Combined analysis of the high sensitivity Fourier transform and ICLAS-VeCSEL absorption spectra of D2O between 8800 and 9520 cm

The absorption spectrum of dideuterated water, D₂O, has been recorded between 8800 and 9520 cm⁻¹ by intracavity laser absorption spectroscopy (ICLAS) based on a vertical external cavity system emitting laser (VeCSEL) and by high sensitivity Fourier Transform spectroscopy. The combined analysis of the spectra has allowed attributing 1223 transitions to the D₂O species. The spectrum assignment was performed on the basis of the recent results of variational calculations based on an optimized potential energy surface of D₂O. A set of 687 energy levels was derived from transitions assigned to eight upper vibrational states, 577 of them being reported for the first time. A detailed line list has been generated. The line intensities were retrieved mainly from the FTS spectrum and the absolute integrated intensities of the 2v₁ + v₂ + v₃ and the v₂ + 3v₃ bands dominating the spectrum have been determined.     

Provability in predicate product logic

We sharpen Hájek’s Completeness Theorem for theories extending predicate product logic, ${\Pi\forall}$ . By relating provability in this system to embedding properties of ordered abelian groups we construct a universal BL-chain L in the sense that a sentence is provable from ${\Pi\forall}$ if and only if it is an L-tautology. As well we characterize the class of lexicographic sums that have this universality property.     

Theoretical line list of D2 O up to 16,000 cm with an accuracy close to experimental

A line list for D₂ ¹⁶O isotopologue of water molecule was calculated in the region 0-16,000 cm⁻¹ with energy levels up to J=30. Variational calculations are based on the semi-theoretical potential energy surface obtained by morphing ab initio potential using the experimental energy levels of D₂ ¹⁶O. For energy levels with J=0, 2, 5 and 10, the standard deviation of the fit is 0.023 cm⁻¹. This line list should make an excellent starting point for spectroscopic modeling and analysis of D₂O rovibrational spectra.     

Synthesis,Spectroscopic Characterization and DFT/TD-DFT Calculations of new Fluorescent Derivatives of Imidazo[4′,5′:3,4]Benzo[<Emphasis Type="Italic">c</Emphasis>]Isoxazole

An increasingly wide variety of fluorescent compounds is used in biotechnology, genomics, immunoassays, array technologies, imaging, and drug discovery. Therefore, synthesis of fluorophores with novel structural features can be interesting and useful in various fields. In this paper, four new fluorescent heterocyclic compounds with high quantum yields are introduced. These new fluorophores are synthesized in moderate to high yields via regioselective nitration of 3-alkyl-8-(4-chlorophenyl)-3 H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. The latter compounds are obtained from the reaction of 1-alkyl-5-nitro-1 H-benzoimidazoles with (4-chlorophenyl)acetonitrile in basic MeOH solution. Physical spectral (UV-vis, IR, ¹HNMR, ¹³C NMR, NOESY and fluorescence) and analytical data have established the structures of synthesized compounds. The fluorescence properties of new fluorescent heterocyclic compounds are studied. The fluorescence of all compounds is very intense and fluorescence quantum yields are high (> 0.52). Density functional theory (DFT) calculations are performed to provide the optimized geometries, relevant frontier orbitals and the prediction of ¹H NMR chemical shifts for confirming the exact structure of fluorescent compounds. Calculated electronic absorption spectra were also obtained by time-dependent density functional theory (TD-DFT) method.

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Graphical Abstract ?

     

1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions

Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α, β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.     

Synthesis, characterization and catalytic oxidation of cyclohexene with molecular oxygen over host (zeolite-Y)/guest (nickel(II) complexes of R2[12]1,3-dieneN2O2 and R2[13]1,4-dieneN2O2; R = H, Me, Ph) nanocatalyst (HGN)

12- and 13-Membered diaza dioxa Schiff-base nickel(II) complexes were successfully prepared in a nanoscale microreactor by the template condensation of (1,8-diamino-3,6-dioxaoctane)nickel(II) complex with bifunctional diketones within the nanodimensional pores of zeolite Y. The host–guest nanocatalyst (HGN); ([Ni((R₂[12]1,3-dieneN₂O₂)]²⁺-NaY, [Ni(R₂[13]1,4-dieneN₂O₂)]²⁺-NaY; R = H, Me and Ph) is catalytically very efficient as compared to other neat complexes for oxidation of cyclohexene with molecular oxygen as oxidant in the absence of solvent at 70 °C, affording 2-cyclohexene-1-ol and 2-cyclohexene-1-one.     

Improvements of physical and mechanical properties of electron beam irradiation—crosslinked EVA foams

In this work, ethylene–vinyl acetate (EVA) copolymer foams were prepared and crosslinked by using high‐energy electron beam (e‐beam) radiation (10 MeV). The effect of parameters such as irradiation dose, the contents of foaming agent, radiation activator, and radiation sensitizer on improvement of physical and mechanical properties of the EVA foamed samples were investigated. The foams were obtained through a four‐step process of melt mixing, forming, crosslinking, and foaming. During the melt mixing process EVA was compounded with different amounts of azodicarbonamide (ADCA) as a blowing agent, zinc oxide (ZnO) as a radiation activator, and trimethylol propane‐trimethacrylate (TMPTMA) as a radiation sensitizer. The samples were compression molded into flat sheets at low temperature (110°C) and were then radiation‐crosslinked by 20–80 kGy e‐beam. Finally, the crosslinked samples were converted to foams by a high temperature (210°C) compression molding process. The foamed samples were analyzed in terms of gel content, density, compression molding set, tensile properties, and micro‐structural features. It was found that an increase in absorbed radiation dosage increases crosslink density, elasticity, percentage recovery, tensile strength, and compression properties of the EVA foams. Due to the increased recovery the percentage of compression set was reduced. Similarly increasing the TMPTMA content in the formulation increased the crosslink density and the resulting mechanical properties. Contrary to these findings, addition of ADCA led to the formation of extra gases which in turn reduced the crosslink density, and resulted in the deterioration of the mechanical properties and hence an increase in the compression set. However, addition of ZnO and TMPTMA led to the formation of smaller and more uniform cell size with improved mechanical properties. Copyright © 2008 John Wiley & Sons, Ltd.     

Preparation and characterization of a silica‐based magnetic nanocomposite and its application as a recoverable catalyst for the one‐pot multicomponent synthesis of quinazolinone derivatives

An environmentally benign magnetic silica‐based nanocomposite (Fe₃O₄/SBA‐15) as a heterogeneous nanocatalyst was prepared and characterized using Fourier transform infrared and ultraviolet–visible diffuse reflectance spectroscopies, scanning electron microscopy, X‐ray diffraction, vibrating sample magnetometry and Brunauer–Emmett–Teller multilayer nitrogen adsorption. Its catalytic activity was investigated for the one‐pot multicomponent synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones starting from isatoic anhydride, ammonium acetate and various aldehydes under mild reaction conditions and easy work‐up procedure in refluxing ethanol with good yields. The nanocatalyst can be recovered easily and reused several times without significant loss of catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

SYNTHESIS,REACTIVITY AND CONFORMATION OF 10,11-DIHYDRODIBENZO-[b,f]PHOSPHEPIN AND DIBENZO[b,f]PHOSPHEPIN DERIVATIVES. PHOSPHORUS ANALOGUES OF IMINOBIBENZYL ANTIDEPRESSANTS

Abstract

Derivatives of the novel dibenzo[b,f]phosphepin system are prepared from 10,11-dihydro-5-phenyl-5H-bibenzo[b,f]phosphepin 5-oxide (2). New members in the 10,11-dihydro-5H-dibenzo[b,f]phosphepin series, including phosphorus analogues (7, 10) of the andidepressant drug imipramine (30), are also reported. Products of nucleophilic substitution at tetrahedral phosphorus in 2 appear to be determined by the relative apicophilicity of the nucleophile. Conformational analysis based on ¹H NMR data suggests folded (“butterfly”) conformation for the tricyclic compounds. The twisted boat conformation of the central ring in the 10,11-dihydro compounds bears a pseudo-equatorial P[dbnd]O oxygen or a P[dbnd]S sulfur, in solution. Symmetric AA‘BB’ spin systems are found in 4,5 and 7, and their solution conformations appear to be similar to those of analogous 10,11-dihydrodibenzo[b,f]azepine derivatives. The interaction of some compounds with NMR shift reagents and their mass spectral fragmentations are discussed.