Direct Cu‐Catalyzed Allylic Acetoxylation of Δ5‐Steroids at 7‐Position

The efficiency and selectivity of Cu‐catalyzed allylic acetoxylation of alkene in different solvent systems is improved by the presence of different metallic salts in the reaction medium. The methodology is particularly well employed for the direct allylic acetoxylation of Δ⁵‐steroids at 7‐position, for which the resulting acetoxylated product obtained was exclusively α‐isomer. Excellent yield was achieved (up to 90%) under optimized conditions, while significantly reducing the costs and environmental hazards and increasing the yield as compared to the other previously reported methods.     

Single-step link of the superdeformed band in 143Eu

A discrete γ-ray transition with an energy of 3360.6 keV deexciting the second lowest SD state in ¹⁴³ Eu has been discovered. It carries 3.2 % of the full intensity of the band and feeds into a nearly spherical state which is above the I = 35/2⁽⁺⁾, E_x=4947 keV level. The exact placement of the single-step link is, however, not established due to the specially complicated level scheme in the region of interest. The energy of the single-step link agrees well with the previously determined two-step links.     

Capillary forces between surfaces with nanoscale roughness

The flow and adhesion behavior of fine powders (approx. less than 10 microm) is significantly affected by the magnitude of attractive interparticle forces. Hence, the relative humidity and magnitude of capillary forces are critical parameters in the processing of these materials. In this investigation, approximate theoretical formulae are developed to predict the magnitude and onset of capillary adhesion between a smooth adhering particle and a surface with roughness on the nanometer scale. Experimental adhesion values between a variety of surfaces are measured via atomic force microscopy and are found to validate theoretical predictions.     

Enantiomerically pure tetrahydroisoquinolines by enzyme catalysis and gold-catalyzed phenol synthesis

Five different furfural derivatives were converted to chiral cyanohydrins by enzyme catalysis in good enantiomeric excess. After a sequence of silyl protection, nitrile reduction, tosylation and propargylation, substrates for the gold(I) catalyzed cycloisomerization of δ-alkynyl furans delivered good yields of enantiomerically pure dihydroxytetrahydroisoquinoline building blocks. Neither racemization nor elimination to quinolines was observed.     

Experimental and theoretical FT‐IR and FT‐Raman spectroscopic analysis of N1‐methyl‐2‐chloroaniline

In this work, the experimental and theoretical vibrational spectra of N1‐methyl‐2‐chloroaniline (C₇H₈NCl) were studied. FT‐IR and FT‐Raman spectra of the title molecule in the liquid phase were recorded in the region 4000–400 cm^?1 and 3500–50 cm^?1, respectively. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method (B3LYP) with the 6‐311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT‐IR and FT‐Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. ¹³C and ¹H NMR chemical shifts results were compared with the experimental values. The optimized geometric parameters (bond lengths and bond angles) were given and are in agreement with the corresponding experimental values of aniline and p‐methyl aniline. Copyright © 2008 John Wiley & Sons, Ltd.     

Superabsorbent Capability and High Retention Ability of China Clay (Kaolinite)/Polyacrylic Acid Composites for Aqueous Solution

Majority of superabsorbent polymers (SAPs) yet reported either have low gel strength or high production cost. Therefore, we synthesized a novel polyacrylic acid-grafted China clay (Kaolinite) super-absorbent polymer composite (SAPC) with high thermal stability, low cost of production and superior sorption and retention capability for water and salt solution. The resulting SAPCs were extensively characterized and analysed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results suggested that the composites were thermally stable. Water absorbency increased with increase of clay content up to 45%, while further increase in clay content decreased the water absorbency. Percentage of acrylic acid (AA) and clay by weight shows the optimum absorbency in 35% and 40% respectively. Crosslinker and initiator contents were optimized to be 0.5% and 0.3% by weight respectively. The resulting polymer composite showed high water absorbency of about 785 g/g and 103 g/g of 1% NaCl solution with above 90% retention ability at 50 oC.     

Mössbauer effect study of Ni1−xCuxMnyFe2−yO4 system

The Mössbauer effect technique has been employed for the study of magnetic properties of spinel series Ni_1?xCu_xMn_yFe_2?yO₄ with 0.0≤x≤1.0, and y=0.6. The substitution of Mn³⁺ and Cu²⁺ ions results in a slight decrease of the hyperfine field at B‐ as well as A‐sites. The area ratio of Fe³⁺ ions at the A‐ and B‐site at 77 K indicates that Cu²⁺, Ni²⁺ and Mn³⁺ ions occupy the octahedral sites in an evidence for complete inverse spinel in this system. The temperature dependence of the hyperfine parameters has been studied for composition with x=0.5 where Nèel point T_N and Debye temperature θ_D are found to be 650 and 679 K, respectively. The temperature dependence of the sublattice magnetization σ(T) obeys a one‐third‐power law in the range 0.5N<0.99.     

Cladioxazole: a novel sesquiterpene from a marine soft coral of genus Cladiella

Chemical investigations on the methanolic extract of Cladiella species, collected from Andaman Island, India, yielded a novel sesquiterpene, cladioxazole (1). Its structure was established with the aid of extensive spectral studies.     

Present status and future aspects of nuclear structure close to 100Sn

The present status of experimental approach to ¹⁰⁰Sn in the spectroscopy of excited states is landmarked by the T_z=3/2 nuclei between ⁹⁵Pd and ¹⁰¹In and the T_z=1 nuclei ⁹⁴Pd and ⁹⁸Cd. The detection limits with Pre-EUROBALL γ-arrays and ancillary detectors are below the 10^?5 level of the total fusion- evaporation residue cross section. A large scale shell model analysis of the existing data reveals the shell structure at ¹⁰⁰Sn, which shows a remarkable similarity to ⁵⁶Ni. Evidence for an increasing proton-neutron interaction in approaching the N=Z line is deduced from high spin isomers and spherical yrast lines. The effective E2 operator for protons and neutrons and implications for a low lying particle-hole (ph) E2 excitation in ¹⁰⁰Sn are discussed.     

Chiroptical properties of some N-5(6)benzofuroxanoyl-L-α-amino acids and esters

The CD spectra of a series of N-5(6)benzofuroxanoyl-L-α-amino acids and esters reveal, in ethanol and acetonitrile, cotton effect (CE) bands around 365, 320, 265 and 223 nm. It was found that the signs of the CE maxima, located at longest and shortest wavelengths, were both positive for the L -aliphatic series, whereas these bands display sign inversion in the CD spectra of the L -aromatic counterparts. This chiroptical behaviour might be attributed to conformational differences. Nmr spectral data give support to this assumption. Mass spectral fragmentations of these compounds are discussed.