Encapsulation of Candida antarctica lipase B in metal-organic framework under ultrasound and using it to one-pot synthesis of 1,3,4,5-tetrasubstituted pyrazoles.

Encapsulating the enzyme in metal-organic frameworks (MOFs) is a convenient method to prepare MOF-enzyme biocomposite. In this study, Candida antarctica lipase B (CAL-B) was chosen to immobilize in Cu-BTC MOF under ultrasound irradiation. CAL-B was immobilized in Cu-BTC under ultrasound at 21 kHz and 11.4 W/cm2 and incubation. 98% of CAL-B was immobilized in Cu-BTC with 99 U/mg activity (threefold more active than the free CAL-B). The prepared biocomposite was characterized using FT-IR, XRD, TGA, SEM, EDX, and BET. The thermal and solvent stability of CAL-B@Cu-BTC was investigated. It was found that at a temperature of 55 â„ƒ, CAL-B@Cu-BTC maintains its activity even after 2 h of incubation. Furthermore, in the presence of 20% and 50% concentrations of MeCN, THF, and DMF, CAL-B@Cu-BTC was found to have an activity of over 80%. A prepared biocatalyst was used to synthesize 1,3,4,5-tetrasubstituted pyrazole derivatives (50-75%) in a one-pot vessel, by adding phenyl hydrazine hydrochlorides, benzaldehydes, and dimethyl acetylenedicarboxylate.

Introducing Bluish-Green Light-Emitting Diodes (OLEDs) and Tuning Their Color Intensity by Uranium Complexes: Synthesis, Characterization, and Photoluminescence Studies of 8-Hydroxyquinoline Complexes of Uranium.

To improve our understanding of the chemistry of actinide complexes and to spur their development in the field of actinide markers, two new uranium complexes were synthesized using 8-hydroxyquinoline and 5,7-dichloro-8-hydroxyquinoline. The prepared complexes were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet-visible spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The impact of the electron-withdrawing group of the ligand on the photoluminescence spectra of the complexes in solution and in the solid state was scrutinized. The bandgap of the complexes was calculated using the density functional theory (DFT) method to investigate the effects of the electron-withdrawing groups on energy levels. The synthesized uranium complexes demonstrated appropriate levels of the lowest unoccupied molecular orbital energy, leading to favorable dye stability. The prepared uranium complexes showed blue fluorescent emission, and the sample with the most intense fluorescence was used to construct bluish-green organic light-emitting diodes using simple solution processing fabrication methods. Absorbance spectra, emission spectra, DFT-calculated energy levels, and comparisons of the fabricated organic light-emitting diodes indicated that the electron-withdrawing group was a key factor in photoluminescence behavior.

Dispersive magnetic solid-phase extraction of phthalate esters from water samples and human plasma based on a nanosorbent composed of MIL-101(Cr) metal-organic framework and magnetite nanoparticles before their determination by GC-MS.

In this study, a magnetic metal-organic framework was synthesized simply and utilized in the dispersive magnetic solid-phase extraction of five phthalate esters followed by their determination by gas chromatography with mass spectrometry. First, MIL-101(Cr) was prepared hydrothermally in water medium without using highly corrosive hydrofluoric acid, utilizing an autoclave oven heat supply. Afterward, Fe3 O4 nanoparticles were decorated into the matrix of MIL-101(Cr) to fabricate magnetic MIL-101 nanocomposite. The nanocomposite was characterized by various techniques. The parameters affecting dispersive magnetic solid-phase extraction efficiency were optimized and obtained as: a sorbent amount of 15 mg; a sorption time of 20 min; an elution time of 5 min; NaCl concentration, 10% w/v; type and volume of the eluent 1 mL n-hexane/acetone (1:1 v/v). Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.08-0.15 and 0.5-200 µg/L, respectively. The intra- and interday RSD% values were obtained in the range of 2.5-9.5 and 4.6-10.4, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the model analytes in water samples, and human plasma in the range of microgram per liter and satisfactory results were obtained.

Preparation and characterization of the pH and thermosensitive magnetic molecular imprinted nanoparticle polymer for the cancer drug delivery.

A novel pH and thermosensitive magnetic nanoparticle polymer composite [poly(NIPAAM@Fe3O4 MNPs/TMSPMC/DOX)] was synthesized by radical polymerization of N-isopropylacrylamide (NIPAAM) and the methacrylate functionalized Fe3O4 nanoparticles/DOX complex using AIBN and EGDMA, and used as a drug carrier for the DOX drug delivery. Formation of poly(NIPAAM@Fe3O4 MNPs/TMSPMC/DOX) was confirmed by FTIR, XRD, UV-Vis, VSM, TGA-DTA and SEM. The results showed the high DOX loading controls release. Moreover, it showed the lower critical solution temperature of 40°C which can be beneficial in cancer drug delivery, since the temperature of cancer cells is higher than normal ones, and DOX can be released selectively in cancer cells.

Porous-membrane-protected polyaniline-coated SBA-15 nanocomposite micro-solid-phase extraction followed by high-performance liquid chromatography for the determination of parabens in cosmetic products and wastewater.

A SBA-15/polyaniline para-toluenesulfonic acid nanocomposite supported micro-solid-phase extraction procedure has been developed for the extraction of parabens (methylparaben, ethylparaben, and propylparaben) from wastewater and cosmetic products. The variables of interest in the extraction process were pH of sample, sample and eluent volumes, sorbent amount, salting-out effect, extraction and desorption time, and stirring rate. A Plackett-Burman design was performed for the screening of variables in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by using a central composite design. The optimum experimental conditions found at 50 mL sample solution, extraction and desorption times of 40 and 20 min, respectively, 500 µL of 3% v/v acetic acid in methanol as eluent, 0.01 M salt addition, and 10 mg of the sorbent. Under the optimum conditions, the developed method provided detection limits in the range of 0.08-0.4 ng/mL with good repeatability (RSD% < 7) and linearity (r(2) = 0.997-0.999) for the three parabens. Finally, this fast and efficient method was employed for the determination of target analytes in cosmetic products and wastewater, and satisfactory results were obtained.

Occurrence of non-steroidal anti-inflammatory drugs in Tehran source water, municipal and hospital wastewaters, and their ecotoxicological risk assessment.

Pharmaceuticals are becoming widely distributed in waters and wastewaters and pose a serious threat to public health. The present study aimed to analyze non-steroidal anti-inflammatory drugs (NSAIDs) in surface waters, drinking water, and wastewater in Tehran, Iran. Thirty-six samples were collected from surface waters, tap water, and influent and effluent of municipal and hospital wastewater treatment plants (WWTP). A solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry method was used for the determination of pharmaceuticals, namely ibuprofen (IBP), naproxen (NPX), diclofenac (DIC), and indomethacin (IDM). IBP was found in most of the samples and had the highest concentration. The highest concentrations of NSAIDs were found in the municipal WWTP influents and hospital WWTP effluents. In the municipal WWTP influent samples, the concentrations of IBP, NPX, DIC, and IDM were 1.05, 0.43, 0.23, and 0.11 µg/L, respectively. DIC was found only in one river sample. All NSAIDs were detected in tap water samples. However, their concentration was very low and the maximum values for IBP, NPX, DIC, and IDM were 47, 39, 24, and 37 ng/L, respectively, in tap water samples. Results showed that the measured pharmaceuticals were detected in all rivers with low concentrations in nanograms per liter range, except DIC which was found only in one river. Furthermore, this study showed that the aforementioned pharmaceuticals are not completely removed during their passage through WWTPs. A potential environmental risk of selected NSAIDs for the urban wastewater has been discussed. However, given their low measured concentrations, no ecotoxicological effect is suspected to occur.

N-Functionalized L-proline anchored MCM-41: a novel organic-inorganic hybrid material for solvent-free aminolysis of styrene oxide under microwave irradiation.

A novel organic-inorganic hybrid material, namely L-prol-N-pMCM-41, was synthesized via two steps by covalently anchoring N-functionalized proline derivative (L-prol-N-pTMS) into the pore channels of MCM-41 silica. The prepared material was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), nitrogen adsorption-desorption isotherm, Brunauer-Emmett-Teller (BET) surface area analysis, and Fourier Transform Infrared spectroscopy (FTIR). The immobilized catalyst demonstrated moderate to high catalytic activity and excellent regioselectivity for the ring opening of styrene oxide with aniline derivatives under microwave irradiation and solvent-free conditions. The catalyst could be rapidly separated from the reaction mixture and reused up to five runs with good conversion and high regioselectivity.

Novel modified carbon nanotubes as a selective sorbent for preconcentration and determination of trace copper ions in fruit samples.

In this work, multiwalled carbon nanotubes were reacted with N-[3-(triet-hoxysilyl)propyl]isonicotinamide to prepare pyridine-functionalized carbon nanotubes. This novel sorbent was characterized by infrared spectroscopy, thermal and elemental analysis, and scanning electron microscopy. Functionalized carbon nanotubes were applied for the preconcentration and determination of copper ions using flame atomic absorption spectrometry. Various parameters such as sample pH, flow rate, eluent type and concentration, and its volume were optimized. Under optimal experimental conditions, the limit of detection, the relative standard deviation, and the recovery of the method were 0.65 ng/mL, 3.2% and 99.4%, respectively. After validating the method using standard reference materials, the new sorbent was applied for the extraction and determination of trace copper(II) ions in fruit samples.

Application of a magnetic molecularly imprinted polymer for the selective extraction and trace detection of lamotrigine in urine and plasma samples.

Magnetic molecularly imprinted polymers have been synthesized for the selective preconcentration and trace determination of lamotrigine (LTG) in urine and plasma samples. The magnetic nanoparticles were modified by tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane before imprinting. The magnetic molecularly imprinted polymers were prepared via surface molecular imprinting technique, using Fe3 O4 as a magnetic component, LTG as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and 2,2'-azobisisobutyronitrile as a radical initiator in methanol/acetonitrile (50:50, v/v) as the porogen. The obtained sorbent was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal analysis. Separation of the sorbent from the sample solution was simply achieved by applying an external magnetic field. Determination of the extracted drug was performed by high-performance liquid chromatography with UV detection. Under the optimum extraction conditions, the method detection limits were 0.7 µg/L (based on S/N of 3) for urine samples and 0.5 µg/L for plasma samples. A linear dynamic range of 1-1000 µg/L was obtained for LTF in plasma and urine samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of LTG in urine and plasma samples.

One-Pot Synthesis of 1,3,5-Trisubstitued Pyrazoles via Immobilized Thermomyces lanuginosus Lipase (TLL) on a Metal-Organic Framework.

A regioselective enzyme-catalyzed system is selected for the synthesis of 1,3,5-trisubstituted pyrazole derivatives by adding phenyl hydrazines, nitroolefins, and benzaldehydes. The reaction is performed in a one-pot vessel with a yield ranging from 49 to 90%. TLL@MMI, immobilized Thermomyces lanuginosus lipase (TLL) on a multivariate of MOF-5/IRMOF-3 (MMI), showed good performance for the catalysis of this reaction. The prepared biocatalyst was characterized by FTIR, XRD, SEM, and EDX. The thermal and solvent stability of TLL@MMI was investigated in MeOH and EtOH after 24 h incubation. In the presence of 100% concentrations of EtOH, TLL@MMI has 80% activity.

A high selective ion-imprinted polymer grafted on a novel nanoporous material for efficient gold extraction.

In this work, for the first time, an ion-imprinted polymer was developed for selective extraction and determination of gold ions. To increase the sorbent efficiency, this polymer was coated on a novel nanoporous carbon-based material, carbohydrate-derived Max-Planck Gesellschaft 1, which is also the first example of grafting imprinted polymer on nanoporous-carbon material. These particles were applied successfully for preconcentration of ultratrace amount of gold ions, following determination by flame atomic absorption spectrometry. Some effective factors on the efficiency of gold ions extraction, such as concentration and volume of eluent, sample and eluent flow rates, and also effect of interfering ions especially palladium and platinum ions, were investigated. The LOD was determined to be 0.27 ng/mL. Furthermore, the precision of the method was calculated to be 2.14% under optimal conditions with recovery more than 97.3%. The technique was also used to determine the concentration of gold ions in mine stone samples with satisfactory results. The accuracy of this method was investigated by determination of gold ions concentrations in several reference materials with certified gold content.

Pyridine-2,6-diamine-functionalized Fe3O4 nanoparticles as a novel sorbent for determination of lead and cadmium ions in cosmetic samples.

A novel sorbent based on pyridine-2,6-diamine-functionalized Fe(3)O(4) nanoparticles was developed and characterized by X-ray powder diffraction (XRD), elemental analysis, IR spectroscopy and scanning electron microscopy (SEM). The application of the sorbent was investigated for pre-concentration and determination of lead and cadmium ions in aqueous samples. Effects of various factors such as the sample pH, eluent parameters (type, concentration and volume) and time (adsorption and desorption) were appraised. The effects of several interfering ions on method recovery were also investigated. The limit of detection (LOD) was found to be 1.3 and 0.089 µg L(-1) for lead and cadmium ions, respectively. Recovery and precision (RSD%) of the method were above 97.9% and below 0.6%, respectively. Validation of the outlined method was performed by analysing several certified reference materials. This method was successfully used for determination of lead and cadmium ions in several cosmetic samples, which are usually contaminated by lead and cadmium ions.

Chromate removal using novel modified MCM-41 nanoporous silica: synthesis and characterization of novel terpyridine-modified MCM-41.

Novel terpyridine-functionalized MCM-41 nanoporous silica was synthesized and characterized by X-ray powder diffraction (XRD), infrared (IR) spectroscopy, transmission electron microscopy (TEM), and thermal (TGA-DSC) and elemental analyses. The application of functionalized nanoporous silica was investigated for the removal of chromate, which is one of the most harmful pollutants in the environment. The effects of several parameters including the sample pH, adsorption kinetic and maximum adsorption capacity of functionalized nanoporous silica in the removal of chromate were studied.

Synthesis and characterization of 8-hydroxyquinoline complexes of tin(IV) and their application in organic light emitting diode.

A series of 8-hydroxyquinoline complexes of tin, Q(2)SnCl(2) (Q = 2-methyl-8-hydroxyquinoline, 8-hydroxyquinoline, 5,7-dibromo-8-hydroxyquinoline, 5-chloro-8-hydroxyquinoline, 5,7-dichloro-8-hydroxyquinoline and 5-nitro-8-hydroxyquinoline) were prepared by reacting stannous dichloride with 8-hydroxyquinoline and its derivatives. All complexes were characterized by elemental analysis, mass spectrometry and infrared, UV-vis and (1)H NMR spectroscopes. Furthermore, the molecular structure of a representative complex, dichlorido-bis(5-nitro-quinolin-8-olato-2N,O)tin(IV), was determined by single-crystal X-ray diffraction. The photoluminescence (PL) properties of all prepared compounds and electroluminescence (EL) property of a selected complex (Q = 5-chloro-8-hydroxyquinoline) were investigated. The results showed that the emission wavelength can be tuned by electron donating or withdrawing group substituent on 8-hydroxyquinoline. Application of prepared complexes in fabrication of an OLED has been demonstrated.

Preparation and Characterization of a New Example of a Double Salt of Nickel(II) Complexes.

A new double salt of nickel(II) complexes, formulated as, [Ni(bipy)(H2O)4][Ni(H2O)6][Ni(pydc)2]2 • 6H2O, (1), (pydc = pyridine-2,6-dicarboxylate anion, bipy = 2,2'-bipyridine) has been hydrothermally synthesized. Complex was characterized by FT-IR spectroscopy, elemental analysis and X-ray diffraction studies. The compound 1 consists of [Ni(H2O)6]2+, [Ni(bipy)(H2O)4]2+, two symmetry-independent anionic complexes [Ni(pydc)2]2- and six co-crystallized water molecules. In the crystal structure of compound 1, the formation of extensive O-H…O hydrogen bonds between uncoordinated water molecules and cationic or anionic complexes play important roles in stabilizing the corresponding lattice and formation of 3-dimensional networks.

Diaqua-dichloridomethyl-phenyl-tin(IV)-1,4,7,10,13-penta-oxacyclo-penta-decane (1/1).

The asymmetric unit of the title cocrystal, [Sn(CH(3))(C(6)H(5))Cl(2)(H(2)O)(2)]·C(10)H(20)O(5), contains two independent for-mula units. The organotin molecules exhibit a six-coordinate metal atom and are linked to the crown ether molecules by water-crown ether O-H⋯O hydrogen bonds into a linear chain running along [101]. Each coordinated water mol-ecule forms a pair of hydrogen bonds to the same crown ether; for the crown ether mol-ecules, only four of the five O atoms are engaged in hydrogen-bonding inter-actions. The metal ions show a distorted trans-C(2)SnCl(2)O(2) octa-hedral coordination geometry [C-Sn-C = 175.3 (1) and 178.9 (1)°].

Dimeth-yl(1,10-phenanthroline-κ(2) N,N')bis-(thio-cyanato-κN)tin(IV).

The Sn(IV) atom in the title compound, [Sn(CH3)2(NCS)2(C12H8N2)], is located on a twofold rotation axis in a distorted octa-hedral enviroment. The methyl groups are trans to each other [C-Sn-C = 175.7 (3)°], whereas the thio-cyanate groups are cis to each other.

Di-µ2-ethano-lato-octa-methyl-bis-(µ-4-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-ido-κ(2) N (1):N (2))di-µ3-oxido-tetra-tin(IV).

The tetra-nuclear title compound, [Sn4(CH3)8(C2H5O)2O2(C3H4N3S)2], lies about a center of inversion; the mol-ecule features a three-rung-staircase Sn4O4 core in which two Sn(IV) atoms are bridged by the 4-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-ide group. The negatively charged N atom of the group binds to the terminal Sn(IV) atom at a shorter distance [Sn-N = 2.240 (3) Å] compared with the neutral N atom that binds to the central Sn(IV) atom [Sn← N = 2.641 (3) Å]. The terminal Sn(IV) atom is five-coordinate in a cis-C2SnNO2 trigonal-bipyramidal geometry [C-Sn-C = 127.5 (2)°], whereas the central Sn(IV) atom is six-coordinate in a C2SnNO3 skew-trazepoidal bipyramidal geometry [C-Sn-C = 145.0 (2)°].

Di-µ2-isopropano-lato-octa-methyl-bis-(µ-4-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-ido-κ(2) N (1):N (2))di-µ3-oxido-tetra-tin(IV).

The tetra-nuclear title compound, [Sn4(CH3)8(C3H7O)2O2(C3H4N3S)2], lies about a center of inversion; the mol-ecule features a three-rung-staircase Sn4O4 core in which two Sn(IV) atoms are bridged by the 4-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-ide group. The negatively charged N atom of the group binds to the terminal Sn(IV) atom at a shorter distance [Sn-N = 2.236 (2) Å] compared with the neutral N atom that binds to the central Sn(IV) atom [Sn← N = 2.805 (2) Å]. The terminal Sn(IV) atom is five-coordinate in a cis-C2SnNO2 trigonal-bipyramidal geometry [C-Sn-C = 136.4 (1)°], whereas the central Sn(IV) atom is six-coordinate in a C2SnNO3 skew-trazepoidal bipyramidal geometry [C-Sn-C = 145.4 (1)°]. The C atoms of the isopropoxy group are disordered over two positions in a 0.591 (7):0.409 (7) ratio.

[µ-1,2,3,4-Tetra-kis(pyridin-4-yl)butane-κ(2) N (1):N (4)]bis-[trimeth-yl(thio-cyanato-κN)tin(IV)].

In the title compound, [Sn2(CH3)6(NCS)2(C24H22N4)], the 1,2,3,4-tetra-kis-(pyridin-4-yl)butane ligand uses the pyridine N atoms at the ends of the butyl chain to coordinate to two trimethylthiocyanatotin(IV) units, forming a dinuclear structure. The Sn(IV) atom in the mol-ecule shows a distorted trans-trigonal-bipyramidal coordination with the methyl groups in equatorial positions. The mol-ecule lies on a center of inversion, with the mid-point of the butyl chain coinciding with this symmetry element. In the crystal, weak C-H⋯π inter-actions occur between pyridine rings of adjacent mol-ecules.