Restricted rotation involving the tetrahedral carbon: XXIII—comparison of barriers to rotation of 9-(2-isopropylphenyl) fluorene obtained by 1H DNMR, 13C DNMR,double resonance and kinetic measurements

Rates of rotation about the C-9-C-ar bond of 9-(2-isopropylphenyl) fluorene were measured by ¹H DNMR, ¹³C DNMR, double resonance, and a kinetic method. The kinetic data obtained by these methods were critically examined. The DNMR methods afforded satisfactory results if rate data obtained by total line shape analyses of complicated signals with couplings were used, and those derived from simple patterns were abandoned. Agreement among the data yielded by the four different methods was excellent, provided that the data which might contain dubiously large errors were excluded.     

Nitrogen implantation in GaAs1−xPx (x=0.4; 0.65)

Nitrogen ions were implanted in GaAs_1−xP_x (x=0.4; 0.65) at room temperature at various doses from 5×10¹² cm⁻² to 5×10¹⁵ cm⁻² and annealed at temperatures from 600°C up to 950°C using a sputtered SiO₂ encapsulation to investigate the possibility of creating isoelectronic traps by ion implantation. Photoluminescence and channeling measurements were performed to characterize implanted layers. The effects of damage induced by optically inactive neon ion implantation on photoluminescence spectrum were also investigated. By channeling measurements it was found that damage induced by nitrogen implantation is removed by annealing at 800°C. A nitrogen induced emission intensity comparable to the intensity of band gap emission for unimplanted material was observed for implanted GaAs_0.6P_0.4 after annealing at 850°C, while an enhancement of the emission intensity by a factor of 180 as compared with an unimplanted material was observed for implanted GaAs_0.35P_0.65 after annealing at 950°C. An anomalous diffusion of nitrogen atoms was found for implanted GaAs_0.6P_0.4 after annealing at and above 900°C.     

Novel synthetic approach to creating PtCo alloy nanoparticles by reduction of metal coordination nano-polymers

PtCo alloy nanoparticles with different metal elemental ratios (Pt/Co = 0.9, 1.6, 2.9, and 3.6) were prepared by a novel synthetic approach, using the transformation reaction of platinum(IV)/cobalt tetracyanoplatinate metal coordination nano-polymers (Pt(II)-CN-Pt(IV)/Co)via a H2 gas-phase reduction.     

Laser-induced trench etching of GaAs in aqueous KOH solution

Maskless etching of n-type GaAs in a KOH aqueous solution by irradiation of an argonion laser has been investigated to obtain high etching rates and aspect-ratios of etched grooves. High etching rates of up to 805 m/s and an aspect ratio of 8 have been achieved by a single scan of a laser beam. Microprobe photoluminescence (PL), Raman scattering, and Auger electron spectroscopy (AES) measurements were carried out on the trench surface to characterize damage induced by laser wet etching.     

Thermolysis of [1,2,4]triazolo[1,5-a]pyrimidine n-ylides

5,7-Dimethyl[1,2,4]triazolo[1,5-a]pyrimidinio-3-phenacylide ($\text{3}$) generated by the reaction of an iminium salt ($\text{2}$) with 1 eq. of triethylamine, underwent a new thermal ring cleavage of the triazole moiety to give the pyrimidine derivative. However reaction of $\text{2}$ with 2 eq. of triethylamine afforded the 2-iminooxazoline derivative. The iminooxazoline reacted with nucleophiles such as alcohols or amines to give imidazoles.     

Extraction Chemistry of Palladium(II). Mechanism of Antagonistic Synergistic Extraction of Palladium By A 4-Aroyl Derivative of 1-phenyl-3-Methyl-Pyrazolone-5- one and Trialkylamine of High Molecular Weight

The synergistic extraction behavior of Pd^II, one of the main radioactive fission products in the reprocessing process, from HNO₃ solutions with a 4-aroyl derivative of 1-phenyl-3-methyl-pyrazolone-5-one (PMP), a weakly acidic chelating extractant 1-phenyl-3-methyl-4-(2-methoxybenzoyl)-pyrazolone-5-one (HPMMBP), and a trialkylamine of high molecular weight, tri-iso-octylamine (TiOA), has been studied. An obviously antagonistic extraction effect was observed in the extraction system under the given conditions. To understand this phenomenon, a preliminary investigation was performed to explain the mechanism of this reaction. According to the theory of the corresponding solutions (TCS), the association between HPMMBP and TiOA is presented and discussed in the organic phase. An associated species HPMMBP·TiOA formed through hydrogen bonding in a CHCl₃ medium might be the main reason why an antagonistic extraction effect occurred. The association constant between HPMMBP and TiOA was calculated to be 0.212 ± 0.03     

The structure of paraherquamide,a toxic metabolite from penicilliumparaherquei

A new toxic metabolite was isolated from $\text{Penicillium}$$\text{paraherquei}$ and the structure was determined by X-ray diffraction analysis. The metabolite was designated as paraherquamide.     

Synthesis of novel cyclic sulfilimines, 2-azathiabenzene derivatives

The synthesis and some properties of novel cyclic sulfilimines, 2-methyl-1-aza-2-thianaphthalene and 9-methyl-10-aza-9-thiaphenanthrene are described.     

Electrochemical synthesis of aldehydes and acetals from α-phenylthiocarboxylic acid

α-Phenylthiocarboxylic acids were converted to the corresponding aldehydes or acetals with oxidative decarboxylation and desulfurization by electrolysis.