1,5-dimethyl-2,3,3,4-tetrachloro-1,5,2,4-diazadiphosphorinan-6-one and some derivatives. Part II

The title compound 1 was allowed to react with catechol, 2,3-dihydroxynaphthalene, tetrabromocatechol, resorcinol, saligenin, and 3,5-di-tert-butylcatechol in the presence of triethylamine to form compounds 4a–4d and 4f. Whereas the catechol derivative 4a, the naphthol derivative 4b, and the tetrabromocatechol derivative 4c could be readily obtained, the saligenin derivative 4d and the 3,5-di-tert-butylcatechol derivative 4f were found to be stable only in solution. Contrary to expectation, compound 4e was not formed in the reaction of 1 with resorcinol. The reaction of 1 with 1,2,4,5-tetrahydroxybenzene led to the pentacyclic derivative 4g. Reaction of hydroquinone with 1 led to the formation of the dimeric structure 4h. Crystal structure analyses of 4a and 4b show that the nine-membered rings adopt essentially identical “tub” conformations in which the P and O atoms are coplanar. The P-C-P angles (across the CCl₂ bridge) are wide (ca. 119°). © 1997 John Wiley & Sons, Inc.     

Fused tricyclic phosphiranes--analysis of phosphorus chemical shieldings

1,2-Addition of transient W(CO)(5)-complexed phosphinidenes exo to hexamethyl Dewar benzene affords the novel 3-phosphatricyclo[3.2.0.0(2,4)]hept-6-ene complexes. The fused tricyclic phosphiranes are obtained as both the Z and the thermally less stable E isomers, the (31)P NMR chemical shifts of which differ by about 60 ppm. A computational investigation shows that the phosphorus pyramidalization and the presence of the gamma double bond are responsible for this effect. The semiquantitative results contribute to a more systematic understanding of the structural influences on (31)P chemical shieldings. The congested double bond of the Z isomer can be epoxidized with m-chloroperbenzoic acid (MCPBA) to afford a fused tetracyclic P,O bis-adduct.     

Photoemission and electronic structure of crystalline Co3B and amorphous Co - P - B

We present an XPS and UPS study of crystalline Co, Co₃B and Co₇₈P₁₄B₈ glassy metal. For Co₃B the electronic distribution curves (EDC) of the valence band and the previous specific heat and magnetic results are interpreted in a qualitative model where : i) the s-p cobalt-boron bonding states lie in the low part of the band, the upper levels being mainly cobalt d states and ii) a large density of states of the majority spin band is present at the Fermi level. For amorphous Co₇₈P₁₄B₈ the EDC shows that E_F is located in a high density of states region, it is suggested that the phosphorus p states ae centred at 7.5 eV. The photoemission and the magnetic results can be also interpreted in the framework of the previous model.     

Fluordiazadiphosphetidine, 24. Mitt.: Reaktion monosubstituierter Fluordiazadiphosphetidine mit Kaliumfluorid/Kronenether

Summary The reactivity of some monosubstituted fluorodiazadiphosphetidines towards potassium fluoride utilizing 18-crown-6-ether as a phase transfer catalyst has been studied. The following compounds were investigated: 2,2,2,4,4-pentafluoro-4-methoxy-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, 2,2,2,4,4-pentafluoro-4-methylamino-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, 2,2,2,4,4-pentafluoro-4-methylthio-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, and a 1:1 mixture of 2,2,2,4,4-pentafluoro-4-(N²,N²-dimentyl-hydrazino)-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine and 2,2,2,4,4-pentafluoro-4-methylamino-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine. All reactions proceeded in a similar way and led to the disubstituted derivates of the starting materials and the potassium salt K₂(CH₃NPF₄)₂. In this way 2,2,4,4-tetrafluoro-2-methylamino-4-(N²,N²-dimethylhydrazino)-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine has been synthesized for the first time and a new way has been found for the synthesis of several compounds reported in literature.

Verstorben     

f-State occupancy at the gamma-alpha phase transition of Ce-Th and Ce-Sc alloys

Resonant inelastic x-ray scattering spectra were measured for a series of Ce solid solutions (Ce-Th and Ce-Sc) across the gamma-alpha phase transition. They reveal a well-defined feature associated with the 4f2 configuration when the incident energy is tuned to the Ce L3 preedge region. This component is normally hidden in x-ray absorption spectra because of lifetime broadening. The f1/f2 ratio estimated by resonant inelastic x-ray scattering presents a sharp drop across the gamma-alpha transition and hysteresis as a function of temperature that closely resemble the magnetization loop. These measurements confirm recent dynamical mean-field theory calculations that unexpectedly predict significant double occupancy of f orbitals in the ground state.