Fluorescence Properties of Frog Skeletal Muscles Treated with Lanthanide Ions

Laser-induced fluorescence from frog skeletal muscle fibers treated with lanthanides, Eu³⁺ and Tb³⁺, was recorded. The fluorescence was weak and overlapped with the Raman scattering by the Ringer solution when the muscle fibers were illuminated with an argon-ion laser. The fluorescence decay rate of the lanthanide in Ringer's solution was 2–3 times larger than that of the lanthanide bound to the muscle fiber. The number of water molecules coordinated to the lanthanide bound to the muscle fiber was determined to be about three. This suggests that lanthanide ions bind superficially to the outer membrane of the muscle fiber.     

Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes

The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe₃)₂]₃(μ-Cl)Li (THF)₃ as the catalysts, it was found a broad range of aromatic amines and esters were efficiently converted into various amides in good yields under mild conditions. A plausible mechanism for this transformation was experimentally supported as starting from an amide exchange reaction between the lanthanide tris (amide) complex and the substrate amine.     

Exceptionally Plastic/Elastic Organic Crystals of a Naphthalidenimine-Boron Complex Show Flexible Optical Waveguide Properties

The design of molecular compounds that exhibit flexibility is an emerging area of research. Although a fair amount of success has been achieved in the design of plastic or elastic crystals, realizing multidimensional plastic and elastic bending remains challenging. We report herein a naphthalidenimine–boron complex that showed size-dependent dual mechanical bending behavior whereas its parent Schiff base was brittle. Detailed crystallographic and spectroscopic analysis revealed the importance of boron in imparting the interesting mechanical properties. Furthermore, the luminescence of the molecule was turned-on subsequent to boron complexation, thereby allowing it to be explored for multimode optical waveguide applications. Our in-depth study of the size-dependent plastic and elastic bending of the crystals thus provides important insights in molecular engineering and could act as a platform for the development of future smart flexible materials for optoelectronic applications.     

Interaction of modulated pulses in nonlinear oscillator chains

We formally derive and rigorously justify the modulation equations of lowest order for the interaction of two modulated pulses on a one-dimensional nonlinear oscillator chain. We show that solutions with the initial form of the assumed ansatz preserve this form over time intervals with positive macroscopic length, and we show a bound on the possible shift of the envelope caused by the interaction. Thus, we rigorously justify and quantify the statement that under the given conditions there is almost no interaction of the modulated pulses.     

Direct Proof of Determinant Representation for Scalar Products of the XXZ Gaudin Model with Generic Non-Diagonal Boundary Terms

After constructing the Bethe state of the XXZ Gaudin model with generic non-diagonal boundary terms,we analyze the properties of this state and obtain the determinant representations of the scalar products for this XXZ Gaudin model.     

Cationic Lanthanide Luminescent Copolymer: Design,Synthesis and Interaction with DNA

Polymerizable rare earth complex Eu(AA)₃Phen was synthesized by complexion of europium ion, acrylic acid (AA), and 1,10-phenanthroline (Phen). The structure and fluorescence properties of the complex were studied by elemental analysis, ¹H-NMR spectroscopy, and fluorescence spectroscopy. Eu-containing copolymer poly(PEGMA-co-MMA-co-METAC-co-Eu(AA)₃Phen) (PPMMEu) was then synthesized by free radical copolymerization of Eu(AA)₃Phen and other functional monomers including poly(ethylene glycol) methyl ether methacrylate (PEGMA) and [2-(Methacryloyloxy) ethyl] trimethylammonium chloride (METAC). ¹H-NMR spectroscopy and fluorescence spectroscopy were used to characterize the copolymer and the interactions between the copolymer and DNA was investigated by TEM, fluorescence spectroscopy, and agarose gel electrophoresis. The desired luminescent cationic copolymer was successfully obtained. The copolymer can form micelles in water solution and can efficiently bind to DNA molecules through electrostatic interaction. The results suggest the potential use of PPMMEu in bioprobes and gene vectors.     

Complexation of M3+ Lanthanide Cations by Calix[4]arene-CMPO Ligands: A Molecular Dynamics Study in Methanol Solution and at a Water/Chloroform Interface

Abstract

We report a molecular dynamics study on the 1:1 M³⁺ lanthanide (La³⁺, Eu³⁺ and Yb³⁺) inclusion complexes of an important extractant molecule L: a calix[4]arene-tetraalkyl ether substituted at the wide rim by four NH-C(O)-CH₂-P(O)Ph₂ arms. The M(NO₃)₃ and MCl₃ complexes of L are compared in methanol solution and at a water / chloroform interface. In the different environments the coordination sphere of M³⁺ involves the four phosphoryl oxygens and three to four loosely bound carbonyl oxygens of the CMPO-like arms. Based on free energy simulations, we address the question of ion binding selectivity in pure liquid phases and at the liquid-liquid interface where L and the complexes are found to adsorb. According to the simulations, the enhancement of M³⁺ cation extraction in the presence of the calixarene platform, examined by comparing L to the (CMPO)₄ “ligand” at the interface, is related to the fact that (i) the (CMPO)₄Eu(NO₃)₃ complex is more hydrophilic than the LEu(NO₃) one and (ii) the free CMPO ligands spread at the interface, and are therefore less organized for cation capture than L.