1,4‐Bis[(1‐methyl‐1‐phenylethyl)peroxymethyl]benzene

The title compound, C₂₆H₃₀O₄, is one of the first alkyl bis‐peroxides to be structurally characterized. The mol­ecule lies on a centre of inversion and therefore the terminal phenyl rings are parallel. Although there are three aromatic rings in the mol­ecule, the C—O—O—C torsion angle of 163.10 (10)° is close to the value found in Me₃COOCMe₃.     

The chemical behaviour of di(2-pyridyl)sulphide,dps. Crystal and molecular structure of μ-di(2-pyridyl)sulphidebis(trans-dichlorotriethylphosphine platinum(II)), [{Pt(PEt3)Cl2}2μ-dps] and its reactivity towards stannylated species

The coordinating ability of the ligand di(2-pyridyl)sulphide, dps, was studied in several situations. Dps behaved as a bidentate chelating agent with SnX4 (X=Cl or Br) and also with Pd and Pt (PdCl2 and K2PtCl4), whereas with [Pt2(PR3)2Cl4], (R = Et or Ph), it formed bridging complexes: [{Pt(PR3)Cl2}2-dps]. The crystal and molecular structure of [{Pt(PEt3)Cl2}2-dps] was determined. This complex, as well as [M(dps)Cl2], (M = Pd or Pt), underwent reactions with SnCl2, which inserts into the M–Cl bonds producing heterobimetallic products, which are important in catalysis.     

N(B(NMe2)2)(Si(NMe2)3)(Ti(NMe2)3), [N(Si(NMe2)3)(Ti(NMe2)2)]2 und N(SiMe3)(Si(NMe2)3)(Ti(NMe2)3) — Synthese und Charakterisierung neuer molekularer Einkomponentenvorläufer für nitridische und carbonitridische Keramiken

N(B(NMe₂)₂)(Si(NMe₂)₃) (Ti(NMe₂)₃), [N(Si(NMe₂)₃)(Ti(NMe₂)₂)]₂ und N(SiMe₃)(Si(NMe₂)₃)(Ti(NMe₂)₃) — Synthesis and Characterization of New Molecular Single-source Precursors for Nitride and Carbonitride Ceramics Synthesis and spectroscopic data of the title compounds are reported. [N(Si(NMe₂)₃)(Ti(NMe₂)₂)]₂ crystallizes in the space group P1 , a = 8.406(7), b = 10.673(8), c = 10.872(6) Å, α = 68.45(4)°, β = 71.72(4)°, γ = 78.11(7)°, 2 877 diffractometer data (F_o ? 2σF_o), R = 0.051. The compound is characterized by a planar four-membered Ti₂N₂-ring with exocyclic tris(dimethylamino)silyl substituents attached to the nitrogen atoms of the ring.     

Metal-oxide interfacial reactions: encapsulation of Pd on TiO2 (110)

The model system Pd/TiO2 (110) was used to evaluate the correlation between metal encapsulation and electronic structure of TiO2 crystals. We observed encapsulation of Pd clusters supported on TiO2 crystals, which were heavily Ar+ sputtered, Nb-doped, or reduced by vacuum annealing. In contrast, encapsulation was not observed on unreduced, undoped, or slightly sputtered TiO2 crystals. Our results indicate a strong dependence of the encapsulation process on the electron density in the conduction band of TiO2 and on the space charge formed at Pd/TiO2 interfaces. This behavior is controlled by the initial position of the Fermi energy level (EF) of the metal and the oxide before contact is established. We proved that encapsulation reactions are favored by n-type doping of the oxide and a large work function of the metal. On the basis of this mechanism, we conclude on general trends controlling encapsulation reactions of oxide-supported metal clusters and the strong metal-support interaction (SMSI).     

Silacarbocycles from ring expansion

Ring enlargement of silicon heterocycles is accomplished from derivatives which contain an exocyclic chloromethyl substituent by reaction with aluminum halide catalyst or with potassium fluoride. Tricyclic derivatives with a silicon atom in a central five-, six-, or seven-membered ring form silins, silepins and silocins, respectively, and are isolated by quenching the product chlorosilanes with H₂O, MeOH, Na/MeOH, LiAlH₄, MeMgBr or MeLi. A stoichiometric quantity of fluoride ion also results in conversion of 9-chloromethyl-9-silaanthracene to 5-fluoro-dibenzo[b,e] silepin but the percent conversion of the 9-iodomethyl precursor is higher. The limitations of the two methods are discussed briefly.     

Betrachtungen zur Kinetik und zum Mechanismus der Auflösung von Metalloxiden in sauren Lösungen

Ohne Zusammenfassung