Laser induced fluorescence of Sb2. I. Visible B–X system

Diatomic antimony molecules have been produced in a heat-pipe oven at pressures from 10^?2 to 10 Torr. Laser induced fluorescence of Sb₂ has been studied in the spectral range 420–730 nm with various laser sources. In order to investigate different isotopic molecules and to enhance fluorescence intensity, intracavity measurements have been performed. For the isotopic molecules rotational and vibrational constants of the ground state X(¹Σ_g⁺) and for the excited state B(O_u⁺) have been determined. RKR potential curves have been calculated and used to comput Franck—Condon factors.     

Benzothiazolium derivatives. III. Nucleophilic substitution reactions of benzothiazolium salts

The reactions of 2,3-dihydrothiazolo[2,3-b]benzothiazolium bromide 1 (A^? ?Br^?) with certain nucleophilic reagents have been performed for the purpose of ascertaining the reaction pathways and identifying the group that is displaced from the central carbon atom of the dithiocarbamate system. The nature of complex salt-like intermediates formed initially from 1 (A^? ?Br^?) has been studied and confirmed. For comparison, a number of nucleophilic substitution reactions of 2-methylthio-3-methylbenzothiazolium iodide 17 and 2-dimethylamino-3-methylbenzothiazolium perchlorate 18 have been examined.     

STUDIES OF PHOSPHAZENES. PART VI.1 THE PREPARATION OF THE ISOMERIC TETRACHLOROBIS-ISOPROPYLAMINOCYCLOTRIPHOSPHAZATRIENES

Abstract

The three isomers of N₃P₃Cl₄(NHPr¹)₂ have been prepared and separated by gas-liquid chromatography. Their structures have been assigned on the basis of ¹H and ³¹P nmr data.     

Five ingol esters and a 17-hydroxyingenol ester from the latex of Euphorbia Kamerunica. Assignment of esters using 13C.N.M.R. methods.

The structures of five ingol esters and a 17-hydroxyingenol ester from the latex of $\text{Euphorbia kamerunica}$ have been determined. The ¹³C n.m.r. spectra of these compounds have been assigned using 2D δ_C/δ_H correlations. The specific positions of attachment of esters have been assigned unambiguously using ¹³C n.m.r. methods including 2D long range δ_C/δ_H correlation.     

Alkaloids ofNitraria sibirica. Structure and absolute configuration of sibirinine

The chemical properties of sibirinine have been studied, its synthesis has been performed, and its¹H and¹³C NMR spectra have been analyzed. From the results obtained its structure and absolute configuration have been deduced.     

31P N.M.R. studies of some pseudo-halogeno-derivatives of phosphorus

Abstract

Several new pseudo-halogeno phosphorus species, including isomeric N- and O-bonded cyanato-derivatives of the PCl₆ ^? ion, cyano-derivatives of RPCl₅ ^? ions (R [dbnd] Ph or Me), and organo-phosphorus (III) cyanide adducts RP(CN)₂X^? (R [dbnd] Me, Et, Ph or C₆F₅; X [dbnd] Cl, Br or I) have been prepared in solution, and identified by means of ³¹P n.m.r. spectroscopy. Isomeric configurations in the six-coordinate species have been assigned by the method of pairwise interactions.     

The use of the selective population inversion technique in the assignment of carbon-13 n.m.r. resonances in 3,6-epoxy-pentacyclo[6.2.1.02,7.04,10.05,9]undecane

Different applications of the selective population inversion technique in an n.m.r. study of 3,6-epoxypentacyclo-[6.2.1.0^2,7.0^4,10.0^5,9] undecane have been demonstrated. The intensity gain accompanying heteronuclear ¹³C—{¹H} experiments allowed the detection of fine structure due to long range C? H couplings otherwise hidden in normal proton coupled ¹³C spectra. Definite assignments of two very similar, directly bonded, C? H couplings within a methylene group have been made.     

N.m.r. studies in the heterocyclic series: XVI—determination of the structure of 3-azidoindazole by 1H and 13C n.m.r. spectroscopy

The 1-NH structure for 3-azidoindazole has been demonstrated by the observation of ¹H? ¹H and ¹³C? ¹H couplings involving the hydrogen atom attached to nitrogen. A comparison between 3-azidoindazole and indazole shows that both compounds have the same tautomeric structure.     

Interaction of radium with freshwater sediments and their mineral components. I.

The radiotracer method has been used for investigation of the adsorption and desorption of traces of radium on ferric hydroxide and quartz under conditions similar to those prevailing in waste and surface waters. The effects of pH, liquid to solid ratio, ionic strength and presence of Ca²⁺ or SO ₄ ^2- ions have been studied. It has been concluded that at pH less than 7 and at concentration of suspended sediments (of common composition) less than 100 mg·1^–1 ferric hydroxide and quartz have negligible effect on the state and migration of radium in surface waters. Radium adsorbed on quartz can be easily desorbed with dilute solutions of hydrochloric acid or sodium chloride.     

Analogs of purine nucleosides. 3. Alkoxyalkylation of hypoxanthine by the silyl method

The reaction of bis(trimethylsilyl)hypoxanthine with methyl trichloromethyl ether has been investigated. 1-Methoxymethyl-, 7-methoxymethyl-, and 9-methoxymethyl-hypoxanthine, as well as 1,7-, 1,9-, and 3,7-bismethoxymethylhypoxanthine, have been isolated from the reaction mixture. The structures of the isomers have been established on the basis of an analysis of their UV, IR, ¹H NMR, ¹³C NMR, and ¹⁵N NMR spectra. The influence of the conditions under which the reaction is carried out on the yield of the alkylation products and the isomeric composition of the reaction mixture has been studied.For report 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 518–524, April, 1986.     

13C n.m.r. investigation on the first and second nitrogen protonation in the diazanaphthalenes

The ¹³C chemical shifts of the diazanaphthalenes have been recorded as a function of the pH value, providing classical titration curves. From these curves the pK₁ and pK₂ values have been determined taking into account the activity coefficients. The changes in ¹³C chemical shift under the influence of nitrogen protonation (Δδ) can be described by two protonation parameter sets.     

15N nuclear magnetic resonance spectroscopy. Natural-abundance 15N spectra of aliphatic oximes

¹⁵N chemical shifts of the Z and E isomers of twenty-two ketoximes and fourteen aldoximes have been determined at the natural-abundance level of ¹⁵N, using Fourier transform methods. The influences of π delocalization, methyl substituents and solute concentration on the oxime nitrogen shielding have been determined. The ¹⁵N shifts for oximes of several cycloalkanones have been measured and the influence of ring size on the chemical shifts is discussed.     

Studies with inorganic precipitate membranes. III. Consideration of energetics of electrolyte permeation through membranes

The permeability of various electrolytes through parchment-supported ferrocyanide membranes of manganese, cobalt, silver, and cadmium has been measured at 10, 15, 20, 25, and 30°C. The order of permeability at a given temperature was Cl^- > NO₃^- > CNS^- > CH₃COO^- > SO₄^2- for both monovalent and divalent cations. For any given anion, the cations followed the sequence NH₄⁺ > Li⁺ > Ba²⁺ > Ca²⁺ > Mg²⁺ > Al³⁺. This sequence has been correlated with the size of the hydrated ion. Further, the data have been considered from the standpoint of the theory of rate processes and the values for the entropy of activation (ΔS′) have been derived assuming an equilibrium distance of 3 Å in the membrane. The values of ΔS′ were all negative and decreased with increasing valence of the ions. This was interpreted to mean electrolyte permeation with partial immobilization in the membrane.     

Thermodynamique de composes azotes. VII. Etude thermochimique du pyrazole et de l'imidazole

Enthalpies of sublimation for pyrazole and imidazole have been obtained by calorimetry at 298.15K. The ΔH⁰_sub (298.15 K) values for these two compounds are, respectively, 69.16 ± 0.32 and 74.50 ± 0.40 kJ mole^?1. From literature data obtained by combustion calorimetry for ΔH⁰_f (c, 298.15 K), the enthalpies of formation of these compounds in the gaseous state (pyrazole: 185.1 ± 2.3 kJ mole^?, imidazole: 133.0 ± 1.7 kJ mole^?1) have been derived. Several energy values related to the molecular structure of these two compounds (as resonance energy, enthalpy of isomerization, …) have been determined. The study of pyrazole has enabled us to contribute to the evaluation of some characteristics of the NN bond.     

Synthetic inorganic ion exchangers. XI. Preparation,properties and ion-exchange behaviour of zirconium tungstate

Summary Samples of zirconium tungstate have been prepared under different conditions and their physico-chemical properties, composition, IR spectra and cation-exchange behaviour are reported. Separations of a number of metal ions from Bi³⁺ and from Pb²⁺ have been worked out.Part X. Ref. [1].     

Raman spectra of gases: XIV. Hexachlorodisiloxane

The Raman spectra (50–1200 cm^?1) of gaseous, liquid, and solid (Cl₃Si)₂O have been recorded. The infrared spectra of the gas and solid have been recorded from 55–2000 cm^?1 . The spectra of the gas have been interpreted in detail on the basis of C_2v symmetry with the A₁ skeletal Si-O-Si bend assigned at 63 cm^?1. The spectra gave evidence that there are structural changes upon condensation of the gas and the Si-O-Si angle approaches linearity in the solid state. The opening of this angle is probably due to crystal packing factors.     

Über Chalkogenolate. 134. Untersuchungen über Ester von Halogenoameisensäuren 2. Darstellung und Eigenschaften von Se-Alkylestern der Chloromonothiomonoselenoameisensäure [1]

On Chalcogenolates. 134. Studies on Esters of Haloformic Acids 2. Synthesis and Properties of Se-Alkyl Esters of Chloromonothiomonoselenoformic Acid The hitherto unknown esters RSe? CS? Cl with R ? C₂H₅ and ⁿC₃H₇ have been prepared by reaction of thiophosgene with the corresponding alkane selenol. The compounds have been characterized with electron absorption, nuclear magnetic resonance (¹H, ¹³C, and ⁷⁷Se), infrared, and mass spectra.     

Fulvene,VII. Analyse der 13C- und 1H-NMR.-Spektren

Carbon-13 and proton NMR. spectra of pentafulvene and of a series of 6-substituted fulvenes have been analysed and assigned by homo- and heteronuclear double resonance and with the aid of iterative computation. ¹³C and ¹H chemical shifts are interpreted in terms of substituent effects and compared with π-electron charges calculated for the unsubstituted fulvene. From ¹³C shifts a 10 percent contribution of dipolar structures to the electronic configuration of fulvene may be estimated. All long-range proton-proton coupling constants including relative signs and some proton-carbon couplings in the fulvene spin system have been determined and assigned.     

Spectra and structure of organophosphorus compounds: XVII. Infrared and Raman spectra. vibrational assignment and barriers to internal rotation for t-butylphosphine

The infrared spectra of gaseous and solid tertiary-butylphosphine, [(CH₃)₃CPH₂], have been recorded from 50 cm^?1 to 3500 cm^?1. The Raman spectra of gaseous, liquid and solid (CH₃)₃CPH₂ have been recorded from 10 to 3500 cm^?1. A vibrational assignment of the 42 normal modes has been made. A harmonic approximation of the methyl torsional barrier from observed transitions in the solid state gave a result of 4.22 kcal mol^?1 and 3.81 kcal mol^?1 in the gaseous state. Hot band transitions for the phosphino torsional mode have been observed. The potential function for internal rotation about the C-P bond has been calculated. The two potential constants were determined to be: V₃ = 2.79 ± 0.01 kcal mol^?1 and V₆ = 0.07 ± 0.01 kcal mol^?1.     

The chemistry and kinetic behavior of Cu-Cr-As/B wood preservatives. IV. Fixation of CCA to wood

The kinetic behavior of copper–chromium–arsenic (CCA) wood preservatives in their reaction with wood, lignin, cellulose, and their respective simple model compounds, guaiacol and D(+)-glucose, has been elucidated. Copper chromates^VI/lignin guaiacyl units and chromium^III arsenates/lignin guaiacyl units, which are stable and insoluble complexes formed during the reaction, have been characterized. No copper arsenates were formed during the reactions (which were carried out using a CCA of type C). The sequence, nature, and combined effect of the reactions of CCA with wood, lignin, and cellulose are similar to that already described for the “CrO₃ alone,”¹ Cu/Cr², and Cr/As³ systems. Rate constants, energies of activation, and Arrhenius equations have been obtained and reported. The distribution of Cr^VI, Cr^III, As^v, and Cu²⁺ in CCA-C-treated wood has been calculated. The results obtained have allowed meaningful comparisons of several commercial CCA formulations.