Polyarylenes and Poly(arylenevinylene)s, V. Synthesis of Tetraalkyl‐Substituted Oligo(1,4‐
aphthylene)s and Cyclization to Soluble Oligo(peri‐
aphthylene)s2)
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AbstractA homologous series of oligo(1,4-naphthylene)s from the binaphthyl 6 to the sexinaphthylene derivative 10 were synthesized successively. The Pd(O)-catalyzed reaction between aryl bromides and arylboronic acids was used as a coupling method. By appropriate choice of the stoichiometry, the method allowed isolation of the intermediates 20 and 21. Under the influence of potassium in 1,2-dimethoxyethane the 1,4-bridged naphthylenes 6—10 were partially cyclized to perylene and terrylene units. This anionic cyclization displayed a high regioselectivity. Complete cyclization to the oligorylenes 3b, 4b and 5b was achieved under the influence of AlCl3 and CuCl2 on the bichromophoric systems 24, 25 and 28. The synthetic sequence allowed substitution by tert-butyl groups, so that the oligorylenes 2b, 3b, 4b and 5b were amenable to spectroscopic investigations. The trends in absorption maxima and fluorescence are discussed.Do you want to read the rest of this article?Request full-text
CitationsCitations99ReferencesReferences23Consequently, the perylene and terrylene emit strong fluorescence while the quaterrylene and longer rylenes show much weaker or undetectable fluorescence as observed in experiments. [57, 58] Following the molecular design rule based on the quantity ?, we try to vary the frontier orbital nature by introducing the electron-withdrawing heteroatom bridges along the side-chain (seen in Scheme 4). ABSTRACT: Theoretical understanding of organic light-emitting diodes (OLEDs) started from the quest to the nature of the primary excitation
in organic molecular and polymeric materials. We found the electron correlation strength, bond-length alternation as well
as the conjugation extent, have strong influences on the orderings of the lowest-lying excited states through the first application
of density matrix renormalization group (DMRG) theory to quantum chemistry. The electro-injected free carriers (with spin
1/2) can form both singlet and triplet bound states. We found that the singlet exciton formation ratio can exceed the conventional
25% spin statistics limit. We proposed a vibration correlation function formalism to evaluate the excited state decay rates,
which is shown to not only give reasonable estimations for the quantum efficiency but also a quantitative account for the
aggregation-induced emission (AIE). It is suggested to unravel the AIE mechanism through resonant Raman spectroscopy.Article · Apr 2016 ABSTRACT: Two different approaches for the synthesis of structurally defined ladder-type polymers are described. Repetitive Diels-Alder reaction as well as polymer analogous cyclization of suitable open-chain precursors are used for generating novel band-type structures. Polymeric [2.2]-cyclophanes and ethene-bridged polyacene precursors are prepared via [4 + 2] cycloaddition reactions. Ladder-type poly(p-phenylene) and oligo(perinaphthylenes) as planar π-systems are obtained by Friedel-Crafts- rsp. by alkali-metal induced electrocyclic ring-closure reactions.Article · Feb 1992 +1 more author...ABSTRACT: Communication: The relationship between charge-storage capacity and pi-topology in conjugated polymers needs to be understood in order to optimize polymer structures for use in, for example, anodic electrodes in secondary lithium battery elements. Cyclic voltammetry has been used to study the redox behavior of conjugated oligomers related to that shown in the figure.Article · Feb 1992 +1 more author...ABSTRACT: The energy spectrum of a group of poly(periacene)s (PPAcs) is investigated theoretically. The topological (Δtop), geometrical (Δgeom) and correlation (Δcorr) contributions to the energy gap ΔE∞ are examined, with . If the number of benzene rings n within the elementary unit reaches infinity (), the bandgap vanishes, but the ΔE∞(n) values do not decrease in a monotonic fashion. It appears that PPAc can be classified into the following two series: the (3n+2) and the (3n+p) series with p = 1, 3; in each series ΔE∞ decreases monotonically. The frontier MOs of the two series, which determine the energy gap, belong to different irreducible representations of the symmetry group D(2m)h. The MOs of the (3n+2) series are symmetric with respect to reflection in the mirror plane σh, while the MOs of the (3n+p) series are symmetric. The connection between the symmetry of the frontier MOs and the energy spectrum of the PPAcs is discussed.Article · Apr 1992 +1 more author...ABSTRACT: Conductivity and charge-storage capacity of conjugated polymers are significant properties with respect to applications of these materials. The actual macromolecules are not the appropriate objects to investigate in order to gain a deeper understanding of the charging mechanisms of electroactive polymers. Therefore, we turned to the synthesis of structurally defined soluble oligomers, which differ in the nature of the building blocks and in the mode of linkage, as models for electroactive polymers. The title systems 1–15 were investigated by cyclic voltammetry in solution. Information can be gained on the relationship between the structure and electronic properties, which in turn can be extrapolated towards the corresponding polymers. A general division into two categories, conducting polymers and redox polymers, borderline cases arise, however, if the conjugative interaction of the electroactive building blocks suffers from severe steric hindrance.Article · Apr 1992 ABSTRACT: The synthesis of two novel n-alkyl- or aryl-substituted perylenes and of an n-alkylated terrylene is possible by an alkalimetal induced cyclization of the corresponding bi- or trinaphthyls. Differences in reactivity of the naphthylenes in the ringclosure reaction are caused by the different substitution pattern. UV and fluorescence spectra as well as the stability of the resulting rylenes[2] are discussed as a function of substitution.Article · Oct 1992 ArticleAugust 1978 · Analytica Chimica Acta · Impact Factor: 4.51A sensitive fluorimetric method for the determination of aromatic aldehydes is based on their reaction in dilute sulfuric acid with a new reagent, 2,2'-dithiobis(l-amino-naphthalene) in the presence of tri-n-butylphosphine, sodium sulfite and sodium phosphite at ambient temperature. The fluorescences produced are fairly characteristic of individual aldehydes. The method is extremely selective... ArticleSeptember 1977 · Bulletin of the Chemical Society of Japan · Impact Factor: 2.21A general method of transforming a cyclic ketone to the next higher ring homolog chlorinated at the α-carbon or alternatively to its parent ketone is described. Treatment of a dichloromethyllithium-carbonyl adduct 2 with butyllithium affords a β-oxido carbenoid 3 at low temperature. Upon warming, 3 decomposes to a lithium enolate 4, which is quenched with diluted hydrochloric acid to give the... ArticleNovember 1988 · ChemInform · Impact Factor: 0.74Aryne cycloaddition of hexabromobenzene (I) to mesitylmagnesium bromide (II) leads, after quenching with water, to the formation of the diaryne adduct (III). ArticleAugust 1990 · Journal of Organometallic Chemistry · Impact Factor: 2.173-Methoxy-1-(tributylstannyl)-1-propene (1) can be readily transformed into the silylated analogue (2), which can react both as a vinyltin and as an allylsilane. Thus, transmetallation of 2 with n-butyllithium, followed by quenching with various electrophiles, gives functionalized allylsilanes. Although reagent 2 can react with benzaldehyde as an allylsilane, the diastereoisomeric mixture of... Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.This publication is from a journal that may support self archiving.Last Updated: 08 Sep 17Bioremediation Technologies, Ex Situ and Bioreactors
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CitationsCitations6ReferencesReferences0However, development and optimization of bilge waste treatments to minimize costs are research topics of worldwide interest. Bioreactor systems are attractive to carry out bioremediation in ex situ applications because of its low cost compared to other means of waste treatment (Alexander, 1999; Van Hamme et al., 2003). Since petroleum-derived products and residues are complex mixtures of hydrocarbon compounds, microbial communities have been used to achieve wide hydrocarbon biodegradation (Vi?as et al., 2002; Van Hamme et al., 2003; Venkateswaran and Harayama, 1995; Rahman et al., 2002). ABSTRACT: Oily residues that are generated in normal ship operation are considered hazardous wastes. A biodegradation assay with autochthonous microbiota of Bilge Waste Oily Phase (BWOP) was performed in a bioreactor under controlled conditions. Petroleum, diesel oil, and PAH degraders were isolated from bilge wastes. These bacteria belong to the genus Pseudomonas and are closely related to Pseudomonas stutzeri as shown by 16S rDNA phylogenetic analysis. The indigenous microbial community of the bilge waste was capable of biodegrading the BWOP (1% v/v) with biodegradation efficiencies of 70% for hexane extractable material (HEM), 68% for total hydrocarbons (TH) and 90% for total aromatics hydrocarbons (TA) in 14 days. Solid phase microextraction (SPME) was successfully applied to evaluate hydrocarbon evaporation in a control experiment and demonstrated a mass balance closure of 88%. The SPME and biodegradation results give useful information to improve and scale up the process for BWOP treatment.Article · Jan 2007 +1 more author...ABSTRACT: This chapter presents an overview of fungal solid-state fermentation (FSSF). Fungal fermentation metabolites have an enormous impact on the food, pharmaceutical, and agricultural industries. The basis of production of fungal products has largely been by liquid-based submerged fermentation (SmF). At present, interest in solid-state fermentation (SSF) in the USA is small compared to the oriental countries where fungi are exploited for their natural affinity for moist environments. Japan has always been a trendsetter in the area of SSF and has some of the largest SSF production plants in the world. SSF can be defined as the growth of microorganisms on moist, water-insoluble solid substrates in the absence or near-absence of free liquid. One of the main advantages of FSSF is the ease with which fungi can grow on complex natural solid substrates like agro-industrial wastes, without much pretreatment. The bioreactor is the critical stage of the FSSF process as all the earlier and later stages are dependent on its capabilities. Unlike submerged fermentation, in FSSF, the choice of a suitable reactor system is difficult, given the heterogeneity of the substrate matrix. The selection depends on factors such as substrate type, process variables, extent of control required, etc. In the classical FSSF koji process, tray reactors have been traditionally employed. Other major types of reactors are the packed column, rotating drum, and fluidized bed.Article · Dec 2001 ABSTRACT: This chapter presents and discusses four most active frontier areas: molecular techniques in genetic improvement of mushrooms, molecular mechanisms underlying growth and fruiting, recent advances in substrate preparation technologies, and edible fungi as tools for bioremediation. Mushroom genetic resources have been considered important for agriculture, human food, cattle feed, human health, and for chemical and pharmaceutical industry. Transformation of the vegetative mycelium into the fruitbodies represents an interesting phenomenon for the researchers to study the morphogenesis of multi cellular eukaryotes. Newer biotechnological techniques and tools are likely to play important role in the genetic improvement of mushrooms in future. Though, economically profitable level has been achieved in the substrate preparation technology, but understanding at the microlevel may result in a breakthrough breaking the yield barrier, which seems to have currently plateaued. Nutritional, medicinal, commercial and environmental importance of edible fungi will continually force the researchers to study these wonderful microbes at the molecular level.Article · Dec 2002 ABSTRACT: In this report, bisphenol A (BPA) was selected as a model xenobiotic compound in soil slurry, and the bioremoval of BPA by white rot fungi in shaking flask, roller bottle reactor and bubble column reactor were studied. The initial weight ratio of liquid and soil over some level is found to be necessary to form soil slurry. The threshold of the ratio for soil slurry forming seems to be the maximum moisture content of soil. In shaking flask, the removal ratio of BPA was 0.97 (n=2) in 24 h. The period for achieving this ratio was shortened about 30 times in comparison to our previous experiment in solid state. In case that the soil slurry was observed in shaking flask, the removal ratios of BPA at 24 h were constant (0.98±0.01) and independent to shaking speeds (60, 100 rpm). The roller bottle reactor could achieve effective bioremoval reaction in lower rotation speed comparing with shaking flask, and the removal ratio reached almost 1 at 12 h. In bubble column reactor, the differences in BPA removal rates were observed among bubble columns with different shape. The shape of reactor seems to affect the mixing state of soil slurry rather than oxygen supply.Article · Jan 2013 ABSTRACT: Mono-substituted phenol derivatives (cresol, aminophenol and hydroxybenzoic acid) were selected as model xenobiotic compounds in environment, and bioremoval kinetics of phenol derivative regioisomer by white rot fungi Coriolus hirsutus IFO 4917 in shaking flask were studied. As a result, the linear relation representing Hammett equation was confirmed in the plot of the removal rate constants of m- and p-mono-substituted phenol derivatives and the substituent constant (σ) of Hammett equation. The plot showed a negative slope. A mathematical model to estimate the biodegradation rates of the m- and p-mono-substituted phenol derivatives was formulated.Article · Jan 2014 +1 more author...ABSTRACT: This study encompasses the biodegradation capacity of Anabaena fertilissima to model PAH (Polycyclic Aromatic Hydrocarbon) compounds namely Anthracene (ANT) and Pyrene (PYR) at different LC50 concentrations viz., 5.0 mg/L and 3.0 mg/L, respectively, on growth in terms of Chlorophyll-a and protein. Depletion in chlorophyll-a and protein content was registered with rise in PAHs concentration while the inhibition of nitrogen fixing enzymes such as nitrate reductase and glutamine synthetase activity was also concentration dependent and showed more sensitivity for high molecular weight aromatic compound PYR as compared to ANT. GC/MS analysis explained the degradation of ANT by 46% and PYR by 33%, at 5.0 mg/L and 3.0 mg/L, respectively. Moreover, the common degraded product for ANT was 2, 4-Dimethyl-1-heptene and for PYR it was 2, 3, 4-Trimethylhexane. Results indicate that PYR was more stable and recalcitrant compared to ANT. This study suggests that Anabaena fertilissima could be used for bioremediation of ANT and PYR pollution in surface waters and terrestrial environments. 2016 Full-text · Article · Dec 2015
Full-text · Article · Dec 2015 +1 more author...Article · Oct 2017 +1 more author...Article · May 2017 +1 more author...Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.This publication is from a journal that may support self archiving.Experimental investigation of newly synthesized gemini cationic surfactants as corrosion inhibitors of mild steel in 1.0 M HCl
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28.51Egyptian Petroleum Research InstituteAbstractThree Gemini cationic surfactants named N?,N?,N?,N?-tetramethyl-N?,N?-bis(3-octanamidopropyl) propane-1,3-diaminium bromide (C8-S3-C8), N?,N?,N?,N?-tetramethyl-N?,N?-bis(3-dodecanamidopropyl) propane-1,3-diaminium bromide (C12-S3-C12) and N?,N?,N?,N?-tetramethyl-N?,N?-bis(3-hexadecanamidopropyl) propane-1,3-diaminium bromide (C16-S3-C16) were evaluated as corrosion inhibitors for mild steel in 1.0 M HCl. The corrosion rate of mild steel in 1.0 M HCl at three different temperatures 25, 45 and 60°C was investigated gravimetrically. The corrosion rate of mild steel was confirmed electrically at 25°C. The corrosion inhibition efficiency directly proportionally with the hydrophobic chain length of inhibitors. The inhibition efficiency exhibit a positive trend with raising the solution temperatures. The potentiostatic polarization study revealed that the tested gemini cationic surfactants act as mixed type inhibitors with predominant control of cathodic reaction. The Villamil isotherm provide the best describing of the adsorption process on the selected steel in 1.0 M HCl. The adsorption of the tested inhibitors on the steel surface is a mixture of chemical and physical adsorption.Do you want to read the rest of this article?Request full-text
CitationsCitations0ReferencesReferences58ABSTRACT: Three cationic surfactants containing amide groups were prepared by quaternization of dimethylaminopropylamine with benzyl chloride. FTIR and 1H-NMR spectroscopy were used to confirm the chemical structure of the prepared cationic surfactants. The surface parameters were estimated using surface tension measurements at three different temperatures. The prepared cationic surfactant showed a lower CMC than conventional cationic surfactants. Thermodynamic parameters of adsorption and micellization depend mainly of alkyl chain length and temperature. The adsorption process is more favorable than micellization. The biological activity of the three surfactants was estimated using inhibition zone showing that amidoamine cationic surfactants have good activity and the surfactants C12Bn is the most effective one.Article · May 2016 ABSTRACT: The effects of N-(3-(dimethyl benzyl ammonio)propyl)lauramide chloride (DMBL), N-(3-(dimethyl benzyl ammonio)propyl)myristamide chloride (DMBM) and N-(3-(dimethyl benzyl ammonio)propyl)palmitamide chloride (DMBP) on the corrosion of mild carbon steel in acidic medium (1.0 M HCl) were investigated using weight loss and electrochemical measurements. The inhibition efficiency was found to be hydrophobicity- and temperature-dependent. Increasing the hydrophobic chain length increased the efficiency due to greater adsorption on the metal surface. The inhibition efficiency is directly proportional to the tested temperature. The electrochemical polarization study revealed that the tested cationic surfactants are mixed-type inhibitors. The Villamil adsorption isotherm is the better-fitted model for describing the adsorption process on the selected steel in 1.0 M HCl medium. The change in the free energy of adsorption of the synthesized cationic surfactants on the metal surface indicates that the adsorption process is chemisorption. Double-layer capacitance values obtained from electrochemical impedance spectroscopy decrease in the presence of the synthesized surfactant. Quantum chemical calculations support the experimental data and the adsorption on the metal surface.Article · Jan 2016 ABSTRACT: The adsorption and micellization behavior at aqueous surface of synthesized amido-amine cationic surfactants was studied using surface tension and conductometric measurements at three different temperatures of 25, 40 and 60 °C. The chemical structure of the synthesized cationic surfactants was confirmed using Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. The synthetic route is simple and comprises two steps. The first is amidation between palmitic acid and dimethyl amino propyl amine, while the second step is quaternization of the first step product with different alkyl bromides. The study evaluated the effect of temperature and the hydrophobic chain length of the synthesized amidoamine cationic surfactants on the studied surface parameters. In aqueous system the adsorption tendency of the synthesized cationic surfactants is higher than micellization and both increase by increasing the hydrophobic character and the solution temperatures. The synthesized surfactants were found to have good antibiotic effect against gram positive and negative bacteria and fungi.Article · Apr 2016 +1 more author...ABSTRACT: The chain length of the synthesized cationic surfactant effect on the amount and stability of the formed silver nanoparticles. The stability of prepared silver nanoparticles increases by increasing the chain length of the synthesized cationic surfactants. The amount of the formed silver nanoparticles increases by increasing the chain length of synthesized cationic surfactants. The chemical structure of synthesized surfactants has been confirmed using FTIR and 1HNMR spectroscopy. The used method for synthesizing silver nanoparticles produces uniform with very narrow size range. Transmission electron microscope, dynamic light scattering, UV–Vis spectroscopy and energy dispersive X-ray have been used to confirm the formation of silver nanoparticles and the effective role of the used cationic surfactants. The synthesized cationic surfactants and their silver nanoform showed a good antibiotic effect against fungi and bacteria. The silver nanoparticles enhanced the antibiotic effect of synthesized cationic surfactants.Article · Apr 2016 ABSTRACT: The chemical structures of three prepared amidoamine Gemini surfactant were confirmed using FTIR and 1HNMR spectroscopic methods. The synthetic routes passed through two steps, the first one is the formation of the amide and the second one is the quaternization of the prepared amide with dibromo propane. The surface and thermodynamic parameters were determined from surface tension and conductivity measurements. The obtained critical micelle concentrations from both techniques are similar. The values of CMC were found to depend on both solution temperature and hydrophobic character. The change in free energy of micellization and adsorption showed a tendency of synthesized Gemini surfactants to adsorb at the interface first then forming micelle in the bulk. The prepared Gemini surfactants act as good antibiotic against some tested bacteria and fungi.Article · Dec 2015 ABSTRACT: Three amidoamine cationic surfactants with double tailed were prepared and their chemical structures was confirmed using spectroscopic analysis like FTIR and 1H NMR. The surface parameters of the amidoamine surfactants were determined from surface tension and conductance measurements. The double tailed amidoamine surfactant shown low critical micelle concentration than conventional surfactants with their dependence on chain length and temperatures. Thermodynamic parameters clarified the tendency of surfactants to adsorb at interface than to form micelle and both of the two processes depend on the alkyl chain and temperature. The prepared surfactants were evaluated against microorganism showing that they have good biological activity against both Gram positive and negative bacteria but they have no effect on fungi.Article · Dec 2015 ProjectData provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.This publication is from a journal that may support self archiving.Last Updated: 20 Oct 17}