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1Author    Axel Blecher, Martin Dräger, Bernd MathiaschRequires cookie*
 Title    (MeSn)4Se6, Geometrie und Schwingungsformen eines Adamantan-Gerüstes aus Zinn-Selen-Bindungen (MeSn)4Se6, Geometry and Vibrational Modes of an Adamantane Framework Formed by Tin-Selenium Bonds  
 Abstract    The title compound has been synthesized by reaction of MeSnBra and NaHSe in aqueous solution. The X-ray structure determination showed adamantane-like molecules (Sn-Se 253(1), Sn-C 215(1) pm) arranged in a quasi hexagonal-close packing. The atomic coordinates were used for an analysis of the vibrational spectra, yielding information on the distribution of the potential energy for the normal modes in terms of internal co-ordinates and a set of force constants. The valence force constants f(Sn-Se) 154(6), f(Sn-C) 216(2) N/m) are compared with those in related monocyclic molecules. 
  Reference    Z. Naturforsch. 36b, 1361—1367 (1981); eingegangen am 7. Mai 1981 
  Published    1981 
  Keywords    Tin, Selenium, Cage, Molecular Vibrations 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1361.pdf 
 Identifier    ZNB-1981-36b-1361 
 Volume    36 
2Author    Bernt Krebs, Andreas Schäffer, Marita HuckeRequires cookie*
 Title    Oxotrihalogenoselenate(IV)  
 Abstract    Darstellung, Struktur und Eigenschaften von P(C6H5)4SeOCl3, P(C6H5)4SeOBr3 und As(C6H5)4SeOBr3 Oxotrihalogenoselenates(IV): Preparation, Structure and Properties of P(C6H5)4SeOCl3, P(C6H5)4SeOBr3 and As(C6H5)4SeOBr3 The novel oxotribromosolenate(IV) SeOBr3~ anion was prepared from the reaction of stoichiometric quantities of SeOBi'2 and bromide in acetonitrile solution, and it was isolated as the tetraphenylphosphonium and -arsonium salts in crystalline form. For the synthesis of the analogous SeOCl3 _ as P(C'6H5)4SeOCl3, SeCl4 was reacted in the presence of a small quantity of H«() with P(CeH5)4Cl in acetonitrile. Complete N-ray structural analyses of P(C6H5)4SeOCi3 (space group P I, a = 10.981(3), b = 11.059(3), c = 10.358(3) A, a = 73.77(2)°, ß = 83.33(2)°, -/ = 80.51(2)°, V -1187.9(6) A 3) and of P(C6H5)4SeOBr3 (space group P 2i/c, a = 11.719(4), b = 16.088(4), c = 13.124(4) A, ß = 94.72(3)°, V = 2466(1) A 3) show dimeric centrosymmetric Se202Cl6 2-and Se202Br6 2 -anions being present in the solid. In the anions two square-pyramidal (y-octahedral) SeOHal4 groups are connected through a common Hal-Hal edge. The axial oxygen ligands (Se-O: 1.597(4) and 1.584(6) A) cause a pronounced stereochemical iraws-activation of the inert pairs at the Se atoms. As(C6H5)4So()Br3 is isotypic with P(C6H5)4SeOCl3. 
  Reference    Z. Naturforsch. 37b, 1410—1417 (1982); eingegangen am 13. Mai 1982 
  Published    1982 
  Keywords    Oxohalogenoselenate, Crystal Structure, Selenium 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-1410.pdf 
 Identifier    ZNB-1982-37b-1410 
 Volume    37 
3Author    Willy GomblerRequires cookie*
 Title    NMR-spektroskopische Untersuchungen an Chalkogenverbindungen, II [1] 12o Te-, 77 Se-, 19 F-und 13 C-chemische Verschiebungen von CF3-substituierten Selen-und Tellurverbindungen [2] NMR Spectroscopic Studies on Chalcogen Compounds, II [1] 125 Te, 77 Se, »F and * 3 C Chemical Shifts of CF3 Substituted Selenium and Tellurium Compounds [2]  
 Abstract    77 Se chemical shifts of compounds CF3SeX exhibit an extraordinary good linear correla-tion with Huggins' electronegativities of X, %x-A range of 1051 ppm is covered for yx values between 1.9 and 3.15. Effective electronegativities are derived from the <5(77 Se) values. For some compounds unexpected 77 Se chemical shifts are found. This indicates an uncommon electronic constitution at selenium. Electron excitation energies are reported for some of the compounds and their importance for the paramagnetic shielding term is discussed. The relative shieldings of the tellurium compounds are analogous to those of the corresponding selenium compounds. In contrast to 77 Se, the 19 F shieldings of CF3EX compounds (E = chalcogen) depend inversely on the electronegativity of E and X. The 13 C chemical shifts do not correlate with the xx values. NMR data of some CF3Se(IV) and CF3Te(IV) compounds are also reported for comparison. 
  Reference    Z. Naturforsch. 36b, 535—543 (1981); eingegangen am 21. Januar 1981 
  Published    1981 
  Keywords    NMR Spectra, Trifluoromethyl Group, Selenium, Tellurium 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0535.pdf 
 Identifier    ZNB-1981-36b-0535 
 Volume    36 
4Author    Maria Konieczny, CarlA. Olson, PeterL. Gutierrez, George SosnovskyRequires cookie*
 Title    In the Search for New Anticancer Drugs, IV+ Antitumor Activity of Seleno-TEPA  
 Abstract    In order to test the effect of selenium on the anticancer activity of alkylating drugs, Seleno-TEPA (4), the selenium analog of the clinically used Thio-TEPA (1) was tested in vivo against the lymphocytic P 388 and lymphoid L1210 murine leukemias. Compound 4 is more active against P 388 leukemia than against L1210, and appears to be active over a narrower concentration range than Thio-TEPA (1). Compound 4 is less active against P 388 leukemia than 1, as evidenced by the T/C values of 164 for 4 and 239 for 1 at a dose of 4.2 mg/kg. The activity of 4 was also evaluated on the HL60 and K 562 human cell lines. Under the conditions of the cell colony assay technique, Seleno-TEPA (4) is less effective than Thio-TEPA (1). 
  Reference    Z. Naturforsch. 38b, 1138—1141 (1983); received August 30 1982/March 14 1983 
  Published    1983 
  Keywords    Thio-TEPA, Selenium, Seleno-TEPA, Anticancer Drugs 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-1138.pdf 
 Identifier    ZNB-1983-38b-1138 
 Volume    38 
5Author    G.Erhard Thiele, HeinzW R Otter, I. M. Br, Jochen Artin Lietz, EllermRequires cookie*
 Title    Chemie polyfunktioneller Moleküle, 80 [1] Kristall-und Molekülstrukturen der Heteronoradamantane 5-Methyl  
 Abstract    2.2.8.8-tetra-ethoxycarbonyI-1.3.7-triarsa-tricyclo[3.3.1.03,7]nonan und 5-Methyl-1.3.7-triarsa-2.8-diselena-tricyclo[3.3.1.03,7]nonan Chemistry of Polyfunctional M olecules, 80 [1] Crystal and M olecular Structures of the H eteronoradam antanes 5-M ethyl-2.2.8.8-tetra-ethoxycarbonyl-1.3.7-triarsa-tricyclo[3.3.1.03'7]nonane and 5-M ethyl-1.3.7-triarsa-2.8-diselena-[3.3.1.037]nonane The m olecular and crystal structures of the nor-heteroadam antanes C H 3C (C H 2A s)3[C (C O O C H ;C H 3)2]2 (1) and C H 3C (C H 2A s)3Se2 (2) have been investigated in order to obtain confirm ation of the rare structures deduced earlier from mass, 'H NM R and vibrational spectroscopy. Crystals of 1 are triclinic, space group P I —Cf with a — 769.27(30), b = 1036.09(14), c = 1599.18(17) pm , a = 98.236(10)°, ß = 97.987(18)°, y = 103.633(20)° and Z = 2. On the basis of 1821 unique reflections the structure was refined to a weighted R value of 5.28% . The crystals of 2 are monoclinic, space group P 2 ,/c—Cih with a = 1102.73(23), b — 727.49(14), c = 1281.27(42) pm . ß = 98.803(21)° and Z = 4. On the basis of 1065 unique reflections the structure was refined to a weighted R value of 5.93%. Several attem pts to synthesize C H 3C (C H :A s)3Te2 failed. 
  Reference    Z. Naturforsch. 39b, 1344—1349 (1984); eingegangen am 23. März 1984 
  Published    1984 
  Keywords    Crystal Structures, H eteronoradam antanes, A rsenic, Selenium 
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 TEI-XML for    default:Reihe_B/39/ZNB-1984-39b-1344.pdf 
 Identifier    ZNB-1984-39b-1344 
 Volume    39 
6Author    Lothar Weber, Georg Meine, Roland Boese, Norbert NiederprümRequires cookie*
 Title    Übergangsmetall-substituierte Diphosphene, XIV [1]  
 Abstract    Zur Reaktivität des Diphosphenylkomplexes (i/ 5 -C 5 Me5)(CO) 2 Fe—P=P—Ar (Ar = 2,4,6-r-Bu 3 C 6 H 2) gegenüber Schwefel, Selen und Tellur. Synthese und Struktur des ersten Thioxo-A s -diphosphenyl-Komplexes (!7 5 -C 5 Me 5)(CO) 2 Fe-P(=S)(=P-Ar) Transition Metal Substituted Diphosphenes, XIV [1] On the Reactivity of the Diphosphenyl Complex (?; ; '-C5Me5)(CO) 2 Fe-P=P-Ar (Ar = 2,4,6-J-Bu 3 C 6 H 2) towards Sulfur, Selenium, and Tellurium. Synthesis and X-Ray Structure Analysis of the First Thioxo-A 5 -diphosphenyl Complex (>/ 5 -C 5 Me 5) (CO) 2 Fe -P(=S)(=P -Ar) The diphosphenyl complex (?7 5 -C 5 Me 5)(CO) 2 Fe-P=P-Ar (la) (Ar = 2,4,6-rm-Bu 3 C 6 H 2) reacts with an equimolar amount of sulfur to yield the first thioxo-A 5 -diphosphenyl com-plex (/7 5 -C 5 Me 5)(CO) 2 Fe-P(= S) = P-Ar (2). Heating of 2 in boiling benzene affords the metal functionalized thiadiphosphirane 3. Similarily the selenoxo-A 5 -diphosphenyl complex (^ 5 -C 5 Me 5)(CO) 2 Fe —P(=Se) = P—Ar (5) and selena-diphosphirane 6 are synthesized. The prod-ucts have been characterized by elemental analysis as well as by spectroscopic data (IR, 'H, 13 C, 31 P NMR, MS). The molecular structure of 2 has been elucidated by single crystal X-ray analysis. 
  Reference    Z. Naturforsch. 43b, 715—721 (1988); eingegangen am 26. Oktober 1987 
  Published    1988 
  Keywords    Diphosphenyl Complex, Sulfur, Selenium, Tellurium, X-Ray Analysis 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0715.pdf 
 Identifier    ZNB-1988-43b-0715 
 Volume    43 
7Author    M. Wachhold, W. S. SheldrickRequires cookie*
 Title    Methanolothermale Synthese von Rb3AsSe4 * 2 Se6 und Cs3AsSe4 * 2 Cs2As2Se4 * 6 Te4Se2, zwei Selenidoarsenate mit sechsgliedrigen Chalkogenringen Methanolothermal Synthesis o f Rb3A sSe4 * 2 Se6 and Cs3AsSe4 * 2 Cs2A s2Se4 * 6 Te4Se2. Two Selenidoarsenates with Six-Membered Chalcogen Rings  
 Abstract    The methanolothermal reaction of Rb2C 0 3 with As2Se3 and black selenium leads to the formation of Rb3AsSe4 and the new selenidoarsenate(V) Rb3AsSe4 • 2 Se6 (1), which crys­ 
  Reference    Z. Naturforsch. 52b, 169—175 (1997); eingegangen am 29. Juli 1996 
  Published    1997 
  Keywords    Selenium, Tellurium, Ring Systems, Selenidoarsenate, Methanolothermal Synthesis 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-0169.pdf 
 Identifier    ZNB-1997-52b-0169 
 Volume    52 
8Author    K. Urt, O. KleppRequires cookie*
 Title    Preparation and Crystal Structure of Na4TiSe4. A Selenotitanate with Discrete Tetrahedral Anions  
 Abstract    Red crystals of Na4TiSe4 were obtained by reacting an intimate mixture of Na2Se, Ti and Se at 750°C. Na4TiSe4 is monoclinic, space group I2/a with a = 24.027(6), b = 7.346(4), c = 21.572(6) A, (3 = 104.52(2)°, Z = 16. Its crystal structure was determined from diffractometer data (AgK a-radiation) and refined to a conventional R of 0.036 for 2673 F0's and 158 variables. The crystal structure is of a new type, characterized by the presence of discrete tetrahedral complex anions, [TiSe,*]4" , which are arranged in slabs parallel to (100). The average Ti-Se bond length is 2.385(1) A. The Na+ cations are in different chalcogen environments with distorted octahedral, square pyramidal or planar configurations, respectively. 
  Reference    (Z. Naturforsch. 55b, 39—44 [2000]; received September 28 1999) 
  Published    2000 
  Keywords    Crystal Structure, Chalcogenides, Titanium, Sodium, Selenium 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0039.pdf 
 Identifier    ZNB-2000-55b-0039 
 Volume    55 
9Author    Helmut Sies, Lars-Oliver Klotz, VictorS. Sharov, Annika Assmann, Karlis BrivibaRequires cookie*
 Title    Protection against Peroxynitrite by Selenoproteins  
 Abstract    Cellular defense against excessive peroxynitrite generation is required to protect against DNA strand-breaks and mutations and against interference with protein tyrosine-based sig­ naling and other protein functions due to formation of 3-nitrotyrosine. We recently demon­ strated a role of selenium-containing enzymes catalyzing peroxynitrite reduction. Glutathione peroxidase (GPx) protected against the oxidation of dihydrorhodamine 123 (D H R) by perox­ ynitrite more effectively than ebselen (2-phenyl-l,2-benzisoselenazol-3(2///)-one), a selenoor-ganic compound exhibiting a high second-order rate constant for the reaction with peroxynit­ rite, 2 x 106 M_ 1s _1. The maintenance of protection by GPx against peroxynitrite requires GSH as reductant. Similarly, selenomethionine but not selenomethionine oxide exhibited inhibition of rhodamine 123 formation from D H R caused by peroxynitrite. In steady-state experiments, in which peroxynitrite was infused to maintain a 0.2 |.im con­ centration, GPx in the presence of GSH, but neither GPx nor GSH alone, effectively inhib­ ited the hydroxylation of benzoate by peroxynitrite. Under these steady-state conditions peroxynitrite did not cause loss of 'classical' GPx activity. GPx, like selenomethionine, pro­ tected against protein 3-nitrotyrosine formation in human fibroblast lysates, shown in West­ ern blots. The formation of nitrite rather than nitrate from peroxynitrite was enhanced by GPx , ebselen or selenomethionine. The selenoxides can be effectively reduced by glutathione, establishing a biological line of defense against peroxynitrite. The novel function of GPx as a peroxynitrite reductase may extend to other selenoproteins containing selenocysteine or selenomethionine. Recent work on organotellurium compounds revealed peroxynitrite reductase activity as well. Inhibition of dihydrorhodamine 123 oxidation correlated well with the GPx-like activity of a variety of diaryl tellurides. 
  Reference    Z. Naturforsch. 53c, 228 (1998); received January 15/February 2 1998 
  Published    1998 
  Keywords    Peroxynitrite, Glutathione Peroxidase, Phospholipid Hydroperoxide Glutathione Peroxidase, Selenium, Ebselen 
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 TEI-XML for    default:Reihe_C/53/ZNC-1998-53c-0228.pdf 
 Identifier    ZNC-1998-53c-0228 
 Volume    53 
10Author    Maria Konieczny, George SosnovskyRequires cookie*
 Title    Reaction of Trivalent Organophosphorus Compounds with Selenium  
 Abstract    Selenium derivatives of pentavalent organophosphorus compounds 9, 10, 11 (R = 2,2,6,6-tetramethyl-l-oxyl-4-piperidyl), 12 and 13 were prepared in 79-99% 
  Reference    Z. Naturforsch. 33b, 1040—1046 (1978); received June 2 1978 
  Published    1978 
  Keywords    Nitroxyl Radical, Selenium, Organoselenophosphorus Compounds, Phosphorus Compounds, Spin-labeling 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-1040.pdf 
 Identifier    ZNB-1978-33b-1040 
 Volume    33 
11Author    Bernt Krebs, Marita Hucke, Michael Hein, Andreas SchäfferRequires cookie*
 Title    Monomere und dimere Oxotrihalogenoselenate(IV): Darstellung, Struktur und Eigenschaften von [As(C6H5)4]SeOCl3 und [N(C2H5)4]SeOCl3 Monomerie and Dimeric Oxotrihalogenoselenates(IV): Preparation, Structure and Properties of [As(C6H5)4]SeOCl3 and [N(C2H5)4] SeOCl3  
 Abstract    The monomeric SeOCl3~ ion, which can be prepared as the tetraphenylarsonium salt from SeOCl2 and As(C6Hs)4C1, was structurally characterized by a low-temperature single crystal X-ray diffraction analysis. [As(C6Hs)4]SeOCl3 is monoclinic, space group P2i/c, with a = 9,332(3), b = 13,761(4), c = 18,985(6) A, ß = 110,97(3)° (at —135 °C), Z = 4; it contains a novel type of y>-trigonal bipyramidal oxotrichloroselenate(IV) anion which is not associated to dimers or polymer chains as in known structures. The equatorial positions are occupied by doubly bonded oxygen (Se-O 1,601(3) Ä) and by one Cl (Se-Cl 2,234(1) A), the axial Se-Cl bonds (2,430(1) and 2,475(1) A) being significantly longer. [N(C2H5)4]SeOCl3, which was obtained as crystals by oxidation of trichloroselenate(II), is triclinic, space group P I, with a = 10,607(3), b = 8,950(2), c = 8,862(2) A, a = 119,79(2)°, ß = 101,07(2)°, y = 96,28(2)°, Z = 2. The X-ray structure analysis shows the anions to be present as centrosymmetric dimers Se202Cl6 2 " like in the [P(CeH5)4] + salt, with two tetragonal SeOCU pyramids linked through a C1---C1 edge and the lone pairs trans to the axial Se-0 bonds (1,589(4) A). Se-Cl bond lengths are 2.270(1) and 2,351(2) A (terminal); 2,698(1) and 2,920(1) A (bridging). The results show that the nature of the reaction products of the Lewis acid SeOCl2 with halogenides as bases changes very sensitively with small variations in cations and environment. The vibrational spectra are discussed. 
  Reference    (Z. Naturforsch. 38b, 20—29 [1983]; eingegangen am 23. September 1982) 
  Published    1983 
  Keywords    Oxohalogenoselenates, Crystal Structure, Selenium, Inert Electron Pair, Selenium Oxychloride 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0020.pdf 
 Identifier    ZNB-1983-38b-0020 
 Volume    38 
12Author    H. Erbert, W. Roesky, H. Artm, Ut HofmRequires cookie*
 Title    Cyclisation of Bis(2,2,2-trifluoroethoxy)-l,2-diim inoethane with Sulfur, Selenium, Phosphorus, and Arsenic Chlorides  
 Abstract    By the reaction of cyanogen with 2,2,2-trifluoroethanol in the presence o f a base catalyst, 
  Reference    Z. Naturforsch. 39b, 1315 (1984) 
  Published    1984 
  Keywords    eingegangen 1984 Cyanogen, Five-mem bered Rings, Phosphorus, Sulfur, Selenium 
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 TEI-XML for    default:Reihe_B/39/ZNB-1984-39b-1315.pdf 
 Identifier    ZNB-1984-39b-1315 
 Volume    39 
13Author    Anja Loose, WilliamS. SheldrickRequires cookie*
 Title    Solventothermal Synthesis of the Lamellar Selenidostannates(IV) A2Sn4Se9*H20 (A = Rb, Cs) and Cs2Sn2Se6  
 Abstract    Reaction of A 2C O 3 with Sn and Se in an H 2O /CH 3OH mixture at 115 -130°C affords the isotypic lamellar selenidostannates A2Sn4Se9-H20 1 (A = Rb) and 2 (A = Cs). The polyanions ^ [Sn4Se92~] exhibit S ^ S e s molecular building units, in which two adjacent Sn(IV) atoms of an Sn4Se4 8-membered ring are bridged by an additional Se atom. These units connect through (SnSe)2 4-mem bered rings to afford a 44 anionic net with 16-membered cavities. Cs2Sn2Se6 (3) may be prepared by methanolothermal reaction of CstCO^ with SnSe and Se at 130°C and contains porous 2 [SnTSeö2 -] sheets in which [SnSes--] ribbons are linked through Se-Se bonds. The resulting 4 net displays 14-membered pores in which the Cs cations reside. 
  Reference    Z. Naturforsch. 53b, 349—354 (1998); received December 29 1997 
  Published    1998 
  Keywords    Tin, Selenium, Selenidostannates(IV), Lamellar Structures, Solventothermal Synthesis 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0349.pdf 
 Identifier    ZNB-1998-53b-0349 
 Volume    53