Use of a carboxylate exchanger in the determination of copper in distilled water by neutron activation analysis

Copper in distilled water is collected on Zeokarb 226(NH ₄ ⁺ ) and irradiated with thermal neutrons. By comparison of the induced activity of 0.51 MeV photopeak of⁶⁴Cu with that of a standard, irradiated under comparable conditions, copper at ppb levels is easily determined.     

Volumetric, ultrasonic and viscometric studies of binary mixtures of dimethyl sulphoxide with chloro and nitro substituted aromatic hydrocarbons at T = 303.15 K

Excess volumes (V^E) ultrasonic sound velocities (u), isentropic compressibilities (K_s) and viscosities (η) have been measured for the binary mixtures of dimethylsulphoxide (DMSO) with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at T = 303.15 K. The measured V^E values were positive over the entire composition range in all the binary mixtures. Isentropic compressibilities (K_s) have been computed for the same systems from precise sound velocity and density data. Further, deviation in isentropic compressibility (ΔK_s) from ideal behaviour was also calculated. The viscosity data are analysed on the basis of corresponding states approach. Deviation in viscosities are positive over the entire composition range. The measured data is explained on the basis of intermolecular interactions between unlike molecules.     

Highly Efficient and Selective Deprotection Method for Prenyl,Geranyl, and Phytyl Ethers and Esters Using Borontrifluoride–Etherate

An efficient, simple, and practical method has been developed for the deprotection of prenyl, geranyl, and phytyl ethers and esters of aromatic and aliphatic compounds using borontrifluoride–etherate (BF₃ · OEt₂) at room temperature in good to excellent yields for the first time.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Design,synthesis, and biological activity studies of a new class of sulfonated aurones: First synthesis of acidoaurone isolated from Phyllanthus acidus

A novel series of aurones were designed by introducing sulfonic acid group on ring-A and ring-B of known natural aurones such as hispidol, sulfuretin, maritimetin, and aureusidin. These sulfonated aurones were synthesized by a unique approach. Sulfonation on ring-A or ring-B converts water-insoluble aurones into highly water-soluble aurones. The sulfonated aurones were tested for their antioxidant, antiinflammatory, and AChE inhibition activities along with their natural aurones. Ring-A sulfonated aurones displayed higher antioxidant activity, 5-LOX, and AChE inhibition in comparison with their corresponding natural aurones. Ring-B sulfonated aurones exhibited potent 5-LOX inhibitory activity and significant antioxidant activity. Acidoaurone, a first sulfonated aurone isolated from Phyllanthus acidus was synthesized for the first time and was well characterized using NMR, LC–MS, and further confirmed by HMBC.     

Forbidden hyperfine transitions in electron spin resonance of Mn2+ in NaCl single crystal

Forbidden hyperfine transitions are observed in the electron spin resonance spectrum of divalent Mn⁵⁵ ion in NaCl single crystal for a particular associated pair. From the measurements of the M = + 1/2 → ?1/2, Δm = ± 1 transitions the parametersQ′ and Q″ of the nuclear electric quadrupole part of the spin-Hamiltonian H_o = Q′ [I_z ² ? 1/3 I (I + 1)] + Q″ (I_x ²?I_y ²) are found to be + 1.70 × 10^?4 cm.^?1 and +0.16 × 10^?4 cm.^?1 respectively.     

Optical absorption of Co2+ doped NH4Cl: Phase transformation studies

The absorption spectrum of Co²⁺ doped NH₄Cl has been studied from the room temperature to the liquid nitrogen temperature. A sudden change in the spectrum is observed between 243° K and 233° K which is attributed to the phase transition in the crystal. From the observed spectrum it is suggested that Co²⁺ goes in interstitially as well as substitutionally. Both the types of centers exist at room temperature, but with decrease in temperature substitutional ions migrate to interstitial sites, the process being stimulated at the phase transformation point so that the 77° K spectrum seems to be mostly due to the interstitial centers. The 77° K spectrum is analyzed in the approximation of octahedral symmetry for interstitial ions and the band positions are fitted fairly well with B = 870 cm.^?1 Dq = 850 cm.^?1 and C = 4·4 B. A blue shift of about 100 cm.^?1 is observed for⁴T₁ (P) band at the phase transition which is attributed to the increase in Dq value with the anomalous lattice contraction at the phase transition. The decrease in the lattice parameter calculated from this blue shift is around 0·4% which is in good agreement with the results of X-ray measurements. Two possible models for the interstitial complex are examined and the one with fourfold chlorine coordination associated with two neutral water molecules at the first neighbour (NH₄)⁺ site lying along < 100> direction is suggested to be more probable.     

Use of zeo-karb 226 and dowex a-l in the analysis of high-purity zinc and zinc-base alloys for Tl and In

Utility of Zeo-Karb 226 and Dowex A-l for the separation of Tl and In at 5-ppm level from high-purity zinc and zinc-base alloys has been investigated. With Zeo-Karb 226 (NH(4)(+)), T1(+) is conveniently separated from these materials and also from many other cations, with l.0M ammonium nitrate as the eluent. It is subsequently determined with Rhodamine B. This separation principle is also applied to the analysis of Pb-Tl alloys. Both Tl and In (along with Fe) are preconcentrated on Zeo-Karb 226(H(+)) from a solution of the sample at pH 3.0. Suitable methods of subsequent determination of Tl and In are described. In the case of Dowex A-1(H(+)), Tl(+), In(3+), Fe(3+) and Cu(2+) are retained from a solution of the sample at pH 2.0. An o-phenanthroline solution at pH 2.0 elutes all but traces of Cu(2+). In(3+) along with Fe(3+) is eluted with l.0M hydrochloric acid. Finally, Tl is eluted with 2.0M hydrochloric acid containing sulphurous acid.     

Molecular vibrations of HCOF and DCOF

The harmonic wave numbers for HCOF and DCOF have been calculated using the observed fundamentals and the force constants have been evaluated on the basis of the general quadratic and Urey-Bradley force fields. The out-of-plane fundamental in HCOF, which has not been reported so far, is calculated. The thermodynamic properties of HCOF and DCOF have been calculated for fourteen temperatures ranging from 200° K. to 1500° K. for the ideal gaseous state at one atmosphere pressure and for a rigid rotor, harmonic oscillator approximation.     

Urey-bradley force field: Borine carbonyl and borine carbonyl-d 3

A normal co-ordinate treatment has been carried out to calculate the force constants of BH₃CO and BD₃CO molecules, on the basis of a Urey-Bradley potential force field.