Luminescent characteristics of tetraphenylporphyrin and its derivatives with lutetium

The spectral and luminescent characteristics of new tetraphenylporphyrin derivatives that contain the lutetium atom in their structure are studied in comparison with the most completely studied unsubstituted tetraphenylporphyrin and its complex with zinc. The luminescence quantum yields in liquid and frozen solutions are measured. The specific features of luminescent characteristics of these compounds and their possible applications are discussed.     

Penetration of an Electric Field into Conductive Media

The penetration of an electric field into a conductor with conduction electrons in a nondegenerate state is investigated. It is shown that the screening of an electric field is much more efficient in a nonlinear mode than in a linear mode.     

Full four‐component relativistic calculations of the one‐bond 77Se–13C spin‐spin coupling constants in the series of selenium heterocycles and their parent open‐chain selenides

Four‐component relativistic calculations of ⁷⁷Se–¹³C spin–spin coupling constants have been performed in the series of selenium heterocycles and their parent open‐chain selenides. It has been found that relativistic effects play an essential role in the selenium–carbon coupling mechanism and could result in a contribution of as much as 15–25% of the total values of the one‐bond selenium–carbon spin‐spin coupling constants. In the overall contribution of the relativistic effects to the total values of ¹J(Se,C), the scalar relativistic corrections (negative in sign) by far dominate over the spin‐orbit ones (positive in sign), the latter being of less than 5%, as compared to the former (ca 20%). A combination of nonrelativistic second‐order polarization propagator approach (CC2) with the four‐component relativistic density functional theory scheme is recommended as a versatile tool for the calculation of ¹J(Se,C). Solvent effects in the values of ¹J(Se,C) calculated within the polarizable continuum model for the solvents with different dielectric constants (ε 2.2–78.4) are next to negligible decreasing negative ¹J(Se,C) in absolute value by only about 1 Hz. The use of the locally dense basis set approach applied herewith for the calculation of ⁷⁷Se–¹³C spin‐spin coupling constants is fully justified resulting in a dramatic decrease in computational cost with only 0.1–0.2‐Hz loss of accuracy. Copyright © 2014 John Wiley & Sons, Ltd.     

Luminescence of ytterbium complexes with octaphenyltetraazaporphyrins

We have synthesized outer complexes of ytterbium with octaphenyl-and octa(para-tert-butylphenyl)tetraazaporphyrins, in which for the first time we have detected luminescence of ytterbium with maximum at 980 nm. We have shown that the 4f-luminescence quantum yield in the complexes depends primarily on the nature of the outer ligand. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 693–696, September–October, 2006.     

Features of the 9Be → 2He fragmentation in an emulsion for an energy of 1.2 GeV per nucleon

The results of investigation of the fragmentation of relativistic nuclei ⁹Be in an emulsion, which is accompanied by the formation of two 1.2-A-GeV He fragments, are presented. The angular measurements of the ⁹Be → 2He events are analyzed. The ⁹Be → ⁸Be + n fragmentation channel with the decay of ⁸Be from the ground (0⁺) and first excited (2⁺) states into a pair of α particles appears to be dominant.     

Atom-field entanglement in two-atom Jaynes-Cummings model with nondegenerate two-photon transitions

An exact solution of the problem of two two-level atoms with nondegenerate two-photon transitions and nondegenerate Raman transitions interacting with two-mode radiation field is presented. Asymptotic solutions for system state vectors are obtained in the approximation of large initial coherent fields. The atom-field entanglement is investigated on the basis of the reduced atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process for both models is shown. Conditions and times of disentanglement are derived.     

Flow effects in 84Kr induced collisions in emulsion at 0.95 GeV per nucleon

Using emulsion detector the collective flow signals in inelastic interactions of ⁸⁴Kr nuclei with Ag(Br) at 950 MeV/nucleon are studied. A transverse momentum analysis is performed to determine the reaction plane. The bounce-off of spectator fragments is observed. In azimuthal distributions relative to the reaction plane squeeze-out and side-splash of participants are seen. Received: 27 September 1999     

Infrared Luminescence of Ytterbium Ion in Complexes with Calix[4]resorcinarenes

New ytterbium complexes with seven calix[4]resorcinarenes containing methoxycarbonyl, methyldiethylamino groups, and bromine as the substituents in the resorcinol ring and methyl or phenyl substituents in the macro ring were synthesized. The absorption, excitation, phosphorescence, and luminescence spectra of these complexes were studied. The positions of triplet levels of the ligands were measured and the values of relative quantum yields for the complexes were calculated. The paths of ligand–lanthanide energy transfer are discussed.     

Peripheral interactions of relativistic 14N nuclei with emulsion nuclei

The results of investigation of the dissociation of the 2.86-A-GeV/c ¹⁴N nucleus in an emulsion are presented. The cross sections for various fragmentation channels are given. The invariant approach to analysis of fragmentation is used. The momentum and correlation characteristics of the α particles for the ¹⁴N → 3α + X channel in the laboratory system and c.m.s. of three α particles are examined. The results obtained for the ¹⁴N nucleus are compared with similar data for the ¹²C and ¹⁶O nuclei.     

Synthesis and cytotoxicity of 28-carboxymethoxy lupane triterpenoids.Preference of 28-O-acylation over 28-O-alkylation of betulm by ethyl bromoacetate

28-Carboxymethoxy lupane tritepenoids 3 and 4 were synthesized by alkylation of betulin with the THP protected 2- hydroxyethyl iodide followed by oxidation and reduction.Direct reaction of betulin(5) or betulone(10) with ethyl bromoacetate led to 28-O-acylation,instead of 28-O-alkylation.The targeted compounds 3 and 4 were not cytotoxic at the highest concentration tested(75μmol/L),suggesting that elongation of the chain length at the 28-position in both betulinic acid(1) and betulonic acid(2) was detrim...