UV Spectral Characteristics Research Articles

Crystal and molecular structure of isogarcinol

The controversy with regard to the structures of the closely related polyisoprenylated phenolic compounds, garcinol, isogarcinol, camboginol, cambogin, xanthochymol and isoxanthochymol is cleared by X-ray crystallographic analysis of the naturally occurring isogarcinol. The unusual UV spectral characteristics of the chromophore of isogarcinol are discussed.

Evidence for sulphur implantation in Europa's UV absorption band

The International Ultraviolet Explorer (IUE) spacecraft has obtained observations of the galilean satellites over the past 2 years which fortuitously span the periods of the Voyager encounters with the jovian system. Our IUE observing programme is designed to determine the UV spectral characteristics of the galilean satellites as a function of orbital position, large-scale areal variability and temporal dynamics. During the past year we have concentrated on the albedo variations of each body1,2. We report here the discovery of an absorption feature at 280 nm in Europa's reflection spectrum. Observations with the IUE show that this absorption is strongest on Europa's trailing hemisphere (central longitude 270°). We identify the feature as an SO2 absorption band and hypothesize that SO2 may form when energetic jovian magnetospheric sulphur ions are injected into Europa's water-ice surface.

9-R-10-Telluroniaanthracene perchlorates

10-Telluroniaanthracene perchlorates with various substituents in the 9 position were obtained by the action of 70% HClO4, on 9-R-10-tellura-9-anthracenols and of trityl perchlorate on 9-R-10-tellura-9-anthracenols and 9-R-9H-10-telluraanthracenes. The IR, UV, and PMR spectral characteristics of the products' were investigated.

Substituted 4(5h)-oxazolones and their salts

2,3,5-Substituted 4(5H)-oxazolonium perchlorates were obtained by condensation of 2-methyl-substituted 4(5H)-oxazolonium perchlorates with aromatic and furan aldehydes and ketones and acetone, and their IR, UV, and PMR spectral characteristics were investigated.

Ionization and solubility of an amphoteric β-lactam antibiotic

Solution equilibria of an experimental antibiotic (code named CP-38, 371) were investigated. In the pH range 2–4 the compound has two pK values. These overlapping macroconstants were determined by three methods: potentiometric titration, spectro-metric titration, and curve-fitting of pH—solubility data. Potentiometric values of pK 1 = 2.86 and pK 2 = 3.81 at 25°C ( μ = 0.2) were in agreement ( ± 0.1 unit) with the constants determined by the other methods. CP-38,371 is amphoteric and pK 3 = 7.50 was determined by potentiometric and solubility methods. The complete microionization scheme for the compound was simplified by consideration of the UV spectral characteristics of the ionizing groups. Using absorbance—pH data, 4 microconstants for the important processes were calculated by the method of Edsall et al. (1958), and by a method developed by the authors. The two procedures gave identical results.

Synthesis and study of poly(oxine‐methylene)s

AbstractThe work presented in this paper comprises synthesis and study of poly(oxine‐methylene)sSystematic name: poly(8‐hydroxyquinolinediylmethylene)s. . The synthesis is based on Friedel‐Crafts polyalkylation of 8‐quinolinol, commonly known as oxine, with dichloromethane in presence of anhydrous aluminium trichloride. Five polymer samples are prepared by varying molar proportions of the two monomers. The polymer samples are insoluble in commonly used organic solvents. They are soluble in acetic acid, formic acid, and in conc. sulfuric acid. The IR and UV spectral characteristics of the polymer samples are reported. Molecular weight of the polymer samples is estimated by conductometric titration in pyridine against standard sodium methoxide. Viscometric study is carried out both in formic acid and glacial acetic acid at 35°C. Solutions of polymer samples in formic acid show normal behaviour and those in glacial acetic acid show abnormal behaviour. Various empirical relations are applied to correlate these data in glacial acetic acid. Acetic acid containing water and simple electrolytes is used as a medium to suppress abnormal behaviour. The thermal properties of the polymer samples are also studied. All the results of analysis are adequately correlated. One oxine‐formaldehyde polymer sample was also synthesized for comparison.

13,14-Dehydrosophoridine fromSophora alopecuroides

A new alkaloid, C15H22ON2, with mp 84–85°C [α] D 20 + 77.9° (c 0.56; ethanol) has been isolated fromSophora alopecuroides L. On the basis of UV, IR, PMR, and mass spectral characteristics and the hydrogenation reaction, its most probable structure has been determined as 13,14-dehydrosophoridine.

Hydrolysis of Procaine and Its Quaternary Derivatives within Lyotropic Smectic Mesophases

The effect of solvent anisotropicity on ester hydrolysis was studied in lyotropic liquid crystalline phases. Procaine hydrochloride and two of its quaternary derivatives, procaine methyl chloride and procaine ethyl chloride, were employed as substrates, and an aqueous gel consisting of 55% polyoxyethylene tridecyl ether, identified as a neat smectic system, was chosen as the solvent medium. Pseudo‐first‐order rate constants for the hydrolysis were obtained in the apparent pH range 8.80‐11.40, at a temperature of from 30 to 50°, over a surfactant span of 50‐65% in the mesophase. Rate measurements were also carried out in aqueous media and in mixed aqueous systems containing polyethylene glycol 300 and 400. The esters were located within the aqueous polyoxyethylene layers as indicated by their UV spectral characteristics. The reaction rates were found to be considerably slower (300‐ to 1100‐fold) in the liquid crystalline phases than in aqueous media. The reactions, as they occur within the smectic phase, are characterized by relatively low apparent activation energies and by large negative entropies of activation.

Inhibitory Effects of Detergents in Membrane Filters

Aqueous filtrates from membrane filters contain material(s) with UV spectral characteristics quite similar to those of a nonionic isooctyl phenoxy polyethoxy ethanol (IPPE)-type detergent. A permeability test utilizing mammalian cell cultures was employed to evaluate the inhibitory properties of the extract and commercial IPPE. The cell culture test was sensitive to IPPE in concentrations as low as 0.006 percent and produced comparable results with extract concentrations having spectral absorbance (283 mμ) values equal to those of IPPE. Dose-response patterns were markedly similar. Spectral analyses of successive aqueous filtrates were used to study the extractability of the offending agent(s). Treatment of membrane filters with hot water prior to autoclaving rendered the filters safe for sterilization of solutions including cell culture media components.