Features of spectral properties of Sm(3+) complexes with dithia- and diselenophosphinate ligands.

The samarium complexes Sm(S2PPh2)3(THF)2 (1) and Sm(Se2PPh2)3(THF)2 (2) with soft-donor dithia- and diselenophosphinate ligands were synthesized and their photophysical properties were studied in detail. Both complexes displayed the metal-centered photoluminescence (PL) in visible and NIR regions corresponding to (4)G5/2→(6)HJ (J=5/2, 7/2, 9/2, 11/2, 13/2, 15/2), (6)FJ (J=1/2, 3/2, 5/2, 7/2, 9/2, 11/2) f-f transitions of Sm(3+). Luminescence decay curves exhibit an initial short build-up region and can be described by double or triple exponential function owing to multiphonon relaxation from the (4)F3/2 energy level to the (4)G5/2 one and reversible energy transfer from the Sm(3+) excited states to the triplet ((3)T1) state of phosphinate ligand. A Judd-Ofelt analysis was performed to estimate PL quantum efficiency (QE), branching ratios (ß) and induced-emission cross section (σem) of the compounds obtained. It was found that the Judd-Ofelt parameter Ω2 of 1 is significantly greater than that of 2. This feature is responsible for large values of ß (50.98%) and σem (4.29×10(-21)cm(2)) which suggest 1 as a good candidate for the development of samarium doped polymethylmethacrylate (PMMA) laser medium acting on the (4)G5/2→(6)H9/2 transition at 645nm. The estimated room-temperature PL QE of 1 and 2 equals to 1.9 and 0.17%, respectively.

Ln3I5(S2N2)(S2)(THF)10 - a new type of molecular compounds.

Unprecedented complexes of the composition Ln3I5(S2N2)(S2)(THF)10 were obtained in the reactions of neodymium and dysprosium iodide-nitrides with sulfur. The inorganic core of the molecules contains the cyclic fragments Ln(µ-S2)Ln, LnSNSN and LnSN. Ten of the fourteen atoms of the core are coplanar, the remaining four S2 and I2 atoms lie in the other two orthogonal planes. The dysprosium complex upon excitation with UV light exhibits the metal-centered luminescence characteristic of the Dy(3+) ion. Geometric parameters of the molecules, computational data, electron spectroscopy and fluorescence suggest the existence of some conjugation in the mentioned heterocycles.

Synthesis, structure and luminescent properties of lanthanide fluoroalkoxides.

Alkoxides [Ln(OR)3(DME)]2 (R = CH(CF3)2, Ln = Sm (1), Yb (2)), [Ce(OR)3(Phen)]2 (3) (Phen = 1,10-phenanthroline), [Ce(OR')3(DME)2]2 (R' = C(CF3)3) (4), {Gd(OR')3(DME)2} (5), {Ln2[O(CF3)2C­C(CF3)2O]3} (Ln = Ce (6), Gd (7)), {Ce2[O(CF3)2C­C(CF3)2O]3(Phen)2} (8), and {Ce[O(CF3)2C­C(CF3)2O][O(CF3)2­C(CF3)2OH](Phen)2} (9) were synthesized by the reactions of silylamides Ln[N(SiMe3)2]3 with respective fluorinated alcohols. The heterovalent trinuclear complex {Sm2(µ2-OR)3(µ3-OR)2Sm(OR)2(THF)2.5(Et2O)0.5} (10) was obtained by treatment of SmI2(THF)2 with ROK. The reaction of europium(II) and yttrium(III) silylamides with ROH afforded the heterobimetallic alkoxide {Eu2(µ2-OR)3(µ3-OR)2Y(OR)2(DME)2} (11) containing divalent europium. The molecular structures of 1, 2, 3, 9, 10 and 11 were determined by X-ray analysis. All the prepared cerium derivatives as well as the europium­yttrium isopropoxide upon UV excitation exhibited photoluminescence in the regions of 370­425 (for Ce3+) and 485 nm (for Eu2+) which was assigned to 4d→5f transitions.

[Comparative Analysis of DNA Homology in Pericentric Regions of Chromosomes of Wood Mice from Genera Apodemus and Sylvaemus].

In the present study, an analysis of the DNA homology of the pericentric chromosomal regions and pericentric heterochromatin in distantly related species of wood mice (species from the Apodemus genus, as well as from the Apodemus and Sylvaemus genera) was conducted by fluorescent in situ hybridization (FISH) with microdissected DNA probes obtained from the corresponding chromosomal regions of these species. Cross-hybridization of microdissected DNA probes obtained from pericentric C-positive blocks of chromosomes of Sylvaemus species with chromosomes of Apodemus species, as well as DNA probes from pericentric C-positive blocks of chromosomes of Apodemus species with chromosomes of Apodemus and Sylvaemus species, showed that DNA repeats homologous to the pericentric regions in other species represented. dispersed repeats in C-negative chromosomal regions, as well as in several regions bordering pericentric C-positive and C-negative regions in heterochromosomes and autosomes and in distal regions in the long arms of several autosomes. The results indicate that the level of DNA homology in pericentric chromosomal regions decreases with an increase in the differentiation level and a decrease in the kinship between the compared forms and species of wood mice. Most likely, degeneration of the DNA repeats is accompanied by a gradual destruction of repeat clusters and their replacement by new, nonhomologous repeats in almost all pericentric regions (some old repetitive sequences might be "extruded" into interstitial or telomeric regions of chromosomes). These processes, which are observed in some species from Sylvaemus genus in distantly related species of Sylvaemus and Apodemus genera, have almost achieved the final stages.

Cyclometallated platinum(II) complexes containing NHC ligands: synthesis, characterization, photophysics and their application as emitters in OLEDs.

A series of square planar [Pt(N^C)(NHC)L] complexes containing cyclometallated N^C ligands (phenylpyridine and benzoquinoline) and N-heterocyclic carbene (NHC)--N^C = 2-phenylpyridine, 7,8-benzoquinoline; NHC = 1,3-dibenzylbenzimidazolium, 1,3-diethylbenzimidazolium, 1,3-dibenzylimidazolium; L = Cl, Br, -C2Ph--have been synthesized in moderate to good yields. The complexes obtained were characterized using chemical analysis, MS-ESI spectrometry, NMR spectroscopy and X-ray crystallography. The complexes display moderate to strong phosphorescence in solution (Q.Y. 0.3-7.9%) and in the solid state (Q.Y. 2.7-16.0%), which is related to metal modulated intraligand π-π* transitions located at the aromatic system of cyclometallated ligands with some contribution of the MLCT excited state. Emission lifetimes fall in the range of 0.2-1.5 µs in solution and amount up to 13 µs in the solid state. Analysis of the spectroscopic data together with the density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations clearly support this assignment and show negligible contribution of the auxiliary ligands to the emissive excited states. The compounds obtained were also used to prepare organic light emitting diode (OLED) devices, which display good luminance efficiency emitting in the green area of the visible spectrum.

[Multiplicity of B microchromosomes in a Siberian population of mice Apodemus peninsulae (2n = 48 + 4-30 B chromosomes)].

Differentiation of four Siberian populations of East-Asian (Korean) field mice (Apodemus peninsulae) inhabiting the basin of the mid-stream of the Yenisei River was carried out according to the variants of the B chromosome system. A multiplicity of B microchromosomes (from 4 to 30) was found for the first time in all 26 mice from the left shore of the Yenisei River in the mid-stream area. All of them probably belong to a population with B microchromosomes. It is likely that in this population further reorganization of B microchromosomes into B macrochromosomes typical of this species does not occur. Two mice from this population had a large number of B chromosomes (26) earlier not observed in this species. In one mouse, the modal number of B microchromosomes was 30. This is a new maximum number of B chromosomes in this mouse species.

[Comparative FISH analysis of C-positive blocks of centromeric chromosomal regions of pygmy wood mice Sylvaemus uralensis (Rodentia, Muridae)].

The composition and homology of centromeric heterochromatin DNA has been compared in representatives of the Asian race and two chromosomal forms (Eastern European and Southern European) of the European race of the pygmy wood mouse Sylvaemus uralensis by means of in situ hybridization with metaphase chromosomes of microdissection DNA probes obtained from centromeric C-blocks of mice of the Southern European chromosomal form and the Asian race. Joint hybridization of both DNA probes yielded all possible variants of centromeric regions in terms of the presence of repetitive sequences homologous to those of some or another dissection region, which indicates a diversity of centromeric regions differing in DNA composition. However, most variations of the fluorescent in situ hybridization (FISH) patterns are apparently related to quantitative differences of repetitive elements of the genome. Experiments with the DNA probe obtained from the genome of the Southern European form of the pygmy wood mouse have shown that the number of intense FISH signals roughly corresponds to the number of large C-segments in representatives of the European race, which is characterized by a large amount of the centromeric C-heterochromatin in the karyotype. However, intense signals have been also detected in experiments on hybridization of this probe with chromosomes of representatives of the Asian race, which has no large C-blocks in the karyotype; thus, DNA sequences homologous to heterochromatic ones are also present in nonheterochromatic regions adjacent to C-segments. Despite the variations of the numbers of both intense and weak FISH signals, all chromosomal forms/races of S. uralensis significantly differ from one another in these characters. The number of intense FISH signals in DNA from the samples of pygmy wood mice from eastern Turkmenistan (the Kugitang ridge) and southern Omsk oblast (the vicinity of the Talapker railway station) was intermediate between those in the European and Asian races, which is apparently related to a hybrid origin of these populations (the hybridization having occurred long ago in the former case and recently in the latter case).

[The mechanisms of formation and evolution of B chromosomes in Korean field mice Apodemus peninsulae (Mammalia, Rodentia)].

Several hypotheses concerning variations in the frequency of some elementary events determining the formation and reorganization of mammalian B chromosomes are proposed on the basis of the data on their number, morphology, and DNA composition in Korean field mice Apodemus peninsulae (Mammalia, Rodentia) from natural populations of Altai, Buryatia, Irkutsk oblast, and Primorye. The mechanisms and causes responsible for the formation of B chromosomes and differences in their organization in populations of mice from geographically separated regions are discussed.

[Diversity and individuality of variants of the system of B chromosomes in mice Apodemus peninsulae].

A complicated population system of B chromosomes has been revealed in the karyotypes of the East-Asian mouse Apodemus peninsulae over the whole range. Based on our previous data for mice from Altai, Siberia, Pribaikal'e, and Mongolia and on the results of the present work, we infer that most of animals studied (196 out of 312, or 63%) have an individual variant of the B chromosome system. Only three mice lacked B chromosomes. New data for 44 A. peninsulae mice caught in 2000-2005 in 16 localities of seven regions of Altai, Siberia, and Pribaikal'e showed that all of them had individual variants of the system of B chromosomes due to different combinations (from 2 to 18 B chromosomes) of five classes of B macro- and microchromosomes.

A chemical definition of the effective reducing power of thulium(II) diiodide by its reactions with cyclic unsaturated hydrocarbons.

Thulium diiodide reduces cyclic aromatic hydrocarbons that have reduction potentials more positive than - 2.0 V versus SCE. Thus, TmI2 reacts with cyclooctatetraene or acenaphthylene in THF, or with lithium anthracenide in 1,2-dimethoxyethane (DME) to give thulium triiodide and the thulium(III) complexes [(eta8-C8H8)TmI(thf)2] (1), rac-ansa-[(eta5-C12H8)2TmI(thf)] (2), or [(eta2-C14H10)TmI-(dme)2] (3), respectively. The molecular structures of 1-3 were determined by single-crystal X-ray diffraction.

[Chromosomal evolution of the Common Shrew Sorex araneus L.from the Southern Ural and Siberia in the postglacial period]. / Khromosomnaia évoliutsiia obyknovennoi burozubki Sorex araneus L. v poslelednikovoe vremia na Iuzhnom Urale i v Sibire.

This paper summarizes a series of studies on chromosomal geography of the common shrew Sorex araneus L. in Siberia and the Southern Urals. Chromosomal races inhabiting the Southern Urals and the Western Siberian Plain sequentially replace each other in the latitudinal direction. In this region, karyotypes of each two adjacent races differ from each other by a single whole-arm reciprocal translocation. In the Eastern Siberian branch, the neighboring races differ mainly in the number or set of metacentric chromosomes. Analysis of the race distribution in the common shrew in the context of paleophysiology of the glacial period allowed us to reconstruct the sequence of events leading to the establishment of the present-day structure of the species.

[The detection of the location of glucose-6-phosphate dehydrogenase in the fibroblasts of voles and mice and in rat myoblasts by using monoclonal antibodies against glucose-6-phosphate dehydrogenase]. / Vyiavlenie lokalizatsii gliukozo-6-fosfatdegidrogenazy v fibroblastakh polevok i myshi i v mioblastakh krysy s pomoshch'iu monoklonal'nykh antitel protiv gliukozo-6-fosfatdegidrogenazy.

Monoclonal antibodies (MAs) were produced against glucose-6-phosphate dehydrogenase (G6PD) of two vole species--Microtus arvalis and M. subarvalis. The binding level of the MAs to G6PD in both species were almost the same, which suggested that these MAs may be specific for the antigenic determinants common to G6PD of these species. The MAs produced against the vole G6PD were used for its intracellular localization. The patterns obtained after staining cells with the use of MAs against G6PD were the same as those obtained after staining with the use of antibodies against F-actin. There was a good conformity between the results of light and electron microscopic immunoenzyme analyses with regard to the binding of MAs produced to the actin microfilaments. It is concluded that G6PD is closely associated with actin microfilaments of the cell cytoskeleton.

[Heterochromatin as a factor influencing X-chromosome inactivation in hybrids of the common vole (Microtinae, Rodentia)]. / Geterokhromatin kak faktor, vliiaiushchii na inaktivatsiiu X-khromosomy u gibridov obyknovennoi polevki (Microtidae, Rodentia).

Expression of X-linked genes for G6PD and alpha-GAL was studied in female interspecific hybrids of Microtus. The G6PD and alpha-GAL isozymes of Microtus arvalis were found to predominate in all cases when a species carrying a heterochromatin block on the X-chromosome served as one partner of hybridization and M. arvalis containing no heterochromatin block served as another. The proportions of G6PD and alpha-GAL parental forms were approx. equal in hybrid females when both species participating in hybridization contained heterochromatin blocks on X-chromosomes. Cytological analysis for revealing active and nonactive X-chromosomes on metaphase spreads of hybrid females supports the biochemical data. Non-random inactivation of X-chromosomes carrying the heterochromatin blocks in the interspecific hybrids with M. arvalis and a random one, when both parents contain heterochromatin blocks on the X-chromosomes are supposed to be the cause for the phenomenon observed. The study provided data supporting our previous hypothesis that heterochromatin affects the X-chromosome inactivation process in interspecific hybrid voles.

Evidence for tetrameric structure of mammalian hypoxanthine phosphoribosyltransferase.

A fast electrophoretic variant of hypoxanthine phosphoribosyltransferase (HPRT) has been detected in Mus musculus bactrianus, a mouse subspecies from Middle Asia (USSR). The electrophoretic HPRT pattern yielded by hybrids between the somatic cell of LMTK- (deficient in thymidine kinase) and the splenocytes of a male of M. m. bactrianus was five-banded. The pattern obtained from the germ cells of the ovaries from 14.5-day-old embryos from laboratory CBA mice X M. m. bactrianus crosses was also composed of five bands. The hybrids between the somatic cells of human fibroblasts X LMTK- cells gave a three-banded electrophoretic HPRT pattern because the asymmetrical heteropolymeric isozymes are probably unstable. Taken together, all the evidence is in favor of a tetrameric structure of mammalian HPRT.

Regional assignment of the genes for TK1, GALK, ALDC, and ESD on chromosome 8 in the American mink by chromosome-mediated gene transfer.

A panel of clones of mink-Chinese hamster somatic cell hybrids was analysed to obtain data for assigning the genes for thymidine kinase-1 (TK1), galactokinase (GALK), subunit C of aldolase (ALDC), and esterase D (ESD) to specific mink chromosomes. The results demonstrate that the genes for TK1, GALK, ALDC and ESD are syntenic and located on mink chromosome 8. Prometaphase analysis of transformed mouse cells obtained by transfer of mink genes by means of metaphase chromosomes demonstrated the presence of mink chromosome 8 fragments of different sizes in some of the independent transformants. Segregation analysis of these fragments and mink TK1, GALK, ALDC and ESD allowed us to assign the genes for TK1 and GALK to 8p24, ALDC to pter-8p25, and ESD to 8q24-8qter.

Chromosome localization of the genes for ENO1, HK1, ADK, ACP2, MPI, ITPA, ACON1 and α-GAL in the American mink (Mustela vison).

Twenty-eight American mink × Chinese hamster somatic cell hybrids were analysed for the expression of mink enzymes and the segregation of mink chromosomes. The results demonstrated that the gene for enolase-1 is located on the long arm of mink chromosome 2, and those for hexokinase-1 and adenosine kinase, on its short arm. Segregation analysis of mink chromosomes and mink acid phosphatase-2, mannose phosphate isomerase, inosine triphosphatase and aconitase-1 provided data allowing us to assign the genes for these markers to mink chromosomes 7, 10, 11 and 12, respectively. The expression of mink α-galactosidase was highly coincidental with mink × chromosome as well as with its markers: hypoxanthine-phosphoribosyltransferase, glucose-6-phosphate dehydrogenase and phosphoglycerate kinase-1. This result confirms the assignment of the gene for α-galactosidase to the mink × chromosome.