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2000 (185)
1Author    Fritz Preuss, Jens PemRequires cookie*
 Title    Alkylsubstituierte Cyclopentadienylvanadium(V)-Komplexe: 'C4H9N=VCpRCl2  
 Abstract    Alkylated Cyclopentadienylvanadium(V) Complexes, P reparation,51V NMR Data The synthesis of alkylated ?75-cyclopentadienylvanadium(V) complexes tC4H9N=VCpRCl2 (CpR = C5H4R, C5H3R2, C5HMe4, C5Me5) is described. The compounds have been investigated by 1V NMR spectroscopy; th e 51V resonances are found downfield of the unsubstituted complex 'C 4H9N=V(r75-C5H5)Cl2. The deshielding of the 51V nucleus increases with the number of substituents R. E inleitung 
  Reference    (Z. Naturforsch. 55b, 1—1 [2000]; eingegangen am 12. November 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0001.pdf 
 Identifier    ZNB-2000-55b-0001 
 Volume    55 
2Author    TeresaB. Orow Iaka, IrenaW. Olska3, A.Rtur Korzańskia, W. Olfgang, M. Iliusb, W. Olfgang Schnickb, W. Iesław, A. Ntkow IakcRequires cookie*
 Title    A Comparison of the Enamino Carbonyl Conjugation Efficiency for Hy­ drogen Bonding Formation in Pyridone and Dihydropyridone Systems  
 Abstract    The crystal structures of two compounds containing enaminone heterodiene systems and forming intermolecular hydrogen bonds N-H--O are reported: 1) 3-ethoxycarbonyl-2-methyl-4-pyridone (hereafter ETPY) and 2) 3-ethoxycarbonyl-2-phenyl-6-methoxycarbonyl-5,6-di-hydro-4-pyridone (hereafter EPPY). The crystal packing is controlled by intermolecular hydro­ gen bonds N-H-0 = C connecting the heteroconjugated enaminone groups in infinite chains. In ETPY crystals the intermolecular hydrogen bond involves the heterodienic pathway with the highest 7r-delocalization that is effective fo ra very short N -O distance of 2.701(9) A (average from two molecules in the asymmetric unit). Probably due to the steric hindrance, the hydrogen bond in EPPY is formed following the heterodienic pathway that involves the ester C = 0 group, although 7r-delocalization along this pathway is less than that along the pyridone-part pathway resulting in a longer N -O distance of 2.886(3) A. In tro d u c tio n 
  Reference    (Z. Naturforsch. 55b, 5—11 [2000]; received August 8 1999) 
  Published    2000 
  Keywords    Pyridone, Dihydropyridone, Enaminone 7r-Conjugated System, Intermolecular Hydrogen Bond, Steric Hindrance 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0005.pdf 
 Identifier    ZNB-2000-55b-0005 
 Volume    55 
3Author    G. Ünter, Paulus Schiem, Ralph Bukowski, Lars Eckholtz, B. Ernhard VamskiihlerRequires cookie*
 Title    peri-Interactions in Naphthalenes, 3 [1]. On Hypercoordination in 8-Dim ethylamino-naphth-l-yl-phosphonium salts and -phosphines  
 Abstract    In (alkyl)di(aryl)(8-dim ethylamino-naphth-l-yl)phosphonium salts and in the parent phos­ phines, there is no experimental evidence of dative N -^ P interactions. Conclusions to the contrary are based on the choice of improper standards of comparison. In tro d u c tio n 
  Reference    (Z. Naturforsch. 55b, 12—20 [2000]; received October 28 1999) 
  Published    2000 
  Keywords    Naphthalenes, 'H NMR Data, ''P NMR Data, Interatomic Distances, Repulsive Interaction 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0012.pdf 
 Identifier    ZNB-2000-55b-0012 
 Volume    55 
4Author    Prof Sonderdruckanforderungen, M. Dr, BinnewiesRequires cookie*
 Title    Untersuchungen zur Thermolyse von Si2OCl6  
 Abstract    The thermolysis of gaseous Si2OCl6 leads to a mixture of higher chlorosiloxanes with up to 8 silicon atoms per molecule. The unexpected formation of larger molecules from smaller ones by high temperature pyrolysis is due to three basic reactions: a) Formation of highly reactive 0 = S iC l2 as an intermediate, b) insertion of 0= S iC l2 into Si-Cl bonds (growth reaction), and c) thermally induced elimination of SiCl4 from chlorosiloxanes formed in (b). Temperature and time dependencies of the thermolysis have been investigated and are discussed. 
  Reference    (Z. Naturforsch. 55b, 21—25 [2000]; eingegangen am 8. September 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0021.pdf 
 Identifier    ZNB-2000-55b-0021 
 Volume    55 
5Author    G. Reta, R. Patzke, M. Ichael, B. Innew IesRequires cookie*
 Title    Chemischer Transport fester Lösungen am Beispiel von Mischspineilen Chem ical Transport o f Solid Solutions: M ixed Spineis  
 Abstract    Chemical vapor transport is a suitable pathway to controllable syntheses of mixed spinel systems. Solid solutions of spinels on the basis of 3d transition metal oxides and gallium oxide can be prepared using various transport agents (TeCl4, Cl2, HC1). Transport processes observed are consistent with theoretical predictions. 
  Reference    (Z. Naturforsch. 55b, 26—34 [2000]; eingegangen am 10. November 1999) 
  Published    2000 
  Keywords    Chemical Vapor Transport, Mixed Spinel Systems, Solid Solutions 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0026.pdf 
 Identifier    ZNB-2000-55b-0026 
 Volume    55 
6Author    M. Ichaela, W. Ilhelm, W. Olfgang Saak, H. Enry StrasdeitRequires cookie*
 Title    Phenylmercury Chloride: Its Single-Crystal X-Ray Structure and Some Aspects of its Biological Chemistry  
 Abstract    A single crystal of phenylmercury chloride (PhHgCl) was obtained by serendipity from a solution of diphenylmercury (HgPh2) and dihydrolipoic acid in tetrahydrofuran / carbon tetrachloride. The crystal structure of PhHgCl is pseudotetragonal. It is best described in the orthorhombic space group Cmma with a = 6.856(1), b = 6.882(1), c = 14.309(2) A (at 193 K), and Z = 4. The Cl-Hg-C moiety of the PhHgCl moleculeois exactly linear. The bond lengths at the Hg atom are Hg-Cl 2.345(2) and Hg-C 2.044(9) Ä. In the crystal, the molecules are arranged in double layers parallel to the a,b plane. In a model medium for the gastric juice (0.1 M DC1 in D 20 / [Dg]dioxan, 37 °C), HgPh2 reacts to form PhHgCl. HgCl2, which would result from complete dearylation, cannot be isolated from the reaction mixture. However, it appears that a small equilibrium concentration of HgCl2 may be present, because on addition of 1,4,7-trithiacyclononane (ttcn) and diethyl ether, the dichloride can be trapped as solid [Hg(ttcn)2][HgCl4]. We estimate that after oral uptake of HgPh2 20 -90% are transformed into PhHgCl in the stomach after 30 min. In tro d u ctio n 
  Reference    (Z. Naturforsch. 55b, 35—38 [2000]; received October 18 1999) 
  Published    2000 
  Keywords    Acidolysis, Bioinorganic Chemistry, Crystal Structure, Mercury, Organomercury Compounds 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0035.pdf 
 Identifier    ZNB-2000-55b-0035 
 Volume    55 
7Author    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 
8Author    W. PreetzRequires cookie*
 Title    Kristallstrukturen  
 Abstract    , Schwingungsspektren und Normalkoordinatenanalyse von (Ph3PNPPh3)[O sF5C l] CH2Cl2 und cis-(Ph3PNPPh3)[OsF4C\2]C H 2Ch Crystal Structures, Vibrational Spectra and N orm al C oordinate A nalysis o f (Ph3P N PP h3) [O sF5Cl] C H 2C12 and ris-(P h 3PN PPh3)[O sF4C l2]-CH2C l2 B. L orenzen By careful oxidation of the pure fluorochloroosmates(IV) with BrF3 in dichloromethane the mixed pentavalent complex anions [OsF5C1]_ and m -[O sF 4Cl2] _ are formed. X-ray structure determinations on single crystals have been performed of (Ph3PNPPh3)[OsF5C l]C H 2Cl2 (1) (triclinic, space group P i, a = 12.153(5), b = 12.387(5), c = 14.229(5) A , a = 70.07(1), ß = 65.46(1), 7 = 72.87(1)°, Z = 2) and ds-(P h 3PNPPh3)[OsF4Cl2] C H 2Cl2 (2) (triclinic, space group P i, a = 11.987(2) b = 13.083(2), c = 14.456(2) A , a = 66.30(1), ß = 65.47(1), 7 = 71.22(1)°, Z = 2). Based on the molecular parameters of the X-ray determinations the IR and Raman spectra for the anions of 1 and 2 have been assigned by normal coordinate analysis. Due to the mutual trans influences the valence force constants of asymmetrically coordinated octahedral axes F*-Os-Cl' differ from those of the symmetric F-Os-F axes. The data are for 1: fd(OsF*) = 3.95, fd(OsF) = 4.07, fd(OsCl') = 2.51 and for 2: fd(OsF*) = 3.45, fd(OsF) = 3.97, fd(OsCl') = 2.42 mdyn/A. 
  Reference    (Z. Naturforsch. 55b, 45—50 [2000]; eingegangen am 9. November 1999) 
  Published    2000 
  Keywords    Pentachlorofluoroosmate(V), ds-Tetrachlorodifluoroosmate(V), Crystal Structure, Vibrational Spectra, Normal Coordinate Analyses 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0045.pdf 
 Identifier    ZNB-2000-55b-0045 
 Volume    55 
9Author    M. Atthias, W. Esterhausen, Tobias Bollw, Kurt PolbornRequires cookie*
 Title    Synthese, Struktur und Reaktivität von Aminomethylpyridin- zinkdihalogeniden Synthesis, Structure and R eactivity o f A m inom ethylpyridine Zinc D ihalides  
 Abstract    Zinc dichloride reacts with aminomethylpyridine (AMP) to the corresponding 1:1 adduct 1, whereas ZnBr2 forms an ionic 1:2 complex of the type [(AMP)2ZnBr]+ Br~ 2, which loses one neutral coligand upon heating in M e-C (0)0E t to yield nearly insoluble (AM P)ZnBr2 3. The condensation reaction of these compounds with acetone yields propylideneaminomethylpyri-dine zinc dichloride (4) and dibromide (5), respectively. The reaction of Z nl2 with AMP and acetone gives propylideneaminomethylpyridine zinc dichloride (6) in quantitative yield. The structures of 3, 4, and 6 confirm the linear relationship between the Zn-N distance and the X-Zn-X angle in compounds of the type (L2)ZnX2 with L2 being a bidentate amino base, whereas short Zn-N bonds enforce small X-Zn-X angles. Compound 2 consists of separated ions in the solid state with a five coordinate zinc atom in a distorted trigonal bipyramidal coordination sphere. 
  Reference    (Z. Naturforsch. 55b, 51—59 [2000]; eingegangen am 9. November 1999) 
  Published    2000 
  Keywords    Halide, Pyridine Complexes, Zinc, X-Ray Data 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0051.pdf 
 Identifier    ZNB-2000-55b-0051 
 Volume    55 
10Author    M. Elanie Piilm, Joachim Becht, R. Einhold TackeRequires cookie*
 Title    Singly Charged A6Si-Silicate Anions with an Si¥5C Skeleton: Syntheses and Crystal Structure Analyses of the Ionic Hexacoordinate Silicon Compounds [Me3NH][F5SiCH2N M e2H ]H 20 and [Me3NH][F5SiCH2NMe3] H2 0  
 Abstract    The zwitterionic A^S/'-tetrafluorosilicates F4SiCH 2N M e2H (1) and F4SiCH2NM e3 (2) behave as Lewis acids and react with [Me3NH]F (molar ratio 1:1) in aqueous solution to yield the ionic A657-pentafluorosilicates [Me3NH][F5SiCH2N M e2H] (3) and [Me3NH][F5SiCH2N M e3l (4), respectively. These hexacoordinate silicon compounds contain singly charged A6S/-silicate anions ([F.sSiCHiNM eiH]-, [F5SiCH2NM e3]-) with an S/F 5 C skeleton. Compounds 3 and 4 were isolated as the crystalline hydrates 3 H 20 (yield 80%) and 4 H 20 (yield 82%) which were structurally characterized by single-crystal X-ray diffraction. The ^/-coordination polyhedra in the crystals of 3 H 20 and 4 H20 are slightly distorted octahedra. 
  Reference    (Z. Naturforsch. 55b, 60—64 [2000]; received October 5 1999) 
  Published    2000 
  Keywords    Pentacoordinate Silicon, Hexacoordinate Silicon, Lewis Acid, Crystal Structure 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0060.pdf 
 Identifier    ZNB-2000-55b-0060 
 Volume    55 
11Author    C. Hennig, H. OppermannRequires cookie*
 Title    Thermische Zersetzung und Lösungskalorimetrie von Ammoniumneodymiodiden Thermal Decomposition and Solution Calorimetry of Ammonium Neodymium Iodides  
 Abstract    The thermodynamical data of ammonium neodymium iodides (N H 4)3N dI6 and (NH4)2NdI5 were derived by the determination of their decomposition equilibria by total pressure measurements. Moreover, solution calorimetry was applied. The enthalpies of for­ mation of these phases were calculated from their heats of solution and from the enthalpies of formation and the heats of solution of N dl3 and NH4I in 4n HI (aq.) at 298 K. Data by total pressure measurement: ZlH ^(N H 4),N dI6f298) = -306,7 ± 4,9 kcal/mol; S°((NH4)3NdI6f298) = 152,8 ± 5,7 cal/K-mol; Z)H ^(NH 4)-,N d i,f,98) = -260,9 ± 4,2 kcal/mol; S°((NH4)2N dI3,f,298) = 114,3 ± 4,7 cal/K-mol. Data by solution calorimetry: ZlHß(Ndl3 f 298) = -154,3 ± 2,0 kcal/mol; z!HB((NH4j,N dI6f298) = -299,6 ± 3,2 kcal/mol; /1H^((NH4)2NdIsf998) = -255,2 ± 2,8 kcal/mol. 
  Reference    (Z. Naturforsch. 55b, 65—73 [2000]; eingegangen am 14. O ktober 1999) 
  Published    2000 
  Keywords    Ammonium Neodymium Iodides, Neodymium Iodide, Thermal Decomposition, Thermodynamical D ata Solution Calorimetry 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0065.pdf 
 Identifier    ZNB-2000-55b-0065 
 Volume    55 
12Author    H. Möhrle, M. JeandréeRequires cookie*
 Title    Reaktionsbeteiligung elektrophiler Funktionen bei der Dehydrierung 4-substituierter Piperidine Participation of Electrophilic Groups with the Dehydrogenation of 4-Substituted Piperidines  
 Abstract    Benzoquinolizidone, Quinolone, N-Arylpiperidone, Neighboring Group Participation. M ercury(II)-EDTA Dehydrogenation Dehydrogenation of 2-(l-piperidinyl)-benzaldehydes 1 -3 using mercury(II)-EDTA gen­ erated the lactams 4-6, indicating a reversible reaction of a carbinolamine intermediate with the formyl group. The yields and oxidation rates decreased by 4-substitution in the piperidine moiety. The 2-(l-piperidinyl)-acetophenones 11, 16-19 showed a similar behavior with mer-cury(II)-EDTA but gave rise to a product pattern. The /rans-benzoquinolizidones 12, 20. 23, 26, 29 resulted from the cyclic iminium compounds reacting with the acetyl group as nucleo­ phile. By another oxidation these species were partially transformed to the quinolinones 13, 21, 24. 27. 30. An intermediate electrophilic neighboring of the carbonyl group with the cyclic hemiaminals led finally to the lactams 14, 22, 25. 28. 31. Mechanisms for the reactions are proposed. 
  Reference    (Z. Naturforsch. 55b, 74—85 [2000]; eingegangen am 26. O ktober 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0074.pdf 
 Identifier    ZNB-2000-55b-0074 
 Volume    55 
13Author    Jutta Knaudta, Stefan Försterb, Ulrich Bartsch3, Anton Riekerb, Ernst-G JägeraRequires cookie*
 Title    Catalytic Oxidation of a Trialkyl-Substituted Phenol and Aniline with Biomimetic Schiff Base Complexes  
 Abstract    The catalytic oxidation of 2,4.6-tri-f6rr-butylphenol and 2,4,6-tri-te/-r-butylaniline with mo­ lecular oxygen and rerf-butylhydroperoxide was investigated using biomimetic Mn-, Fe-and Co-complexes as catalysts. The catalytic activity and product distribution were determined and compared with those observed in the reactions of the well-known Co(salen) complex. 
  Reference    (Z. Naturforsch. 55b, 86—93 [2000]; received Septem ber 22 1999) 
  Published    2000 
  Keywords    Biomimetic Catalysts, Oxidation, Macrocycles, Manganese, Iron, Cobalt 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0086.pdf 
 Identifier    ZNB-2000-55b-0086 
 Volume    55 
14Author    Gerhard Bringmanna, Doris Feineis3, Ralph Brückner, Eva-Maria Petersb, Karl PetersbRequires cookie*
 Title    2-Hexanoyl-l-tribromomethyl-l,2,3,4-tetrahydro-/?-carboline: Crystal Structure Analysis of a Potent Inhibitor of Complex I of Mitochondrial Respiration  
 Abstract    The molecular structure of the title com pound 2-hexanoyl-l-tribromomethyl-l,2,3,4-tetra-hydro-/3-carboline (3), a potent inhibitor of complex I of the mammalian mitochondrial respi­ ratory chain, has been studied by single-crystal X-ray diffraction analysis. In the crystal, two heterochiral molecules of 3 (i.e., one R-and one S-configured molecule each) were found to be connected with one other in pairs via two intermolecular hydrogen bonds [0(215) • • • H(212)' and 0(215)' • • • H(212)] to form an overall achiral 'dimeric' subunit. 
  Reference    (Z. Naturforsch. 55b, 94—99 [2000]; received O ctober 21 1999) 
  Published    2000 
  Keywords    Crystal Structure, Bromal-Derived Tetrahydro-ß-carbolines Mitochondrial Respiration, Parkinson's Disease, Neurotoxicity 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0094.pdf 
 Identifier    ZNB-2000-55b-0094 
 Volume    55 
15Author    Rub Hafiz, Abdul Nawaz, Pir Malik, Saeed Muhammad, Muhammad Ahmed, RiazRequires cookie*
 Title    Chemical Constituents of Ajuga parviflora  
 Abstract    Ajuga parviflora, Labiatae, Antifungal Withanolides, Alkaloids Two new antifungal withanolides, (1) and (2) have been isolated from the defatted metha-nolic extract of A juga parviflora. Their structures were established as 3/3,17/3,20-trihydroxy-l-oxo-(20/?, 22/?)-witha-5,14,24-trienolide (1), 28-hydroxy-14,20-epoxy-l-oxo-(22/?)-witha-2,5,24-trienolide (2) on the basis of spectroscopic data including two dimensional NMR tech­ niques. The pyrrolizidine alkaloids senecionine (3) and integerrimine (4) are also reported for the first time from A. parviflora. 
  Reference    (Z. Naturforsch. 55b, 100—103 [2000]; received July 20 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0100.pdf 
 Identifier    ZNB-2000-55b-0100 
 Volume    55 
16Author    LailaM. Chabaka, YehiaA. Allam, GalalA M NawwarRequires cookie*
 Title    Amino Acid Derivatives in Organic Synthesis, Part 4 [1]: Facile Synthesis of Heterocycles Containing a Glycine Residue  
 Abstract    N-Cyanoacetylglycinates, Thiazolo[2,3-ö] pyridines, Pyridin-l-acetic Acid, Pyrazolo[4,5-6]pyrans 
  Reference    (Z. Naturforsch. 55b, 104—108 [2000]; received August 20 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0104.pdf 
 Identifier    ZNB-2000-55b-0104 
 Volume    55 
17Author    George Sosnovsky3, Mikolaj Jawdosiuk3, J.Michael ClumpnerbRequires cookie*
 Title    Di-ferr-alkyl Nitroxyl Radicals. Synthesis, Physical Properties and Applications as Inhibitors of Vinyl Polmerization at Elevated Temperatures  
  Reference    (Z. Naturforsch. 55b, 109 [2000]) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0109.pdf 
 Identifier    ZNB-2000-55b-0109 
 Volume    55 
18Author    Aym An, W. E. Rian, Y. Vette, A. Issacb, SherifM. Sherif3Requires cookie*
 Title    A Novel Synthesis of Sulfone Systems as Antimicrobial Agents  
 Abstract    Sulfone Systems, Antimicrobial Agents The applicability and synthetic potency of novel reagent, 2-aryl-l,l-dicyano-3-(phenylsulfo-nyl)propenes 3 to develop an expeditious convenient synthetic route of unique polyfunction-ally substituted carbocyclic and heterocyclic sulfone systems is reported. Chemical and spec­ troscopic evidence for the structures o f the newly synthesized compounds are described. Some of the obtained compounds were tested for their antimicrobial activity. 
  Reference    (Z. Naturforsch. 55b, 127 [2000]; received August 3 1999) 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0127.pdf 
 Identifier    ZNB-2000-55b-0127 
 Volume    55 
19Author    H. Andm Ann, M. Arkus, M. Erget, R. Einhold TackeRequires cookie*
 Title    Vera Iris  
 Abstract    4-Sila-proline Skeleton, 4,4-Dimethyl-4-sila-proline Ethyl Ester, a-Amino Acids, Asymmetrie Synthesis, Bioorganosilicon Chemistry In context with studies on silicon-containing a-amino acids and peptides, a strategy for the synthesis of the 4-sila-proline skeleton was developed. The synthesis of rac-and (/?)-4,4-dimethyl-4-sila-proline ethyl ester [rac-2 and (/?)-2] is described. Compounds rac-2 and (R)-2 (> 99% ee) were prepared by two-step syntheses, starting from 3,6-diethoxy-2,5-dihydro-pyrazine and (/?)-3,6-diethoxy-2-isopropyl-2,5-dihydropyrazine, respectively. 
  Reference    Z. Naturforsch. 55b, 133—138 (2000); received October 26 1999 
  Published    2000 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0133.pdf 
 Identifier    ZNB-2000-55b-0133 
 Volume    55 
20Author    A. N. Ägele3, E. A. Nokhinab, J. Sitarb, H.-JM. Eyer3, A. LachgarbRequires cookie*
 Title    Synthesis and Crystal Structures of ATi[Nb6Cli8] Compounds (A = K, Rb, Cs, In, Tl)  
 Abstract    New quaternary niobium cluster chlorides corresponding to the general formula ATi[Nb6Clis] (A = K, Rb, Cs, In, Tl) have been synthesized in sealed quartz tubes at 720 °C, starting from stoichiometric amounts of NbCls, niobium metal, TiCb, and AC1 (A = K, Rb, Cs), or In or Tl metals. The structures of RbTi[Nb6Clis] and CsTifNböClis] were determined using single­ crystal X-ray diffraction. RbTifNböClis] crystallizes in the rhombohedral crystal system, space group R3 (no. 148), Z = 3, with lattice parameters: a = 9.163(4), c = 25.014(14) A (hexagonal setting). The structure refinement converged to R] = 0.044 and wRi = 0.058 for all data. In this structure, discrete [NböClig]4-cluster units are linked by Rb+ and Ti3+ cations, located in a 12-coordinated anticubeoctahedral and octahedral chloride coordination environment, respectively. In contrast, CsTifNböClis] crystallizes in the trigonal crystal system, space group P31c (no. 163), Z = 2. The lattice parameters were determined to be a -9.1075(6), c = 17.0017(8) A. The structure refinement gives the reliability factors Ri = 0.029 and wRa = 0.063 for all data. The structure is built up of discrete octahedral [N bödis]4-cluster units, linked by Cs+ and Ti3+ cations which are located in a distorted hexagonal antiprismatic and octahedral chloride coordination environment, respectively. The structures of the compounds ATifNböClis] (A = K, In, Tl) were found to be isotypic with RbTi[NböCli8], and their unit cell parameters were refined using X-ray powder diffraction analysis. In tro d u ctio n 
  Reference    Z. Naturforsch. 55b, 139—144 (2000); received September 13 1999 
  Published    2000 
  Keywords    Niobium, Titanium, Cluster, Chlorides, Synthesis 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0139.pdf 
 Identifier    ZNB-2000-55b-0139 
 Volume    55 
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