Dibenzyl Research Articles

A novel anion exchange membrane comprised of three aromatic units for fuel cells

Anion exchange membrane fuel cell (AEMFC) has made great progress recently due to the continuous improvement of anion exchange membrane (AEM). Aryl ether bond-free membranes are considered to be promising for improving the overall performance of AEMs. Here, we present a copolymer consisting of m-terphenyl, diphenyl ethane and biphenyl (PMDBP) to further enhance the microphase separation structure by introducing a third structural unit, biphenyl. Meanwhile, the more compact biphenyl structure enhances the mechanical strength of AEMs. Specifically, PMDBP AEMs possess superior OH- conductivity (up to 113 mS cm−1) and excellent mechanical properties (tensile strength up to 42 MPa). Furthermore, the PMDBP has an outstanding single-cell performance with a peak power density (PPD) of up to 95 mW cm−2 with a platinum-carbon (Pt/C) catalyst at 80°C in H2-air. In addition, PMDBP is provided with excellent durability, including NMR spectral consistency and over 90% ion conductivity retention in 1 M NaOH at 60°C for 720 h. This study provided a copolymer structure suitable for anion exchange membrane that can provide excellent performance for fuel cells and electrolyzers.

Development of a near‐infrared reflecting EVA cooling compound with flame retardant property

AbstractA high near‐infrared (NIR) reflective cooling compound with flame retardant characteristics was fabricated by incorporating antimony trioxide (Sb2O3) and decabrominated diphenyl ethane (DBDPE) into ethylene‐vinyl acetate copolymer (EVA). The solar reflectivity and cooling capacities of the control sample and EVA compounds with either Sb2O3 or DBDPE, and EVA composites embedded with Sb2O3 and DBDPE, were evaluated by ultraviolet–visible–near infrared analysis and temperature tests. The effect of Sb2O3 and DBDPE on the flammability, thermal behavior, and mechanical properties of EVA copolymer were determined via the UL‐94 burning test, limiting oxygen index (LOI), differential scanning calorimetry, thermogravimetric analysis, and tensile and tearing tests. Compared with the glass blank, EVA compound filled with 10 wt% Sb2O3 and 30 wt% DBDPE showed a roughly 17.3°C and 38.0°C decrease during sunlight exposure and in indoors, respectively, accompanied by the maximum NIR reflectivity of 68.8% in all as‐prepared blends. Moreover, this as‐prepared compound met a UL‐94 V‐0 classification and reached a LOI value of 29.3%. Notably, the singular addition of either Sb2O3 or DBDPE improved the cooling capability of EVA but rarely fulfilled the fire retardant demand. In contrast, the incorporation of Sb2O3 and DBDPE improved the desirable cooling and flame retardant properties.

Synthesis, Characterization and Structural Studies of Di benzyl dithiocarbamate and Use Them in CPE

In this study the Cloud Point Extraction has been used as a separation technique that uses a surfactant instead of organic solvents for phase separation. CPE has been alsoutilized as a pre-concentration strategy prior to the determination of trace levels of Copper and Nickel ions in water by flame atomic absorption spectrometry (FAAS). Di benzyl dithiocarbamate have beenprepared from amines in the presence of sodium salts and carbon disulfide. The prepared compounds were characterized by means of Elemental Analysis, IR, 1H NMR, Mass, and CHN spectroscopy. Application of the Cloud Point Extraction formation of the complexes dithiocarbamate with Copper and Nickel has been investigated, which was characterized by (UV-Vis), where it has been shown a stoichiometry of the complex. When Its ratio was 1:2, the results were identical to what is expected scientifically after studying the optimal experimental conditions. Then, the optimal conditions for the Cloud Point Extraction such as pH of the aqueous solution, concentration of the DDTC, amount of the surfactant, incubation temperature and time was covered. Under the optimal experimental conditions with a limit of detection, LOD at 0.012μg/ml, limit of quantization, LOQ, of 0.04μg/ml, and sensitivity of 5*10−3. The developed method was successfully applied for the determination of trace levels of lead ion in samples electrical power plant water.

Plastic additives and legacy persistent organic pollutants in the preen gland oil of seabirds sampled across the globe

Plastic pollution, and its associated impacts on marine fauna due to chemical contamination, is an area of growing global concern. We analyzed 145 preen gland oil samples from 32 seabird species belonging to 8 families with different foraging habits and life history strategies from around the world for plastic additives and legacy persistent organic pollutants. The additives included two brominated flame retardants (decabromodiphenyl ether, BDE209; decabromo diphenyl ethane, DBDPE) and six benzotriazole UV stabilizers (BUVSs; UVP, UV326, UV329, UV328, UV327, and UV234). Polychlorinated biphenyls (PCBs) and organochlorine pesticides (Dichlorodiphenyltrichloroethane and its metabolites: DDTs and hexachlorocyclohexane: HCHs) were detected ubiquitously. High concentrations of PCBs (up to 20,000 ng/g-lipid) were observed in the seabirds from higher-trophic level taxa. These patterns can be attributed to PCB exposure via their diet and associated biomagnification. DDT concentrations showed strong positive correlations with PCB concentrations, suggesting that DDTs in seabirds are also a result of diet and biomagnification. Plastic additives were detected sporadically as BDE209 and DBDPE were detected in 16 seabirds from 10 species (range: 3–379 ng/g-lipid) and BUVSs were detected in 46% (67) of the examined individuals (range: 2–7,055 ng/g-lipid). UV stabilizers were more frequently detected than flame retardants because UV stabilizers are more widely applied to plastic products. None of the plastic additives were correlated to the presence of PCBs, nor were they explained by the foraging area or trophic level. High concentrations of additives were detected in the species with high levels of plastic in their digestive tracts. In some of these species, such as Hawaiian petrels (Pterodroma sandwichensis) from Hawaii and flesh-footed shearwaters (Ardenna carneipes) from Western Australia, plastics were directly observed in the stomach. For other species, including great shearwaters (Ardenna gravis) from Gough Island, blue petrels (Halobaena caerulea) from Marion Island, and black-footed and Laysan albatrosses (Phoebastria nigripes and P. immutabilis) from Hawaii, plastic ingestion has been documented in literature. These patterns can be explained if the additives are mainly from ingested plastics rather than diet. The detection of BFRs and BUVSs demonstrated that a significant proportion of the examined seabirds accumulated chemicals from ingested plastics.

Evaluation of the Burdening on the Czech Population by Brominated Flame Retardants.

The completed environmental study was concerned with assessing the exposure of the Czech population to polybrominated diphenyl ethers (PBDEs). Simultaneously, the levels of polychlorinated pollutants such as polychlorinated biphenyls (PCBs) and chlorinated diphenyl ethanes (DDTs) were also monitored. The pollutant levels were newly measured in solid fat tissue removed during plastic surgery. A total of 107 samples of fat were taken from 19–76-year-old volunteers. A total of 16 PBDE congeners were determined, of which only six occur in more than 38% of fat tissue samples. The total PBDE level attains an average value of 3.31 ng/g, which is 25% less than was measured in 2009. On the other hand, there was an increase in the levels of two PCB congeners, which was caused by an increase of the total PCB concentration from level of 625.5 ng/g, published in 2009, to the current level of 776 ng/g. The level of DDTs decreased and currently has a value of 467.4 ng/g, which is about 24% lower than in 2009. The contamination of obese middle-aged women in Czechia by more modern types of pollutants, such as PBDEs, is incomparably lower than that by PCBs and DDTs and is also decreasing in time.

Dibenzyl Trisulphide (GUINEAHEN WEED) for Stage IV Cancer

Dibenzyl Trisulphide (GUINEAHEN WEED) for Stage IV Cancer

Growth and characterization of stilbene doped bibenzyl scintillator crystal by solution growth technique

The search for organic crystals with high efficient fast neutron detection with short decay time have become more demand nowadays. These are being used in the frontline areas in radiation medicine, neutron spectroscopy and special nuclear material detection. We explored the growth progress and characterized the pure and stilbene doped bibenzyl (BBS) organic scintillator crystal by solution growth technique. The solubility of bibenzyl was determined in methanol by thermogravimetric method. The grown crystal was subjected to single X-ray diffraction to find the cell parameters which shows the monoclinic structure. The crystallinity was examined by powder X-ray diffraction pattern. Fourier transform infrared spectra was carried out for the doped crystal and compared that of pure bibenzyl (BB) crystal. The absorption and transmittance range were measured by UV-Vis-NIR analysis. The emission spectrum was measured by photoluminescence, two significant peaks were observed at 353 and 373 nm. The grown BBS crystal decay time 0.8 and 1.65 ns was calculated for prompt and delayed emission by using pulsed nano-LED source. Thermal steadiness of BBS was verified by thermo-gravimetric and differential scanning calorimetry.

Discovery of efficient stimulators for adult hippocampal neurogenesis based on scaffolds in dragon's blood

Reduction of hippocampal neurogenesis caused by aging and neurological disorders would impair neural circuits and result in memory loss. A new lead compound (N-trans-3′,4'-methylenedioxystilben-4-yl acetamide 27) has been discovered to efficiently stimulate adult rats' neurogenesis. In-depth structure-activity relationship studies proved the necessity of a stilbene scaffold that is absent in highly cytotoxic analogs such as chalcones and heteroaryl rings and inactive analogs such as diphenyl acetylene and diphenyl ethane, and validated the importance of an NH in the carboxamide and a methylenedioxy substituent on the benzene ring. Immunohistochemical staining and biochemical analysis indicate, in contrast to previously reported neuroprotective chemicals, N-stilbenyl carboxamides have extra capacity for neuroproliferation-type neurogenesis, thereby providing a foundation for improving the plasticity of the adult mammalian brain.

Pyrolysis behaviors of two coal-related model compounds on a fixed-bed reactor

The bibenzyl (BB) and benzyloxybenzene (BOB) were selected as coal-related model compounds, and their pyrolysis behaviors between 500°C and 700°C were investigated on a fixed-bed reactor. The pyrolysis products were analyzed by gas chromatography–mass spectrometer (GC–MS) and gas chromatography (GC), and the bond dissociation energy (BDE) was calculated with density functional theory (DFT) methods at B3LYP/6-31G (d) level. The results showed that the conversion in pyrolysis of BOB was higher than that of BB. The pyrolysis product distributions and BDE calculation indicate that Caliphatic–Caliphatic bond dissociation is the primary step for BB pyrolysis, while Caliphatic–O bond dissociation is the primary step for BOB pyrolysis. The differences in pyrolysis behaviors between BB and BOB indicate that the existence of oxygen atom will reduce the BDE thus being preferentially dissociated under pyrolysis. The initial radicals should be stabilized by some more reactive radicals, which lead to higher liquid yield.

ChemInform Abstract: Antifungal Variant Bis(bibenzyl)s from the Liverwort Asterella angusta.

AbstractTwo antifungal bis(bibenzyl)s, riccardin I (I), and angustatin A (II), are isolated from the title plant.

Efficient DDT and trichlorophenol detoxification using NaBH4 and Devarda alloy

DDT—1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane—is a pesticide that has been widely used to control insects in agriculture. TCP—2,4,6-trichlorophenol—has been used in pesticide formulations as a preservative, disinfectant and antiseptic. Detoxification of DDT and TCP is very difficult due to their stable chemical structure. Here, a mixture of NaBH4 and Devarda alloy was applied for the first time to detoxify DDT and TCP. Results show 94 % dechlorination of DDT at 100 °C and 97 % dechlorination of TCP at 80 °C. The presence of diphenyl ethane suggests the complete dechlorination of DDT. The formation of benzene suggests a strong reduction. The method is efficient, cost-effective and may be applied at the industrial-level.

Application of Nanoscale Zero-Valent Iron in the Remediation of DDT from Contaminated Water

Nanoscale zero-valent iron (NZVI) was synthesized and tested to remediate DDT (Dichlorodiphenyltrichloroethane ) from the contaminated water. The influence of experimental variables such as reaction time, NZVI particle dosage and pH were studied. Mixing an aqueous solution of 3 mg L �1 DDT with 30 mg L -1 Fe 0 resulted in 99.2% loss of DDT within 4 h. Solvent extraction of the Fe 0 revealed that DDT removal was not through adsorption and as Fe 0 treatment of DDT lead to new chromatographic peaks (degradation products) in GC analysis and chloride release, removal occurred through dechlorination. GC/MS analysis confirmed the formation of completely dechlorinated hydrocarbon skeleton of DDT namely, diphenylethane (DPE), as the end product in this treatment; thereby implying the removal of all five chlorine atoms (three alkyl and two aryl) of DDT.

Concomitant polymorphism in the stereoselective of a ß-benzyl-ß-hydroxyaspartate analogue

Two concomitant polymorphs, (I) and (II), of a -benzyl- -hydroxyaspartate analogue [systematic name: dibenzyl 2-benzyl-2-hydroxy-3-(4-methylphenylsulfonamido)succinate], C32H31NO7S, crystallize from a mixture of ethyl acetate and cyclohexane at ambient temperature. The structure of (I) has triclinic (P1) symmetry and that of (II) monoclinic (P21/c) symmetry. Both crystal structures are made up of a stacking of homochiral racemic dimers (2S,3S and 2R,3R) which are internally connected by a similar R2 2(9) hydrogen-bonding pattern consisting of intermolecular N--H O andO--H O hydrogen bonds. The centroid of the racemic dimer lies on an inversion centre. The main structural difference between the two polymorphs is the conformational orientation of two of the four aromatic rings present in the molecule. Polymorph (II) is found to be twinned by reticular merohedry with twin index 3 and twin fractions 0.854 (1) and 0.146 (1).

The biliary metabolites of butylated hydroxytoluene in the rat.

Abstract The biliary metabolites from intravenous and intraperitoneal doses of small amounts of [14C]butylated hydroxytoluene have been separated and estimated. The metabolites recognized were the alcohol (II), aldehyde (III) and acid (IV) together with small amounts of the diphenyl ethane (VI). Three other metabolites appear to be present in relatively large amounts. The pattern of metabolites in bile and urine has been compared. It is suggested that the relatively low excretion of the acid (IV) in the urine compared to bile is due to a selective reabsorption of this compound after biliary excretion.

Synthesis of trans-stilbene through the hydrogenation of diphenylacetylene

Trans-stilbene ( trans-ST) was produced through the hydrogenation of diphenylacetylene (DPA). Pd-based intermetallic compounds (IMCs) supported on silica were applied to the selective hydrogenation of DPA into cis- and trans-ST. Pd 3Bi/SiO 2 showed the highest selectivity to stilbenes without accelerating the deep hydrogenation into diphenylethane (DPE), after DPA was completely converted. Proton-type zeolites were examined for the isomerization of cis-ST, the main product in the hydrogenation of DPA, into trans-ST. H-USY zeolite partially exchanged with Na + ions gave the highest activity owing to the appropriate acid strength and enough space inside the pores for cis-ST to enter. The mixture of Pd 3Bi/SiO 2 and H-USY gave trans-ST yield of 74 mol% through the one-pot reaction of DPA. The isomerization rate was significantly retarded by coexisting DPA and DPE molecules.

Vertical flow soil filter for the elimination of micro pollutants from storm and waste water

A technical scale activated soil filter has been used to study the elimination rates of diverse environmentally relevant micro pollutants from storm and waste water. The filter was made of layers of peat, sand and gravel. The upper (organic) layer was planted with reed ( phragmites australis) to prevent clogging and was spiked with activated sludge to enhance microbial biomass and biodegradation potential. Compounds used as UV filters, antioxidants or plasticizers, namely 4-methylbenzylidene camphor (4-MBC), benzophenone-3 (BP-3), butylated hydroxytoluene (BHT), N-butylbenzenesulfonamide (NBBS), 2,6-di- tert-butyl-1,4-benzoquinone (2,6-DTB-1,4-BQ), 1,1-biphenyl-3,3-dimethyl (1,1-BP-3,3-DM) and dibenzyl (DB) have been included in this study. The chemical characteristics of these compounds ranged from the hydrophilic (p K OW 2.6) to the lipophilic (p K OW 5) properties. For the elimination studies, synthetic waste water spiked to 3000 ng L −1 with the selected compounds was used. Elimination rates with low hydraulic load (61 L m −2 d −1, water retention time: 2 d) were higher than 96%. During a storm water simulation experiment (hydraulic load: 255 L m −2, water retention time: <1 h), the elimination rates of the most analytes decreased to 79–96%. The elimination performance of the hydrophilic compound NBBS declined to 21%. Balancing studies including the soil of the filter system revealed that degradation or transformation were both relevant elimination mechanism.

Tantalum−Benzylidene Complexes Supported by C5Me5 and Diazadiene Ligands: Synthesis, Kinetic Analysis of the Formation, and Reactive Studies

Reaction of half-metallocene dichloro complexes Cp*TaCl2(η4-supine-Ar-DAD) (1a: Ar = p-MeO; 1b: Ar = p-Me; 1c: Ar = p-F; 1d: Ar = p-Cl) (Cp* = pentamethylcyclopentadienyl; Ar-DAD = 1,4-di(aryl)-1,4...

Optical, electrical and photovoltaic properties of thermally annealed PPHT:DDE blend thin films

We have investigated the optical, electrical and photovoltaic properties of devices based on 1,2-diazoamino diphenyl ethane (DDE) and poly(3-phenyl hydrazone thiophene) (PPHT):DDE blend. It is observed from the J– V characteristics of the Al/DDE/ITO (ITO—indium tin oxide) device that the electron current injected from Al contact was shown to be space charge limited (SCL), indicating that Al forms nearly ohmic contact for electron injection into lowest unoccupied molecular orbital (LUMO) of DDE. The effect of thermal annealing and composition, on the optical, electrical and photovoltaic response of blend of PPHT and DDE sandwiched between a transparent ITO electrode and an Al back contact are investigated. The observed absorption quenching in the PPHT:DDE blend is attributed to the disordering of PPHT chains and charge transfer between PPHT and DDE as evidenced by FTIR spectra. The observed red shift in the absorption peak on thermal annealing is due to the improvement in the ordering and increases in conjugation length in PPHT. The observed dark current–voltage curves agree well with trap-controlled SCL transport theory. The photophysics of the blend material and influence of thermal annealing on the performance and morphology of these devices were discussed. Annealing process results in the formation of PPHT:DDE complex and increase in the ordering of polymer chain, that increases the incident photon to current efficiency (IPCE) and power conversion efficiency of the photovoltaic devices.

Fragmentation pathways and mechanisms of aromatic compounds in atmospheric pressure studied by GC–DMS and DMS–MS

Abstract Differential mobility spectrometry (DMS) is a highly sensitive sensing technology capable of selecting and detecting ions based on the difference between ion mobility at high and low electric field. The combination of a micro-fabricated DMS with gas chromatography (GC) has allowed extensive investigation of the ion chemistry and collisionally induced dissociation (CID) of diaryl molecules on a millisecond timescale at temperatures up to 130 °C. DMS-pre-filtered time-of-flight mass spectrometry (DMS–MS) has been used to verify the chemical composition of the ion species resolved by GC–DMS. This work focuses on the fragmentation of diaryl compounds, including diphenyl methane (DPM) and bibenzyl (BB), using information from the DMS and DMS–MS spectra of a series of aromatic compounds. Density functional theory calculations have been used to investigate the geometry and the energy along the reaction coordinate for the loss of benzene from DPM·H+ and BB·H+ for comparison with GC–DMS and DMS–MS experimental results and with previously reported chemical ionization MS. DPM–H+ is observed to undergo field-induced fragmentation in the DMS to produce C7H7+(Bz+) and unobserved neutral benzene with a low energy barrier. In contrast, BB·H+ fragments to C8H9+ and benzene with a higher energy barrier. Calculated barriers and experimental results are in qualitative agreement. Depletion of the ionized fragments in favor of ion-neutral clusters was also observed at higher concentrations. It is suggested that CID in DMS can further enhance DMS analytical performance.

The Prototypical Inhibitor of Cholesterol Esterification, Sah 58-035 [3-[Decyldimethylsilyl]-N-[2-(4-methylphenyl)-1-phenylethyl]propanamide], Is an Agonist of Estrogen Receptors

We have shown recently that estrogen receptor (ER) ligands share a diphenyl ethane pharmacophore with Sah 58-035 [3-[decyldimethylsilyl]-N-[2-(4-methylphenyl)-1-phenylethyl]-propanamide], a prototypical inhibitor of the acyl-cholesterolacyl-transferase (ACAT), which enabled us to establish that ER ligands were potent inhibitors of ACAT and blocked the formation of foam cells. In the present study, we have tested whether this structural similarity means that Sah 58-035 is an ER modulator. We report that Sah 58-035 bound to ERalpha and ERbeta with an IC(50) of 2.9 and 3.1 microM, respectively. Docking studies using molecular modeling of Sah 58-035 with the X-ray structure of the ER showed that Sah 58-035 fits well into the ligand binding site known for 4-hydroxy-tamoxifen. Despite having high three-dimensional structural similarities with the pure antiestrogen ICI 164,384 [(N-n-butyl-N-methyl-11-[3,17beta-di-hydroxyestra-1,3, 5(10)-trien-7alpha-yl]-undecanamide], we showed that Sah 58-035 is an agonist of ER for transcription and cellular proliferation. These data showed that Sah 58-035 was an estrogen receptor agonist and that the size and the chemical nature of the side chain were critical for agonist versus antagonist activity on ER. This new molecular mechanism of action for Sah 58-035 has to be taken into account in understanding better its pharmacological activities. Moreover, these data give new structural insights into the understanding of agonist versus antagonist activities of ER ligands and also for the conception of new drugs with a dual ACAT inhibition and ER modulation potential and their evaluation in different pathologies where both targets are involved, such as atherosclerosis, Alzheimer's disease, and cancer.