Étude thermodynamique de la complexation de l'argent par la pipéridine et ses dérivés méthylés

Enthalpies of silver complexes formation with piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine and 2,6-dimethylpiperidine are determined at 25°C by means of direct calorimetry, in aqueous medium with 0.5 M KNO₃ as a constant ionic strength.Free energies from a previous work and corresponding entropies are also given in this paper.All the thermodynamic functions are discussed in relation to the substituent position. Particularly, a linear relationship is found between complexation enthalpies and proton ionization enthalpies already determined in a previous study.     

Boronates allyliques,alleniques et propargyliques: Preparations et proprietes

An easy synthesis of linear cyclic 2-unsaturated boronates via organometallic reagents has been achieved. The final structure of the carbon framework is related to the tetracoordinated intermediate. Intermolecular rearrangement, disproportionation and reactions with carbonyl compounds have been studied.     

Complexation metallique des imides. I. Grandeurs thermodynamiques de formation des complexes de Ag(I), Cd(II), NI(II), Cu(II) avec la succinimide

Thermodynamic values for the formation of Ag⁺, Cd²⁺, Ni²⁺ and Cu²⁺ complexes with succinimide were determined at 25°C in aqueous medium 0.5 M KNO₃. The stability constants were calculated from pH metric measurements and the related enthalpies from direct calorimetric determinations. An interpretation of the results is given, based on the character of the established bonds.     

Die Photooxidation von Polypropylen-Monofilamenten. II. Physikalische Ver?nderungen und Mikrostruktur

Ohne Zusammenfassung     

Monophotonically UV excited delayed luminescence in rigid solutions of aromatic amines

During a study of neutralization luminescence following photoionization of aromatic solutes in rigid organic glasses, a new type of long-lived luminescence has been observed simultaneously with the well-known neutralization luminescence following biphotonic ionization. It has been extensively studied for tetramethyl-p-phenylenediamine in methylcyclohexane or ethanol: it is one-photon excited but differs from the ordinary luminescence by the emission spectrum (λ_max 430 nm compared to λ_{max f.} 395 nm and λ_{max ph.} 490 nm in ethanol) and by the excitation spectrum, the present luminescence being observed only for short wavelength excitation. Finally the lifetime (of the order of seconds) depends on experimental conditions. Other solid and liquid phase studies suggest that the precursor of this new luminescence is a solute-solvent charge transfer state.     

Remarques sur la cinétique de l'oxydation à l'air du monoxyde de titane

Thermogravimetric results on the oxidation of TiO by air obtained by one of the authors (M. J. Blais) and untimely exploited by Garnaud¹ are placed in bibliographical outline, described more in detail and carefully rediscussed.     

Control and tomography of a three level superconducting artificial atom

A number of superconducting qubits, such as the transmon or the phase qubit, have an energy level structure with small anharmonicity. This allows for convenient access of higher excited states with similar frequencies. However, special care has to be taken to avoid unwanted higher-level populations when using short control pulses. Here we demonstrate the preparation of arbitrary three level superposition states using optimal control techniques in a transmon. Performing dispersive readout, we extract the populations of all three levels of the qutrit and study the coherence of its excited states. Finally we demonstrate full quantum state tomography of the prepared qutrit states and evaluate the fidelities of a set of states, finding on average 95%.     

Mutation Classes of Skew-Symmetric 3 × 3-Matrices

In this article, we establish a bijection between the set of mutation classes of mutation-cyclic skew-symmetric integral 3 × 3-matrices and the set of triples of integers (a, b, c) such that 2 ≤ a ≤ b ≤ c and ab ≥ c. We also give an algorithm allowing to verify whether a matrix is mutation-cyclic or not. We prove that given a, b, the two cases depend on whether c is large enough or not.     

Mass spectroscopic observation of shock-induced chemistry in liquid CS2

We have observed, via time-of-flight mass spectrometry, 13 chemical species more massive than CS2 produced by shocking liquid CS2 to very high pressure/temperature. The stoichiometry of three of these species is uniquely determined from the 12CS2 experiments; these species are C2S2, C3S2, and C4S2. The stoichiometry of the other 10 structures cannot be uniquely determined from 12CS2 experiments. However, by redoing the experiments using isotopically labeled CS2 (i.e., 13CS2), we determined the stoichiometry of nine of the remaining structures. The nine structures are Sn (n = 3-8) and CS3, C2S5, and C4S6. A structure with mass 297.1 amu was also observed in the 12CS2 experiments but was not detected in the 13CS2 experiments. This structure must be C6S7, C14S4, or C22S; given the low carbon content of the other observed carbon species, it is probably C6S7. The shockwaves to which the CS2 molecules were subjected were produced by the detonation of high mass-density solid explosives. The explosives used were either a plastic bonded form of cyclotetramethlylene tetranitramine or pure hexanitrostilbene. Numerical compressible fluid-mechanical simulations were done to estimate the pressures, temperatures, and time scales of the processes that occurred in the shocked CS2. The results obtained in the present experiments are related to earlier work on CS2's chemical reactivity that used both shockwave methods and static techniques to produce very high pressure.