Published by De Gruyter

Volume 55 Issue 5

Issue of Zeitschrift für Naturforschung B

Contents
Journal Overview

June 2, 2014

Crystal and Molecular Structures of the Sulfurization and Selenation Products of Bis[bis(trimethylsilyl)amino]germanium(II). Crystal Structure of (Triphenylphosphine)gold(I) Bis(trimethylsilyl)amide

Gerald L. Wegner, Alexander Jockisch, Annette Schier, Hubert Schmidbaur

Page range: 347-351

Abstract

Treatment of bis[bis(trimethylsilyl)amino]germanium(II) with elemental sulfur or selenium affords high yields of the corresponding monosulfide [(Me 3 Si) 2 N] 2 GeS and selenide [(Me 3 Si) 2 N] 2 GeSe, respectively. The crystalline products have now been shown to be cyclic dimers with (GeS/Se) 2 four-membered rings by X-ray single crystal structure analysis. The crystal structure of (triphenylphosphine)gold(I) bis(trimethylsilyl)amide (Ph 3 P)Au-N(SiMe 3 ) 2 has also been determined. The molecule is a monomer with a tricoordinate nitrogen atom in a planar configuration [Si 2 NAu]. The compound does not undergo insertion of the bis[bis(trimethylsilyl)amino]germylene.

June 2, 2014

New Diazasilaphosphetidines and their Precursors

Bettina Eichhorn, Heinrich Nöth

Page range: 352-360

Abstract

A series of aminosilanes (R′HN) 2 SiR 2 : have been prepared. In case of bulky substituents R′ the aminolysis of Ph 2 SiCl 2 stops at the (R′HN)ClSiPh 2 stage. Replacement of the Cl atom is achieved with LiNHR′ which allows the synthesis of mixed bisaminosilanes (R′HN)(R″HN)SiPh 2 . The X-ray structures of three of these compounds have been determined. There are no intermolecular N-H···N hydrogen bonds in these compounds in the solid state. Several 1,3,2,4-diazaphosphetidines have been synthesized using bis(N-lithioamino)silanes and bis(N-lithioamino)phosphanes . Amongst these the heterocycle 18 possesses an almost planar four membered N 2 SiP ring system.

June 2, 2014

The Solid State Conformation of Diaryl Ditellurides and Diselenides: The Crystal and Molecular Structures of (C₄H₃E₂)₂E'₂ (E = O, S; E' = Te, Se)

Raija Oilunkaniemi, Risto S. Laitinen, Markku Ahlgrén

Page range: 361-368

Abstract

The crystal and molecular structures of dithienyl ditelluride (C 4 H 3 S) 2 Te 2 (1), difuryl ditelluride (C 4 H 3 O) 2 Te 2 (2), dithienyl diselenide (C 4 H 3 S) 2 Se 2 (3), and difuryl diselenide (C 4 H 3 O) 2 Se 2 (4) are reported in this paper and compared to those of other simple diaryl ditellurides and diselenides. The chalcogen-chajcogen bonds exhibit approximately single bond lengths [Te-Te = 2.7337(8) and 2.7240(4) Å in 1 and 2, respectively; Se-Se = 2.357(1) and 2.368(2) Å in 3 and 4, respectively], as do the chalcogen-carbon bond lengths [Te-C = 2.095(9) - 2.104(6) in 1 and 2.091(6) - 2.105(9) Å in 2; Se-C = 1.87(1) - 1.90(1) Å in 3 and 1.887(8) - 1.897(10) Å in 4]. The aromatic rings are disordered. The dihedral angles C-E-E-C range from 79(2) to 96(1)° are consistent with the concept of minimized p lone-pair repulsion of adjacent chalcogen atoms. The dependence of molecular parameters on the angle between the aromatic rings and the chalcogen-chalcogen bonds follow trends established previously for aromatic disulfides. Though the bond parameters and conformations of 1 - 4 are similar, the packing of the molecules is different. The two ditellurides 1 and 2 show short Te···Te contacts (3.900 - 4.002 Å in 1 and 4.060 - 4.172 Å in 2). The two diselenides 3 and 4 do not exhibit close chalcogen-chalcogen interactions. The NMR spectroscopic properties of 1 - 4 are discussed.

June 2, 2014

Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung / Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung

Henri Brunner, Peter Schmidt

Page range: 369-372

Abstract

2-Aryl-substituted propionic acids, such as the important anti-inflammatory agent Naproxen, exist in two enantiomeric forms. The (S)-enantiomer of 2-(6-methoxynaphth-2-yl)propionic acid 1 is about 28 times more effective than the (S)-enantiomer. A new catalytic method to synthesize Naproxen (S)-1 involves the enantioselective decarboxylation of suitably substituted malonic acid derivatives. Thus, 2-(6-methoxynaphth-2-yl)-2-methylmalonic acid 6 and its monoester 7 were stirred in THF with catalytic amounts of chiral bases, which induced decarboxylation. After work-up, optical inductions up to 39.8% ee were found in the resulting products 1 and 9. The optically active bases may be fully recycled by extraction.

June 2, 2014

Synthesis and Structure of a Palladium(II) Chloride Complex with 2-(2-Methyl-3-phenyl-isoxazolidin-5-yl)-pyridine

Andrey B. Lysenko, Oleg V. Shishkin, Rostislav D. Lampeka

Page range: 373-376

Abstract

The 1:1 complex of palladium(II) chloride with 2-(2-methyl-3-phenyl-isoxazolidin-5-yl)- pyridine (L) has been prepared and studied by means of elemental analysis, 1 H NMR spectroscopy and X-ray diffraction (monoclinic, space group P2 1 /n with parameters: a = 8.141(2), b = 9.750(2),c = 20.691(6)Å ,β = 95.62(3)°,V = 1634.4(7)Å 3 ,Z = 4 ;R1= 0.054 and wR2= 0.144 for 3352 unique reflections). A square-planar coordination polyhedron has been established for the palladium atom both in acetone solution and in the solid state. The organic ligand is coordinated toometal in a bidentate manner via nitrogen atoms of the pyridine substituent (Pd-N(2) 2.125(3) Å) and the isoxazolidine heterocycle (Pd-N(l) 2.102(3) Å). The other two coordination positions of palladium are occupied by chlorine atoms (Pd-Cl(l) 2.321(1) and Pd-Cl(2) 2.333(1) Å). The six-membered chelate ring formed by Pd, N(2), C(4), C(1), 0(1) and N (1) possesses a “twist-tub” conformation. The isoxazolidine cycle has an envelope conformation with an equatorial orientation of the methyl group.

June 2, 2014

Synthesis and Characterization of Bromo- and Bromochloroplumbates(II). Crystal Structures of [Ph₄E]₂[Pb₃Br₈] (E = P, As) and [Ph₄P][PbBrCl₂] • CH₃CN

Thomas M. Klapötke, Burkhard Krumm, Kurt Polbom, Claudia M. Rienäcker

Page range: 377-382

Abstract

[Ph 4 P] 2 [Pb 3 Br 8 ] and [Ph 4 As] 2 [Pb 3 Br 8 ] crystallize both in the monoclinic space group P 2 1 /n. The lattice parameters of [Ph 4 P] 2 [Pb 3 Br 8 ] are a = 14.637(7), b = 8.151(3), c = 23.388(8) Å, β = 106.02(3)°, Z = 2 and of [Ph 4 As] 2 [Pb 3 Br 8 ] are a = 14.697(7), b = 8.219(3), c = 23.527(8) Å, β = 106.27(3)°, Z = 2. The lattice parameters of [Ph 4 P][PbBrCl 2 ]·CH 3 CN, which crystallizes in the triclinic space group (P 1̅), are a = 9.435(3), b = 10.2577(14), c = 14.055(2) Å, α = 88.320(11)°, β = 84.82(2)°, γ = 84.19(2)°, Z = 2. 207 Pb NMR shifts of halogenoplumbates in solution are reported.

June 2, 2014

Kristallstruktur und schwingungsspektroskopische Daten von Silbercyanamid / Crystal Structure and Spectroscopic Data of Silver Cyanamide

Michael Becker, Jürgen Nuss, Martin Jansen

Page range: 383-385

Abstract

Ag 2 CN 2 precipitates on mixing aqueous solutions of H 2 CN 2 and silver nitrate as a yellow crystalline solid. The title compound was characterised by single crystal X-ray diffraction and IR-spectroscopy (monoclinic, P2 1 /c (No. 14), a = 7.315(1), b = 6.010(1), c = 6.684(1) Å; β = 102.29( 1)°; Z = 4). The anion is slightly bent (177.1 (5)°) and exhibits two significantly different bond lengths (C-N(l): 1.194(6), C-N(2): 1.266(5) Å).

June 2, 2014

Luminescence Detection and Photodimerization of 1,3-Dimethyluracil Coordinated to Copper(I)

Horst Kunkely, Amd Vogler

Page range: 386-388

Abstract

1,3-Dimethyluracil (DMU) forms a complex with copper(I) iodide which shows a green luminescence at λ max = 505 nm. With PF 6 - counter ions a photoactive Cu(I)DMU complex is generated which shows a long-wavelength absorption at λ max = 335 nm. Light absorption by this band leads to a dimerization of DMU to its cyclobutane dimer.

June 2, 2014

Supersilylsilane RSiX₃: Darstellung, Charakterisierung und Strukturen; sterische und van-der-Waals Effekte der Substituenten X [1] / Supersilylsilanes RSiX₃: Syntheses, Characterization and Structures; Steric and van-der-Waals Effects of Substituents X [1]

Nils Wiberg, Wolfgang Niedermayer, Heinrich Nöth, Jörg Knizek, Werner Ponikwar, Kurt Polbom

Page range: 389-405

Abstract

Supersilylsilanes R*SiX 3 (R* = supersilyl = SitBu 3 ; X = H, Me, tBu, Ph, SiMe 3 , F, Cl, Br, I, OMe, OSO 2 CF 3 ) are prepared (i) by reactions of supersilylhalosilanes with supersilyl sodium NaR* (Hal/R* exchange), (ii) by reactions of supersilylhalosilanes with hydride H - (Hal/H exchange), (iii) by reactions of supersilylsilanes with halogens Hal 2 (H/Hal exchange, R*/Hal exchange), (iv) by reactions of supersilylhalosilanes with nucleophiles like F - , MeO - (Hal/F or Hal/OMe exchange) and (v) by reactions of supersilylsilanes with strong acids (H/OSO 2 CF 3 exchange). NMR chemical shifts δ ( 29 Si) of the SiX 3 groups of R*SiX 3 strongly depends on the nature of X. The supersilylsilanes R*SiX 3 are in part moisture sensitive (especially compounds with SiX 3 ≡SiHHal 2 and SiH 2 Hal), in part sensitive against oxygen (compounds with SiX≡SiBr or SiI), and some of them react with supersilyl sodium by supersilanidation (for example R*SiF 3 , R*SiH 2 Cl, R*SiMeHCl) or by reduction (for example R*SiCl 3 , R*SiMeBr 2 , R*SiPhBrCl). X-ray structure analyses of disilanes tBu 3 Si-SiX 3 with SiX 3 ≡SitBu 3 , SiPh 3 , Sil 3 , SiPhCl 2 show a staggered conformation. Due to steric repulsion of the tBu 3 Si and SiX 3 groups as well as van-der-Waals attraction of the substituents tBu and X in tBu 3 Si-SiX 3 the SiSi bonds are longer than 2.34 Å (the normal SiSi single bond length) and the torsion angles are smaller/larger than 60° (the ideal staggered conformation). From the extent of SiSi bond elongation and CSiSiX angle compression it is concluded that the bulkiness of X increases in direction Cl < I < Ph < SiMe 3 < CMe 3 (tBu 3 Si-SitBu 3 has to date the longest SiSi bond of all disilanes) and the van-der-Waals forces between tBu/X increase in direction tBu/I < tBu/tBu < tBu/Ph.

June 2, 2014

Supersilylsilane RSiX₃: Umwandlung in Disilane RX₂Si-SiX₂R, Silylene RXSi, Cyclosilane (RXSi)_n, Disilene RXSi=SiXR, Tetrasupersilyl-tetrahedro-tetrasilan [1] / Supersilylsilanes RSiX₃: Conversion into Disilanes RX₂Si-SiX₂R, Silylenes RXSi, Cyclosilanes (RXSi)_n, D isilenes RXSi=SiXR, Tetrasupersilyl-tetrahedro-tetrasilane [1]

Nils Wiberg, Wolfgang Niederm

Page range: 406-416

Abstract

Supersilylmonohalosilanes R*R SiHCl (R * = Supersilyl = SitBu 3 ) react with Na in C 6 H 6 at 65 °C or with NaC 10 H 8 in THF at - 78 °C with formation of disupersilyldisilanes R*RHSi- SiHRR * in quantitative (R = H , Me) or moderate yields (R = Ph). In the latter case, R *PhSiH 2 is obtained additionally at 65 °C (exclusively with Na in THF at 65 °C). Obviously, the supersilylsilanides NaSiHRR* are generated as interm ediates which react with educts R *RSiHCl with NaCl elimination and formation of R*RHSi-SiHRR* (R = H , Me) or R *RSiH 2 and R *R Si (R = Ph). The silylene intermediate R*PhSi inserts into the SiH -bonds of the educt R*PhSiHCl and of the product R *PhSiH 2 with formation of the disupersilyldisilanes R*PhSiH -SiClPhR* and R*PhSiH -SiHPhR* which are reduced by Na at 65 °C to R*PhSiH 2 (and by NaC 10 H 8 at low tem peratures to give R*PhSiH-SiHPhR*). The addition of NaR * to R*RSiHCl in THF at low temperatures leads with NaCl elimination to R* 2 RSiH (R = H , Me) or to R*RHSi-SiHRR* (R = Me) besides R*C1, or to R*RHSi-SiClRR* (R = Ph) besides R*H and NaR , whereas the addition of R*PhSiH Cl to NaR* in THF at low temperatures results in the formation of NaSiPhR* 2 besides R*H and NaCl. In the latter cases (R = Ph), NaR* react with R*PhSiHCl to release the silylene R*PhSi, the transistory existence of which could be proven by trapping it with Et 3 SiH (formation of R *Ph(Et 3 Si)-SiH ). Subsequently, R*PhSi inserts into the SiH bond of R*PhSiH Cl (addition of NaR* to R*PhSiHCl) or into the NaSi bond of NaR * (addition of R*PhSiHCl to NaR *). - Supersilyldihalosilanes R*SiHCl 2 are converted by Mg in C 6 H 6 at 65 °C into cyclosilanes (R *SiH) n (n = 3, 4) and R*PhSiBrCl by Na at low temperatures - via the silylene R*PhSi - into the disilene R*PhSi=SiPhR*. which is reduced by excess Na to an anion radical. - Supersilyltrihalosilanes R*SiBr 2 Cl, R*SiBr 3 and R*SiI 3 react with Na, NaC 10 H 8 or NaR* in T H F with formation of tetrasupersilyl-terrahedro-tetrasilane (R*Si) 4 in quantitative yields, whereas the reactions of R*SiCl 3 with LiC 10 H 8 in THF at 45 °C lead to (R*Si) 4 only in m oderate yields. Obviously, the tetrahedrane is formed from R*SiHal 3 via R*SiHal 2 Na and R*HalSi=SiHalR* as reaction intermediates. The results lead to the following conclusions: (i) Silylenes play a rôle in dehalogenation of “sterically overloaded" supersilylhalosilanes R*R 3-n SiHal n· - (ii) A straight-forward procedure for a high-yield synthesis of (R *Si) 4 from easily available educts consists in supersilanidation of SiH 2 Cl 2 with NaR*, bromination of the formed supersilylsilane R*SiH 2 Cl with Br 2 and dehalogenation of the bromination product R*SiBr 2 Cl with Na.

June 2, 2014

Chemistry of Seven-Membered Heterocycles, VI. Synthesis of Novel Bicyclic Heterocyclic Compounds as Potential Anticancer and Anti-HIV Agents

Abou Elfatooh G. Hammam, Nagla A. Abd El-hafeza, Wanda H. Midurab, Marian Mikołajczyk

Page range: 417-424

Abstract

Several new pyridines, pyridones and pyrans fused to benzothiepine or benzoheptene ring were synthesized as potential anticancer and anti-HIV agents. The fused-ring pyridines 6. 7 and 17-19 were obtained via the reaction of the seven-membered ring ketones 1, 2 and 3 with an arylidene-malononitrile and by treatment of the ylidenemalononitriles 14, 15 and 16 with aromatic aldehydes, respectively. The corresponding pyridones 11, 12 and 13 were prepared from the ketones 1, 2 and 3 and arylmethylenecyanoacetamide. The synthesis of the fused-ring pyranes 8 and 9 involved the condensation of the ketones 4 and 5 with malononitrile under basic conditions. The rearrangement of 8 under acidic conditions gave the tetrahydropyridine 10. The pyran 20 was obtained from 15 and benzaldehyde. The screening tests showed that many of the compounds obtained exhibit good anticancer activity comparable to 5-fluorodeoxyuridine used as reference compound and moderate anti-HIV activity in comparison with AZT.

June 2, 2014

Crystal Structure and Properties of the Titanium Stannide Ti₂Sn₃

Bernd Künnen, Wolfgang Jeitschko, Gunter Kotzyba, B. D. Mosel

Page range: 425-430

Abstract

The recently reported binary stannide Ti 2 Sn 3 is confirmed. Its structure was determined from single-crystal X-ray diffractometer data: Cmca, a = 596.7(4), b = 1995(2), c = 701.3(4) pm , Z = 8, R = 0.027 for 817 structure factors and 30 variable parameters. The crystal structure is compared to that of V 2 GaSn 2 , which has the same space group symmetry and atomic positions. The Ga atoms of V 2 GaSn 2 occupy those Sn positions of Ti 2 Sn 3 which have the smaller coordination number. The two different titanium atoms of Ti 2 Sn 3 have 11 neighbors of which 3 and 4, respectively, are titanium atoms. The three different tin atoms have 5 titanium with 8 or 10 additional tin neighbors. They show only a slightly broadened but unresolved 119 Sn Mössbauer signal with an isomer shift reflecting the high tin content of this intermetallic compound and a relatively large quadrupole splitting of 2.10 mm·s -1 . Ti 2 Sn 3 is a good metallic conductor and a Pauli paramagnet.

June 2, 2014

Regeneration of Carbonyl Compounds from Oximes under Microwave Irradiation in Solventless System

Majid M. Heravia, Dariush Ajami, Rahim Hekmatshoar, Yahya Sh. Beheshtiha, Karim Assadollah, Mitra Ghassem

Page range: 431-433

Abstract

A new, mild, efficient and environm entally benign method for the cleavage of oximes has been achieved by a simple reaction f oximes with wet alumina supported chromium (VI) oxide under microwave irradiations in solvent-free condition.

June 2, 2014

Umsetzung von N-Alkylpyridinium-Salzen mit Hydroxylamin / Reaction of N-Alkylpyridinium Salts with Hydroxylamine

Hans Möhrle, Robert Nießen

Page range: 434-442

Abstract

1-Methylpyridinium salts showed no reaction with excessive hydroxylamine, but nicotinic acid derivatives in HMPT gave the corresponding N-oxides. 3-Acetyl-1-methylpyridinium iodide generated the hydroximino-pyridine 1-oxide 13 and the isoxazoles 14, 15E, and 15Z. 2- and 4-Cyano-l-methylpyridinium iodides underwent no ring cleavage, but altered only the functional group. However, the 3-cyano compound was converted into the corresponding pyridine N-oxides with carboxamide, hydroxyamidine and carbaldoxime groups.

June 2, 2014

Enaminouraciles as Precursors for Synthesis of Pyrimido[4,5-a]pyrimidine- 2,4-diones

W. S. Hamama

Page range: 443-447

Abstract

The reaction of 6-aminouracil 1 with formaldehyde and secondary amines in ethanol at room temperature gave the corresponding 5-alkylaminomethyl derivatives (2a-c) and bis(4- pyrimidyl) methane (4). Also, Mannich reaction with primary aliphatic and aromatic amines at room temperature afforded pyrimid[4,5-d]pyrimidine (5 and 6). Treatment of 1 with o-phenylenediamine through transamination gave com pound 7 which cyclized through intramolecular Mannich reaction with formalin to yield pyrimido[4,5-e]-[l,4]diazepine (8).

June 2, 2014

[Co₄(ν₃-NPEt3)₂(HNPEt₃)₂(O₂C-CH₃)₂- (ν-OSiMe₂OSiMe₂O)₂] - ein vierkerniger Cobalt(II)-Komplex mit Leiterstruktur / [Co₄(ν₃-NPEt₃)₂(HNPEt₃)₂(O₂C-CH₃)₂-(ν-OSiMe₂OSiMe₂O)₂] - a Tetranuclear Cobalt(II) Complex with Ladder Structure

Hartmut Ackermann, Frank Weller, Kurt Dehnicke

Page range: 448-452

Abstract

The title compound has been prepared from cobalt( II) acetate and Me 3 SiNPEt 3 in boiling toluene in the presence of silicon grease and traces of water as blue single crystals which were characterized by IR spectroscopy and by a crystal structure determination. Space group Pbca, Z = 8, lattice dimensions at -50 °C: a = 1449.3(1), b = 1724.9(1), c = 2356.6(2) pm, R = 0.0548. [Co 4 (ν 3 -NPEt 3 ) 2 (HNPEt 3 ) 2 (O 2 C-CH 3 ) 2 -(v-OSiMe 2 OSiMe 2 O) 2 ] has a centrosymmetric structure. The four cobalt atoms which are coordinated tetrahedrally are v 3 -bridged via the N atoms of the two (NPEt 3 - ) groups and v 2 -bridged by the O atoms of the chelating (OSiMe 2 OSi-Me 2 O 2- ) units. The core atoms are arranged in three four-membered rings which are connected in a stair-like way.

About this journal

Objective
Zeitschrift fuer Naturforschung B (ZNB) publishes novel research in all areas of inorganic chemistry, organic chemistry, and analytical chemistry. In particular, the journal focuses on solid state chemistry, coordination chemistry, main group element chemistry, synthetic organic chemistry, natural product chemistry and, to a lesser extent, on analytical chemistry. For more than 65 years Zeitschrift fuer Naturforschung B has been open to contributions from all fields of experimental and theoretical chemistry. Zeitschrift fuer Naturforschung B publishes 12 issues per volume/year. Sometimes double issues occur.

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Solid state chemistry
Coordination chemistry
Main group element chemistry
Organic chemistry
Natural product chemistry

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Original (full) papers, research notes and preliminary communications, reports on specific research topics of current interest (reviews)

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Volume 55 Issue 5

Issue of Zeitschrift für Naturforschung B

Crystal and Molecular Structures of the Sulfurization and Selenation Products of Bis[bis(trimethylsilyl)amino]germanium(II). Crystal Structure of (Triphenylphosphine)gold(I) Bis(trimethylsilyl)amide

Abstract

New Diazasilaphosphetidines and their Precursors

Abstract

The Solid State Conformation of Diaryl Ditellurides and Diselenides: The Crystal and Molecular Structures of (C4H3E2)2E'2 (E = O, S; E' = Te, Se)

Abstract

Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung / Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung

Abstract

Synthesis and Structure of a Palladium(II) Chloride Complex with 2-(2-Methyl-3-phenyl-isoxazolidin-5-yl)-pyridine

Abstract

Synthesis and Characterization of Bromo- and Bromochloroplumbates(II). Crystal Structures of [Ph4E]2[Pb3Br8] (E = P, As) and [Ph4P][PbBrCl2] • CH3CN

Abstract

Kristallstruktur und schwingungsspektroskopische Daten von Silbercyanamid / Crystal Structure and Spectroscopic Data of Silver Cyanamide

Abstract

Luminescence Detection and Photodimerization of 1,3-Dimethyluracil Coordinated to Copper(I)

Abstract

Supersilylsilane R*SiX3: Darstellung, Charakterisierung und Strukturen; sterische und van-der-Waals Effekte der Substituenten X [1] / Supersilylsilanes R*SiX3: Syntheses, Characterization and Structures; Steric and van-der-Waals Effects of Substituents X [1]

Abstract

Abstract

Chemistry of Seven-Membered Heterocycles, VI. Synthesis of Novel Bicyclic Heterocyclic Compounds as Potential Anticancer and Anti-HIV Agents

Abstract

Crystal Structure and Properties of the Titanium Stannide Ti2Sn3

Abstract

Regeneration of Carbonyl Compounds from Oximes under Microwave Irradiation in Solventless System

Abstract

Umsetzung von N-Alkylpyridinium-Salzen mit Hydroxylamin / Reaction of N-Alkylpyridinium Salts with Hydroxylamine

Abstract

Enaminouraciles as Precursors for Synthesis of Pyrimido[4,5-a]pyrimidine- 2,4-diones

Abstract

[Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2- (ν-OSiMe2OSiMe2O)2] - ein vierkerniger Cobalt(II)-Komplex mit Leiterstruktur / [Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(ν-OSiMe2OSiMe2O)2] - a Tetranuclear Cobalt(II) Complex with Ladder Structure

Abstract

The Solid State Conformation of Diaryl Ditellurides and Diselenides: The Crystal and Molecular Structures of (C₄H₃E₂)₂E'₂ (E = O, S; E' = Te, Se)

Synthesis and Characterization of Bromo- and Bromochloroplumbates(II). Crystal Structures of [Ph₄E]₂[Pb₃Br₈] (E = P, As) and [Ph₄P][PbBrCl₂] • CH₃CN

Supersilylsilane RSiX₃: Darstellung, Charakterisierung und Strukturen; sterische und van-der-Waals Effekte der Substituenten X [1] / Supersilylsilanes RSiX₃: Syntheses, Characterization and Structures; Steric and van-der-Waals Effects of Substituents X [1]

Crystal Structure and Properties of the Titanium Stannide Ti₂Sn₃

[Co₄(ν₃-NPEt3)₂(HNPEt₃)₂(O₂C-CH₃)₂- (ν-OSiMe₂OSiMe₂O)₂] - ein vierkerniger Cobalt(II)-Komplex mit Leiterstruktur / [Co₄(ν₃-NPEt₃)₂(HNPEt₃)₂(O₂C-CH₃)₂-(ν-OSiMe₂OSiMe₂O)₂] - a Tetranuclear Cobalt(II) Complex with Ladder Structure