1,2,3-Triazolo[1,5-c]pyrimidine,a novel heterocycle in the polyazaindolizine series

The synthesis and struetural properties of the novel heterocycle 1,2,3-triazolo[1,5-c]pyrimidine are described. No evidence of a triazole-diazoalkylideneazine valence tautomerism process was observed at room temperature.     

First lanthanide dipolar complexes for second-order nonlinear optics

New push-pull NLO-phores based on lanthanide complexes (Ln = La, Gd, Dy, Yb) featuring an annelated dibutylaminophenyl functionalised terpyridyl ligand have been synthesised and shown to exhibit large first-order hyperpolarizability.     

Femtosecond Spectroscopy and Nonlinear Optical Properties of aza-BODIPY Derivatives in Solution

The fast relaxation processes in the excited electronic states of functionalized aza-boron-dipyrromethene (aza-BODIPY) derivatives ( 1 – 4 ) were investigated in liquid media at room temperature, including the linear photophysical, photochemical, and nonlinear optical (NLO) properties. Optical gain was revealed for nonfluorescent derivatives 3 and 4 in the near infrared (NIR) spectral range under femtosecond excitation. The values of two-photon absorption (2PA) and excited-state absorption (ESA) cross-sections were obtained for 1–4 in dichloromethane using femtosecond Z-scans, and the role of bromine substituents in the molecular structures of 2 and 4 is discussed. The nature of the excited states involved in electronic transitions of these dyes was investigated using quantum-chemical TD-DFT calculations, and the obtained spectral parameters are in reasonable agreement with the experimental data. Significant 2PA (maxima cross-sections ∼2000 GM), and large ESA cross-sections ∼10⁻²⁰ m² of these new aza-BODIPY derivatives 1–4 along with their measured high photostability reveal their potential for photonic applications in general and optical limiting in particular.     

Boundary Integral Equations Method for the Analysis of Acoustic Scattering from Line-2 Elastic Targets

The prediction of the acoustic scattering from elastic structures is a recurrent problem of practical importance as, for example, in underwater detection and target identification. We aim at setting out the diffraction problem of a transient acoustic wave by an axisymmetric shell composed of a cylinder bounded by hemispherical endcaps, called Line-2. Its time-dependent response is expanded in terms of the resonance modes of the fluid-loaded structure. The latter are well suited when the structure is submerged in a heavy fluid: it is an alternative to modal methods whose expansions as series of natural modes of the in vacuo shell are much better for describing the interaction between a structure and a light fluid. The resonance frequencies are defined as solutions of the nonlinear eigenvalue problem described by the set of homogeneous equations governing the structure displacement coupled to the acoustic radiated pressure. The resonance modes of the coupled system are the corresponding eigenvectors. Both hemisphere and cylinder equations are modeled by the approximation of Donnel and Mushtari which governs thin shells oscillations. The modeling of the sound pressure by a hybrid potential integral representation leads to a system of integro-differential equations defined on the surface of the structure only (boundary integral equations). The unknowns, the hybrid potential density as well as the shell displacement vector, are developed into Fourier series with respect to the natural cylindrical coordinate. Each angular component of the unknown functions is then expanded as series of Legendre polynomials, the coefficients of which are calculated thanks to a Galerkin method derived from the energetic form of the equations. The whole method can also be applied to predict the response of the coupled structure to a harmonic or a random excitation. This revised version was published online in July 2006 with corrections to the Cover Date.     

The future of the cern ad infrastructures in the context of elena machine design and integration

ELENA will lower the energy of AD antiprotons from 5MeV to 100keV, thus increasing by a factor of up to 100 the number of antiprotons usable by the experiments (Oelert et al. 2014). The AD infrastructures must be adapted to cope with another 20 years of low energy antiproton physics. To fit the ELENA ring in the already crowded AD hall, old kicker generators must be relocated to a new technical building, existing and new services and racks must be re-arranged also at height, preserving access and maintenance capabilities. The ELENA beam will be delivered to existing experiments via new transfer lines without compromising the possibility to maintain a visitors path to this very popular place at CERN. New experimental areas being designed to house new experiments (GBAR, BASE), and re-arrangement for future experiments (cleaning rooms relocation in the new technical building, control rooms in a separate building with a cafeteria and a conference room) are also detailed.     

d-f heterobimetallic association between ytterbium and ruthenium carbon-rich complexes: redox commutation of near-IR luminescence

We describe how the association between an ytterbium ion and a ruthenium carbon-rich complex enables the first switching of the near-IR Yb(III) luminescence by taking advantage of the redox commutation of the carbon-rich antenna.     

Cationic Biphotonic Lanthanide Luminescent Bioprobes Based on Functionalized Cross-Bridged Cyclam Macrocycles

Cationic lanthanide complexes are generally able to spontaneously internalize into living cells. Following our previous works based on a diMe-cyclen framework, a second generation of cationic water-soluble lanthanide complexes based on a constrained cross-bridged cyclam macrocycle functionalized with donor-π-conjugated picolinate antennas was prepared with europium(III) and ytterbium(III). Their spectroscopic properties were thoroughly investigated in various solvents and rationalized with the help of DFT calculations. A significant improvement was observed in the case of the Eu³⁺ complex, while the Yb³⁺ analogue conserved photophysical properties in aqueous solvent. Two-photon (2P) microscopy imaging experiments on living T24 human cancer cells confirmed the spontaneous internalization of the probes and images with good signal-to-noise ratio were obtained in the classic NIR-to-visible configuration with the Eu³⁺ luminescent bioprobe and in the NIR-to-NIR with the Yb³⁺ one.     

Comparative Analysis of Conjugated Alkynyl Chromophore–Triazacyclononane Ligands for Sensitized Emission of Europium and Terbium

A series of europium and terbium complexes based on a functionalized triazacyclononane carboxylate or phosphinate macrocyclic ligand is described. The influence of the anionic group, that is, carboxylate, methylphosphinate, or phenylphosphinate, on the photophysical properties was studied and rationalized on the basis of DFT calculated structures. The nature, number, and position of electron‐donating or electron‐withdrawing aryl substituents were varied systematically within the same phenylethynyl scaffold in order to optimize the brightness of the corresponding europium complexes and investigate their two‐photon absorption properties. Finally, the europium complexes were examined in cell‐imaging applications, and selected terbium complexes were studied as potential oxygen sensors.     

New neutrino experiments

Following incredible recent progress in understanding neutrino oscillations, many new ambitious experiments are being planned to study neutrino properties. The most important may be to find a non-zero value of θ₁₃. The most promising way to do this appears to be to measurev _μ →v _e oscillations with anE/L near Δm _atmo ² . Future neutrino experiments are great.