The mass spectra of several dibenzo (d.f)-1,3,2,-dioxaphosphorepines of the type where X=0, S, Se and R=2,2′-biphenylylene, have been studied. Dibenzochalcogen ions [RX]+˙ stemming directly from [M]+˙ were observed with high intensities, indicating specific migration of X from phosphorus to carbon with simultaneous destruction of the dioxaphosphorepine ring. Simple cleavage of P? Y as usually observed in similar organophosphorus compounds is not a common process here. 相似文献
The electron-impact-induced elimination of piperidine from the title compound could be established by investigation of the unsymmetrically 2H-labelled compound. The mechanism of a 1,1-elimination can be excluded be unequivocally. 相似文献
Summary The intermolecular complex formation of bilirubin and biliverdin with two proteins (basic pancreatic trypsin inhibitor and lysozyme) were studied by optical and chiroptical methods. Evidence for specific intermolecular interactions of biliverdin with both proteins was found. Bilirubin forms a soluble complex only with lysozyme.
UV-VIS und CD-spektroskopische Untersuchungen intermolekularer Wechselwirkungen von Gallenpigmenten mit kleinen Proteinen
Zusammenfassung Die intermolekulare Komplexbildung von Bilirubin und Biliverdin mit zwei Proteinen (basischer pankreatischer Trypsininhibitor und Lysozym) wurden mittels optischer und chiroptischer Spektroskopie untersucht. Für Biliverdin konnten intermolekulare Wechselwirkungen mit beiden Proteinen nachgewiesen werden. Bilirubin bildet nur mit Lysozym einen löslichen Komplex.
Zusammenfassung Die Zusammensetzung der verschiedenen Metall-DDTC-Verbindungen, ihre Fällbarkeit und Extrahierbarkeit bei verschiedenen pH-Werten sowie bei Anwesenheit von Komplexbildnern und die Absorptionsspektren ihrer Lösungen in CCl4 werden mitgeteilt. Hinweise für die Brauchbarkeit des DDTC bei der Analyse der einzelnen Elemente werden gegeben. 相似文献
The 1H and 13C nmr spectra of 1,4,5,7-tetrahydro-3H-2,6-benzodiselenine (1) and three 4-spiro derivatives 2–4 as well as the 77Se nmr spectra of 2 have been recorded at different temperatures in order to investigate their conformational behavior. It was found that in analogy to corresponding dithionins the molecules adopt a chiral ground state conformation (Figure 2), and coalescence effects are due to racemization. 相似文献
Zusammenfassung Na-cyklohexyldithiocarbaminat reagiert im pH-Bereich 6,6 bis 7,2 mit Uranylsalzen unter Bildung eines in Wasser mit gelber Farbe lösliehen Komplexes, der bei pH 6,6 ein Absorptionsmaximum bei 392 bis 394 nm besitzt. Die wäßrige Lösung wird durch Zusatz von Alkalilauge bis zum pH 8 bis 9 momentan entfärbt.Es wird ein Kaliumdoppelsalz KUO2(S2HCNC6H11)3 · 3 H2O beschrieben; ferner wird über die Umwandlung des Calciumdoppelsalzes beim Kochen mit NaOH berichtet.
Summary Sodium cyolohexyldithiooarbamate reacts, in the pH range 6.6 to 7.2, with uranium salts to yield a complex which gives a yellow aqueous solution. The absorption maximum is at 392–394 nm at pH 6.6. The aqueous solution loses its color immediately when caustic alkali is added to raise the pH to 8 or 9.A potassium double salt, KUO2(S2HCNC6H11)3 · 3 H2O is described. A report is also given of the transformation of the calcium double salt on boiling with NaOH.
Résumé Le dithiocarbamate de cyclohexylsodium réagit dans le domaine de pH 6,6 à 7,2 sur les sels d'uranyle avec formation d'un complexe coloré en jaune, soluble dans l'eau, qui possède à pH 6,6 un maximum d'absorption pour 392–394 nm. Par addition de lessive alcaline jusqu'à pH 8 à 9 on décolore momentanément la solution aqueuse.On décrit un sel double de potassium KUO2(S2HCNC6H11)3 · 3 H2O; on rend compte, de plus, de la transposition du sel double de calcium par chauffage avec la soude.
Gewidmet zur 100. Wiederkehr des Geburtstages vonFriedrich Emich. 相似文献
Novel cyclopentadienyl (Cp)-alkali metal complexes 1-M and 2-M (M = Li, Na, K), in which the Cp ring is annelated with two bicyclo[2.2.2]octene units and substituted with a phenyl group for 1 and a tert-butyl group for 2, were synthesized, and their structures and dynamic behaviors were investigated by means of X-ray crystallography, dynamic (13)C NMR, and DFT calculations. The X-ray crystallography results indicated that 1-Li, 1-Na, and 2-Na form monomeric contact ion pairs (CIP) with three THF molecules coordinated to the metal atom. Also, in THF-d(8), all of the 1-M and 2-M form monomeric CIP in the ground state. However, variable-temperature (13)C NMR measurements of 1-M and 2-M in THF-d(8) demonstrated dynamic behavior in which the metal ion exchanges positions between the upper and lower faces of the Cp ring. From a study of the concentration dependence of the dynamic behavior, the exchange was found to proceed principally as an intramolecular process at concentration ranges lower than 0.2 M. The experimentally observed deltaG values for the intramolecular exchange process for all the 1-M and 2-M (except for 2-Li, whose intramolecular process was too slow to observe) were found to be quite similar in THF-d(8) solution and to fall within the range of 12-14 kcal mol(-)(1). Within this range, a tendency was observed for the deltaG values to increase as the size of the metal decreased. Theoretical calculations (B3LYP/6-31G(d)) afforded considerably large values as the gas-phase dissociation energy for 1-M (162.7 kcal mol(-)(1) for M = Li; 131.6 kcal mol(-)(1) for M = Na; 110.9 kcal mol(-)(1) for M = K) and for 2-M (170.0 kcal mol(-)(1) for M = Li; 137.5 kcal mol(-)(1) for M = Na; 115.4 kcal mol(-)(1) for M = K). These values should be compensated for by a decrease in the solvation energies for the metal ions with increasing size, as exemplified by the calculated solvation energy for M(+)(Me(2)O)(4), which serves as a model for metal ions solvated with four molecules of THF (-122.9 kcal mol(-)(1) for M = Li; -94.7 kcal mol(-)(1) for M = Na; -67.7 kcal mol(-)(1) for M = K). This compensation results in a small difference in the overall energy for dissociation of 1-M or 2-M in ethereal solutions, thus supporting the similar deltaG values observed for the intramolecular metal exchange. 相似文献