Efficient copper-mediated reactions of nitrenes derived from sulfonimidamides

[reaction: see text] Sulfonimidamides lead efficiently to nitrenes and have been converted to sulfimides, sulfoximines, and aziridines in good yields, through a copper-mediated multicomponent reaction. The stereogenic sulfur atom and the trivalent nitrogen atom present in the molecules open the way to asymmetric synthesis, whose first results are presented.     

Ligandbewegungen in űbergangsmetallkomplexen XI 1H-NMR-spektroskopische untersuchungen an acetylacetonat-bis(olefin)-rhodium(I)-komplexen

The temperature-dependent ¹H NMR spectra of acetylacetonatebis(ethylene)-rhodium, (acac)Rh(C₂H₄)₂ (I), of some related complexes containing methoxy-substituted ethylenes have been measured in toluene-d₈ solution. Both monosubstituted [(acac)Rh(C₂H₄)(olefin), olefin = tetramethoxyethylene (II), $\text{cis}$- and $\text{trans}$-dimethoxyethylene (III and IV)] and disubstituted [(acac)Rh(olefin)₂, olefin = $\text{cis}$- and $\text{trans}$-dimethoxyethylene (V and VI), methyl vinyl ether (VII)] derivatives of I have been investigated with respect to hindered intramolecular movements of the ligands. The barriers of olefin rotation increase with an increasing number of methoxy substituents. When the olefin rotation is frozen out; the methoxy substituents of the olefins tend to be turned away from the acetylacetonate ligand unless steric interaction occurs between the two π-coordinated olefins. A hindered movement of the acetylacetonate ligand has been observed in II and V. For this movement which is independent of the olefin rotation, a degenerate rearrangement is proposed of the tetragonal-planar complexes via a tetrahedral transition state.     

Synthese einiger 8-substituierter 2-Methyl-1,2,3,4-tetrahydroisochinoline

Synthesis of Some 8-Substituted 2-Methyl-1,2,3,4-tetrahydroisoquinolines A general route to 8-substituted tetrahydroisoquinolines is exemplified by the preparation of the 2-methyl-1,2,3,4-tetrahydroisoquinolin-8-ol ( 11 ), the -8-carbaldehyde oxime ( 12 ) and the -8-carbonitrile ( 13 ). It involves the conversion of isoquinoline ( 1 ) by partially modified Steps 1, 2, 3, and 5 (see the Scheme) into the 5-bromo-8-nitro derivative 5 , reduction of the latter to the 8-amino derivative 8 and replacement of the NH₂-group with an appropriate substituent by a Sandmeyer-like reaction. The selective reductions of the N-containing ring in 6 (Steps 5, 6, and 8) and of the NO₂-group in 5 (Steps 4 and 7) were also studied.     

Die Trennung des Kobalts von Nickel mit Anionenaustauschern und die photometrische Bestimmung des Kobalts als Cyanatkomplex

Zusammenfassung Die rasche Sorbierbarkeit des Kobalts als anionischem Kobalt(II)-cyanatkomplex an ruhendem oder bewegtem Austauscher Dowex 1X8 erlaubt Trennungen Kobalt/Nickel für das Verhältnis 150. Die anschließende photometrische Bestimmung des Kobalts als Cyanatkomplex bei 620 m ist bequem durchführbar, nachdem das Kobalt mit Salzsäure eluiert worden ist.Herrn Prof. Dr. O. Glemser, Direktor des Instituts, danken wir für stete Förderung der vorliegenden Untersuchungen.Dem Herrn Bundesminister für Atomkernenergie und Wasserwirtschaft, sowie der Deutschen Forschungsgemeinschaft danken wir für Unterstützung.     

Mikrogravimetrische Bestimmung von Gold als Dekamethonium-Tetrabromoaurat(III)

Zusammenfassung Die mikrogravimetrische Bestimmung von Gold als Bis(trimethyl)-dekamethylendiammoniumtetrabromoaurat(III) [(CH₃)₃N-(CH₂)₁₀-N(CH₃)₃] [AuBr₄]₂ erlaubt die Erfassung von 700g Au neben 200fachen Überschüssen an Cu²⁺ und Ni²⁺ sowie 50fachen Mengen anderer Übergangsmetalle.

---

Summary The microgravimetric determination of gold as bis-(trimethyl) decamethylenediammoniumtetrabromaurate(III) [(CH₃)₃N-(CH₂)₁₀-N(CH₃)₃] [AuBr₄]₂ permits the determination of 700g Au in the presence of 200-fold excesses of Cu²⁺ and Ni²⁺ as well as 50-fold amounts of other transition metals.

---

Résumé Le microdosage gravimétrique de l'or à l'état de tétrabromoaurate-III de bis(triméthyl)décaméthylènediammonium [(CH₃)₃N-(CH₂)₁₀-N(CH₃)₃] [AuBr₄]₂ permet de descendre jusqu'à 700g Au en présence d'un excès de 200 fois Cu²⁺ et Ni²⁺ et d'une quantité 50 fois plus grande des autres métaux de transition.

     

Synthesis of [1]benzothieno[2,3-e]pyrrolo[1,2a]pyrazines and related compounds

The synthesis of several [1]benzothieno[2,3-e]pyrrolo[1,2-a]pyrazines and other related heterocycles has been described. A study of the nmr spectra of these compounds was also reported.     

Derivatives of 1,5-diamino-1H-tetrazole: a new family of energetic heterocyclic-based salts

1,5-Diamino-1H-tetrazole (2, DAT) can easily be protonated by reaction with strong mineral acids, yielding the poorly investigated 1,5-diaminotetrazolium nitrate (2a) and perchlorate (2b). A new synthesis for 2 is introduced that avoids lead azide as a hazardous byproduct. The reaction of 1,5-diamino-1H-tetrazole with iodomethane (7a) followed by the metathesis of the iodide (7a) with silver nitrate (7b), silver dinitramide (7c), or silver azide (7d) leads to a new family of heterocyclic-based salts. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, X-ray structure determination, and initial safety testing (impact and friction sensitivity). Most of the salts exhibit good thermal stabilities, and both the perchlorate (2b) and the dinitramide (7c) have melting points well below 100 degrees C, yet high decomposition onsets, defining them as new (7c), highly energetic ionic liquids. Preliminary sensitivity testing of the crystalline compounds indicates rather low impact sensitivities for all compounds, the highest being that of the perchlorate (2b) and the dinitramide (7c) with a value of 7 J. In contrast, the friction sensitivities of the perchlorate (2b, 60 N) and the dinitramide (7c, 24 N) are relatively high. The enthalpies of combustion (Delta(c)H degrees ) of 7b-d were determined experimentally using oxygen bomb calorimetry: Delta(c)H degrees (7b) = -2456 cal g(-)(1), Delta(c)H degrees (7c) = -2135 cal g(-)(1), and Delta(c)H degrees (7d) = -3594 cal g(-)(1). The standard enthalpies of formation (Delta(f)H degrees ) of 7b-d were obtained on the basis of quantum chemical computations using the G2 (G3) method: Delta(f)H degrees (7b) = 41.7 (41.2) kcal mol(-)(1), Delta(f)H degrees (7c) = 92.1 (91.1) kcal mol(-)(1), and Delta(f)H degrees (7d) = 161.6 (161.5) kcal mol(-)(1). The detonation velocities (D) and detonation pressures (P) of 2b and 7b-d were calculated using the empirical equations of Kamlet and Jacobs: D(2b) = 8383 m s(-)(1), P(2b) = 32.2 GPa; D(7b) = 7682 m s(-)(1), P(7b) = 23.4 GPa; D(7c) = 8827 m s(-)(1), P(7c) = 33.6 GPa; and D(7d) = 7405 m s(-)(1), P(7d) = 20.8 GPa. For all compounds, a structure determination by single-crystal X-ray diffraction was performed. 2a and 2b crystallize in the monoclinic space groups C2/c and P2(1)/n, respectively. The salts of 7 crystallize in the orthorhombic space groups Pna2(1) (7a, 7d) and Fdd2 (7b). The hydrogen-bonded ring motifs are discussed in the formalism of graph-set analysis of hydrogen-bond patterns and compared in the case of 2a, 2b, and 7b.     

Pentamethylcyclopentadienyl Halfsandwich Complexes of Vanadium and Tantalum with Amido‐, Imido‐ Nitrido‐ and Azido Ligands

Lithium bis(trimethylsilyl)amide, LiN(SiMe₃)₂, reacts with Cp*V(O)Cl₂ and Cp*TaCl₄ to give trimethylsilylimido complexes such as [Cp*V(NSiMe₃)(μ‐NSiMe₃)]₂ ( 7 ) and Cp*Ta(Cl)(NSiMe₃)[N(SiMe₃)₂] ( 19 ), respectively. Substitution of the chloro ligand in 19 by anionic groups leads to complexes with 3 different N‐containing ligands, Cp*Ta(X)(NSiMe₃)[N(SiMe₃)₂] (X = N₃ ( 20 ) or NPEt₃ ( 21 )). Complex 7 is air‐ and moisture‐sensitive, and several derivatives containing oxo and trimethylsiloxy ligands have been identified. Trimethylsilyl azide, Me₃Si‐N₃, is able to replace the oxygen‐containing ligands for azido ligands. The two complete series of bis(azido)‐bridged complexes, [Cp*VCl_n(N₃)_2‐n(μ‐N₃)]₂ (n = 2, 1, 0) and [Cp*TaCl_n(N₃)_3‐n(μ‐N₃)]₂(n = 3, 2, 1, 0), are accessible from the reactions of Cp*VCl₃ and Cp*TaCl₄, respectively, with trimethylsilyl azide. A bis(nitrido)‐bridged azido‐vanadium complex, [Cp*V(N₃)(μ‐N)]₂ ( 18 ), has also been obtained and structurally characterized.     

Synthesis of [1,5]benzothiazepine derivatives

Various derivatives of 2,3-dihydro[1,5]benzothiazepin-4(5H)-ones were synthesized. Alternative route for the synthesis of 5-dimethylaminoethyl-2,3-dihydro[1,5]benzothiazepin-4(5H)-ones and 4-dimethylaminopro-poxy-(2H,5H)-[1,5]benzothiazepines are described.     

Thermal and mechanical cracking in bis(triisopropylsilylethnyl) pentacene thin films

Bis(triisopropylsilylethnyl) pentacene (TIPS pentacene) was synthesized to increase its solubility in common liquid solvents and, at the same time, enhance the π–π stacking between neighboring acenes in the crystallized state in comparison with unmodified pentacene. Hot-stage microscopy experiments revealed that during heating voids develop along the long axis of the TIPS pentacene films {along the [210] direction/parallel to the (120 ) planes} and crystals overlap along the short axis {along the [120 ] direction/parallel to the (210) planes}. From molecular mechanics simulations, the predominant twin boundaries of (120 ) and commonly observed cracking planes of (120), (120 ), and (210) had relatively low surface energies in comparison with planes with similar Miller indices. Organic thin-film transistors with TIPS pentacene as the active layer were fabricated, and the mobility values decreased from 0.4–1.0 cm²/V s before cracking to ∼0.2 cm²/V s after cracking. To maintain the high charge carrier mobility of TIPS pentacene devices, these cracks should be avoided. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3631–3641, 2006