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  • Analytical Chemistry and Spectroscopy  (4,318)
  • Inorganic Chemistry  (3,506)
  • 1980-1984  (7,824)
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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1984), S. 573-576 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed energy-resolved study of the fragmentation of CH2=CHCH(OH)CD2CD3 (1-d5) has been carried out using metastable ion studies and charge exchange techniques, combined with collision-induced dissociation studies to establish the structures of fragment ions. At low internal energies (metastable ions) the molecular ion of 1-d5 rearranges to the 3-pentanone structure and fragments by loss of C2H5 or C2D5 leading to the acyl structure, [CH3CH2C≡O]+ or [CD3CD2C≡O]+, for the fragment ion. However, with increasing internal energy of the molecular ion this rearrangement process decreases rapidly in importance and loss of C2D5 by direct cleavage, leading to [CH2=CHCH=OH]+, becomes the dominant fragmentation reaction. As a result the [C3H5O]+ ion seen in the electron impact mass spectrum of 1-penten-3-ol has predominantly the protonated acrolein structure.
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 312-315 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that under field desorption conditions some less volatile or non-volatile compounds such as oligosaccharides, sulphonic acids and fatty acids can be ionized below the threshold of field electron emission by clustering with anions. In all cases the sample, together with polyethylene oxide 4000, is dissolved in water. The source of the clustering anion is provided either by a small amount of a salt added to this solution (sugars) or by the compounds themselves (sulphonic and fatty acids). The solution is applied to unactivated and/or slightly activated 10 μm tungsten wire cathodes. Suitable clustering ions for the sugars appear to be [Cl]-, [NO3]- and to a lesser extent [Br]- and [I]-. Most of the sulphonic acids studied give rise to the formation of [Mn - H]- ions (n≤5), but their potassium salts yield only unclustered sulphonate anions. However, the addition of a small amount of LiCl to the mixture of benzene sulphonic acid and polyethylene oxide 4000 promotes the formation of clustered anions, [(M - H)2Li]- being by far the most abundant if activated cathodes are used. This addition of some LiCl is essential in the case of fatty acids: without LiCl no anions may be desorbed at all from activated wires, but with the presence of LiCl both [M - H]- and the most abundant [(M - H)2Li]- anions are easily generated.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1983), S. 525-529 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The positive ion field desorption (FD) spectrum of arginine taken at the best anode temperature only contains a peak due to [M+H]+ ions. At higher emitter temperatures a considerable amount of fragmentation is induced and the [M+H—NH3]+ ions become most abundant. Specific 15N labelling reveals that the eliminated ammonia molecule, exclusively, contains one of the terminal nitrogen atoms of the guanidyl group. This also applies to the ammonia loss from metastably decomposing [M+H]+ ions. The positive ion fast atom bombardment (FAB) spectrum shows more fragmentation than the FD spectrum. In contrast with the FD results, the [M+H]+ ions generated upon FAB with ion lifetimes 〈10-6 s eliminate both ammonia containing one of the terminal nitrogen atoms of the guanidyl group and ammonia containing the α-amino group in the ratio of 1.35, as found by 15N labelling. The metastably decomposing [M+H]+ ions, however, eliminate only the former ammonia molecule. In the negative ion FD and FAB spectra no other peak than that corresponding to the [M—H]- ion is observed. Some attention has been paid to the thermal degradation of arginine on the basis of a few Curie-point pyrolysis experiments.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 169-171 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Glass capillary columns ; Trimethylsilyl derivatives ; Pregnant mares' urine estrogens ; Estrone-equilin separation ; OV-225, Silar 10C stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glass capillary columns coated with OV-225 and Silar 10C were used to analyze estrogens (as their trimethylsilyl derivatives) present in pregnant mares' urine. Such columns provide better resolution in a shorter time than the corresponding packed columns, as exemplified by the separation of estrone from equilin.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3089-3093 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Di- and Polyamino Sugars, XXIII. Elimination Reactions Accompanying the Synthesis of 2,3-Diamino-2,3-dideoxy-D-glucoseBy-products of the synthesis of 2,3-diamino-2,3-dideoxy-D-glucose were found to be hex-2- and -3-enopyranosides (4, 5). Structure proofs by spectroscopy were corroborated by hydroboration and direct elimination reactions.
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 21 (1983), S. 315-318 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of the 1H NMR spectra of 2,8-dithia-1,5-diphosphabicyclo[3.3.0]octane, 2,8-dithia-1-phospha-5-azabicyclo[3.3.0]octane and 2,8-dithia-1-arsa-5-phosphabicyclo[3.3.0]octane is supported by means of 2D- J-resolved NMR measurements. The spectra suggest a preferred conformer with strong puckering of the fused five membered rings.
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  • 7
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 31P and 195Pt N.M.R. Investigations on Diplatinum (I) Complexes of the Type [Pt2(μ-SPR2)2L2] (L = PR3, PhP(OPh)2, P(OPh)3, CNR)31P-, 195Pt-chemical shifts and 195Pt-31P- resp. 31P-31P-coupling constants of a series of doubly bridged diplatinum(I) complexes are reported. 31P-coordination chemical shifts of the terminal ligands of complexes of type [Pt2(μ-SPR2)2(P′R3′)2] and some of the various coupling constants are strongly influenced by the π-acceptor strength of these ligands. J(195Pt-195Pt) is found to change the sign among the series of complexes investigated. Thermal singlett triplet exitation giving rise to the paramagnetism of these complexes observed by preliminary EPR-measurements and confirmed by EHT-calculations is deduced from the large values of 2J(P-P′) and 3J(P′P′) as well as the unusually high temperature dependence of some coupling constants and other NMR features. The chemical stability of the doubly bridged core, the coordination shifts of the bridging phosphorus atoms and EHT-calculations suggest a view of aromaticity of the [Pt2(μ-SPR2)2](M-M) unit of these complexes.
    Notes: Es werden 31P-, 195Pt-chemische Verschiebungen und 195Pt31P-Kopplungskonstanten einer Reihe von doppelt verbrückten Diplatin(I)-Komplexen mitgeteilt. 31P-koordinationschemische Verschiebungen der ternären Liganden von Komplexen des Typs [Pt2(μ-SPR2)2(P′R3′)2] und verschiedene Kopplungskonstanten werden stark von der π-Akzeptor-Stärke dieser Liganden beeinflußt. J(195P-195Pt) wird innerhalb der Reihe der untersuchten Komplexe mit wechselndem Vorzeichen gefunden. Aus den großen Werten von 2J(Pt-P′) und 3J(P′P′) sowie der ungewöhnlich starken Temperaturabhängigkeit einiger Kopplungskonstanten und anderen NMR-Eigenschaften wird auf Paramagnetismus dieser Komplexe aufgrund thermischer Singlett-Triplett-Anregung geschlossen, der in vorläufigen EPR-Messungen gefunden und durch EHT-Rechnungen gestützt wird. Die chemische Stabilität des doppelt verbrückten Kerns, die koordinationschemischen Verschiebungen der Brückenphosphoratome und EHT-Rechnungen weisen auf Aromatizität der [Pt2(μ-SPR2)2](M-M)-Einheit dieser Komplexe hin.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 494 (1982), S. 189-195 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Mobility of Phosphin-3η-allyl Palladium Chloride ComplexesThe diastereomers of the complexes cis- and trans-2.3-diphenyl-1.3-oxaphosphorinan-3η-allyl palladiumchloride interchange. The activation parameters of the diastereomerization are estimated by line-shape analysis of the 31P - NMR signals.The exchange of allyl protons is described by 16 permutations involved in three graphes of the proposed seven modes of intramolecular movement.The cross-peaks in the 2D-exchange-1H - NMR spectrum display the exchanging protons.The results suggest a π-σ-transition together with a trigonal-bipyramidal arrangement of ligands in the transition state.
    Notes: Die Diastereomere der Komplexe cis- und trans-2,3-Diphenyl-1,3-oxa-phosphorinan-3η-allylpalladiumchlorid wandeln sich ineinander um. Die Aktivierungsparameter für diese Diastereomerisierung werden durch Linienformanalyse der 31P-NMR-Signale bestimmt.Der Positionswechsel der Allylprotonen wird durch 16 Permutationen beschrieben und in je drei Graphen den sieben vorgeschlagenen intramolekularen Bewegungsmechanismen zugeordnet. Aus den cross-peaks im 2D-Austausch-1H - NMR-Spektrum werden die miteinander im Positionswechsel befindlichen Protonen bestimmt.Die Ergebnisse sprechen für einen π-σ-Übergang mit trigonalbipyrymidaler Ligandenanordnung im Übergangszustand.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 495 (1982), S. 115-119 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkali Phosphorus Compounds and their Reactivity. 79. NMR Investigations of Alkali Organophosphides. IThe 31C and 31P NMR spectra display a further separation of ion-pairs of alkali-organophosphides in THF solution after addition of cryptandes . An exception presents LiP(Ph)2, T1—13C-NMR measurements suggest a tetrameric structure in THF.
    Notes: Anhand der 13C- und 31P-NMR-Daten läßt sich zeigen, daß sich die Ionenpaare der Alkali-organophosphide in THF durch Zugabe von Kryptanden entsprechend weiter trennen lassen. Eine Ausnahme bildet LiP(Ph)2, das aufgrund von T1—13C-NMR-Messungen eine tetramere Struktur in THF aufweist.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 4 (1981), S. 6-10 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Retention index calculation by correlation techniques ; Use of n-dialkyl sulphides as standards ; Use of selective detectors ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Retention indices were determined for a homologous series of n-dialkyl sulphides on three stationary phases (SE-30, OV-17 and XE-60) under isothermal and linear temperature programming conditions. Under these two different GC conditions, equations were derived for each of the three stationary phases which showed the dependence of retention index on the number of carbon atoms and the boiling points for a homologous series of n-dialkyl sulphides. The equation for the correlation isothermal retention index was shown to be applicable to the identification of n-dialkyl sulphides using linear temperature programming. It was found that the GC behaviour of n-dialkyl sulphides makes these compounds suitable for use as a standard series instead of n-alkanes for the calculation of retention indices in GC analysis in which detectors insensitive to n-alkanes are employed. The use of the homologous series of n-dialkyl sulphides for the calculation of sulphide retention indices can be great practical importance in the microanalysis of natural compounds. We have used this method successfully in the analysis of pesticides containing S-atoms.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 306-309 
    ISSN: 0935-6304
    Keywords: Liquid chromatography, HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for separation of low amounts of DHETX m. s. from human plasma, based on extraction and determination by high performance liquid chromatography with fluorimetric detection.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2285-2310 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Thermal Isomerization of Tricyclo[4.1.0.02,7]hept-1(7)-ene: Formation and Trapping Reactions of 1,2,3-CycloheptatrieneThe reaction of (7-bromotricyclo[4.1.0.02,7]hept-1-yl)trimethylsilane (1d) with potassium fluoride or cesium fluoride in dimethyl sulfoxide led to the formation of tricyclo[4.1.0.02,7]hept-1(7)-ene (2) which, above 80°C, rearranged almost completely to 1,2,3-cycloheptatriene (6). 6, as a short-lived reactive intermediate, afforded cycloaddition products with numerous 1,3-dienes and with some 1,3-dipoles. The primary adduct of 6 with N, α-diphenylnitrone isomerized at room temperature to the bridgehead olefin 41, the structure of which has been established by an x-ray analysis. When 6 was generated via 2 from 1-chlorotricyclo[4.1.0.02,7]heptane (1f) and potassium tert-butoxide in tetrahydrofuran above 30°C, the cyclocumulene 6 even in the presence of anthracene yielded the vinyl ether 8.
    Notes: Die Reaktion von (7-Bromtricyclo[4.1.0.02,7]hept-1-yl)trimethylsilan (1d) mit Kaliumfluorid oder Caesiumfluorid in Dimethylsulfoxid führt zur Bildung von Tricyclo[4.1.0.12,7]hept-1(7)-en (2), das sich oberhalb von 80°C praktisch vollständig in das 1,2,3-Cycloheptatrien (6) umlagert. Als kurzlebige, reaktive Zwischenstufe ergibt 6 mit zahlreichen 1,3-Dienen und mit einigen 1,3-Dipolen Cycloadditionsprodukte. Das Primäraddukt von 6 an N, α-Diphenylnitron isomerisiert bei Raumtemperatur zum Brückenkopfolefin 41, dessen Konstitution durch Röntgenstrukturanalyse gesichert wurde. Erzeugt man 6 über 2 aus 1-Chlortricyclo[4.1.0.02,7]heptan (1f) und Kalium-tert-butylat in Tetrahydrofuran oberhalb von 30°C, so entsteht aus dem Cyclocumulen 6 auch in Gegenwart von Anthracen hauptsächlich der Enolether 8.
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 968-974 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Thermal Behavior of Some 1-(Tricyclo[4.1.0.02,7]hept-1-yl)aziridinesThe reaction of 1-chlorotricyclo[4.1.0.02,7]heptane (1) and lithium aziridides 4 led to the formation of the 1-(tricyclohept-1-yl)aziridines 5a-d which, on thermolysis, decomposed to the carbonitrile 10 and (stereospecifically) to the respective olefin 11. A retro-carbene ringopening reaction of the bicyclobutane unit in 5 forming 13 as an intermediate is proposed as mechanistic pathway.
    Notes: Aus 1-Chlortricyclo[4.1.0.02,7]heptan (1) und den Lithium-azirididen 4 wurden die 1-(Tricyclohept-1-yl)aziridine 5a-d erhalten, die bei der Thermolyse zum Carbonitril 10 und (stereospezifisch) zum entsprechenden Olefin 11 fragmentierten. Als Mechanismus wird eine Retrocarbenspaltung der Bicyclobutan-Einheit in 5 mit 13 als Zwischenstufe vorgeschlagen.
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  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3896-3905 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Disila[4.1.1]propellanes: Synthesis and StructureThe reaction of tricyclo[4.1.0.02,7]hept-1-yllithium with dichlorosilanes or tetrachlorosilane afforded silyl-Substituted tricyclo[4.1.0.02,7]heptane derivatives 2, 4 which, after metalation of the bicyclo[1.1.0]butane bridgehead positions, could be cyclized with dichlorosilanes to give disila[4.1.1]propellanes 5, 6. The structure of 5a has been determined by X-ray analysis.
    Notes: Durch Umsetzung von Tricyclo[4.1.0.02,7]hept-1-yllithium (1b) mit Dichlorsilanen oder mit Siliciumtetrachlorid wurden silylsubstituierte Tricylco[4.1.0.02,7]heptan-Derivate 2, 4 erhalten, die nach erneuter Metallierung der Bicyclo[1.1.0]butan-Brückenkopfpositionen mit Dichlorsilanen zu Disila[4.1.1]propellanen 5, 6 cyclisiert werden konnten. Die Struktur von 5a wurde durch Röntgenanalyse ermittelt.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 370-374 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Trace analysis ; On-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Large sample volume on-column injection (up to 250 μL) of n-pentane solutions of halogenated hydrocarbons has been employed for the direct measurement of both low-boiling and high-boiling compounds in what is essentially a single run. Two-bonded phase, fused-silica capillary columns are joined in series, through which the low-boiling compounds are first chromatographed and detected with an electron capture detector. High-boiling compounds are then trapped in a section joining the two columns, and subsequently chromatographed in the second column, using the same detector. This procedure permits analysis at the ppt level.
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  • 16
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 497 (1983), S. 229-238 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gleichgewichtsuntersuchungen im System M(CH3COO)2—CH3OH—H2O (Me = Mg2+, Ca2+, Ba2+) bei 25°CDie Komplexbildungs- und Dehydratationsvorgänge im System M(CH3—COO)2—CH3OH—H2O (Me = Mg2+, Ca2+, Ba2+) wurden bei 25°C untersucht. Das Methanol kann im System Mg(CH3COO)2—CH3OH—H2O als Lösungsmittel, in welchem Komplexbildungserscheinungen stattfinden, betrachtet werden, und zwar tritt eine Solvatation der Magnesiumionen mit Methanol ein. Die Kristallisationsfelder von zwei neuen, bisher in der Literatur unbekannten Verbindungen sind festgestellt worden, nämlich Mg(CH3COO)2 · 3 H2O · CH3OH und Mg(CH3COO)2 · 1,5 CH3OH. In den Systemen M(CH3COO)2—CH3OH—H2O (M = Ca2+, Ba2+) übt das Methanol nur eine Dehydratationswirkung aus.
    Notes: The complex formation and dehydration processes in the system M(CH3COO)2—CH3OH—H2O have been studied by the methods of the physico-chemical analysis at 25°C; (M = Mg2+, Ca2+ and Ba2+). In the Mg(CH3COO)2—CH3OH—H2O system. methanol was found to behave as a solvent in which complex formation reactions take place, including also methanolation of Mg2+. The fields of equilibrium existence of two new compounds have been found: Mg(CH3COO)2 · 3H2O · CH3OH and Mg(CH3COO)2 · 1,5 CH3OH. In the systems M(CH3COO)2—CH3OH—H2O (M = Ca2+, Ba2+), methanol was found to react as a dehydrating reagent.
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  • 17
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 17 (1982), S. 74-78 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation pathways of RDX in chemical ionization mass spectrometry have been rationalized, using data from different reagent gases, including CD4 and iso-C4D10. The dependence of spectra taken with different gases on the acid strength of the reactant ions in the gases is accounted for.
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  • 18
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 502 (1983), S. 199-208 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchung von CuCl2/SiO2- und Al2O3-Träger-KatalysatorenDie Natur und Stabilität von Oberflächenspezies des CuCl2 auf α-Al2O3, γ-Al2O3 und SiO2 wurden mittels Röntgendiffraktometrie und Reflexionsspektroskopie untersucht. An inertem α-Al2O3-Träger wird keine spezifische chemische Wechselwirkung mit CuCl2 beobachtet im Gegensatz zu den hydratisierten Trägern SiO2 und γ-Al2O3. Bei diesen Trägern besteht die Koordinationssphäre des Cu2+ aus Oberflächengruppen (OH- oder O- nach Trocknung bzw. Aktivierung), H2O und Cl-; mit abnehmender Konzentration an H2O-Liganden im Verlauf von Tränkung, Trocknung und Glühen.γ-Al2O3-Proben, geglüht bei 400°C, zeigen γ-Cu2(OH)3Cl gegenüber CuAl2O4 bei höheren Temperaturen. Das Fehlen von Cu2(OH)3Cl auf SiO2 ist auf die Säure-Base-Eigenschaft der Träger zurückzuführen. Die verschiedenen Träger können in folgender Stabilitätsreihe der gebildeten Oberflächenkomplexe angeordnet werden: γ-Al2O3 〉 SiO2 ≫ -Al2O3.
    Notes: The nature and stability of surface species of CuCl2 supported on α-Al2O3, γ-Al2O3, and SiO2 were investigated by using X-ray diffraction techniques and reflectance spectroscopy. No specific chemical interaction of CuCl2 is observed on an inert α-Al2O3 support, as opposed to hydrated carriers as SiO2 and γ-Al2O3. On these supports the coordination sphere of Cu2+ consists of surface groups (OH- or O- at drying and activation, resp.), H2O and Cl-, with the H2O ligands decreasing in concentration in the process of impregnation, drying and calcination.γ-Al2O3 samples, calcined at 400°C, show γ-Cu2(OH)3Cl as opposed to CuAl2O4 at higher temperatures. The absence of Cu2(OH)3Cl on SiO2-supported samples is related to the acid-base characteristics of the carriers. The various supports can be arranged in the following order of stability of the complexes formed: γ-Al2O3 〉 SiO2 ≫ -Al2O3.
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  • 19
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 476 (1981), S. 41-54 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the Basicity of Alkyl and Silyl AlkylaminesThe basicity of N has been investigated in primary and secondary alkyl und silyl alkylamines by means of the vC-D band shift of CDCl3 associated to the amine group by potentiometrically determined pKs-values, and by mass spectroscopically measured ionisation potentials.The results show a dependence on electronic and steric effects, but they do not give arguments for a conjugative interaction between N and Si,
    Notes: Die Basizität des N in primären und sekundären Alkyl- und Silylalkyl-aminen wurde untersucht an der Bandenverschiebung Δṽ der vC-D-Bande des CDCl3 bei Assoziation an das Amin, an potentiometrisch bestimmten pKs-Werten sowie massenspektroskopisch gemessenen Ionisierungspotentialen.Die Ergebnisse zeigen eine Abhängigkeit von elektronischen und sterischen Effekten, geben aber keine Hinweise auf das Vorliegen konjugativer Wechselwirkungen zwischen Si und N.
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  • 20
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2938-2946 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselectivity of Ring Closure Reactions to 1,2,3-Thiadiazoles and 1,2,3-SelenadiazolesUnsymmetrical hydrazones of type 2 exist in a Z/E-equilibrium from which ring closure reactions with SOCl2 or SeO(OH)2 occur. Isomeric 1,2,3-thiadiazoles 3/3′ and 1,2,3-selenadiazoles 4/4′, respectively, are formed. Regioselectivities are discussed concerning the examples 2a-t. For b, c, d, and o product distributions are rationalized on the basis of the Z/E-equilibrium proportions and the ratio of reactivities. Principally, methylene hydrogens are more reactive than methyl hydrogens, even when the reaction on the methyl side predominates.
    Notes: Unsymmetrische Hydrazone 2 liegen in einem Z/E-Gleichgewicht vor, aus dem mit SOCl2 bzw. SeO(OH)2 Ringschlußreaktionen zu konstitutionsisomeren 1,2,3-Thiadiazolen 3/3′ bzw. 1,2,3-Selenadiazolen 4/4′ erfolgen. Anhand der Beispiele 2a-t wird die Regioselektivität der Reaktionen diskutiert. Bei b, c, d und o wird die Produktverteilung im Hinblick auf die Z/E-Gleichgewichtslage und das Reaktivitätsverhältnis aufgeschlüsselt. Methylenwasserstoffe sind beim Ringschluß grundsätzlich reaktiver als Methylwasserstoffe - selbst wenn die Reaktion bevorzugt an der Methylseite stattfindet.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. XXVII 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 22
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 440-446 
    ISSN: 0935-6304
    Keywords: High performance thin-layer chromatography ; β-adrenoceptor blocking drugs ; Continuous development ; Multiple development ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High performance thin-layer chromatography was used for the separation of nine therapeutically important and structurally similar β-adrenoceptor blocking drugs on silica gel plates. In situ scanning of the plate in the reflectance mode gave detection limits in the low nanogram range depending on the individual drug and the wavelength selected for its determination. Scanning the HPTLC plate at several wavelengths can be used to aid the identification of partially resolved components. Continuous development and continuous multiple development techniques are compared for the simultaneous separation of the drug mixture.
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  • 23
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vibrational Spectra and Tentative Structural Characterization of Aluminum Chalcogenide Halides AlSX and AlSeX (X = Cl. Br. I)The title compounds have been prepared according to known procedures. X-ray rotation photographs show a lattice constant along the needle axis (= monoclinic b axis) of 12.0 to 12.8 Å. The Raman and FIR spectra have been registered and assigned, based on characteristic frequency shifts within a series of compounds with different chalcogenide or halide atoms. We propose a dimeric structure for AlSX and AlSeX with planar four-membered Al2S2 (Al2Se2) rings and short (“terminal”) Al—X bonds, which is strongly supported by frequency calculations (approximate normal coordinate analyses) on 5 different structure models. Al is coordinatively saturated by long X—Al interactions, leading to a chain structure.
    Notes: Die Aluminium-sulfid- und -selenidhalogenide AlSX und AlSeX (X = Cl, Br, I) wurden nach bekannten Verfahren dargestellt. Aus Drehkristall-Röntgenaufnahmen ergaben sich in Richtung der Nadelache (b = Achse einer monoklinen Elementarzelle) Gitterkonstanten von 12,0 bis 12,8 Å. Die Raman- und FIR-Spektren wurden registriert und mit Hilfe der innerhalb der Verbindungsreihen charakteristischen Bandengruppen zugeordnet. Aufgrund von Frequenzberechnungen für 5 Strukturmodelle wird eine dimere Struktur mit planaren Al2S2- bzw. Al2Se2-Vierringen und kurzen („terminalen“) Al—X-Bindungen vorgeschlagen. Über längere Al—X-Brückenbindungen wird Al koordinativ abgesättigt und eine Kettenstruktur ausgebildet.
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  • 24
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1984), S. 645-646 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 25
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 12 (1982), S. 165-172 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The temperature dependence of νi, Δν1/21 and the integrated band area for a few solid amides are studied for the γ(N—H) mode in the infra-red. A general theoretical discussion of these structureless broad γ(N—H) bands is presented. The bands are accounted for in terms of coupling of the γ(N—H) mode with longitudinal as well as transversal low-frequency phonons.
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  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 479 (1981), S. 17-31 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Cis and Trans Effects on the Ligand Exchange of Mixed Hexahalo Osmates(IV)The 24 possible ligand exchange reactions in the system of chloro-bromo osmates(IV) are investigated by kinetic measurements. The rate constants kHBr (trans-series) or kHCl (cis-series) determined in 5N HBr or 5N HCl at 80°C are summarized in the following equations \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{{\rm HBr}} = {\rm z} \times {\rm 1,83}^{\rm x} \times 7,5^{\rm y} \times {\rm 1,32} \times {\rm 10}^{{\rm - 4}}\, {\rm min}^{{\rm - 1}} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{{\rm HCl}} = {\rm z} \times {\rm 1,7}^{\rm x} \times 5,5^{\rm y} \times 1,97 \times 10^{ - 4}\, {\rm min}^{{\rm - 1}} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \rm x = {\rm number\, of\, cis}\hspace{-3pt}-\hspace{-3pt}{\rm positioned\,Br\, ligands (0}\,-\,4), $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \rm y = {\rm number\, of\, trans\hspace{-3pt}-\hspace{-3pt}positioned\, Br\, ligands\, (0\, or\, 1),} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm z} = {\rm number\, of\, equivalent\, replaceable\, ligands\, Cl\, or\, Br}{\rm .} $$\end{document} The influence of relative cis and trans effects of ligands and of the geometry of complexes on the rates of ligand exchange is completely described by the three parameters s, y, z. This is supported by the close agreement between calculated and experimental concentration-time diagrams. The equations characterize both consecutive and parallel reactions and permit the calculation of ratios of isomers a t any time. The relative cis-effects forC1:Br:I are about 1:1.8:7, while the trans-effects are 1:6:1000. With the set of kinetic data an equilibrium diagram is derived from which the individual stability constants of the stepwise-formed mised-ligand complexes are deduced. There is good agreement between experimental and calculated values.
    Notes: Für die im System der Chloro-Bromo-Osmate(IV) 24 möglichen Liganden-austauschreaktionen lassen sich die in 5n HBr bzw. 5n HCl bei 80°C durch kinetische Messungen bestimmten Geschwindigkeitskonstanten kHBr (trans-Reihe) bzw.kHCl (cis-Reihe) in den folgenden Gleichungen zusammenfassen: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{{\rm HBr}} = {\rm z} \cdot {\rm 1,83}^{\rm x} \cdot 7,5^{\rm y} \cdot {\rm 1,32} \cdot {\rm 10}^{{\rm - 4}}\, {\rm min}^{{\rm - 1}} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{{\rm HCl}} = {\rm z} \cdot {\rm 1,7}^{\rm x} \cdot 5,5^{\rm y} \cdot 1,97 \cdot 10^{ - 4}\,{\rm min}^{{\rm - 1}} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \rm x = {\rm Anzahl\,\,der\,\,cis\hspace{-3pt}-\hspace{-3pt}st\ddot andigen\,Br\hspace{-3pt}-\hspace{-3pt}Liganden\,(0}-4), $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \rm y = {\rm Anzahl\,\,der\,\,trans\hspace{-3pt}-\hspace{-3pt}st\ddot andigen\, Br\hspace{-3pt}-\hspace{-3pt}Liganden\, (0\,order\,1),} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm z} = {\rm Anzahl\,\, \ddot aquivalent\, substituierbarer\, Liganden\, Cl\,\,bzw}{\rm .\, Br}{\rm .} $$\end{document} Mit Hilfe der drei Parameter x, y, z wird der Einfluß der relativen cis- und trans-Effekte der Liganden sowie der Komplexgeometrie auf die Ligandenaustauschgeschwindigkeiten vollständig erfaßt. Das ergibt sich aus der guten übereinstimmung zwischen den berechneten und den experimentell bestimmten Konzentrations-Zeit-Diagrammen. Mit den Gleichungen lassen sich nicht nur alle Folge-, sondern auch die Parallelreaktionen beschreiben, die die Berechnung der zu jedem Zeitpunkt vorliegenden Isomerenverhältnisse gestatten. Die relativen cis-Effekte verhalten sich für Cl:Br:I etwa wie 1:1,8:7, die trans-Effekte wie 1:6:1000. Mit dem kinetischen Datensatz kann ein Gleichgewichtsdiagramm errechnet werden, aus dem sich die individuellen Stabilitätskonstanten für die stufenweise gebildeten Gemischtligandkomplexe ergeben. Die übereinstimmung mit den Werten aus Gleichgewichtsmessungen ist gut.
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  • 27
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 484 (1982), S. 33-40 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Kinetic Calculations for the Formation of Chloro-Bromo-Iodo-Osmates(IV)Rate constants of formation and ligand exchange reactions of mixed hexahaloosmates(IV) of the type [OsClxBryI6-x-y]2-, x + y = 2-5, are computable taking into account the relative cis- (fClc = 1, fBrc = 1.75, fIc ≍ 6) and trans-effects (fCltr = 1, fBrtr = 6, fItr ≍ 103) of the ligands as well as statistic factors. Using this kinetic data concentration-time diagrams are calculated for reactions including several parallel and consecutive steps. They agree well with the experimentally determined distribution of products in the reaction mixtures. For the preparation of particular mixed ligand complexes the best way of synthesis and maximum yield can be precalculated.
    Notes: Durch Berücksichtigung der relativen cis- (fClc = 1, fBrc = 1,75, fIc ≍ 6) und trans-Effekte (fCltr = 1, fBrtr = 6, fItr ≍ 103) sowie statistischer Faktoren gelingt die Berechnung der Geschwindigkeitskonstanten für die Bildung und für Ligandenaustauschreaktionen von gemischten Hexahalogenoosmaten(IV) der allgemeinen Formel [OsClxBryI6-x-y]2-, x + y = 2-5. Mit den kinetischen Daten ergeben sich für Umsetzungen, die über mehrere Parallelwege und eine Reihe von Folgeschritten verlaufen, Konzentrations-Zeit-Diagramme, die in guter Übereinstimmung mit den experimentell bestimmten Produktverteilungen in den Reaktionsgemischen stehen. Für die gezielte Darstellung spezieller Gemischtligandkomplexe lassen sich der optimale Syntheseweg und die maximal erreichbare Ausbeute vorausberechnen.
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  • 28
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 462 (1980), S. 71-79 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Oxoniccolates: On the Knowledge of Na2[NiO2]The low temperature form of Na2NiO2, dark-red single crystals, obtained by heating Na2O and ‚NiO‘ [Na:Ni = 2,2:1; 680°C, 3d, Ni cylinders] crystallizes orthorhombic with a = 2.820 b = 10.141 c = 8.283 Å, Z = 4 in the space group Cmc21. Due to fourcycle diffractometer data (290 hkl, MoKα, R = 2.8%) a new type of structure occurs, the NiO2 part of which shows the PdCl2 motive like in Li2NiO2. The coordination number of \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 2}{\rm a} $\end{document} towards O is 4, of \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 1}{\rm a} $\end{document} is 5. Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, are discussed.
    Notes: Die Tieftemperaturform von Na2NiO2, dunkelrote Einkristalle, aus Na2O und NiO durch Tempern [Na:Ni = 2,2:1; 680°C, 3d, Ni-Bömbchen] erhalten, kristallisiert ortho-rhombisch mit a = 2,820, b = 10,141, c = 8,283 Å und Z = 4 in Cmc21; es ist drö = 3,85 und dpyk = 3,91 g · cm-3. Nach Vierkreisdiffraktometerdaten (290 hkl, MoKα, R = 2,8%) liegt ein neuer Strukturtyp vor, der wie Li2NiO2 bez. des NiO2-Teiles der Struktur das PdCl2-Motiv zeigt. \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 2}{\rm a} $\end{document} hat 4, \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 1}{\rm a} $\end{document} 5 als Koordinationszahl gegen O. Effektive Koordinationszahlen, diese über Mittlere Fiktive Ionenradien berechnet, sowie der Madelunganteil der Gitterenergie, MAPLE, werden diskutiert.
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  • 29
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 462 (1980), S. 61-70 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Na5NiO4, the First Oxoniccolate(III) with Neso StructureBy heating of Na2O and NaNiO2 we obtained the hitherto unknown compound Na5NiO4 as steel-grey powder and single crystals [powder: Na2O : NaNiO2 = 2.2:1; 550°C, 2d, Al2O3-cylinders; single crystals: Na2O : NaNiO2 = 2.2:1; 650°C, 7d, Ag-cylinders]. Na5NiO4 crystallizes orthorhombic with a = 10.226, b = 5.943, c = 17.98 Å, Z = 8 (isotypic to Na5GaO4); parameter see text; drö = 2.89 and dpyk = 2.93 g · cm-3. Between 21 and 250 K the Curie-Weiss-Law is obeyed [Θ = -41 K, m̈ = 3,9m̈B (spin only)]. Below 20 K antiferromagnetic behavior occured. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, are calculated and discussed.
    Notes: Durch Erhitzen inniger Gemenge von Na2O und NaNiO2 erhalten wir erstmals Na5NiO4 als stahlgraues Pulver [Na2O:NaNiO2 = 2,2:1; 550°C, 2d, Korundbömbchen]. Auch die Einkristalle sehen so aus [analoge Ausgangsmischung, 650°C, 7d, Ag-Bömbchen]. Na5NiO4 ist isotyp mit Na5GaO4, orthorhombisch, Pbca, mit a = 10,226, b = 5,943, c = 17,98 Å, Z = 8. Parameter siehe Text, drö = 2,89 und dpyk = 2,93 g · cm-3. Zwischen 21 und 250 K wird das Curie-Weisssche Gesetz, Θ = -41 K, befolgt. Es ist m̈ = 3,90 m̈B (spin-only). Unterhalb etwa 25 K tritt Antiferromagnetismus auf. Der Madelunganteil der Gitterenergie, MAPLE, und Effektive Koordinationszahlen, ECoN, werden berechnet und diskutiert.
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  • 30
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 462 (1980), S. 80-91 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Oxoniccolates: On the Knowledge of K9Ni2O7K9Ni2O7, deep dark-red, nearly black single crystals, obtained by heating K2O and NiO [K:Ni = 5-6:1, 430°C, 5d, Au-cylinders] crystallizes cubic with a = 10.918 Å (P213, Z = 4, drö = 2.97, dpyk = 2.95 g·cm-3). Due to fourcycle diffractometer data (490 hkl, MoKα, R = 9.9percent;) ‘isolated’ [NiO4]5- (nearly tetrahedral) and [NiO3]4- groups (trigonal-planar) are found. The Effective Coordination Number, ECoN, calculated by means of Mean Fictive Ionic radii, MEFIR, the Madelung Part of Lattice Energy, MAPLE, and the magnetic properties are discussed.
    Notes: K9Ni2O7, tiefdunkelrote, nahezu schwarze Einkristalle, aus K2O und ‚NiO‘ durch Tempern [K:Ni = 5-6:1, 430°C, 5d, Glasampullen oder Goldbömbchen] erhalten, kristallisiert kubisch mit a = 10,918 Å und Z = 4 in P213; drö = 2,97 und dpyk = 2,95 g· cm-3. Nach Vierkreisdiffraktometerdaten (490 hkl, MoKα, R = 9,9percent;) treten ‚isolierte‘ [NiO4]5--Baugruppen mit nahezu tetraedrischer und [NiO3]4--Baugruppen mit trigonal-planarer Umgebung des Nickels auf.Effektive Koordinationszahlen, ECoN, über Mittlere Fiktive Ionenradien, MEFIR berechnet, der Madelungsanteil der Gitterenergie, MAPLE sowie das magnetische Verhalten werden diskutiert.
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  • 31
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    Zeitschrift für anorganische Chemie 462 (1980), S. 92-105 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxides of a New Type of Formula: On the Knowledge of K3Ni2O4 and K3Pt2O4K3Ni3O4, greyblack single crystals, obtained by heating K2O and NaNiO2 [K:Ni = 2:1, 500°C, 7d, Ag-cylinders], crystallizes orthorhombic with a = 6.044, b = 9.049, c = 10.567 Å, Z = 4, space group Cmcm (drö = 3.43, dpyk = 3.32 g · cm-3). Due to four cycle diffractometer data (374 hkl, MoKα, R = 8.6percnt;) a new type of structure is found with wavebands of 1∞[NiO4/2] \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 1} $\end{document} exhibits the C.N. 6, \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 2} $\end{document} the C.N. 4. Effective Coordination Numbers, ECoN, calculated by means of Mean Fictive Ionic Radii, MEFIR, the Madelung Part of Lattice Energy, MAPLE and the magnetic properties are discussed.K3Pt2O4, black single crystals with metallic lustre, obtained by heating KOx (x = 1.55 or 1.88) and Pt (powder) [K:Pt = 4:1,1000°C, lh, 600°C, 2d, Pt-capsules] is isotypic to K3Ni2O4 (four cycle diffractometer data: 458 hkl, MoKα, R = 12percnt;). Cellparameters are a = 6.15, b = 9.27, c = 11.51 Å (single crystal data), drö = 5.79 and dpyk = 5.77 g · cm-3.
    Notes: K3Ni2O4. Grauschwarze Einkristalle, aus K2O und NaNiO2 durch Tempern [K:Ni = 2:1, 500°C, 7d, Ag-Bömbchen] erhalten, kristallisiert orthorhombisch mit a = 6,044, b = 9,049, c = 10,567 Å, Z = 4, Cmcm. Es ist drö = 3,43 und dpyk = 3,32 g · cm-3. Nach Vierkreisdiffraktometerdaten (374 hkl, MoKα, R = 8,6%) liegt ein neuer Strukturtyp vor mit ‚gewellten‘ 1∞ [NiO4/2]-Ketten. \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 1} $\end{document} hat 6, \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm 2} $\end{document} dagegen 4 Sauerstoffnachbarn. Effektive Koordinationszahlen, ECoN, diese über Mittlere Fiktive Ionenradien, MEFIR, berechnet, der Madelungsanteil der Gitter-energie, MAPLE, sowie das magnetische Verhalten werden diskutiert.K3Pt2O4. Schwarze, met. glänzende Kristalle, aus KOx(x = 1,55 bzw. 1,88) und Pt durch Tempern [K:Pt = 4:1, 1000°C, lh, 600°C, 2d, zugeschweißtes Pt-Röhrchen] dargestellt, ist mit K3Ni2O4 isotyp (Vierkreisdiffraktometerdaten: 458 hkl, MoKα, R = 12percnt;). Die Gitterkonstanten sind a = 6,15, b = 9,27, c = 11,51 Å (Einkristalldaten), drö = 5,79 und dpyk = 5,77 g ·cm-3.
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  • 32
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Packed and capillary columns ; Fungicides and insecticides ; Adsorption ; Length of column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 33
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ausgehend vom trihalogensubstituierten Cyclotri(λ3-phosphazan) 1 lassen sich die Derivate 2 - 12 in glatter Reaktion darstellen. Die sterische Belastbarkeit des Sechsring-systems hat mit X = NEt2 in 11 ihre Grenze erreicht, für X = N—iPr2 tritt nur noch Monosubstitution zu 13 ein, die aber eine Weitersubstitution mit sterisch weniger anspruchsvollen Resten, z. B. auch zu den Bicyclen 14 - 16 nicht ausschließt. Die NMR-spektroskopischen Daten legen eine Sesselkonformation der Cyclophosphazanringe nahe, wobei die diequatorial-axiale bzw. diaxial-equatoriale Konfiguration der Phosphoratome (c, d) als thermodynamisch günstigere Alternative zu a oder b verwirklicht ist. Es wird erstmals über eine Ringkontraktion vom Sechs- zum Vierring in der Reihe der Cyclo(λ3-phosphazane) berichtet.Cyclotri(λ3-phosphazanes) (XPNMe)3: Preparation, NMR-Data, and StructureCyclotri(λ3-phosphazanes) 2-12 are easily prepared from the trihalogeno substituted 1. For steric reasons there is only a monosubstitution with X = N—iPr2 to 13, which nevertheless may be further substituted by sterically less demanding substituents to give e.g. the bicyclic compounds 14 - 16. From NMR spectroscopic data a chair conformation of the six membered ring seems probable with the substituents at phosphorus being located either diequatorially axially (c) or vice versa (d) rather than a or b. A thermal ring contraction from a six to a four membered ring in the series of cyclo(λ3-phosphazanes) is reported for the first time.
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  • 34
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    Zeitschrift für anorganische Chemie 461 (1980), S. 53-60 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polynuclear Cobalt Complexes. IV. Preparation and Structure of [(papd)Co(O2)Co(papd)](S2O6)(NO3)2 · 4 H2OThe binuclear peroxo complex [(papd)Co(O2)Co(papd)](S2O6)(NO3)2 · 4 H2O I crystallizes in the triclinic space group P1. Lattice constants are a = 9.405(4), b = 9.270(4), c = 12.218(6)Å, α = 89.58(5), β = 99.08(6), γ = 114.79(5)° for Z = 1. The binuclear cation has a center of symmetry, so the Co—O—O—Co unit is planar. Three chelate rings have a common plane, the ligand configuration is δ.
    Notes: Der binucleare Peroxokomplex [(papd)Co(O2)Co(papd)](S2O6(NO3)2 · 4 H2O I kristallisiert in der triklinen Raumgruppe P1. Die Gitterkonstanten sind a = 9,405(4), b = 9,270(4), c = 12,218(6) Å, α = 89,58(5), β = 99,08(6), γ = 114,79(5)° für Z = 1. Das Kation liegt auf einem Symmetriezentrum, die Co—O—O—Co-Einheit ist planar. Drei Chelatringe liegen in einer gemeinsamen Ebene, die Ligandkonfiguration ist δ.
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  • 35
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    Zeitschrift für anorganische Chemie 483 (1981), S. 44-50 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Thiazylhalides. 9. On the Chemistry of the Cyclopentathiazenium, S5N5+Preparation, properties, and reactions of a new thiazylchloride, S5N5+Cl-, are reported. The chloride is a product of the direct reaction of S4N4 and (NSCl)3. Using S5N5Cl, further new cyclopentathiazenium compounds (S5N5Br, S5N5Br3, S5N5I2Cl, and S5N5SbCl4) could be prepared. Their properties show a strong dependence of the stability of the compound on the size of the anion present.
    Notes: Es wird über die Darstellung, Eigenschaften und Reaktionen eines neuen Thiazylchlorids, S5N5+Cl-, berichtet. Dieses Chlorid wurde durch direkte Reaktion von S4N4 und (NSCl)3 gewonnen. Unter Benutzung von S5N5Cl als Ausgangssubstanz wurden weitere Cyclopentathiazenium-Verbindungen (S5N5Br, S5N5Br3, S5N5I2Cl und S5N5SbCl4) synthetisiert. Die Eigenschaften der dargestellten S5N5+-Verbindungen zeigen, daß ihre Stabilität durch die Größe des Anions stark beeinflußt wird.
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  • 36
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    Biological Mass Spectrometry 17 (1982), S. 614-616 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass fragmentation of three dinucleotide analogues in which D-ribose phosphodiester linkages were replaced by a three methylene unit chain has been investigated. The fragmentation pathways were proposed on the basis of high resolution data and metastable transitions. These compounds demonstrated a unique fragmentation with the formation of the fragment ion containing nitrogen at the end of the C3H6 chain.
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  • 37
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 38
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The translational energy, T, released during CH3· loss from the molecular ions of epimeric steroid ketones and from both molecular and [M-H2O]+· ions of epimeric alcohols of the androstane, pregnane and cholestane series, differing in the mode of the A/B ring junction, has been measured. These data provide a simple and rapid method for identifying the configuration of the epimeric centres. Of the compounds studied, it is found in 3-hydroxy steroids that the 5β-isomers release the smaller amounts of translational energy for CH3· loss. In most of the 3-keto steroids investigated, the opposite is found, i.e. the larger T values are observed for the 5β-isomers. Exceptions occur when further keto groups are introduced at the 11- or 17-positions. A small range of epimeric pairs of 17-hydroxy, 17-keto and 4-keto steroids have also been studied, the 5β-isomer giving the lower T value in each case. The importance of hydroxy and keto groups at the various sites within the steroid structure in determining the T values is discussed.
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  • 39
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    Journal of Raman Spectroscopy 9 (1980), S. 263-265 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectrum of a single crystal of monoclinic B-type (C2h3) gadolinium sesquioxide is presented. The low temperature polarization studies allowed the unambiguous attribution of 20 among the 21 normal modes expected according to the C2h factor group analysis predictions.
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  • 40
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    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3449-3451 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Carbazolylpotassium with 9-Bromoanthracene and NitrobenzeneThe formation of 9-(9-anthryl)carbazole (5) and 9-(2-nitrophenyl)anthracene (6) from 9-bromoanthracene (4), carbazole and nitrobenzene in the presence of potassium carbonate and catalytic amounts of copper is explained with the assumption of a trans-metallation equilibrium between carbazolylpotassium and nitrobenzene.
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  • 41
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2665-2667 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoanilide-Analogous Rearrangements of N-Acyl Derivatives of 5H-Benzo[b]carbazoleThe known photo rearrangement of N-acetylcarbazole yielding carbazole ketones has also been observed for the N-acetyl and N-(2-naphthoyl) derivatives 3,4 of 5 H-benzo[b]carbazole (8), whereas N-(2-naphthoyl)carbazole (2) is photochemically almost stable. An explanation for this different behaviour on the basis of the tern schemes of the compounds studied is suggested.
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  • 42
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substituent Effects on the CC-Bond Strength, 5. Kinetics and Thermochemistry of the Homolytic Dissociation of meso- and D,L-2,3-Dimethoxy-2,3-diphenylsuccinonitrileThe differences in enthalpy and entropy between meso- and DL-2,3-dimethoxy-2,3-diphenylsuccinonitrile (2) were deduced from the equilibrium constants of their interconversion at elevated temperatures via reversible dissociation into α-cyano-α-methoxybenzyl radicals (3). They were reproduced by force field calculations and by the difference in activation enthalpy of dissociation of meso- and DL-2. The identity of ΔH± (2) and ΔH for the dissociation process 2→3 as obtained by ESR spectroscopy proves that the radicals 3 have no kinetic stabilization. From the discrepancy between ΔS± (2) and the entropy of dissociation ΔS (2→3) it is concluded that sandwich radical pair complexes are intermediates in the dissociation process of 2. From the relationships between ΔG± of thermolysis and the strain enthalpies Hs of 2 and from the experimentally determined Ctert-H bond enthalpy of α-methoxybenzyl cyanide (1) it is concluded that no particular capto-dative stability effect exists for the radicals 3.
    Notes: Die Enthalpie- und Entropiedifferenz zwischen meso- und DL-2,3-Dimethoxy-2,3-diphenylbernsteinsäuredinitril (2) wurde aus der Temperaturabhängigkeit des thermisch über reversible Bildung von α-Cyan-α-methoxybenzyl-Radikalen (3) eingestellten Gleichgewichts bestimmt und durch Kraftfeldrechnungen bestätigt. Die Aktivierungsenthalpien der Thermolyse von meso- und DL-2 bestätigen diese Differenz ebenfalls und stimmen überein mit der ESR-spektroskopisch bestimmten Dissoziationsenthalpie von 2 in 3. Die Radikale 3 sind demnach nicht kinetisch stabilisiert. Aus der Diskrepanz zwischen ΔS± von 2 und der Dissoziationsentropie ΔS wird auf primäre Bildung sandwichartiger Radikalpaarkomplexe im Dissoziationsprozeß geschlossen. Aus den Aktivierungsparametern der Thermolyse und den Spannungsenthalpien der Diastereomeren 2 sowie aus der experimentell bestimmten Ctert-H-Bindungsenthalpie von α-Methoxybenzylcyanid (1) ergibt sich kein Hinweis für eine über das Additive hinausgehende capto-dative Stabilisierung der Radikale 3.
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    Biological Mass Spectrometry 16 (1981), S. 328-329 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Biological Mass Spectrometry 16 (1981), S. 52-52 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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    Biological Mass Spectrometry 16 (1981), S. 375-375 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 46
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    Zeitschrift für anorganische Chemie 460 (1980), S. 81-85 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Kristallstruktur von Diselenpentoxid, Se2O5Es wurde die Struktur des monoklinen Se2O5 (Raumgruppe P21/c, Z = 4) bestimmt (Verfeinerung bis R = 0,116 für 855 Reflexe). Die Struktur besteht aus Zick-Zack-Ketten [—Se(O)—O—Se(O)2—O—]n mit alternierenden SeIV - und SeVI-Atomen. Jedes Se-Atom ist tetraedrisch koordiniert, und zwar das SeVI durch 4 O-Atome, das SeIV durch 3 O-Atome und ein freies Elektronenpaar.
    Notes: The structure of monoclinic Se2O5, S. G. P21/c, Z = 4, was solved by direct methods and refined by an anisotropic full matrix least-squares to R = 0.116 for 855 densitometer intensities. The structure consists of zig-zag chaines [—Se(O)—O—Se(O)2—O—]n with alternating Se(IV) and Se(VI) atoms. Each Se atom is coordinated tetrahedrally, Se(VI) by 4 O atoms, Se(IV) by 3 O atoms and a lone electron pair.
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  • 47
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    Zeitschrift für anorganische Chemie 477 (1981), S. 221-224 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Kristallstruktur des [Zn(NH3+CH2(CH3)P(O)O-)Cl2], (α-Aminomethyl(methyl)phosphinic)Zink(II)-dichloridDie Titelverbindung ist monoklin, Raumgruppe P21/c, Z = 4, mit a = 6,632, b = 11,890, c = 10,012 Å und β 90.80°. Die durch Röntgenbeugungsdaten ermittelte und bis zu R = 0,086 für 1783 Diffraktometerdaten verfeinerte Struktur besteht aus unendlichen (—P—O—Zn—O—P—)-Ketten. Die Zn-Atome werden tetraedrisch durch 2 Cl- und 2 O-Atome unterschiedlicher Ligandenmoleküle koordiniert mit Zn—O- und Zn—Cl-Abständen von 1,95 bzw. 2,24 Å.
    Notes: The title compound is monoclinic, space group P21/c, Z = 4, with a = 6.632, b = 11.890, c = 10.012 Å and β 90.80°. The structure, which was solved by direct methods and refined to R = 0.086 for 1783 diffractometer intensities, consists of infinite (—P—O—Zn—O—P—) chaines. Zn atoms are coordinated tetrahedrally by 2 Cl and 2 O atoms of different ligand molecules with Zn—O and Zn—Cl distances of 1.95 and 2.24 Å, respectively.
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    Mass Spectrometry Reviews 3 (1984), S. 479-526 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    Biological Mass Spectrometry 18 (1983), S. 212-214 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The field ionization mass spectrum of diethylamine on a 5 μm activated wire at 300 K yields surface product ions like protonated molecular ions and doubly charged ions as well as gas phase ions like parent minus CH3 group. Variations of the reaction rate as a function of the decomposition times in the range 10-11-10-6 s for the elimination of a CH3 group are studied. The reaction rates are evaluated with the help of the retarding potential technique.
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    Organic Magnetic Resonance 18 (1982), S. 185-189 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The measurements of T1 relaxation times in 13C NMR spectroscopy are used to determine solute-solvent interactions. endo- and exo-Bicyclo[3.2.1]octan-3-ol and the corresponding bromohydrins are used as substrates. In a non-polar solvent, such as cyclohexane, solute-solvent interactions occur exclusively, whereas in the more polar acetone only solute-solvent interactions are observed. In chloroform, which is of intermediate polarity, the two types of interactions (solute-solute and solute-solvent) occur simultaneously.
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    Biological Mass Spectrometry 19 (1984), S. 464-466 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 52
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of 5,5-diphenylmonothiohydantoins and their N- and S-methyl derivatives have been investigated and interpreted in terms of structural correlations. All stable isomers can be easily distinguished by their fragmentation patterns.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: The influence of functional group interaction on the intensity ratios (Q) of product ions from α-fission of ethyl-tert-alkylamines C2H5(C3H7)(HO(CH2)n)C —NHC2H5, in which one side chain of the tert-alkyl moiety is replaced by a hydroxyalkyl group of varying chain length, was investigated. It was found that only through-bond interaction between the functional groups has a major influence on these ratios. By substitution of a hydrogen by a halogen atom in one side chain it was shown that the so-called ‘ion mass effect’ is a degrees of freedom effect.
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    Biological Mass Spectrometry 17 (1982), S. 253-260 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Interpretation of the metastable ion transitions found in normal electron impact mass spectra of appropriate compounds, shows that ions (C4 to C13) of structures \documentclass{article}\pagestyle{empty}\begin{document}${\rm R - CH = }\mathop {\rm O}\limits^{\rm + } {\rm H} $\end{document}, (a), \documentclass{article}\pagestyle{empty}\begin{document}${\rm R}^{\rm 1} ({\rm R}^{\rm 2} ){\rm C = }\mathop {\rm O}\limits^{\rm + } {\rm H}$\end{document} (b), and \documentclass{article}\pagestyle{empty}\begin{document}${\rm R}^{\rm 1} ({\rm R}^{\rm 2} ){\rm C = }\mathop {\rm O}\limits^{\rm + } {\rm R}^{\rm 3}$\end{document} (c) are clearly distinguishable from each other (R = alkyl). Within the latter series c those ions with R3 = methyl and R3〉methyl exhibit totally different behaviour. Low homologues are shown to behave exceptionally. Therefore, general conclusions drawn from their reactions must be regarded with caution. Except for these low homologues, ions b and c only isomerize within their groups, but not to each other or to other acyclic ‘oxonium’ ions. Ions a probably have a minor pathway to isomerize to b, and ions c with R3〉methyl were found not to isomerize at all prior to slow decompositions.
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  • 55
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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    Biological Mass Spectrometry 10 (1983), S. 633-640 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Combined high performance liquid chromatography mass spectrometry using a moving belt interface was used to investigate C-methylation artifacts arising from the permethylation reaction of peptides with methyl sulfinyl carbanion and methyl iodide. C-Methylation was not limited to glycine but, depending on the reaction conditions, other amino acids were also susceptible to it. In the absence of a glycine residue, preference for C-methylation of the C-terminus amino acid was observed. The use of on-line high performance liquid chromatography mass spectrometry allowed the separation of N, O, C-methylated from the N, O, S-permethylated derivatives, thus facilitating interpretation of the mass spectra.
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    Journal of Raman Spectroscopy 9 (1980), S. 166-171 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We have designed and assembled a sensitive vidicon Raman spectrometer which is shown to be well suited for the studies of heme proteins in both Soret (near-ultraviolet) and Q (visible) band regions. This system, employing a dry ice-cooled silicon intensified target (SIT) detector and an additive dispersion double monochromator (two 600 g mm-1 gratings blazed at 400 nm), has excellent stray light rejection and optimum bandpass and resolution (5-12 cm-1) for biological applications. It is demonstrated that a 600 cm-1 wide section of the low frequency Raman spectrum of ferrocytochrome c excited at 413.1 nm (70 mW) can be obtained in 30 ms, which is ˜ 2×104 times faster than that required by the conventional scanning techniques. Our multichannel Raman system has an enhanced detection capability which enables us to identify at least 41 weak Raman lines below 850 cm-1 in the spectrum of ferrocytochrome c. Using the SIT detection system, the Raman excitation profile of a depolarized line at 750 cm-1 in Fe(II) cytochrome c has been constructed and compared with that reported for Ni etioporphyrin. Instead of strong 0-0 Raman intensity, the cytochrome c profile exhibits weaker 0-0 intensity, indicative of the absence of the Jahn-Teller effect. It is further demonstrated that the Soret-excited Raman spectrum of oxyhemoglobin can be readily obtained without photodissociation.
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    Journal of Raman Spectroscopy 11 (1981), S. 150-154 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Interactions of cobalt(III) ion with adenosine-5′-triphosphate in the presence of 1,10-phenanthroline and superoxide were studied by laser Raman spectroscopy. Striking intensity enhancement of two adenine ring vibrations at 734 and 1430 cm-1 was observed upon formation of the complex Co(III)-(phen)-ATP-O2-. The effect could be abolished by addition of cyanide ion to replace the superoxide ion. The spectral features were interpreted as indicating a direct binding of Co(III) to the C6-NH2 group of adenine. The interaction between Co(III) and 1,10-phenanthroline was manifested in the frequency and intensity changes near 436 and 1064 cm-1. Raman intensities at 734, 1312, 1055 and 1430 cm-1 were measured as a function of laser exciting wavelength. The gradual changes in Raman excitation profiles of ATP lines from 647.1 nm to 457.9 nm indicated the preresonance effect with a charge transfer transition between adenine and Co(III), which may lie between 300 and 400 nm as evidenced by the more dramatic enhancement of these lines with 406.7 nm excitation.
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    Organic Magnetic Resonance 22 (1984), S. 131-135 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C and 15N NMR chemical shift and spin-lattice relaxation data have been measured for both meso- and racemic-pentane-2,4-diamine. At high pH (12), relaxation is consistent with hindered rotation of the NH2 group due, in part, to the formation of intramolecular hydrogen bonds. At low pH (2), relaxation is consistent with relatively unhindered rotation of the NH3+ group. Rotational jump rates and barriers are reported, determined from the NT1 ratios between 15N and 13C nuclei. In all cases, the ratios for the racemic diastereomer are higher than those of the meso compounds; this is interpreted in terms of conformationally more stable intramolecular hydrogen bond formation in the meso compound. Chemical shifts for the diastereomeric amines show that 15N shifts move downfield on protonation along with methyl and methylene carbons, while the methine carbon resonances move upfield.
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    Journal of Raman Spectroscopy 15 (1984), S. 347-349 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Brillouin spectra of lithium potassium sulfate have been obtained in its hexagonal phase from room temperature to the orthorhombic phase transition temperature at 435°C. The ν11 longitudinal sound velocity corresponding to the C11 elastic coefficient undergoes a smooth decrease with increasing temperature; the maximum decrease is 6.0% at T0=435°C and the temperature dependence of ν11 satisfies an expression of form \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{V_{11} (T)}}{{V_{11} (293\,{\rm K})}} = A - BT - \frac{C}{{T_c - T}} $$\end{document} with B=(1.13±0.04) × 10-4K-1, C = (0.9±0.1) K and Tc = (467±6)°C=(740±6)K.
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    Mass Spectrometry Reviews 2 (1983), S. 1-45 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    Biological Mass Spectrometry 16 (1981), S. 171-175 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation pathways for the ions generated by electron impact from nonan-4-one have been studied using low energy collision induced dissociation in a triple quadrupole mass spectrometer. Over 400 fragmentation pathways have been identified. These results are compared with data from earlier ion kinetic energy spectrometry studies of nonan-4-one which employed metastable decompositions.
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  • 63
    ISSN: 0935-6304
    Keywords: LC/MS interface ; Nebulizing interface ; Micro-LC ; CI-MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An improved vacuum nebulizing interface with a very short counter nozzle was developed for direct coupling of a micro-LC and a quadrupole MS with CI-chamber. With the LC-MS system using the nebulizing interface, it became possible to take mass fragmentograms for various less volatile compounds such as glutamic acid, steroids, aromatic amines and chlorine-containing insecticides.
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  • 64
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An accurate and time-saving method for the determination of norepinephrine in human plasma is described. The whole device focused on an improvement in the pretreatment. One ml of human plasma was applied to a boric acid gel column without deproteinization and pH adjustment, and norepinephrine was eluted with 2 ml of a 1.3 M acetic acid in methanol solution. The pentafluoropropionic derivative of norepinephrine was analysed by gas chromatography mass spectrometry using deuterated norepinephrine as an internal standard. The level of plasma norepinephrine in healthy subjects at recumbency was 297 ± 95 pg ml-1 (mean ± SD). The lower limit of sensitivity was 25 pg ml-1 of norepinephrine in plasma.
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  • 65
    ISSN: 0935-6304
    Keywords: Liquid chromatography, HPLC ; Post-column detection ; Amino acids ; NBD-CI ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2635-2642 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Method for the Synthesis of 2,4-Disubstituted Morpholinesω-Acetoxyacetophenones (acyloin esters) 1 react with secondary aminoethanols 3 and formic acid according to Leuckart-Wallach's reaction to form 2-(aryl),4-disubstituted morpholines 5. Intermediates of the reaction are discussed. The ω-halogenacetophenones react analogically.
    Notes: Bei der reduktiven Aminierung von ω-Acetoxyacetophenonen (Acyloinestern) 1 mit sekundären Aminoethanolen 3 und Ameisensäure nach der Leuckart-Wallach-Reaktion werden 2-(Aryl),4-disubstituierte Morpholine 5 gewonnen. Die Zwischenstufen der Reaktion werden diskutiert. Die ω-Halogenacetophenone reagieren analog.
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  • 67
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    Biological Mass Spectrometry 11 (1984), S. 594-600 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of metabolites of trinitrotoluene (TNT) have been synthesized and analysed by electron impact (EI) and chemical ionization (CI) mass spectrometry. Identification characteristics of these metabolites by their mass spectra have been determined. Differentiation of isomers is made possible by EI ions which are characteristic of the position of the methyl group with regard to the nitro groups.
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  • 68
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    Biological Mass Spectrometry 18 (1983), S. 47-51 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pressure dependence of several reversed phase liquid chromatographic solvents, including methanol, acetonitrile and mixtures of methanol: water and acetonitrile: water has been investigated. Typical ions, [MH]+, [2M+H]+ and [3M+H]+, were recorded as function of source pressure and as a function of the amount of water in the mixture. Ion formation processes in methanol: water and acetonitrile: water are discussed. The influence of liquid chromatographic mass spectrometric solvent pressure on the mass spectra of samples has been demonstrated on an amino acid sample.
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  • 69
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    Biological Mass Spectrometry 15 (1980), S. 637-639 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of explosives, including TNT, tetryl, nitroglycerin, PETN and RDX have been recorded by direct exposure chemical ionization with isobutane as reagent at source temperatures of 50-100°C. The mass spectra contain major [MH]+ ions, adduct ions and some fragment ions. The configuration of the relative abundances of these ions has been found to be a function of temperature and source pressure. Maximum [MH]+ ion abundance has been obtained at source pressures much lower than normal chemical ionization pressures.
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  • 70
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    Biological Mass Spectrometry 16 (1981), S. 264-266 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A reduction process was found to occur in the ion source when observing the chemical ionization mass spectra of a series of trinitroaromatic compounds, using water as reagent. The [MH-30]+ ions in the CI mass spectra were due mainly to the reduction of the compounds to their corresponding amines. This was proved by using D2O as reagent: the [MH-30]+ ions were shifted to [MD-28]+ ions. The trinitroaromatic compounds investigated included 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene, 2,4,6-trinitro-m-cresol, 2,4,6-trinitroaniline (picramide) and 2,4,6-trinitrophenol (picric acid).
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  • 71
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    Mass Spectrometry Reviews 1 (1982), S. 257-307 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 72
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    Biological Mass Spectrometry 17 (1982), S. 321-326 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A collisional induced dissociation study of 1,3,5-trinitro-1,3,5 triazacyclohexane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) was carried out using mass analyzed kinetic energy spectrometry. High resolution mass spectra and mass analyzed ion kinetic energy/collisional induced dissociation spectra of RDX and HMX were recorded in the electron impact, chemical ionization and negative ion chemical ionization modes. Fragmentation pathways of the compounds investigated were determined in all three modes of ionization. It was found that a major part of the fragment ions in RDX and HMX originate from formation of the aduct ions [M+NO]+ and [M+NO2]+ in electron impact and chemical ionization, and from [M+NO]- and [M+NO2]- in negative chemical ionization, followed by dissociation.
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  • 73
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    Zeitschrift für anorganische Chemie 519 (1984), S. 213-216 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 145. Trimethylgermyl and Trimethylstannyl CarbonatesThe hitherto unknown salts of the hemiesters of carbonic acid Li[O2C—OGe(CH3)3] and Li[O2C—OSn(CH3)3] have been prepared by reaction of Li[OGe(CH3)3] and Li[OSn(CH3)3], respectively, with CO2 at 0°C.Both compounds were characterized by means of diverse spectoscopic methods.
    Notes: Die bisher nicht bekannten Halbestersalze der Kohlensäure Li[O2C—OGe(CH3)3] und Li[O2C—OSn(CH3)3] wurden durch Umsetzung von Li[OGe(CH3)3] bzw. Li[OSn(CH3)3] mit CO2 bei 0°C hergestellt.Beide Verbindungen wurden mit verschiedenen spektroskopischen Methoden charakterisiert.
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  • 74
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    Zeitschrift für anorganische Chemie 519 (1984), S. 204-212 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 144. Synthesis and Properties of Alkali Metal t-Butyl Carbonates. Reinvestigations of Trimethylsilyl CarbonatesThe t-butyl carbonates M[O2C—OC(CH3)3], where M = Li, Na, K, Rb, Cs, have been prepared by reaction of the corresponding t-butoxide with CO2 and characterized by means of diverse methods.The equivalent conductivities of the [O2C—OC(CH3)3]- ion in aqueous solution have been determined and the Stokes radius, the radius of the hydrated ion, and the diffusion coefficient were calculated.The dissociation constant of t-butyl carbonic acid in water at 25°C is Ka = (1.63 ± 0.03)· 10-8. The thermodynamic data of dissociation were calculated.New data of trimethylsilyl carbonates [O2C—OSi(CH3)3]- are given.
    Notes: Die t-Butylcarbonate M[O2C—OC(CH3)3] mit M = Li, Na, K, Rb, Cs wurden durch Umsetzung des entsprechenden t-Butoxids mit CO2 hergestellt und mit verschiedenen Methoden charakterisiert.Die Äquivalentleitfähigkeiten des [O2C—OC(CH3)3]--Ions in wäßriger Lösung wurden bestimmt und der Stokessche Radius, der Radius des hydratisierten Ions und der Grenzwert des Diffusionskoeffizienten berechnet.Die Dissoziationskonstante der t-Butylkohlensäure in Wasser beträgt Ka = (1,63 ± 0,03)· 10-8 bei 25°C. Die thermodynamischen Standardgrößen der Dissoziation wurden ermittelt.Für Trimethylsilylcarbonate [O2C—OSi(CH3)3]- werden neue Daten mitgeteilt.
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  • 75
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    Zeitschrift für anorganische Chemie 466 (1980), S. 188-194 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 96. Studies on Trimethylsilyl Carbonates of Alkali MetalsThe trimethylsilyl carbonates M[O2COSi(CH3)3] with M = Li, Na, K, Rb, Cs have been prepared by reaction of Co2 with the corresponding silanolate. Infrared spectra, electron absorption spectra, 1H-NMR spectra as well as mass spectra are communicated.In aqueous solution the equivalent conductivities of [O2COSi(CH3)3]- have been determined by means of conductivity measurements. The diffusion coefficient of the ion was calculated.The dissociation constant of trimethylsilyl carbonic acid in water at 20°C is Ka = (4,83 ± 0,5) · 10-10. The thermodynamic data of the dissociation were calculated.
    Notes: Die Trimethylsilylcarbonate M[O2COSi(CH3)3] mit M = Li, Na, K, Rb, Cs wurden durch Umsetzung von CO2 mit dem entsprechenden Silanolat dargestellt. Die IR-, UV-, 1H-NMR- und Massenspektren werden mitgeteilt.Mit Hilfe elektrischer Leitfähigkeitsmessungen wurden die Temperaturabhängigkeit der Äquivalentleitfähigkeit des [O2COSi(CH3)3]-- Ions in wäßriger Lösung bestimmt und der Grenzwert des Diffusionskoeffizienten berechnet.Die Dissoziationskonstante der Trimethylsilylkohlensäure in Wasser beträgt Ka = (4,83 ± 0,5) · 10-10 bei 20°C. Die thermodynamischen Standardgrößen der Dissoziation wurden ermittelt.
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  • 76
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    Biological Mass Spectrometry 8 (1981), S. 503-505 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three physiologically important disaturated lecithins have been analyzed quantitatively as the acetate derivatives using a solids inlet probe and ammonia chemical ionization. Concentration independent response factors have been determined over a tenfold range that brackets human plasma levels. The results obtained serve as an independent corroboration of gas chromatographic analyses.
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  • 77
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    Biological Mass Spectrometry 9 (1982), S. 286-292 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of a series of alkyl, alkyl/aryl and biologically important quaternary ammonium and phosphonium compounds have been obtained by a direct thermal process. No means of ionization other than the heating of a salt coated filament is used. The spectra consist primarily of even electron ions for which decomposition schemes involving four-center reactions are proposed. These spectra are similar to those obtained in fission fragment induced desorption, laser induced desorption and field desorption/collisional activation, but they are produced by a far simpler means.
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  • 78
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    Journal of Raman Spectroscopy 15 (1984), S. 55-59 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared spectra (4000-400 cm-1) of pentachlorocyclopropane have been recorded for all three of its physical states. A liquid-phase Raman spectrum of this molecule has also been observed. Based on the Raman depolarization data, gas-phase infrared band contours and expected group frequency correlations, it has been possible to propose an assignment for 20 of the 21 normal vibrations of pentachlorocyclopropane. This assignment agrees well with those proposed for hexachlorocyclopropane, the three isomeric tetrachlorocyclopropanes, 1,1-dichlorocyclopropane and chlorocyclopropane. Further, the vibrational assignment for pentachlorocyclopropane has identified characteristic vibrational frequencies for the three CH(X) modes: CH stretch, 3040 cm-1; in-plane CH bend, 1296 cm-1; and out-of-plane CH bend, 1088 cm-1.
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  • 79
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton-coupled nitrogen-15 NMR spectra of urea, N-methylurea, N,-N′-dimethylurea, N-methyl-N′-benzylurea and N-phenylurea have been obtained at natural abundance level in neutral, basic and acidic solutions at 25°C. Base-catalyzed N—H proton exchange of the —NH2 group of N-methylurea in water was found to be 1.5 times faster than that for the -NH- group, while the corresponding acid-catalyzed exchange is 7.5 times faster. Comparison of urea and N,-N′-dimethylurea in water shows urea to be 10 times faster in base but 2 times slower in acid. The ratio of the base-catalyzed N—H proton exchanges of the two -NH- groups of N-methyl-N′-benzylurea in dimethyl sulfoxide is close to unity, whereas the CH3NH- group exchanges 4 times faster in acid. Similarly, the C6H5NH- group of N-methyl-N′-phenylurea exchanges 50 times faster than the CH3NH- group in base and about 3 orders of magnitude slower in acid. The results are rationalized by consideration of steric and electronic effects.
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  • 80
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The proton-coupled nitrogen-15 NMR spectra of hydrazinecarbothioamide and 4-methylhydrazinecarbothioamide have been taken at the natural-abundance level in neutral, basic and acidic solutions at 25°C. The N—H proton-exchange reactions of the hydrazino-NH2 groups in both compounds were found to be very rapid in the presence of acid, but quite slow in the presence of base. The hydrazino-NH protons of hydrazinecarbothioamide exhange six times and 200 times faster than the amide protons in the presence of either base or acid, respectively. Similarly, acid- and base-catalyzed N—H proton exchanges of the hydrazino-NH group of 4-methylhydrazinecarbothioamide were found to be two to three orders of magnitude faster than those of N-methylamido protons. These results can be rationalized by consideration of the effect of the lone pair on the hydrazino—NH2 group on the reactivity of the adjacent —NH— group.
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  • 81
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    Organic Magnetic Resonance 14 (1980), S. 511-514 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 251 MHz 1H and the natural abundance 63.1 MHz 13C NMR spectra of 1,3-dioxepane (1) and 4,4,7,7-tetramethyl-1,3-dioxepane (2) have been investigated over the temperature range of 5 to -180 °C. While the spectra of 1 show no dynamic NMR effect, compound 2 exists in solution as a 1:1 mixture of a symmetrical (C2) twist-chair and its mirror image conformation. The free energy barrier for the conformational racemization of 2 is 43 kJ mol-1 (10.3 kcal mol-1). Interconversion paths between various conformations of 2 are discussed. Compound 1 is suggested to have a symmetrical (C2) twist-chair conformation which is rapidly pseudorotating via a chair conformation to achieve a time averaged symmetry of C2v, even at -180 °C.
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  • 82
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 15N NMR spectra of several substances with nitrogen - nitrogen bonds have been obtained at the natural-abundance level by high-resolution NMR spectroscopy. Azo (—N=N—) nitrogens are 300-500 ppm deshielded compared with hydrazo (—NH—NH—) nitrogens. The sensitivity of the 15N shifts in these types of substances to substituent changes are reported, along with 15N-1H spin-spin couplings for some hydrazo compounds. Hydrogen-bonding effects arising from solvent changes on the 15N shifts of azoxybenzene are different for its two kinds of nitrogen. The 15N NMR spectrum of N,N'-dinitrosopiperazine in dimethyl sulfoxide at room temperature is consistent with the presence of two different conformations about the N—NO bonds.
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  • 83
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    Biological Mass Spectrometry 19 (1984), S. 250-252 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Organic Magnetic Resonance 14 (1980), S. 153-154 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Ketonic 13C NMR signals of a series of 6-hydroxy-5-oxobicyclo[2.2.2]oct-7-ene-2-carboxylic acid lactones and of haplophytine and related N-substituted 3-piperidinones occur at exceptionally high field; the structural factors which are responsible have been elucidated by comparisons with related compounds.
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    Organic Magnetic Resonance 20 (1982), S. 199-200 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Earlier assignments of 13C NMR signals to C-6 and C-7 in 5,5-dimethyl-2-norbornanone (1) based on lanthanide-induced shifts are interchanged on the basis of studies of deuterium-labeled derivatives of 1. The revised assignments are in accord with predictions based on substituent parameters.
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  • 86
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    Biological Mass Spectrometry 10 (1983), S. 567-571 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In chemical ionization mass spectrometry, the use of a noble reagent gas mixed with a proton transfer reagent gas is known to produce mass spectra which contain both protonated molecules and fragment ions. We have used a mixture of isobutane and argon to improve the mass spectra of peptides which have been derivatized to O-TMS-polyamino alcohols. The molecular weight is deduced from a prominent [M+H]+ ion; the sequence of amino acids is deduced from the usual A- and Z-series fragment ions. This technique enhances the sequence ions for lysine and glycine-containing peptides, and retains the ability to distinguish C-terminal leucine and isoleucine.
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    X-Ray Spectrometry 10 (1981), S. 85-90 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A systematic investigation of the chemical effects on the calcium X-ray K emission spectra from 32 chemical compounds was carried out using a two-crystal X-ray spectrometer. The observed chemical shifts of the Ca Kα1,2, Kα3,4, Kβ1,3 and Kβ5 lines relative to the respective lines from CaF2 varied in the range +0.06 to +0.30, +0.09 to +0.32, -0.06 and +1.1 to +3.2eV, respectively. A certain dependence on the nature of surrounding groups was found in these shifts. The profile changes in the Ca Kβ5 and Kβ5′ bands from all compounds were discussed by subdividing them roughly into three types, depending upon their characteristic features.
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  • 88
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We examine the difference between a linear and a non-linear model for the calculation of analyte concentration by interpolation between standards in isotope dilution/mass spectrometry. Equations are developed for calculating this difference for various increments of the bracketing intensity ratios and for various compositions of the sample; graphs are also presented to depict this difference for these various conditions. As an illustration, the result for a series of measurements on urea are presented and discussed.
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  • 89
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    Journal of High Resolution Chromatography 3 (1980), S. 589-590 
    ISSN: 0935-6304
    Keywords: Liquid chromatography, (HP)LC, CLC ; Capillary, fused silica with chemically bonded phases ; 30 μm i.d., split sampling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of High Resolution Chromatography 4 (1981), S. 83-85 
    ISSN: 0935-6304
    Keywords: HPLC ; Nanoliter volume detector ; 1.5 × 10-5 AU noise (0.1 μl 0.1% benzene in methanol) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of High Resolution Chromatography 6 (1983), S. 348-358 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 92
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    Journal of High Resolution Chromatography 6 (1983), S. 448-450 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Solute focussing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Organic Magnetic Resonance 14 (1980), S. 76-77 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling constants between 11B and 13C, 13C and 1H, and 11B and 1H were obtained for LiB(CH3)4 in 1,2-dimethoxyethane, in which the anion B(CH3)4- is belived to exist as a separate ion pair. The correlations of the coupling constants with the effective nuclear charge of boron, and with the s character of the B—C bond, are discussed.
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    Journal of Raman Spectroscopy 12 (1982), S. 157-161 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Resonance Raman spectra of three types of reaction intermediates, blue, green and yellow species, formed from 1,1-diphenylethylene adsorbed on porous Vycor glass were measured by means of an improved experimental technique and with suitable excitations. The blue species, which is the least stable intermediate, is found to be a cation radical, , and the characteristic Raman bands of and 2 stretching vibrations are clearly observed. For the green and yellow species more detailed spectra were obtained than in previous experiments. The coverages of the three intermediates are θ≈10-3 for each, being in agreement with the values expected from the numbers of Lewis and Brönsted acid sites on porous Vycor glass. Resonance Raman spectrum of the blue species on silica-alumina, a catalyst, was also obtained by using the rotating sample technique.
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  • 95
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    Zeitschrift für anorganische Chemie 514 (1984), S. 205-212 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bildung und Zersetzung von LanthanoxidcarbonatAmorphes Lanthancarbonat wird durch Hydrolyse von Lanthanisopropoxid mit wäßriger Ammoniaklösung an Luft dargestellt. Lanthanoxidcarbonat, La2O(CO3)2 · H2O, kristallisiert, wenn die amorphe Substanz mit heißem Wasser gewaschen wird. Die Kristallisation und das thermische Verhalten des kristallinen Materials werden röntgenographisch, thermoanalytisch und IR-spektroskopisch untersucht. Die Zersetzung des La2O(CO3)2 · H2O in das IA-(LaO)2CO3 wird bei 440 bis 540°C beobachtet. Die Zersetzungsisothermen können durch eine gebrochene rationale Funktion beschrieben werden; die Aktivierungsenergie beträgt 42,6 kcal · mol-1. IA-(LaO)2CO3 zersetzt sich dann zum A-La2O3 bei 750 bis 870°C. Die Kinetik wird ebenfalls durch eine gebrochene rationale Funktion interpretiert; die Aktivierungsenergie beträgt 58,3 kcal · mol-1.
    Notes: Amorphous lanthanum carbonate was prepared by hydrolysis of lanthanum isopropoxide using ammonia water in the atmosphere. Lanthanum monoxocarbonate, La2O(CO3)2 · H2O, crystallizes when this amorphous material was washed with hot water. The crystallization and thermal behavior of the crystalline material are studied by X-ray diffraction, thermal analysis, and infrared spectroscopy. The decomposition of La2O(CO3)2 · H2O into type-IA (LaO)2CO3 is observed at 440 to 540°C. Decomposition isotherms are described by the contracting cube equation, the activation energy being 42.6 kcal mol-1. Type-IA (LaO)2CO3 subsequently decomposes to A-type La2O3 at 750 to 870°C. The kinetics is also interpreted in terms of the contracting cube equation, the activation energy being 58.3 kcal mol-1.
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  • 96
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    Organic Magnetic Resonance 21 (1983), S. 570-572 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR chemical shifts of m- and p-substituted benzyl N,N-dimethylcarbamates were measured in CDCl3. The meta and para 13C substituent chemical shifts were analysed by means of dual substituent parameter (DSP) equations. Good correlations were obtained, especially for the para-carbon substituent chemical shifts. The computed transmission coefficients, ρI and ρR, are consistent with the general features of the fitting parameters. It has been shown that no significant electron demand is imposed by the —CH2OCON(CH3)2 substituent.
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  • 97
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    Organic Magnetic Resonance 22 (1984), S. 439-445 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C NMR spectra of p- and m-substituted phenyl N-methylcarbamates, phenyl N,N-dimethylcarbamates and p- and m-substituted phenyl propionates were recorded, and their para 13C SCS (substituent chemical shifts) were analysed by DSP (dual substituent parameters) and DSP-NLR (non-linear resonance) equations. It was found that the fixed substituent Y, —OCONHCH3, —OCON(CH3)2 and —OCOC2H5, were all mild in the sense that DSP analysis gave a good correlation, leaving little room for improvement by the DSP-NLR treatment. Further, the three series of compounds gave similar ρI and ρR values (para derivatives, 3.2-3.3 and 17.7-18.0; meta derivatives, 5.1-5.2 and 21.8-22.0). Examination of the corresponding analyses of similar compounds indicated that the ρI and ρR values and, hence, their ratio ρR/ρR = λ, depended primarily on the nature of the atom through which the fixed substituent Y (e.g. α-C, α-N and α-O) was bonded to the aromatic ring when the Y substituents are mild. The extent of this tendency for compounds with active fixed substituents is also discussed.
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  • 98
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    Biological Mass Spectrometry 15 (1980), S. 1-3 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact induced fragmentation of 1-benzoylbenzotriazole has been studied by 13C labelling experiments. It has been found that the loss of CO from the [M — N2]+· ions proceeds by two routes; about 78% of the ions decompose via the molecular ions of the corresponding thermal fragmentation product, 2-phenylbenzoxazole, and 22% via those of the corresponding photochemical fragmentation product, 6-phenanthridone.
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  • 99
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    Journal of Raman Spectroscopy 9 (1980), S. 401-402 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By using optical fibres the sample surfaces can be illuminated widely and uniformly. This technique is useful for the Raman measurements of a small amount of surface species and also unstable surface species.
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    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 1336-1344 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydratisierte Oxokohlenwasserstoffe, I. Herstellung und Reaktionen von Tetrakis[organoborandiylbis(oxy)]cyclobutanenAus Octahydroxyclobutan (1) erhält man mit verschiedenen Monoorganoboranen in hohen Ausbeuten die Tetrakis[organoborandiylbis(oxy)]-Derivate 2a-d, die mit tertiären Aminen 1:2-sowie 1:4-Additionsverbindungen bilden. Bei der Alkoholyse lassen sich 2a-d in Abhängigkeit von den Organo-Substituenten an den Bor-Atomen partiell und vollständig entborylieren. Man erhält z. B. Tetraalkoxybis[phenylborandiylbis(oxy)]-Derivate des Cyclobutan-Rings (7b, c) oder, infolge Ringöffnung, Dihydroxyfumarsäure-dimethylester (5).
    Notes: Octahydroxycyclobutane (1) reacts with various monoorganoboranes to give in high yields the tetrakis[organoboranediylbis(oxy)] derivatives 2a-d. These react with tertiary amines to yield either 1:2 or 1:4 adducts. Depending on the organo substituents at the boron atoms, alcoholyses of 2a-d result in either partial or complete deborylation giving e.g. tetraalkoxybis[phenyl-boranediylbis(oxy)] derivatives of the cyclobutane ring (7b, c), or, with ring-opening, dimethyl dihydroxyfumarate (5).
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