support, easy separation, catalyses the production of stilbene derivatives in a short time with excellent yields even for bromo‐ and chlorobenzene, and preservation of its catalytic activity after eight reaction cycles.