Kristallstruktur von Trisilber(I)amidosulfat-3-Ammoniak-2-Wasser,Ag3SO3N · 3NH3 · 2H2O

An X-ray crystal structure analysis of colourless Ag₃SO₃N · 3NH₃ · 2H₂O was carried out at room temperature:M=504.79, orthorhombic, P2₁2₁2₁,a=6.275 (1) Å,b=11.826 (2) Å,c=14.299 (12) Å,V=1061.10 ų,Z=4,d _x=3.160 Mgm^–3,F(000)=940, Mo K, =0.71069 Å (graphite monochromator), =5.60 mm^–1,R=4.71%,R _w=4.96% (982 reflections, 120 parameters). The structure consists of Ag ribbons; each Ag atom is linearly co-ordinated to two N atoms with distances corresponding to covalent Ag-N bonds; no Ag-O coordination is observed; the N atom of the SO₃N group is surrounded by three Ag atoms; compared to amidosulfuric acid, the SO₃N group shows significant deformation.

     

Trifluormethyl-schwefel-stickstoff-verbindungen. IX. Trifluormethansulfonamide

Trifluoromethanesulphonamide forms the following salts: CF₃SO₂NAg₂·NH₃, CF₃SO₂NAg₂, (CF₃SO₂NH)₂Hg and CF₃SO₂NH·NH₄. These salts are more reactive than the initial amide. CF₃SCl reacts with both silver salts to give the corresponding mono- and di-substituted derivatives, CF₃SO₂N(SCF₃)₂ and CF₃SO₂NHSCF₃, respectively. With phosgene and thiophosgene, CF₃SO₂NAg₂ reacts to give the pseudohalides CF₃SO₂NCO and CF₃SO₂NCS, respectively.     

Untersuchungen über Perylen und seine Derivate

Ohne Zusammenfassung     

Dihydrodiazepine aus valenzisomeren diazatricyclo[3.2.0.0.2,4]Heptanen1)

Cycloaddition of diazoalkanes to diazabicyclo[2.2.0]hexenes and subsequent extrusion of nitrogen afford diazatricyclo[3.2.0.0^2,4]heptanes that are easily valence isomerized to novel dihydrodiazepines.     

Probing the limit of weak host-guest interactions: insertion compounds of mercury(II) halides with microporous SiO(2) hosts

Mercury(II) halides HgX(2) (X=Cl, Br, I) were inserted into the voids of the crystalline microporous SiO(2) modifications deca-dodecasil 3R (short term: DDR), silica-theta-1 (TON), silica-ferrierite (FER) and silicalite-1 (MFI) by vapour phase loading. The properties of the occluded guest species were studied by X-ray absorption spectroscopy (X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analysis), UV/Vis spectroscopy, and IR and Raman spectroscopy. The methods reveal the presence of HgX(2) molecules in the insertion compounds. The interactions between these electroneutral guest molecules and the electroneutral surrounding SiO(2) framework are weak. In addition, no indication of any significant guest-guest interaction between the embedded molecules was found, in contrast to the analogous iodine insertion compounds, where these become more important with increasing pore dimensionality (G. Wirnsberger et al., Angew. Chem. 1996, 108, 2951-2953; Angew. Chem. Int. Ed. Engl. 1996, 35, 2777). Analysis of the HgL(3) EXAFS confirms a coordination number of two for Hg and gives HgX bond lengths of 2.26 +/- 0.02, 2.38 +/- 0.02 and 2.57 +/- 0.02 A for the trapped HgCl(2), HgBr(2) and HgI(2) molecules, respectively. These values are very close to those of the corresponding molecules in the vapour phase and are the shortest determined for HgX(2) molecules in solid-state compounds to date (a comparably short distance only appears in the recently reported [Cu(2-pyrazinecarboxylato)(2)HgI(2)] x HgI(2) with d(Hg[bond]I)=2.577(2) A; Dong et al., Angew. Chem. 2000, 112, 4441-4443; Angew. Chem. Int. Ed. 2000, 39, 4271). Thus, there emerges a picture of almost unperturbed HgX(2) molecules, similar to those in the vapour phase or in non-coordinating solvents, in a solid crystalline matrix of high temperature stability, a very unusual state of matter. Despite the weakness of the host-guest interactions, investigations on small crystallites of the HgX(2)-TON composites using a Raman microscope show a strong polarization dependence, providing evidence for an orientational alignment of the HgX(2) molecules inside the one-dimensional pore system of this host. For these reasons, the host matrices used in this study can be viewed as orienting solid solvents, coordinating only very weakly to the inserted HgX(2) guest molecules, but exhibiting a strong geometrical template function for their alignment. The concept of using electroneutral SiO(2) modifications as host components for a modular construction of new host-guest compounds thus allows the designed construction of ordered guest assemblies, with the pore systems of the rigid host matrices acting as space-confining and ordering templates for the guest components.     

Darstellung und thermolyse von hexakis(perfluororganylthio/seleno)ethanen

Thiocarbonylcompounds such as 1a, 1b, 1c, 1d, 1e and 1f were prepared and irradiated with UV- light in hexane solution. The products obtained in this photolyses are 3a, 3b and 3c. Only 3c dissociates in the temperature range 140-190° reversible to 2c. The others, 3a and 3b, decompose yielding bis(trifluoromethyl)diselenide, 6b and 6d, without forming the corresponding methyl radical 2a and 2b. This was proved by spin-trapping experiments utilizing phenyl-t-butylnitrone. Attempts to prepare 3e were unsuccessful but led to the new compounds 7a, 7b, 7c, 1,1,1-tris(trifluoromethylseleno)ethan (7d) and, surprisingly, 9. Physical and spectroscopic data of the newly prepared substances are provided.     

Molybdenum Alkylidyne Complexes with Tripodal Silanolate Ligands: The Next Generation of Alkyne Metathesis Catalysts

A new type of molybdenum alkylidyne catalysts for alkyne metathesis is described, which is distinguished by an unconventional podand topology. These structurally well‐defined complexes are easy to make on scale and proved to be tolerant toward numerous functional groups; even certain protic substituents were found to be compatible. The new catalysts were characterized by X‐ray crystallography and by spectroscopic means, including ⁹⁵Mo NMR.