Die Insertion von Sauerstoffatomen in Ga–Ga- und In–In-Bindungen – Bildung von monomeren Verbindungen R2E–O–ER2 [R = CH(SiMe3)2] mit stark aufgeweiteten E–O–E-Winkeln

The Insertion of Oxygen Atoms into Ga–Ga and In–In Bonds – Formation of the Monomeric Compounds R₂E–O–ER₂ [R = CH(SiMe₃)₂] with Strongly Enlarged Angles E–O–E The tetraalkyldielement compounds R₂Ga–GaR₂ ( 1 ) und R₂In–InR₂ ( 2 ) [R = CH(SiMe₃)₂] reacted with trimethylamine N-oxide by the insertion of oxygen atoms in their element-element single bonds. The products R₂E–O–ER₂ are monomeric in the solid state due to the high steric shielding by the voluminous bis(trimethylsilyl)methyl groups. As shown by crystal structure determinations, the E–O–E bridges have large angles of 142.7 (E = Ga, 3 ) and 138.6° (E = In, 4 ) and short separations between the oxygen and the coordinatively unsaturated Ga and In atoms. Both products are extremely hygroscopic.     

Die infrarotspektrograpische Analyse von Al-, Ga- und In-Oxinatgemischen

Zusammenfassung In den IR-Spektren von Al-, Ga- und Zn-Oxinat treten im CsBr-Bereich charakteristische Banden auf, die zur Analyse binärer Gemische dieser Verbindungen herangezogen werden. Während man die Gesamtmenge der Elemente durch Auswaage der Oxinate erhält, lassen sich aus den Extinktionsverhältnissen dieser Banden die Mischungsverhältnisse und daraus die Anteile der einzelnen Elemente ermitteln.Arbeitsweise und Fehlerquellen des Verfahrens werden angegeben.     

Quantenchemische Untersuchungen zur Struktur und Bindung von Zr6 in Zirconium-Clusterverbindungen

EHT results for the metal core Zr₆ of zirconium cluster compounds are presented. In the case of CZr₆I₁₄ the influence of the interstitial atom and the ligands on the Zr–Zr distances and the chemical bond is discussed.

     

Proton‐Induced Generation of Remote N‐Heterocyclic Carbene–Ru Complexes

The proton‐induced Ru?C bond variation, which was previously found to be relevant in the water oxidation, has been investigated by using cyclometalated ruthenium complexes with three phenanthroline (phen) isomers. The designed complexes, [Ru(bpy)₂(1,5‐phen)]⁺ ([ 2 ]⁺), [Ru(bpy)₂(1,6‐phen)]⁺ ([ 3 ]⁺), and [Ru(bpy)₂(1,7‐phen)]⁺ ([ 4 ]⁺) were newly synthesized and their structural and electronic properties were analyzed by various spectroscopy and theoretical protocols. Protonation of [ 4 ]⁺ triggered profound electronic structural change to form remote N‐heterocyclic carbene (rNHC), whereas protonation of [ 2 ]⁺ and [ 3 ]⁺ did not affect their structures. It was found that changes in the electronic structure of phen beyond classical resonance forms control the rNHC behavior. The present study provides new insights into the ligand design of related ruthenium catalysts.     

Untersuchungen zur atomspektroskopischen Spurenanalyse in AIII BV-Halbleitermikroproben—VI Untersuchungen zur Schichtabtrennung,Profil- und Spurenanalyse an InSb-Materialien

A method for the determination of distribution profiles and traces in InSb-materials is described. Stripping of the layers of several nm thickness was achieved by anodic oxidation (galvanostatic conditions). The stripping method was optimized, and the thickness of the layers stripped was determined by ellipsometric measurements. Traces of elements were determined by atomic emission and flameless atomic-absorption spectrometry. Detection limits in the range of 10¹⁷ atoms/cm³ for a 1-cm² surface layer 60 nm thick were observed. Distribution profiles for Mg and Te in InSb are shown.     

Na3OsH7 – Synthese,Struktur und magnetische Eigenschaften,sowie Untersuchungen zur Existenz einer analogen Rutheniumverbindung

Na₃OsH₇ – Synthesis, Structure, and Magnetic Properties as well as Investigations on the Existence of the Analogous Ruthenium Compound Na₃OsH₇ was synthesized by the reaction of sodium hydride with osmium powder under a hydrogen pressure of more than 1500 bar at 870 K. X‐ray investigations on powdered samples and elastic neutron diffraction experiments on the deuterated compound led to the atomic arrangement (space group: P4₂/mnm), which is characterized by isolated [OsD₇]‐anions. The coordination polyhedron formed by the seven deuterium ligands can be described as a distorted pentagonal bipyramide. Magnetic susceptibility measurements in the temperature range between 3.5 K and room temperature revealed a weak temperature independent paramagnetism. Quantum mechanical calculations confirm these facts and show in detail that the large value of the spin‐orbit coupling constant is responsible for the magnetic behaviour of the osmium (IV) compound. To synthesize the analogous ruthenium hydride it was necessary to increase the hydrogen pressure during the reaction up to 5000 bar. X‐ray investigations showed that Na₃RuH₇ crystallizes in an atomic arrangement isotypic to that of the osmium compound.     

Untersuchungen zur Konstitution und Entwässerung von Natriumtetramethylammoniumsilicathydrat

Investigations of the Constitution and Dehydratation of the Sodium Tetramethylammonium Silicate Hydrate Sodium tetramethylammonium silicate hydrates have a different composition in dependence of the mole-relation silicon dioxide: sodium oxide: tetramethylammonium oxide. The constitution is in all cases a sodium tetramethylammonium tetraanhydrido-bis-cyclotetrasilicate hydrate (double-four-ring silicate hydrate). Investigations of dehydration show that at first double-four-ring silicates with lower water contents are formed before condensation occurs.     

Untersuchungen zur Basizität von Alkyl- und Silylakylaminen

Investigations on the Basicity of Alkyl and Silyl Alkylamines The basicity of N has been investigated in primary and secondary alkyl und silyl alkylamines by means of the v_C–D band shift of CDCl₃ associated to the amine group by potentiometrically determined pK_s-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,     

Preparation,Post‐Modification,and Antibacterial Application of Gelatin Electrospun Membranes

Two bis(diaryldiazomethane)s substituted with amino groups are synthesized and used for the surface modification of membranes electrospun from gelatin. These membranes are then reacted with tolylene‐2,4‐diisocyanate to give urea‐functionalized materials, so that hydrogen peroxide can be reversibly bound onto their surface. These membranes are characterized by scanning electron microscopy, XPS, differential scanning calorimeter, and tensile test to show their surface properties and bulk properties. The surface modification with amino‐substituted diazomethanes and the subsequent cross‐linking reaction with diisocyanates contribute to high loadings of hydrogen peroxide, and greatly increase the antibacterial activity of gelatin‐derived membranes, which open a new horizon in the preparation of high loading antiseptic/antibacterial biomacromolecular surfaces and interfaces.     

C−N,C−S and S−S Bond Cleavage by Rhodium PCcarbeneP Pincer Complexes

Rhodium PC_carbeneP complexes 1‐L {L=PPh₃, PPh₂(C₆F₅)} react with isothiocyanate, carbodiimide and disulphide to enable C?S, C?N and S?S bond cleavage. The cleaved molecules are sequestered by the metal center and the pincer alkylidene linkage, forming η²‐coordinated sulfide or imide centered pincer complexes. When a C?S or S?S bond is cleaved, the resulting complexes can bridge two rhodium centers through sulphur forming dimeric complexes and eliminating a monodentate phosphine ligand.     

Untersuchungen zur Silicationenkonstitution in Trimethyl- und Triethyl-2-hydroxyethylammoniumsilicatlösungen

Investigation on the Silicate Constitution in Trimethyl- and Triethyl-2-hydroxyethyl-ammoniumsilicate Solutions In trimethyl-2-hydroxyethyl-ammoniumsilicate solutions with molar N:Si ratios of 1:1 to 2:1 only double four-ring silicate anions are observed. In triethyl-2-hydroxyethyl-ammoniumsilicate solutions with the same molar N:Si changing quantities of double three-ring and double four-ring silicate anions are detectable. There is a range of SiO₂ concentrations, where these two silicate anion constitutions dominate among all the SiO₂ existing in the solutions. Increased quantities of alkali hydroxides effect the decomposition of double ring silicates, the decomposing effect of sodium and potassium hydroxide differing in their strength.     

Untersuchungen zur atomspektroskopischen spurenanalyse in AB-halbleiter-mikroproben—II : Untersuchungen zur bestimmung von Ga-spuren in In und InAs und von In-spuren in Ga, GaAs und GaP durch AAS mit elektrothermischer atomisierung

The atomic-absorption determination of traces of Ga in In, P, As and InAs and of traces of In in Ga, P, As, GaAs and gap is described. The mechanism of the evaporation of the trace element according to the medium used (HCl or HNO₃) is discussed. Nitric acid medium is recommended for analytical determinations. The evaporation of the trace elements and matrices was investigated by means of absorbance vs. time curves. It is shown that a thermal fractionation of AsO³⁻₄ and PO³⁻₄ matrices and Ga and In traces is possible in the ashing step. In the case of Ga the thermal fractionation of the matrices (In³⁺, In³⁺/AsO³⁻₄) from the trace element is possible in the atomization step. The thermal fractionation of In traces from the matrices (Ga³⁺, Ga³⁺/AsO³⁻₄, Ga³⁺/Po³⁻₄) is impossible. The results and the reasons for the non-specific absorption are discussed. The absolute detection limits are Ga 45 pg, In 35 pg. The relative detection limits are 1 ppm in a 0.1 mg sample.     

Beiträge zur Chemie der Silicium–Stickstoff-Verbindungen. CXXX. Kernresonanz- und infrarotspektroskopische Untersuchungen an Methylaminosilanen

Chemistry of Silicon-Nitrogen Compounds. CXXX. N.M.R. and I.R. Spectroscopic Investigations on Methylaminosilanes The attachment of a silicon atom to methylamino groups leads in the pure compounds I to VII to a HNCH coupling constant for the protons of J = 6–7 Hz. A similar effect is also observed in solution, except in CH₂Cl₂ and CHCl₃. The correct assignment of the n.m.r. signals for IV is shown in Fig. 1. I to VII have practically the same basic properties as can be concluded from the invariable shift of the C? D stretching vibration of 35 cm^?1 for CDCl₃.     

Untersuchungen zur Physisorption und Chemisorption von Wasser auf Zinkoxid-Oberflächen

The investigation of different zinc oxide samples by means of thermogravimetry and infrared spectroscopy has shown that the surface of the samples is covered by an approximately monoatomic layer of hydroxide groups. Furthermore, varying amounts of carbonate groups are found which are due to the presence of zinc hydroxide carbonate II [Zn₅(OH)₆(CO₃)₂]. Below relative water vapour pressures of p/p₀ = 0.2 (25°C), two hydrogen bridges connect one physisorbed water molecule with two chemisorbed surface hydroxide groups. In addition, about the same amount of water is physically adsorbed between vapour pressures of p/p₀ 0.2 and 0.8. At still higher relative humidity, a multimolecular layer is built up which reaches a thickness of about 200 water molecules at p/p₀ = 1.0. All samples show in the v-OH region of the IR. spectrum a broad absorption with four bands, A, B, C, and D. The position of the bands and the change of their intensities when rising the temperature of the samples up to 600°C indicate that both bands of longer wave lengths, C and D, arise from physically adsorbed water molecules, while the bands A and B are due to hydroxide groups located on the crystallographic faces (0001) and (0001 ), respectively.