Synthesis and magnetic properties of liquid crystalline lanthanide complexes with alkylsulfate counterions

The reaction of Schiff"s base L with lanthanide alkylsulfates affords liquid crystalline complexes with the general formula L₃Ln(C_nH_2n+1OSO₃)₃. The liquid crystalline structure and magnetic properties are studied by polarization thermal microscopy, differential scanning calorimetry, X-ray diffraction, and measurement of magnetic susceptibility. The temperatures of the existence of the mesophase and magnetic anisotropy of the complexes with the same lanthanide depend on the chain length of the alkyl fragment in the sulfate anion.     

Luminescent lanthanide complexes with liquid crystalline properties

Lewis-base adducts of tris( β-diketonato)lanthanide(III) complexes were prepared, where the β-diketone is para -alkoxy-substituted 1,3-diphenyl-1,3-propanedione. These compounds are the first examples of liquid crystalline lanthanide complexes in which the mesomorphism is introduced via a β-diketonate ligand. Depending on the type of the Lewis base, the metallomesogens exhibit a monotropic smectic A or a monotropic highly ordered smectic phase. Intense photoluminescence was observed for the europium(III) complexes at room temperature.     

Formation of lanthanide ion networks by orientation of the mesophases of their complexes in magnetic fields

A complex of a Tm(III) perfluoroalkylsulsphate with salicylaldimine Schiff's base was synthesized and its liquid crystallinity characterized by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. An additional phase transition was detected. 2D or 3D anisotropically-organized media were obtained by cooling of the lanthanide complex from different phases in an applied magnetic field. A huge positive magnetic anisotropy was observed for the resulting material.     

Luminescent lanthanide complexes with liquid crystalline properties

Lewis-base adducts of tris(β -diketonato)lanthanide(III) complexes were prepared, where the β -diketone is para -alkoxy-substituted 1,3-diphenyl-1,3-propanedione. These compounds are the first examples of liquid crystalline lanthanide complexes in which the mesomorphism is introduced via a β -diketonate ligand. Depending on the type of the Lewis base, the metallomesogens exhibit a monotropic smectic A or a monotropic highly ordered smectic phase. Intense photoluminescence was observed for the europium(III) complexes at room temperature.     

Photonuclear channel of <Superscript>7</Superscript>Be production in the Earth’s atmosphere

Measurements of average values of cross sections for the A(γ,X)⁷Be photonuclear reactions on nitrogen, oxygen, and carbon of natural isotopic composition were performed in the energy range from the threshold to 90 MeV. On the basis of the measured cross sections for ⁷Be photoproduction and on the basis of the results obtained by simulating the nuclear-electromagnetic cascade in the Earth’s atmosphere, the contribution of the photonuclear mechanism to the production of the cosmogenic radioisotope ⁷Be in the atmosphere and its latitude dependence were investigated for the first time. It is shown that the contribution of the photonuclear mechanism is commensurate with the contribution of the proton and neutron mechanisms of 7Be production in the atmosphere and that the inclusion of this mechanism is mandatory in analyzing the accumulation and transfer of ⁷Be in the planetary boundary layer.