Crystal and Molecular Structure of 3,5-Diphenyl-4,5-dihydro-2-phenylcarboxamide-1H-pyrazole

Crystal structure of the title compound C₂₂H₁₉N₃O is determined by single crystal X-ray diffraction (sp. gr. P2₁/c, Z = 4). The molecule as a whole, is not planar: phenyl cycles are rotated relative to the plane of pyrazole ring. N?H···N intramolecular hydrogen bond forms five-membered ring fused to pyrazole ring. There are also intramolecular C?H···O and C?H···π interactions. Intermolecular C?H···O hydrogen bond links the molecules into a C(7) chain along the a axis. The crystal structure is stabilized also by C–H···π and π···π intermolecular hydrogen bonds.     

Role of the 30° Telescope in Evaluation of Laryngeal Masses During Direct Laryngoscopy

SUMMARY: Visualization of enlarged laryngeal lesions is the most important factor in choosing a surgical technique, especially for partial surgery. For this reason standard microlaryngoscopy, a computed tomography (CT) scan of the larynx, and 30 degrees telescopic microlaryngoscopy were compared during evaluation of the laryngeal ventricul and sub-glottic area. The histopatholgoical findings of the specimens collected under each modality were simultaneously compared. Comparison of the histopathological findings, which corresponded to inspection with the 30 degrees telescopic method, was more significant than with the use of standard microlaryngoscopy or the CT scan. The aim of the current study therefore was to determine the importance of the 30 degrees telescopic microlaryngoscopic method for the evaluation of the laryngeal ventricle and subglottic area.     

Surface pencil with a common line of curvature in Minkowski 3-space

In this paper, we analyze the problem of constructing a surface pencil from a given spacelie （timelike） line of curvature. Using the Frenet frame of the given line of curvature in Minkowski 3-space, we express the surface pencil as a linear combination of this frame and derive the necessary and sufficient conditions for the coefficients to satisfy the line of curvature requirement. We illustrate this method by presenting some examples.     

Photoluminescence dynamics in chalcogenide glasses and crystals

Time-resolved photoluminescence studies reveal distinct differences between the recombination processes in a chalcogenide glass and in its crystalline counterpart. Here the three luminescence bands of a-As₂S₃ are interpreted in terms of the recombination of an excition, a self-trapped exciton and a pair of electron- and hole-like small polarons. The two luminescence bands observed in the crystal are attributed to the recombination of two types of excitons composed respectively of a hole bound to a self-trapped electron, and a hole which is induced to self-trap in the presence of a self-trapped electron.     

A convenient synthesis of functionalized 1H-pyrimidine-2-thiones

The furan-2,3-dione 1 and the thiosemicarbazones 2 combine with loss of carbon dioxide and water yielding the 1-methylenaminopyrimidine-2-thione derivatives 3 in moderate yields (30–60%). Their molecular skeleton is confirmed with aid of an X-ray structure determination of 3c . Hydrolysis of 3 leads to the 1-aminopyrimidine-2-thione 5 .     

Beneficiation of borax by reverse flotation in boron saturated brine

Flotation is one of the plausible methods for recovering borax fines discharged as fine waste to the tailings dam in the Kirka borax processing plant. A literature review dealing with the flotation behavior of boron minerals reveals that clay minerals in the boron ores coat boron minerals and thus deteriorate the quality of boron concentrates produced by direct flotation. The main objective of this study is therefore to recover borax fines from the tailings of the concentrator by reverse flotation. A three-level-factor experimental design was used to determine the main and interaction effects of variables selected on the metallurgical performance of reverse flotation. An analysis of variance for experimental results indicates that interaction effects of the variables for concentrate quality and recovery of B2O3 is nonsignificant and the most important variable for grade of concentrate and recovery is the collector dosage. It is shown that a concentrate assaying 11.25% B2O3 with 89.90% B2O3 recovery could be produced by means of single-stage (rougher) reverse flotation. Additionally, in order to produce a sufficient-quality concentrate, a multistage reverse flotation scheme involving rougher, scavenger, and two cleaners was devised. A final concentrate containing 23.47% B2O3 with 81.78% B2O3 recovery was obtained from these tests. The reverse flotation method can be thus considered as an important option for the beneficiation of borax fines.     

Synthesis of N'-[4'-Benzo(15-Crown-5)]-4-Tolylaminoglyoxime and N'-[4'-Benzo(15-Crown-5)]-4-Chlorophenylaminoglyoxime and Their Complexes with Copper (II), Nickel (II) and Cobalt (II)

N'-[4'-benzo(15-crown-5)]-4-tolylaminoglyoxime (H₂L¹),the sodium chloride salt of H₂L¹ (H₂L¹...NaCl),N'-[4'-benzo(15-crown-5)]-4-chlorophenylaminoglyoxime(H₂L²) and the sodium chloride salt of H₂L² (H₂L²...NaCl)have been prepared from p-chlorophenylchloroglyoxime,p-tolylchloroglyoxime, 4'-aminobenzo[15-crown-5] and sodiumbicarbonate or sodium bicarbonate and sodium chloride. Nickel (II),cobalt (II) and copper (II) complexes of H₂L and H₂L...NaClhave a metal-ligand ratio of 1 : 2 and the ligand coordinatesthrough the two N atoms, as do most of the vic-dioximes. Their IR spectra and elemental analyses are given, together with¹H NMR spectra of the ligands.     

Synthesis of four new vic-dioximes and their nickel(II), cobalt(II), copper(II) and cadmium(II) complexes

Four unsymmetrical vic-dioximes: [L¹H₂] N-(4-butylphenyl)amino-amphi-glyoxime, [L²H₂] N-(4-butylphenyl)amino-anti-glyoxime, [L³H₂] N-(4-phenylazophenyl)amino-amphi-glyoxime and [L⁴H₂] N-(4-phenylazophenyl)amino-anti-glyoxime have been prepared from amphi-chloroglyoxime, anti-chloroglyoxime, 4-butylaniline and 4-(phenylazo)aniline respectively. The complexes of these vic-dioximes with Ni^II, Co^II, Cu^II and Cd^II ions have been investigated. All are insoluble in common solvents. Their i.r. spectra and elemental analyses are given, together with mass and ¹H-n.m.r. spectra of the ligands.     

Adhesion and stable low friction provided by a subnanometer-thick monolayer of a natural polysaccharide

Using a surface forces apparatus, we have investigated the adhesive and lubrication forces of mica surfaces separated by a molecularly thin, subnanometer film of a high-molecular-weight (2.3 MDa) anionic polysaccharide from the algae Porphyridium sp. adsorbed from aqueous solution. The adhesion and friction forces of the confined biopolymer were monitored as a function of time, shearing distance, and driving velocity under a large range of compressive loads (pressures). Although the thickness of the dilute polysaccharide was <1 nm, the friction was low (coefficient of friction = 0.015), and no wear was ever observed even at a pressure of 110 atm over 3 decades of velocity, so long as the shearing distances were less than twice the contact diameter. Atomic force microscopy in solution shows that the biopolymer is able to adsorb to the mica surface but remains mobile and easily dragged upon shearing. The adhesion (adsorption) of this polysaccharide even to negatively charged surfaces, its stable low friction, its robustness (high-load carrying capacity and good wear protection), and the weak (logarithmic) dependence of the friction force on the sliding velocity make this class of polyelectrolytes excellent candidates for use in water-based lubricant fluids and as potential additives to synovial fluid in joints and other biolubricating fluids. The physical reasons for the remarkable tribological properties of the ultrathin polysaccharide monolayer are discussed and appear to be quite different from those of other polyelectrolytes and proteins that act as thick "polymer brush" layers.     

Thermal C2-C6 cyclization of enyne-carbodiimides: experimental evidence contradicts a diradical and suggests a carbene intermediate

Mechanistic details of the thermal C2-C6 cyclization of enyne-carbodiimides are investigated. A variety of product and kinetic studies on solvent and substituent effects open the way for a deeper mechanistic understanding. Nonlinear Hammett correlations suggest that a change of mechanism takes place: the thermal C2-C6 cyclization of enyne-carbodiimides with electron-withdrawing substituents may be best described as a coarctate cyclization to a carbene and with electron-donating substituents as a polar cyclization to a carbene with strong zwitterionic character. Theoretical investigations had originally suggested a diradical intermediate. DFT computations and NBO analysis for the parent diazafulvenediyl are in agreement with a carbene intermediate. While any intermolecular trapping of the intermediate failed, the formation of the C-H insertion product 19 strongly supports the carbene hypothesis.