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. Anthracene, a PAC composed of three fused benzene rings, is routinely found at former manufactured gas plant sites and resides on the EPA's Priority Pollutant List of compounds for its carcinogenic nature and ubiquitous positioning in the environment. During

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Anthracene derivative dimers reveal a thermal monomerization at temperatures higher than the melting points of the corresponding monomers. Thermograms of these dimers are consisting of a broad endotherm followed by a small exotherm. A detailed investigation on 9-chloroanthracene dimer allowed to explain this peculiar behaviour.

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Journal of Thermal Analysis and Calorimetry
Authors: S. Meenakshisundaram, S. Parthiban, U. Pisipaty, G. Madhurambal, and S. Mojumdar

Abstract  

The influence of the highly fluorescent dopant, anthracene (over a concentration range from 5 × 10−4 to 1.2 × 10−2 mol dm−3) on the nonlinear optical properties and fluorescence intensity of potassium hydrogen phthalate (KHP) single crystals grown at 30 °C by a slow evaporation solution growth technique (SEST) has been investigated. Powder XRD and FTIR spectral analyses confirm the slight distortion of the structure of crystal because of doping. UV–Visible study shows that the transparency is not affected much by the dopant. The SEM investigation reveals that KHP suffers from crack development. Thermal analysis indicates that there is no decomposition of the crystal up to the melting point. It is interesting to observe that additions of small quantity anthracene to KHP results in the enhancement of fluorescence intensity. The fluorescence intensity dependence on dopant concentration is observed. Interestingly, second harmonic generation (SHG) efficiency of KHP is dramatically improved by doping with small quantities of anthracene.

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Synthesis and characterization of a novel non-linear optical (NLO) material

Endo anthracene maleic anhydride – Diel’s–Alder adduct of anthracene

Journal of Thermal Analysis and Calorimetry
Authors: G. Madhurambal, P. Ramasamy, P. Srinivasan, and S. Mojumdar

Abstract  

Anthracene is one of the organic molecular crystals, which exhibits peculiar optical and electronic properties. Since the 9, 10 positions are very reactive in anthracene, it undergoes the Diel’s–Alder reaction with maleic anhydride in 99% yield. The synthesis of Diel’s–Alder adduct has been carried out by adopting standard procedure. The product was subjected to various characterization studies such as FTIR, UV and 1H NMR spectroscopy, and thermal studies to check its purity and determine the applicability of adduct in various applications. The second harmonic generation (SHG) efficiency of the adduct has been observed using Nd:YAG laser.

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investigated widely due to their high-NLO properties, rapid response in electro-optic effect and large second- or third-order hyperpolarizibilities compared to inorganic NLO materials [ 1 ]. Anthracene is one of the organic molecular crystals, which exhibits

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Abstract  

The enthalpies and temperatures of melting and sublimation of acridin-9(10H)-one, 10-methylacridin-9(10H)-one, 2,10-dimethylacridin-9(10H)-one, 10-methyl-2-nitroacridin-9(10H)-one, 10-ethylacridin-9(10H)-one and 10-phenylacridin-9(10H)-one were measured by DSC. Enthalpies and temperatures of volatilisation were also obtained by fitting TG curves to the Clausius-Clapeyron relationship. Complementary investigations for anthracene showed the extent to which the thermodynamic characteristics thus obtained compare with those determined by means of other techniques. For compounds whose crystal structures are known, experimental enthalpies of sublimation correspond reasonably well to crystal lattice enthalpies predicted theoretically as the sum of electrostatic, dispersive and repulsive interactions. Analysis of crystal lattice enthalpy contributions indicates that dispersive interactions always predominate. Interactions are enhanced in acridin-9(10H)-one where intermolecular hydrogen bonds occur: this is reflected in the relatively high enthalpy of sublimation.

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A new ligand has been synthesized by anchoring anthracene to l -methionine. The ligand enables easy identification of amino acids on thin-layer chromatography plates by developing distinguishable colors. This paper deals with the detailed synthesis, characterization, and application of the new ligand. Estimation of binding constants of this new ligand with different amino acids are also reported. A theoretical calculation ( Hartree-Fock ) has been performed to investigate interaction of the ligand with the amino acid.

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Abstract  

DSC measurements in open pans are often disturbed by mass losses such as sublimation during melting or release of water during chemical reactions. By simultaneous DSC and TG measurements the DSC signal can be corrected. For this purpose, a temperature dependent calibration function has to be determined by which the SDTA signal from the TGA/SDTA851e measuring cell can be converted into a heat flow curve (DSC). By this procedure, accurate heat of melting can be determined despite ongoing sublimation in open pans. This method is illustrated with reference of the melting of anthracene. Additionally, condensation reactions were investigated and analyzed by DSC/TG even under ambient pressure, knowing the heat of evaporation. Using phenol formaldehyde resins the influence of the presence or the release of volatile reaction products on the reaction rate and kinetic parameters were studied. In general, the method can be used to correct DSC curves for thermal effects related to mass change.

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Abstract  

Experimental values of o-Ps lifetime were compared with model calculations, approximating the voids in a solid by spheres or cuboids. In the case of resorcinol the model of spherical voids is well consistent with the experimental data. For channel-like free volumes the formula, analogous to that for spheres, gives systematically the values of o-Ps lifetime too large. No positronium is found in anthracene, although the radius of free volume is larger than 0.97 Å at which the Ps binding energy should be zero.

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Abstract  

An expression for rate constant for diffusion controlled reaction of positronium atom /Ps/ with acceptor in condensed phase was obtained, accounting the tunnelling of Ps. The obtained equation is good also for description of the reactions of solvated electron with electroneutral molecules. Owing to the tunnelling transfer existence, the rate constant /k/ is the sum of two terms — the first of them is proportional to the coefficient of relative diffusion of reagents and the second one /characterizing the subbarrier reaction/ does not include the diffusion coefficient. The correlation of the calculated and experimentally obtained rate constants for Ps+O2 reaction in liquids with different diffusion coefficients demonstrates good agreement between theoretical and experimental results. The possibility of electron tunnelling in liquid reaction of excited anthracene quenching with dissolved oxygen is also suggested.

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