Synthesis of novel fused β-lactams by intramolecular 1,3-dipolar cycloadditions.51. Triazolocephems and triazolopenams

Tricyclic triazolocephem and triazolopenam carboxylic acids have been synthesized, but only the former exhibited antibacterial activity.     

Line intensities of CO2 in the 2·7 micron region

Individual line intensities have been measured at 0·025 cm^?1 resolution and low pressures for the two strong Σ-Σ bands of C¹²O₂¹⁶ near 2.7 microns, as well as for their associated Π-Π hot-bands. Values of the rotationless dipole-moment matrix elements and vibration-rotation interaction coefficients are reported along with total band intensities. Results for the latter in cm^?2 atm^?1 at 296°K are: 25·7, 1·96, 39·3 and 3·23 for the 02⁰1-00⁰0, 03¹1-01¹0, 10⁰1-00⁰0, and 11¹1-01¹0 bands, respectively.     

The synthesis and properties of bis(μ-phenyldiazenido)octacarbonyldimanganese

Phenyldiazenidotrimethylsilane underwent reaction with bromopentacarbonylmanganese to give bis(μ-phenyldiazenido)octacarbonylmanganese. Triphenylphosphine caused fission of the phenyldiazenido bridge to form two mononuclear five coordinate complexes [Mn(CO)₃N₂Ph(PPh₃)] and [Mn(CO)₂N₂Ph-(PPh₃)₂].     

Quasi-elastic scattering due to fast oxygen diffuson in yttria stabilized zirconia

Evidence for fast oxygen diffusion at high temperatures in single crystal ZrO₂ containing 12 mol % Y₂O₃ is presented from quasi-elastic light scattering data. Lattice vacancies are responsible for the enhanced ionic diffusion and the structural disorder. In the temperature range investigated we estimate the barrier activation energy for the jumping of oxygen vacancies to be 0.25 eV. At 1500°K the jump time is ～ 4 × 10^?12 sec., the diffusion constant is ～ 3.26 × 10^?5 cm²/sec. and the conductivity is ～ 0.24 (Ωcm)^?1.     

Preparation of isomorphously substituted scandium ZSM-5 using aqueous fluoride gels

Sc-ZSM-5 zeolite is synthesised using a hydrothermal fluoride based synthesis medium and evidence, viz. XRF, NMR, XRD, TGA and FT-IR shows that scandium (Sc3+) has been isomorphously substituted into the zeolite framework.     

Entanglement and the phase transition in single-mode superradiance

We consider the entanglement properties of the quantum phase transition in the single-mode superradiance model, involving the interaction of a boson mode and an ensemble of atoms. For an infinite size system, the atom-field entanglement diverges logarithmically with the correlation length exponent. Using a continuous variable representation, we compare this to the divergence of the entropy in conformal field theories and derive an exact expression for the scaled concurrence and the cusplike nonanalyticity of the momentum squeezing.     

Synthesis of the core structure of the fungal metabolite benesudon: use of oxidative decarboxylation

[chemical reaction: see text]. The core structure (5) of the fungal metabolite benesudon (1) was synthesized, the key step being oxidative decarboxylation of acid 17.