Complexation de l'anion fluorure par des tetramines cycliques protonees.

The $\text{s}$ynthesis of the new tetraazamacrocycle [20]N₄ is briefly described; complexation of F by the fully protonated [16]N₄, [18]N₄ and [20]N₄ macrocycles is investigated.     

Action du N-bromosuccinimide sur les dioxolannes. Intermediaires réactionnels

1,3-Dioxolan-2-ylium ion intermediates formed by reaction of bromine or NBS on 4-syn-aryl-3,5-dioxa-tricyclo [5.2.1.0^2.6] décanes have been isolated. 2-Succinimido-1,3-dioxolanes have been prepared for the first time.     

Evidence for a narrow peak in Ksoπ±π+π- at 2.6 gev in 12 gev/cpp interactions

We report the evidence for a narrow charged peak (5.5 s.d.), which we suggest calling the I, in the 6-prong-V⁰ topology of $\text{p}$p interactions at 12 GeV/c. The mass, widht and the product of cross section σ_I times the branching ratio BR into the final state (K_s^oτ±τ⁺τ^? are found to be: $\text{M}{}_{\mathrm{I}}\text{=2.60 ±}\text{0.01}\text{GeV}\text{/}\text{c}{}^2$, $\text{Γ}{}_{\mathrm{I}}\text{?}\text{0.018}\text{GeV}\text{/}\text{c}{}^2$, σ_I·BR≈20 μbarn     

Experimental study on the symmetric modes of vibration of a four bolt clamped square plate

The response of structural components excited by turbulent flow noise depends on the natural resonance frequencies and displacement modes of those components. An experimental program is described which determined those resonance frequencies and modes for a flat plate clamped in the middle of its four sides and also for the case when one of the four bolts had failed. Thirty-three resonances in the range 30·5 to 736 Hz have been identified for the four-bolt normal operation and forty-two in the range 12·5 to 496·1 Hz for the three-bolt accidental situation. Of particular interest to the turbulent flow noise response, the modes symmetrical to the $\text{x-y}$ and diagonal axes have been identified and classified into a two-dimensional matrix form for the $\text{mn + nm}$ and $\text{mn - nm}$ modes combination ($\text{m}$ and $\text{n}$ being the pure modes along the $\text{x-y}$ axis).     

Olefin epoxidation followed by epoxide transformation into 1,2-dibromoalkane by a peroxonickel-dibromomolybdenum bimetallic-system

The interaction of bis(t-butylisocyano)peroxonickel(II) and bis(triphenylphosphine oxide)dibromodioxomolybdenum(VI) in the presence of cyclohexene yields 1,2-dibromocyclohexane as the main product. This result is explained by the prior epoxidation of cyclohexene, followed by its conversion into the 1,2-dibromoalkane.The epoxidation step implies peroxidation of the dioxomolybdenum by the peroxonickel species. It is shown that this occurs by a dioxygen-ligand transfer accompanied by the back transfer of two bromine atom and two triphenylphosphine oxide molecules.