Nuclear spin-lattice and nuclear spin-spin relaxation time measurements in EuB6 at low temperatures using the spin-echo technique

Experimental results on the nuclear spin-lattice and nuclear spin-spin relaxation times in the ferromagnetic EuB₆ at temperatures below 4·2 K are presented using the external magnetic field,H _ext, in the range of 0 ⩽H _ext ⩽ 10 kG. Nuclear spin-spin relaxation time computed on the basis of the Suhl-Nakamura process turns out to be 3·2μs, which compares well with the experimental value 11·1μs obtained with the 10 kG magnetic field at 1·7 K. It is found that in the ferromagnetic EuB₆,T ₁ is approximately 5 × 10³ times larger thanT ₂ at 1·7 K with the 10 kG magnetic field. Thus the effect ofT ₁ onT ₂ can be neglected. From the experimental value ofT ₂, the value of the homogeneous line broadening is found to be 14 kHz. The corresponding value obtained from the cw method is 175 kHz. This evidently shows the presence of the inhomogeneous line broadening in the cw NMR.     

Chiral self-discrimination in a M3L2 subphthalocyanine cage

A tris(3-pyridyl)-substituted C3 symmetric subphthalocyanine (SubPc) was dimerized into a M3L2 cage in the presence of a stoichiometric amount of (en)Pd(NO3)2. NMR studies demonstrated the recognition event to be accompanied by chiral self-discrimination between the two enantiomers of the SubPc. Moreover, the specificity is such that only one of four possible isomers was detected in solution.     

Non-aqueous capillary electrophoresis using non-dissociating solvents. Application to the separation of highly hydrophobic oligomers

The application of non-aqueous capillary electrophoresis for the separation of very hydrophobic oligomers has been studied. N-Phenylaniline oligomers having degrees of polymerisation (n) of 2, 4, 6, and 8 were taken as model compounds. Capillary electrophoresis could be performed using a mixture of non-aqueous solvents with a high percentage of solvents with a low dielectric constant. These solvents, such as tetrahydrofuran (THF), chloroform or dichloromethane, are needed to solubilise the hydrophobic solutes in the electrolyte. The composition of the solvent mixture and the nature of the acid added to the electrolyte, which is needed to obtain electrophoretic motion of the N-phenylaniline oligomers, are discussed in detail. Next, other parameters such as ionic strength, injection time, electric field, and temperature were investigated too and their influence on the separation is discussed as well. The existence of a reversed (anodic) electroosmotic flow in a fused-silica capillary containing a THF-methanol mixture under acidic conditions is reported.     

A generalization of the QD algorithm

A new algorithm for the rational Hermite interpolation table is described. This algorithm reduces to the qd algorithm of Rutishauser in the Padé case. Moreover it shares several properties with Rutishauser's algorithm.     

Accelerating charge transfer in a triphenylamine-subphthalocyanine donor-acceptor system

We have designed, synthesized and probed a dodecafluoro-subphthalocyaninato boron(III) unit, which bears a triphenylamine moiety in its axial position, as a novel electron donor-acceptor system.     

Phthalocyanines: old dyes, new materials. Putting color in nanotechnology

Phthalocyanines are versatile building blocks for fabricating materials at the nanometer scale. These colored macrocycles exhibit fascinating physical properties which arise from their delocalized pi-electronic structure. This article describes why these molecules are targets for different scientific purposes and technological applications.     

Mechanics of bundled semiflexible polymer networks

While actin bundles are used by living cells for structural fortification, the microscopic origin of the elasticity of bundled networks is not understood. Here, we show that above a critical concentration of the actin binding protein fascin, a solution of actin filaments organizes into a pure network of bundles. While the elasticity of weakly cross-linked networks is dominated by the affine deformation of tubes, the network of bundles can be fully understood in terms of nonaffine bending undulations.     

Towards enhancing light harvesting-subphthalocyanines as electron acceptors

One carbon atom is too many. Two subphthalocyanine-extended TTF electron donor-acceptor conjugates were synthesized and characterized. Their photophysical properties prompt the remarkable impact that one extra carbon between the two constitutents exerts on photoinduced processes, that is, charge recombination dynamics in the normal versus inverted region.