Beiträge zur Chemie der Silicium-Stickstoff-Verbindungen. CV. Ringschlußreaktionen mit 1,5-Bis(alkylamino)trisildioxanen

1.5-Bis(methylamino)hexamethyltrisildioxane reacts in the presence of triethylamine easily with germanium tetrachloride (equ. 1) and ethyldichlorophosphine (equ.2) to give the formerly unknown inorganic eightmembered ring systems Si₃GeN₂O₂ and Si₃PN₂O₂. Respectively. By analogous reacting of silicon tetrachloride only open chained Cl₃Si? Nme? Sime₂? O? Sime₂? O? Sime? NHme (IV; equ. 3) is formed. With metallated 1.5-bis(alkylamino)trisildioxanes, dischlorodiorganylsilanes do not give the expected asymmetric-, but the symmetric cyclotetrasildioxdiazanes V–VII. Dichlorophenylborane, in an analogous reaction, leads to the novel eightmembered ring system BSi₃N₂O₂, but the exact position of the N and O atoms in the ring could not be fixed beyond any doubt. The novel sixmembered ring system BSi₂Ni₂O was realized in compound IX via equ. (6).     

N-Methylierte Cyclotetrasilazane und Cyclotetrasiloxazane

Zusammenfassung Die achtgliedrigen Ringverbindungen IX (Rk. 1), XI (Rk. 12), XI (RRk. 13) und XIV (Rk. 9a) (vgl. Schema 1) wurden erstmalig, XII (Rkk. 4, 8; Schema 2) auf neuen Wegen dargestellt, ihre Eigenschaften beschrieben und ihre Struktur durch Massen-, IR-und NMR-Spektren bestätigt. Sie neigen bei thermischem deer katalytischem Einfluß zum Übergang in sechsgliedrige Ringverbindungen (vgl. Schema 3).

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N-Methylated cyclotetrasilazanes and cyclotetrasiloxazanes (chemistry of silicon-nitrogen compounds, CIV)

The eightmembered ring compounds IX (equ. 1), XI (equ. 12), XII (equ. 13) and XIV (equ. 9a) (see scheme 1) were prepared for the first time, XII (equ. 4, 8; scheme 2) on several new routes. Their properties are described and their structure confirmed by mass, infrared and nmr spectroscopy. They tend to transform by thermal or catalytic influence into sixmembered ring compounds (compare scheme 3).

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Herrn Prof. Dr. Dr. h. c.H. Nowotny gewidmet.

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103. Mitt.:U. Wannagat undL. Gerschler, Z. anorg. allgem. Chem. (im Druck).

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Mit Auszügen aus den Dissertationen a)F. Rabet und b)H. J. Wismar, Techn. Universität Braunschweig, 1971.     

Development of a numerical model for the ballistic penetration of Fackler gelatine by small calibre projectiles

Among the different material surrogates used to study the effect of small calibre projectiles on the human body, ballistic gelatine is one of the most commonly used because of its specific material properties. For many applications, numerical simulations of this material could give an important added value to understand the different phenomena observed during ballistic testing. However, the material response of gelatine is highly non-linear and complex. Recent developments in this field are available in the literature. Experimental and numerical data on the impact of rigid steel spheres in gelatine available in the literature were considered as a basis for the selection of the best model for further work. For this a comparison of two models for Fackler gelatine has been made. The selected model is afterwards exploited for a real threat consisting of two types of ammunitions: 9?mm and .44 Magnum calibre projectiles. A high-speed camera and a pressure sensor were used in order to measure the velocity decay of the projectiles and the pressure at a given location in the gelatine during penetration of the projectile. The observed instability of the 9?mm bullets was also studied. Four numerical models were developed and solved with LS-DYNA and compared with the experimental data. Good agreement was obtained between the models and the experiments validating the selected gelatine model for future use.     

Chemical Composition,Antioxidant, and Antimicrobial Activities of Leaves of Ajuga Iva

The main objective of this research was to study the biological characteristics in terms of antioxidant and antimicrobial activities of Ajuga iva and determine the best analytical and extraction methods applicable to this specie and studied compounds. A short screening of its nutritional value in terms of chemical composition is also included. A. iva leaves were analyzed for crude protein (CP), cell wall [neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL)], minerals, fatty acids, essential oils, and phenolic compounds. Mature aerial parts of A. iva were randomly collected during the Spring season from Mograne-Zaghouan, Tunisia. Leaves of A. iva contained 13.4 ± 0.4% CP, 26.3 ± 0.35% NDF, 20.2 ± 0.42% ADF, and 5.13 ± 0.21% ADL. Mineral content (13.0 ± 0.45%) was mainly composed of potassium (4.5% g DM) and magnesium (4.25% DM). Leaves of A. iva had linolenic (26.29 ± 0.760%) and linoleic (37.66 ± 2.35%) acids as the main components of the acid profile. Thymol was found to be the most dominant (23.43%) essential oil, followed by 4-vinylguaiacol (14.27%) and linalool (13.66%). HPLC-PDA-ESI-MS/MS analysis pointed out the presence of phytoecdysteroids. Phenolic acids and flavonoids, such as glycosylated derivatives of naringenin, eriodyctiol, and apigenin, were detected in the methanol extract of A. iva leaves. Our results underline the importance of choosing proper extraction methods and solvents to extract and characterize the described compounds profile of A. iva leaves. Results also show A. iva leaves as a potential source of functional ingredients with beneficial health-promoting properties. Overall, leaves of A. iva have low biological activities (antioxidant and antimicrobial activities) with a chemical composition suitable as a feed for ruminants in rangeland pasture. It also has low-grade antibacterial or medicinal characteristics when fed to ruminants.     

Weitere Reaktionen von 1,3-Dichlordisilazanen und 1,3-Dichlordisiloxanen

Zusammenfassung Spezielle Umsetzungen von 1,3-Dichlordisilazanen werden beschrieben. Die Umsetzung mit einem bestimmten Amin führte zu einer SiNSiN-Verbindung mit 6 verschiedenen Substituenten (I; Rk. 1). Analog bildeten sich mit Hydrazinen Bis(hydrazino)-disilazane der Strukturgruppe NNSiNSiNN (II, III; Rk. 2). Mit Äthylendiamin konnte ein Si₂N₃C₂-Siebenringsystem (IV), mit Bis(trimethylsilyl)harnstoff ein Sechsringsystem Si₂N₃C (VI), mit Diphenylsilandiol das Cyclotrisildioxazan-Sechsringsystem (VIII, IX) aufgebaut werden. 1,3-Dichlordisiloxan ergab in ähnlichen Umsetzungen erstmalig ein Si₂N₂OC₂-Siebenringsystem (V) und ein Si₂N₂OC-Sechsringsystem (VII).

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New reactions of 1.3-dichlorodisilazanes and 1.3-dichlorodisiloxanes. (chemistry of silicon-nitrogen compounds, XCVIII)

Special reactions of 1.3-dichlorodisilazanes give a) with a special amine a SiNSiN-compound with 6 different substituents (I; equ. 1); b) with hydrazines bis(hydrazino)disilazanes of the structural unit NNSiNSiNN (II, III; equ. 2); c) with ethylenediamine a novel Si₂N₃C₂-sevenmembered ring system (IV); d) with bis(trimethylsilyl)urea a sevenmembered ring system Si₂N₃C (VI); e) with diphenylsilanediol the cyclotrisildioxazane ring system (VIII, IX). Analogous reactions of 1.3-dichlorodisiloxanes lead to the novel sevenmembered ring system Si₂N₂OC₂ (V) and to the sixmembered Si₂N₂OC-ring system (VII).

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97. Mitt.:U. Wannagat, L. Gerschler undH. J. Wismar, Mh. Chem.102, 1834 (1971).

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Vorläufige Mitt. von Teilergebnissen:U. Wannagat, Angew. Chem.77, 626 (1965); Pure appl. Chem.13, 262 (1966).

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Mit Auszügen aus den DissertationenE. Bogusch, Techn. Hochschule Graz 1966, undF. Rabet, Techn. Univ. Braunschweig 1971, sowie nach Arbeiten vonP. Geymayer, Techn. Hochschule Graz 1965.     

Real-time Measurement of Projectile Velocity in a Ballistic Fabric with a High-frequency Doppler Radar

Experimental Mechanics - Because of technical limitations, most experimental studies on the energy-absorbing properties of ballistic fabrics are limited to discrete evaluations based on impact and...     

Neue anorganische Ringsysteme. XIII. Einige fünf-, bicycloacht-(?) und zehngliedrige Ringsysteme mit Silicium-, Stickstoff- und Sauerstoffatomen sowie N?N-Bindungen im Ring

By reaction of 1.3-dichloro-pentamethyldisilazane and -tetramethyldisiloxane with hydrazine and 1.2-dimethylhydrazine respectively the novel inorganic ring systems (C), (D)/(D′), (E)/(E′) and (F) (see chapter 1) represented by the compounds I–IV could be constructed. So long it was not possible to decide if the compounds of the systems D/D′ and E/E′ have bicyclo[3.3.0]-octane or cyclobutyl-cyclobutane structure.     

Neue anorganische Ringsysteme X. Die sechsgliedrigen Ringsysteme PIIISi2N3, PIIISi2N2O und PvSi2N2O

Survey on the first-time syntheses of new inorganic ring systems in our team (scheme 1). – The title ring systems were prepared according to equ. (1–5) and varied in the compounds I–IX (table 1). Introduction of a P atom into the SiN ring system gives rise to a splitting of the proton signals of the substituents in the ¹H nmr spectra (table 2), mostly in cause of coupling, partly in cause of steric effects.     

Selenium heterocycles XII. Heat induced transformation of 1,2,3-Selenadiazoles to disubstituted selenophenes

4-Aryl-1, 2, 3-selenadiazoles when subjected to heat afforded 2, 5-diarylselenophenes and small quantities of 2,4-diarylseneophenes. Monoarylacetylenes and selenium behaved similarly. Phenylacetylene and sulfur gave 2,4-diphenylthiophene. Mechanistic aspects of these reactions are discussed.     

Insight into the Interaction of Furfural with Metallic Surfaces in the Electrochemical Hydrogenation Process

Electrocatalytic hydrogenation of furfural on metal surfaces has become an important research subject due to the potential of the reaction product 2-methylfuran as a renewable energy resource. Identifying effective determinants in this reaction process requires a thorough investigation of the complex electrode-electrolyte interactions, which considers a variety of the influential components. In this work, in operando electrochemical Raman Spectroscopy and Molecular Dynamics simulations were utilized to investigate different characteristics of the interface layer in the electrocatalytic hydrogenation of furfural. Hereby, the influence of applied potentials, electrode material, and electrolyte composition were investigated in detail. The studied parameters give an insight into furfural's binding situation, molecular orientation, and reaction mechanism.