Analytical Determination of Polycyclic Aromatic Hydrocarbons in Gases from Coal Conversion by Synchronous Fluorescence Spectrometry.

Abstract

A method to analyze the most hazardous Polyclyclic Aromatic Hydrocarbons (PAH) (acenaphtene, anthracene, benzo(a) anthracene, benzo(a)pyrene, biphenyl, coronene, chrysene, dibenzo (a,h) anthracene, phenantrene, fluoranthene, fluorene, naphtalene and pyrene), by using excitation and energy constant synchronic fluorescence has been researched in depth in this study.

Spectral studies carried out allow characteristic peaks to be obtained for the qualitative identification of 8 from 11 PAH tested. From the quantitative and interference studies, the most important analytical characteristics (linear range, detection limit and reproduciblity) for the determination of ten of these compounds have been obtained.

The method was applied to the PAH determination in two different samples: 1) air filter samples for urban pollution control and 2) air samples from a laboratory scale coal carbonization oven. Fluorene (in the first type) and benzo (a) pyrene (in the second type), were identified and quantified.     

The reaction of anthracenyl-α-hydroxyphosphonate with anthracene: Access to diverse (bis)-anthracenylmethylphosphonates as a suitable source for extensive π-conjugates

Abstract

Molecular anthracene has been used as an arene in the Friedel-Crafts (FC) type arylation reaction of anthracenyl-α-hydroxyphosphonate in the presence of acid. A diverse product formation is observed, in which anthracene unit is found to be linked through its C1 position with α-C of phosphonate. Interestingly, the molecular conformation (X-ray structure) of this phosphonate reveals one of the bond angles of a tetrahedral carbon as 118° which is close to the C of sp² character. Further, molecular anthracene is also recognized to attack at the C10 position of 9-anthracenylphosphonate through C1 or C2 or C9 atoms and the structures of three isomeric phosphonates are established with the help of ¹H and ³¹P NMR studies. The bis-anthracenyl compounds with a P-CH₂ unit have been successfully utilized in Horner-Wadsworth-Emmons (HWE) reactions to afford extensive bis-anthracenyl-linked π-conjugates.     

A Crystalline Quartz,Laser-Excited Fluorescence,Photoacoustic, and Two-Photon Photoionization Detector for HPLC

Abstract

A crystalline quartz flow cell has been developed for simultaneous fluorescence, photoacoustic effect, and two-photon photoionization detection of aromatic compounds in HPLC eluents. Excimer laser-excited three mode detection of naphthalene, 7,8-benzoflavone, N-ethylcarbazole, and anthracene in 70/30 v/v acetonitrile/water is exhibited. The flow cell is suitable for use with deoxygenated solvent systems and is orientation independent.     

Discovery of a Novel C60 Receptor Based on Substituted Anthracene

Abstract

Anthracene diaryl bromide was prepared via the acid catalyzed condensation of veratrole with p-bromobenzaldehyde. Mixing of toluene solutions of anthracene diaryl bromide and C₆₀ fullerene led to the formation of a 1:1 solid state complex. Evidence for the complex is based on microanalysis and FTIR. A crystal structure of the anthracene diaryl bromide is presented and a dimeric butterfly structure has been proposed for the supramolecular species in solution.     

Crystalline inclusion compounds of a new diol host featuring a combination of anthracene and 9-fluorenol units

The diol host compound 2 has been synthesised and its behaviour to form crystalline inclusion compounds is discussed in comparison with an analogous ethynylene spaced host compound 1. The rotation around the fluorenol–anthracene bonds in 2 is highly restricted as indicated by solution NMR spectroscopy, molecular mechanics and semi-empirical calculations. Single-crystal X-ray structures of the inclusion complexes of 2 with 1-BuOH (2a), morpholine/H₂O (2b) and DMSO (2c) are in agreement with the bent geometry of the anthracene ring system suggested by the calculations. The structures exhibit specific modes of hydrogen bond interactions.     

Investigation of Complexation of Sodium Cation by Anthracene Crown Ethers

Abstract

Formation constants for complexes of sodium and anthracene crown ethers were determined using spectrophotometry and cyclic voltammetry. The complexation properties of the ligands examined depend significantly on alkyl substituents at 9 and 10-positions of the anthracene group and are strongly influenced by the solvent.     

蒽类衍生物的电荷传输性质

以具有较高迁移率的对称取代类蒽的衍生物{2,6-二[2-(4-戊基苯基)乙烯基]蒽,DPPVAnt;2,6-二-噻吩蒽,DTAnt;2,6-二[2-己基噻吩]蒽,DHTAnt}为研究对象,采用密度泛函理论的B3LYP方法,在6-31G(d)的基组水平上研究了三种蒽类衍生物的分子结构、电子结构、重组能和电荷传输积分,采用Einstein关系式计算了室温下的载流子迁移率,并与蒽的相关计算结果进行了比较.DPPVAnt是较好的空穴传输材料,其空穴迁移率为0.49cm2·V-1·s-1;DHTAnt有利于电子传输,其电子迁移率为0.12cm2·V-1·s-1;而DTAnt是一种较好的双极性材料,其空穴迁移率和电子迁移率分别为0.069和0.060cm2·V-1·s-1.计算得到的迁移率与实验结果处于同一数量级.三种蒽类衍生物的电子重组能与蒽的相近,而空穴重组能均大于蒽的空穴重组能,大小顺序为蒽DPPVAntDTAntDHTAnt.这与计算的迁移率结果不一致,说明分子的堆积结构决定材料的电荷传输性质.     

A New Synthesis of trans-3,4-Dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydro-7,12-dimethylbenz(a) anthracene

A facile synthesis of trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydro-7,12-dimethylbenz(a) anthracene 1 ; a highly carcinogenic metabolite of 7,12-dimethylbenz(a) anthracene (DMBA) have been described.     

Resolution of Polynuclear Aromatic Hydrocarbons by Packed Column GLC

Abstract

Specific GLC stationary phases have been identified which allow the resolution of certain polynuclear aromatic hydrocarbon (PAH) isomers with packed six foot columns. Phenanthrene and benz(a)anthracene can be measured in the PAH fraction of tobacco smoke condensate without significant interferences from anthracene and chrysene, respectively.     

A fluorescent sensing membrane for iodine based on intramolecular excitation energy transfer of anthryl appended porphyrin

A single anthryl appended meso-tetraphenylporphyrin (TPP) dyad has been synthesized and applied in fluorescence sensing of iodine based on the intramolecular excitation energy transfer. The molecular recognition of the sensor is based on the interaction of iodine with inner anthracene moiety of the dyad, while the signal reporter for the recognition process is the TPP fluorescence quenching. Because the emission spectrum of anthracene is largely overlapped with the Soret band absorption of TPP, intramolecular excitation energy transfer interaction occurs between the donor, anthracene and acceptor, TPP. This energy transfer leads to TPP fluorescence emission by excitation of anthracene. The sensor was constructed by immobilizing the dyad in a plasticized poly(vinyl chloride) (PVC) membrane. The sensing membrane shows higher sensitivity compared to the sensors by using anthracene, TPP, or a mixture of anthracene and TPP as sensing materials. Under the optimum conditions, iodine in a sample solution can be determined from 2.04 to 23.6 mmol·L⁻¹ with a detection limit of 33 nmol·L⁻¹. The sensing membrane shows satisfactory response characteristics including good reproducibility, reversibility and stability, as well as the short response time of less than 60 s. Except for Cr₂O₇²⁻ and MnO₄⁻, other common metal ions and anions in foodstuff do not interfere with iodine determination. The proposed method was applied in the determination of iodine in table salt samples. The results agree well with those obtained by other methods. Supported by the National Outstanding Youth Science Foundation of China (Grant No. 20525518), the National Natural Science Foundation of China (Grant No. 20775005), and the National Natural Science Foundation of Hunan province (Grant No. JJ076021)     

Determination of N-Phenylmaleimide by a Decrease in the Intensity of Anthracene Fluorescence

A highly sensitive method for the determination of N-phenylmaleimide was described. The method is based on the quenching of the fluorescence of an anthracene solution in dioxane in the presence of the analyte. The determination limit is 0.17 ng/mL.     

Solubility of Anthracene in Binary Carbon Tetrachloride + Alkane Solvent Mixtures

Abstract

Experimental solubilities are reported for anthracene in binary solvent mixtures containing carbon tetrachloride with n-hexane, n-heptane, n-octane, cyclohexane, methylcyclohexane and isooctane at 25°C. Results of these measurements, combined with the excess Gibbs free energies of the binary solvents, are used to test predictive expressions derived from the nearly ideal binary solvent (NIBS) model. Expressions based on a volume fraction average of solute properties in the two pure solvents predict anthracene solubilities to within a maximum deviation of 4.5% and an overall average deviation of 1.8%.     

Ionic Liquid Crystals Formed by Self‐Assembly around an Anionic Anthracene Core

We have designed and synthesised a series of modular, mesogenic complexes based on anthracene‐2,6‐disulfonate and trialkoxybenzyl‐functionalised imidazolium cations. Each complex contains a central, rigid, dianionic anthracene core and two flexible monocations bearing paraffin chains anchored on imidazolium rings. Anthracene‐2,6‐disulfonate can be crystallised with various simple alkylammonium ions and, in the case of ⁺N(CH₃)₂(C₁₆H₃₃)₂, a crystal structure determination has shown that the long paraffinic chains are intercalated between the anthracene moieties. The dianion forms columnar mesophases with trialkoxybenzylimidazolium cations, as identified by polarising optical microscopy and X‐ray scattering measurements. Differential scanning calorimetry studies confirmed mesomorphic behaviour from room temperature to about 200 °C for alkyl chains containing 8, 12 and 16 carbon atoms. The strong luminescence of anthracene is maintained in the mesophase and fluorescence measurements confirmed the presence of J aggregates in all cases. The new functional materials described herein provide an easy access to stable and luminescent mesomorphic materials engineered by an ionic self‐assembly process.     

Synthesis of cationic complexes [(C<Subscript>4</Subscript>Me<Subscript>4</Subscript>)CoL]<Superscript>+</Superscript> (L is naphthalene,phenanthrene, and anthracene)

Cationic arene complexes [Cb*Co(naphthalene)]⁺ (2, Cb* = C₄Me₄) and [Cb*Co(phenanthrene)]⁺ were synthesized by the reactions of [Cb*Co(MeCN)₃]⁺ with arenes. The [Cb*Co(anthracene)]⁺ complex was synthesized by the abstraction of the iodide ion from [Cb*CoI]₂ by TIBF₄ in the presence of anthracene. Complex 2 exchanges the naphthalene ligand for other arenes at room temperature. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1861–1863, September, 2007.     

All-trans 2,7-dialkylperhydrophenanthrene as a solvent for measurements of helical twisting power and linear dichroism

Abstract

The values of twisting power of a chiral bridged binaphthyl and (+)-trans-stilbene oxide in a rigid hydrocarbon perhydrophenanthrene nematic are much smaller than in conformationally flexible nematics, indicating the importance of the solvent structure for cholesteric induction. The perhydrophenanthrene phase constitutes an excellent solvent for linear dichroism measurements of anthracene but it is unable to orient 9,9′-spirobifluorene.     

A Simultaneous,Laser-Excited Fluorescence,Photoacoustic, and Two-Photon Photoionization Detector for Liquid Chromatography

Abstract

A laser-excited windowless flow cell has been developed for simultaneous fluorescence, photoacoustic, and two-photon photoionization detection of aromatic compounds in HPLC eluents. Sensitive three-mode detection of acridine, naphthalene, 7,8-benzoflavone, N-ethylcarbazole, and anthracene in 70/30 V/V acetonitrile/water is demonstrated with conservative detection limits in the nanogram range and below.     

Liquid crystalline photoconductors

Abstract

The influence of molecular order as well as of orientation of charge carrier units on photoconductivity has been investigated for the liquid crystal photoconductors H5T (1), thiadiazole (2) and oxadiazole (3). The discotic H5T (1) and both smectic systems 2 and 3 exhibit a higher photocurrent in the highly ordered mesophase than in the polycrystalline or isotropic state. For 1, results concerning charge carrier transport mechanism and Dember effect are given indicating an electronic charge transport comparable with the one known for single crystalline anthracene.     

The Photooxidation of Some Anthryl Phosphorus Compounds

Abstract

The photo-oxidation of anthryl phosphorus compounds occurs via a Type II process. All products observed can be accounted for by involving a 9, 10-endoperoxide, which may subsequently fragment, resulting in cleavage of the phosphorus moiety from the anthracene nucleus.     

The synthesis and X-Ray crystallographic analysis of a stable norbornadienone: 17-Oxo-7,16-methano-7,16-diphenylcyclopenta[d,e]tribenzo[a,h,j]anthracene

The reaction of 4,5-didehydroacenaphthene with phencyclone yields the title compound, a stable dibenzo-fused norbornadienone (8). The X-ray structure of8 is presented and compared with the structure predicted from a MM3, PM3, and a MMX calculation. Thermal decomposition of 8 produces, 7,16-diphenylcyclopenta[d,e]tribenzo[a,h,j]anthracene (9), a hydrocarbon that is computed to have a significantly twisted polycyclic aromatic skeleton with 19 kcal/mole of strain energy.     

Highly Effective Fluorescent Sensor for Hg2+ in Aqueous Solution

A new anthracene fluorophore senses Hg²⁺ selectively in aqueous solution. Among the metal ions examined, fluorescent chemosensor 1 shows selective large CHEQ effects with Hg²⁺ and Ag⁺ at pH 7.