Selective SN2′ Solvolysis in Borohydride Reduction of 2-Isobutylidene-1-indanone/Tetralone

Selective s_N2′ solvolysis in borohydride reduction of the title compounds is described. As a result, an isomer more stable than the normal reduction product is obtained. Confirmative studies have also been carried out to eliminate the probable acid catalysed rearrangement mechanism.     

A Preferred Intramolecular ‘Ene’ Reaction Between Ketene and Olefin

Aplysin (1), a marine sesquiterpene was isolated from ‘aplysia kurodai’ and its structure was ellucidated by Hirata-et-al¹. They also reported the synthesis of racemic aplysin². Their synthetic route involved cyclopentanone (2) as a well-characterized intermediate. We visualized the synthesis of cyclobutanone (3) and its subsequent conversion to (2) as an attractive alternative. But during our attempts to synthesize the said cyclobutanone, we have come across a very facile intramolecular ‘ene’ reaction between ketene and olefin. We report our unexpected observations in this communication.     

Mechanoluminescence,thermoluminescence and photoluminescence studies on Al2O3:Tb phosphors

Terbium activated Al₂O₃ phosphors were synthesized by combustion technique using hydrazine as a reductive non-carbonaceous fuel. X-ray diffraction (XRD) patterns of the samples were recorded to confirm the formation of the sample. Scanning electron microscope (SEM) images were taken to study the surface morphology of the sample. The photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties of the γ-ray irradiated samples were studied. ML was excited impulsively by dropping a piston on the sample. In ML glow curves one peak with a shoulder was observed. ML intensity increases with activator concentration. Optimum ML was observed for the sample having 0.5 mol% of Tb ions. In the TL glow curve two distinct peaks, one around 222 °C and another around 280 °C, were observed for the samples having 0.5 mol% of activator concentration. In the PL spectra the ⁵D₄→⁷F₅ line at 544 nm in the green region is observed, which is the strongest in Al₂O₃ system. It is suggested that de-trapping of trapped charge carriers followed by recombination is responsible for ML and TL in this system.     

Synthesis and addition polymerization of vinylbenzyl transition metal compounds

Summary The synthesis of three vinylbenzyl complexes (n⁵-C₅H₅)-M(CO)_n(CH₂C₆H₄CH=CH₂), [1), M=Mo, n=3; (2), M=W, n=3; (3), M=Fe, n=2] is reported. Complexes (1) and (2) have been copolymerized with monomers, such as styrene, methyl methacrylate, andN-vinyl-2-pyrrolidone, in benzene using azoisobutyronitrile as initiator. The rates of incorporation of (2) into copolymers with styrene and methyl methacrylate were the same as the rate of incorporation of the organic monomer. The homopolymerization of (2) was also carried out. Polymerizations occurred satisfactorily except for the copolymerization of (1) with styrene, where little incorporation of the organometallic monomer occurred.     

Forensic classification of ballpoint pen inks using high performance liquid chromatography and infrared spectroscopy with principal components analysis and linear discriminant analysis

Several varieties of blue ballpoint pen inks were analyzed by high performance liquid chromatography (HPLC) and infrared spectroscopy (IR). The chromatographic data extracted at four wavelengths (254, 279, 370 and 400 nm) was analyzed individually and at a combination of these wavelengths by the soft independent modeling of class analogies (SIMCA) technique using principal components analysis (PCA) to estimate the separation between the pen samples. Linear discriminant analysis (LDA) measured the probability with which an observation could be assigned to a pen class. The best resolution was obtained by HPLC using data from all four wavelengths together, differentiating 96.4% pen pairs successfully using PCA and 97.9% pen samples by LDA. PCA separated 60.7% of the pen pairs and LDA provided a correct classification of 62.5% of the pens analyzed by IR. The results of this study indicate that HPLC coupled with chemometrics provided a better discrimination of ballpoint pen inks compared to IR. The need to develop a suitable IR method for analysing blue ballpoint pen inks has been emphasized and it is hoped that the development of such a method would indeed provide a valuable tool for the non-destructive analysis of blue ballpoint pen ink samples for forensic purposes.     

Thermogravimetric analysis of cobalt sulfate

Morpholine is a base of moderate strength, comparable with that of ammonia, and capable of forming -onium-type salts. Extensive studies [1,2] have been made on the thermal stability of ammonium perchlorate because of its technological use as an oxidant in solid state rocket propellants. The preparation, characterization and thermal behaviour of morpholinium perchlorate are reported in this note. The study was followed by XRD, IR, TG, DTA and mass spectral techniques.     

Electric polarization and dielectric behaviour in dc electric fields of fused KNO2 in phase II at room temperature

On application of dc electric fields to a sample of KNO₂ (99.9% pure) fused between two heavily nickel plated copper plates the sample does not acquire the potential difference equal to the applied emf even though there is no external potential drop in the circuit. Also a very large capacitance of the order of 3000μF is obtained for this sample which is attributed to interfacial polarization effect. An equivalent circuit is given to explain the dc electrical behaviour of the sample. The idea of solid state battery does not seem to be applicable in the case of fused KNO₂. The large value of the capacitance for dc fields in series with large voltage-dependent resistance is the cause of the slow discharge of the condenser.     

Examination of flexibility acquisition policies in dual resource constrained job shops with simultaneous worker learning and forgetting effects

This study investigates worker training related issues in dual resource constrained (DRC)job shop environments with the simultaneous presence of learning, forgetting (which causes relearning) and worker attrition effects. Learning and forgetting occurs as workers are trained in different departments on the shop floor. A recent survey of job shops based in the US indicates that firms are concerned about the relearning losses that accompany worker transfers, and are using a variety of strategies to reduce the effects of relearning. This study uses the learn-forget-learn (LFL) model to capture different learning and forgetting environments in order to understand whether up-front training can be used to reduce relearning and realize the benefits of worker flexibility. Results show that the existing forgetting rate has a significant impact on inventory and customer service performance. Extensive up-front training helps reduce relearning, however, it does not always help improve performance.     

Spectroscopy and decay properties of charmonium

The mass spectra of charmonium are investigated using a Coulomb plus linear(Cornell)potential.Gaussian wave functions in position space as well as in momentum space are employed to calculate the expectation values of potential and kinetic energy respectively.Various experimental states(X(4660)(5~3S_1),X(3872)(2~3P_1),X(3900)(2~1P_1),X(3915)(2~3P_0)and X(4274)(3~3P_1)etc.)are assigned as charmonium states.We also study the Regge trajectories,pseudoscalar and vector decay constants,electric and magnetic dipole transition rates,and annihilation decay widths for charmonium states.