bluuebunny/crossref_metadata_2025 huggingface dataset:
Eisen- und Cobaltkomplexe mit Schwefelliganden: Darstellung und Kristallstrukturen von [Fe { S2P(p-C6H4Me)2}2(MeOH)2] · 2 MeOH, [Fe { S2P(p-C6H4Me)2}2(THF)2], [Fe{ S2P(p-C6H4Me)2}2(THT)2]· THT, [Fe { S2P(p-C6H4Me)2}2(DMF)2]·2 DMF und [Co { S2P(p-C6H4Me)2}2(DMF)2] · 2 DMF / Iron and Cobalt Complexes with Sulfur-Containing Ligands: Preparation and Crystal Structures of [Fe{S,P(p-C6H4Me),},(MeOH),] • 2 MeOH, [Fe{ S,P(p-C6H4Me)2}2(THF)2], [Fe{S2P(p-C6H4Me)2}2(THT)2] · THT, [Fe{S2P(p-C6H4Me)2}2(DMF)2] · 2 DMF, and [Co{S2P(p-C6H4Me)2}2(DMF)2] · 2 DMF
Authors: Kirschbaum Kristin , Greiwe Klaus , Müller Kay , Strasdeit Henry , Krebs Bernt , Henkel Gerald
Published: March 2015

A series of novel Fe(II) and Co(II) complexes containing dithiophosphinate groups and neutral ligands with sulfur and oxygen donor functions was prepared in non-aqueous solutions. The reaction systems FeSO4/Na{S2P(p-C6H4Me)2} and CoCl2/Na{S2P(p-C6H4Me)2} in different organic solvents afford the mononuclear complexes [Fe{S2P(p-C6H4Me)2}2(MeOH)2], [Fe{S2P(p-C6H4Me)2}2(THF),], [Fe{S2P(p-C6H4Me)2}2(THT)2],[Fe{S,P(p-C6H4Me)2}2(DMF)2], [Co {S2P(p-C6H4Me),},(DMF)2] which were isolated as crystalline [Fe{S2P(p-C6H4Me)2}2(MeOH)2]·2MeOH (1), [Fe{S,P(p-C6H4Me)2}2(THF)2] (2), [Fe{S2P(p-C6H4Me)2}2(THT)2]-THT (3), [Fe{S2P(p-C6H4Me)2}2(DMF)2] · 2 DMF (4), and [Co{S2P(p-C6H4Me)2},(DMF)2] · 2DMF (5), respectively. Crystals of 1 are monoclinic, space group P21/c. Z – 2, a⁻ 11.013(3), b = 14.402(3), c = 11 600(3) Å. β = 106.25(2). The structure of 1 was refined to R(Rη) = 0.030 (0.040). Compound 2 is triclinic, space group P 1, Ζ = 1 with a = 6.921(2), b = 9.353(3), c = 14.436(4) Å, α = 83.56(3), β = 85.39(3) and γ = 80.46(2). Its structure was refined to R(Rw) = 0.029 (0.035). 3 crystallizes in the triclinic space group P l̄ with a = 9.204(3), b = 11.378(3), c = 11.389(4) Å α = 97.41(3), β = 114.00(2), γ = 100.69(2) and Ζ = 1. The refinement converged to R(Rw) = 0.057 (0.073). Crystals of 4 and 5 are monoclinic, space group P21/n (Z = 2): Fe(II), a = 12.395(3), b = 11.077(2), c = 16.377(4) Å, β = 95.51(2); Co(II),α= 12.299(3), b = 11.055(2), c = 16.452(4) Å, β = 95.90(2). The refinements converged to R(Rw) = 0.045 (0.046) and 0.027 (0.033), respectively. The neutral complexes 1-5 contain six-coordinated metal centers with either MS4O2 or MS6 chromophores. They represent the first examples of structurally defined mononuclear Fe(II) and Co(II) complexes containing 1,1-dithiolate groups as well as additional neutral ligands with sulfur or oxygen donor functions.
Metal Complexes with Tetrapyrrole Ligands, LV [ 1 ] Improved Syntheses of Oxorhenium(V) Porphyrins and Novel Trichlororhenium(V) Porphyrins
Authors: Buchler Johann W. , Kruppa Steffen B.
Published: March 2015

The reaction of ReCl5 with a porphyrin H2(P) [2, 3] in refluxing trichlorobenzene represents a very efficient synthesis of oxorhenium(V) porphyrins ReO(P)X where X is a uninegative anion. Thus, rhenium is inserted to octaethylporphyrin and a variety of tetraarylporphyrins. The primary products are the paramagnetic trichlororhenium(V) porphyrins, ReCl3(P), which are remarkably resistant to hydrolysis. If moisture is not rigorously excluded from the metal insertion system, chlorooxorhenium(V) porphyrins ReO(P)Cl are formed which during alumina chromatography are converted to the methoxides ReO(P)OMe. All complexes ReO(P)X and ReCl3(P) are subject to alkaline hydrolysis yielding the μ-oxo complexes [ReO(P)]2O which are convenient starting materials for a variety of mononuclear species ReO(P)X [X = OMe, OEt, OiPr, OtBu, F, Cl, Br, OCIO3, OAc, OBz, OCN, NCS] on acidolysis with a number of monobasic inorganic and organic acids HX or reaction with alkali salts MX in presence of acetic acid. In the case of tetramesitylporphyrin, hydrolysis yields a mononuclear hydroxooxorhenium(V) porphyrin. The species ReCl3(P) and ReO(P)X are characterized by UV/VIS, IR, 1H NMR and mass spectra.
Notizen: Na5HfAs3, eine neue Zintl-Phase mit kantenverknüpften HfAs4-Doppeltetraedern / Na5HfAs3, a New Zintl Compound With Two HfAs4-Tetrahedra Sharing a Common Edge
Authors: Adam Arnold , Schuster Hans-Uwe
Published: March 2015

The new compound Na5HfAs3 crystallizes in a Na5SiP3 type structure (monoclinic system, space group P21/n (Nr. 14)) with the lattice constants: a = 1384.4(1) pm, b = 754.9(1) pm, c = 843.3(1) pm, β = 89.63(1)°. Two HfAs4-tetrahedra are connected by a common edge to form (Hf2As6)10-anions.
Notizen: Synthese und Kristallstruktur von [Co(15-Krone-5)(CH3CN)2]CoCl4 · CH3CN / Synthesis and Crystal Structure of [Co( 15-Crown-5)(CH3CN)2]CoCl4 · CH3CN
Authors: Massa Werner , Ernst Thilo , Dehnicke Kurt
Published: March 2015

The title compound has been prepared by the reaction of 15-crown-5 with a solution of CoCl2 in acetonitrile. It forms blue crystals, which were characterized by an X-ray structure determination. Space group Pca 21, Z = 4, 2883 observed unique reflexions, R = 0.032. Lattice dimensions at –80 °C: a = 1420.9(3), b = 1017.2(2), c = 1775.0(3) pm. The lattice contains the complex ions [Co(15-crown-5)(CH3CN)2]2+ and CoCl4
2-, and interstitial CH3CN molecules. In the cation CoII is seven-coordinate by the five oxygen atoms of the crown ether molecule and by two nitrogen atoms of the acetonitrile molecules in axial positions of a pentagonal bipyramide.
Neue Mangan(III)-Fluoridhydrate: Na[MnF4(H2O)2] und Na[MnF4(H2O)2] · H2O / New Fluoride Hydrates of Manganese(III): Na[MnF4(H2O)2] and Na[MnF4(H2O)2] · H2O
Authors: Massa Werner , Schmidt Roland E.
Published: March 2015

Crystalline Na[MnF4(H2O)2] and Na[MnF4(H2O)2] · H2O have been precipitated from aqueous HF solution of MnO(OH) and NaF. The crystal structure determination of the trihydrate (space group C 2/c, Z = 8, α = 1638.1(2), b = 667.6(2), c = 1130.3(1) pm, β = 103.78(1)°; R/wR = 0.038/0.033 for 1696 independent reflections) showed the presence of isolated octahedral trans-[MnF4(H2O)2]- anions with an elongation of the H2O-Mn—OH2 axis due to the Jahn-Teller effect (Mn 1-O 224.6(2), Mn 1—F(mean) 183.7(1); Mn2-0 218.3(2), Mn2— F(mean) 184.7(2) pm). As a consequence, an unusual H-bond geometry is observed with a tetrahedral (instead of trigonal) environment of the coordinated O atoms. Na[MnF4(H2O)2] is monoclinic (space group C 2/m, C 2 or Cm, a = 816.6(4), b = 677.1(1), c = 496.8(2), β = 114.45(3)°), the crystals show twinning and 1-dimensional disorder.
Coordination Chemistry of trans-(NH3)2Pt(II) with Uracil Nucleobases. A Comparison with cis-(NH3)2Pt(II)
Authors: Dieter Iris , Lippert Bernhard , Schöllhon Helmut , Thewalt Ulf
Published: March 2015

Protonated and heteronuclear adducts as well as a series of Pt(IV) oxidation products derived from trans-a2PtL2 (a = NH3, NH2CH3, L = 1-methyluracil anion, C5H5N2O2, or uridine anion, C10HnN2O6) have been prepared and studied by spectroscopic methods and in two cases by X-ray crystallography. trans-(NH3)2Pt(C5H5N2O2)2Ag2(NO3)2H2O · H2O (7) crystallizes in the orthorhombic space group Pna21 with cell dimensions a = 13.206(6), b = 7.238(9), c = 22.051(10) Å, U = 2107.7 Å3, Z = 4. 7 forms a polymeric structure with PtAg2 entities linked via O(4) sites of the 1-methyluracilato ligands. Pt is coordinated through N(3), the Ag centers have a mixed O(2),O(4) coordination, trans,trans,trans-[(NH3)2Pt(OH)2(C5H6N2O2)2](NO3)2 (9) contains two N(3)-bound neutral 1-methyluracil ligands, hence rare tautomers of this model nucleobase. 9 crystallizes in the monoclinic system, space group P21/n with cell dimensions a = 7.098(1), b = 10.395(1), c = 13.295(2) Å, U = 980.4 Å3, Z = 2. While the chemistry leading to Pt(IV) oxidation products from trans-a.2PtL2 is similar to that of the cis-isomer, protonation as well as heteronuclear complex formation of trans-a2PtL2 is more difficult to accomplish than with the cis-isomer. This difference appears to be primarily of steric origin.
[(2-Methylphenyl)phosphin]gold(I)-bromid: Eine neue Strukturvariante für intermolekulare Au ··· Au-Kontakte bei (Phosphan)gold(I)-halogeniden / [(2-Methylphenyl)phosphine]gold(I) Bromide: A New Type of Structure for Au ··· Au Contacts in (Phosphine)gold(I) Halides
Authors: Schmidbaur Hubert , Weidenhiller Gabriele , Steigelmann Oliver , Müller Gerhard
Published: March 2015

(2-Methylphenylphosphine)gold(I) bromide has been prepared from tetrabutylammonium dibromoaurate(I) and the primary phosphine in almost quantitative yield. The structure of the compound has been determined by single crystal X-ray diffraction (space group C2/c, Z = 8). The monomer units (2-MeC6H4PH2)AuBr with an almost linear P—Au—Br axis are aggregated in the solid through short Au ··· Au contacts to give folded chains of gold atoms with alternating Au · · · Au distances of 3.097(1) and 3.380(1) A, respectively, a repetitive angle AuAuAu of 103.5(1)°, and alternating dihedral angles AuAuAuAu of 180 and ± 104.5°, respectively. The monomers in adjacent dimers (RPH2AuBr)2 are related crystallographically by a center of inversion or by a two-fold axis, respectively.
Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XXXVII [1]: Photoreaktion von Dekacarbonyldirhenium mit Phenylallen / Hindered Ligand Motions in Transition Metal Complexes, XXXVII [1]: Photoreaction of Decacarbonyldirhenium with Phenylallene
Authors: Kreiter Cornelius G. , Michels Wolfgang , Exner Reiner
Published: March 2015

Decacarbonyldirhenium (1) and phenylallene (2) form upon UV irradiation four dinuclear complexes: Decacarbonyl-μ-η1:1-(3,4-diphenyl-1,5-hexadien-2,5-diyl)-dirhenium (3), enneacarbonyl-μ-ηl:3-(3-phenyl-2-propen-1,2-diyl)-dirhenium (4), octacarbonyl-μ-hydrido-μ-η1:2-(3-phenyl-1,2-propadien-l-yl)-dirhenium (5) and octacarbonyl-μ-η2:2-(phenyl-1,2-propadiene)-dirhenium (6). The thermolabile complex 4 looses CO and forms the phenylallene bridged compound 6. Similarly 5 is rearranged to 6 by transfer of the hydrido ligand to the 3-phenyl-1,2-propadien-1-yl bridge. The formation of 3 and 4 can be rationalized via pentacarbonyl-phenylpropenediyl-rhenium radicals which dimerize to give 3 or add pentacarbonylrhenium radicals, loose CO and form 4. The crystal and molecular structure of 3 was determined by X-ray structure analysis. In the solid state the molecule is present in the ± ap conformation. In solution at 233 K the ±ap, +sc, and –sc conformations are equally populated. By a hindered rotation around a CC single bond, the three conformers are interconverted with a rotation barrier of ΔG*258 = 52.3 ± 1 kJ · mol-1.
Übergangsmetallkomplexe mit Schwefelliganden, XLIX Außergewöhnliche Säure-Basenreaktionen an niedervalenten Ru-Nitrosyl-Komplexen mit dem Thiolat-amin-Liganden ′S2Ν2Ηχ
'2- (χ = 1, 2) und Mo-Komplexe mit den Liganden′S2N2H2
′2- und ′buS2N2H2
′ 2-, Synthese, Struktur und Reaktionen / Transition Metal Complexes with Sulfur Ligands, XLIX Unusual Acid Base Reactions of Low Valence Ruthenium Nitrosyl Complexes with the Thiolate-amine Ligands ′S2Ν2ΗΧ
'2- (χ = 1, 2) and Molybdenum Complexes with the Ligands ′S2N2H2
′ 2- and ′buS2N2H2
′ 2-, Syntheses, Structure and Reactions
Authors: Sellmann Dieter , Käppler Olaf , Knoch Falk , Moll Matthias
Published: March 2015

In order to find complexes suited as model compounds for oxidoreductases catalyzing reactions of the biological nitrogen cycle, Ru- and Mo-nitrosyl complexes with the ′S2N2H2
'2- and ′buS2N2H2
′ 2--** ligand were synthesized. The reaction of [Ru(NO)(PPh3)2Cl3] with Li2-'S2N2H2' yields the binuclear [Ru(NO)(′S2N2H′)]2 (1) and the mononuclear [Ru(NO)(PPh3)(′S2N2H2′ )]Cl (2). Formation of 1 is explained by HCl and subsequent PPh3 elimination from 2; the coordinatively unsaturated [Ru(NO)(′S2N2H′)] dimerize to give 1. 1 is also obtained a) when [Ru(NO)2(PPh3)2] is reacted with Li2-'S2N2H2′ , b) when 2 is treated with bases, e.g. N2H4, or c) when [Ru(NO)Cl(′S2N2H2′ )] is attempted to be recrystallized from DMSO or THF/MeOH. The very labile [Ru(NO)Cl(′S2N2H2′ )] (5) forms when Ru(NO)Cl3 · 3 H2O is reacted with Na2—'S2N2H2′. The structures of 1 and 2 were determined by X-ray diffraction. They show sixcoordinate RuII centers with the thiolate S atoms in cis positions. The mononuclear complexes [Ru(NO)(PMePh2)(′S2N2H′)] (3) and [Ru(NO)(PMe3)(′S2N2H′)] (4) were obtained by cleavage of 1 with PMePh2 or PMe3, respectively. The formally 14e configurated molybdenum chloro complexes [MoCl2(′S2N2H2′ )] (6) and [MoCl2(′buS2N2H2′ )] (7) were obtained from the reaction of [MoCl4(THF)2] with ′S2N2H2
′ 2- and yields the cis configurated [Mo(NO)2(′S2N2H2′ )] (8) and [Mo(NO)2(′buS2N2H2′ )] (9) respectively. 9 is also obtained from the reaction of [Mo(NO)2Cl2] with ′buH2S2N2H2′ . [Mo(NO)Cl3(CH3CN)2] and Na2-'S2N2H2′ react to give the MoIII complex [Mo(NO)Cl(′S2N2H2′ )] (10).
Alkin-Komplexe des Rheniums in hohen Oxidationsstufen / Alkyne Complexes of Rhenium in High Oxidation States
Authors: Herrmann Wolfgang A. , Felixberger Josef K. , Kuchler Josef G. , Herdtweck Eberhardt
Published: March 2015

The class of π-alkyne complexes of metals in medium and high oxidation states has been extended by the type CH3ReO2(RC≡CR′) (3a—i). Exchange of alkyne for oxo ligands under reducing conditions has been employed as a new general synthesis. Compounds 3 are thus obtained by reaction of methyltrioxorhenium(VII) (1) with the alkynes 2a—i in the presence of a ca. 1.1-fold molar amount of polymer-bound triphenylphosphane as reducing agent (desoxygenation). The structural characterization was carried out for the example of the tolan complex 3 e by virtue of a single-crystal X-ray diffraction study at —80 °C, according to which the description of compounds 3 as “rhenacyclopropenes” seems justified. Evidence from NMR investigations of 3 a and 3 c shows that no fast rotation of the respective alkyne ligand around the axis to the metal atom occurs on the NMR time scale up to at least 105 °C. A minimal rotation barrier of approximately 20 kcal/mol is thus to be estimated. Reaction of type 3 compounds (R = R′ = CH3, b; R = R′ = C2H5, c) with polymer-bound triphenylphosphane under more drastic conditions (boiling toluene) for two days effects further reduction, with the dinuclear, diamagnetic rhenium(IV) complexes 4b and 4c, resp., being formed. Sterically demanding alkynes (e.g., R = R′ = Si(CH3)3, C6H5) seem to prevent this type of reaction. According to an X-ray diffraction study, 4b has an equilateral Re2O-triangular core geometry, with the ligands O, CH3, and butyne(2) arranged in such a way that C2-symmetry results. The alkyne complexes reported here are the first ones of tetra- and pentavalent rhenium.
Eine metastabile Form des dimeren 1,2-Dioxyphenylen-siliciumdichlorids / A Metastable Form of the 1,2-Dioxyphenylene-silicon-dichloride Dimer
Authors: Dettlaff-Weglikowska Urszula , Hönle Wolfgang , Thiery Dagobert , Schnering Hans Georg von
Published: March 2015

Dimeric 1,2-Dioxyphenylene-dichloride (1) crystallizes dimorphically. The already known monoclinic m-form (space group P21/α) is the thermodynamically stable modification and can be obtained by sublimation. The novel triclinic α-form (space group P1̄) is a metastable modification and can be obtained from CH2Cl2 solution. The α-form crystallizes with a = 591.7(5) pm; b = 1457.0(8) pm; c = 991.7(6) pm; α = 96.68(3)°; β = 106.29(3)°; γ = 91.48(3)° and Z = 4 formula units (2 dimers). The molecules of the a- and the m-form are identical with respect to bond distances, bond angles and their conformations, but they are different in their spatial arrangement. The melting point of the α-form is 126.5 °C, of the m-form 140.0 °C. The melt of 1 solidifies as a glass from which the α-form recrystallizes.
Synthese und Kristallstruktur von [CrCl3(H2O)(15-Krone-5)] / Synthesis and Crystal Structure of [CrCl3(H2O)( 15-Crown-5)]
Authors: Ernst Thilo , Dehnicke Kurt , Goesmann Helmut , Fenske Dieter
Published: March 2015

The title compound has been prepared by the reaction of CrCl3 with 15-crown-5 in acetonitrile suspension in the presence of water. It forms violet crystals, which are sparingly soluble in acetonitrile; they were characterized by their IR spectrum as well as by an X-ray structure determination. Space group P21/c, Z = 4, 2902 observed unique reflexions, R = 0.029. Lattice dimensions at —70 °C: a = 1018.8(5), b = 780.0(4), c = 2097.1(10) pm, β = 93.21(3)°. [CrCl3(H2O)(15-crown-5)] has a molecular structure, in which the chromium atom is coordinated by three chlorine atoms, by the oxygen atom of the water molecule, and by two oxygen atoms of the crown ether molecule in a distorted octahedral fashion.
Kristallstrukturen der Tetrachloroniccolate (PPh4)2[NiCl4] und [Na-15-Krone-5]2[NiCl4] / Crystal Structures of the Tetrachloroniccolates (PPh4)2[NiCl4] and [Na- 15-Crown-5]2[NiCl4]
Authors: Ruhlandt-Senge Karin , Müller Ulrich
Published: March 2015

The title compounds were obtained from NiS + PPh4Cl + HCl in dichloromethane, from NiCl2 and PPh4Cl and from NiCl2 + Na2S + 15-crown-5 in acetonitrile or CH2Cl2, respectively. Their crystal structures were determined by X-ray diffraction. (PPh4)2[NiCl4]: monoclinic, space group C 2/c, Z = 4, a = 1094.9(3), b = 1946.1(4), c = 2033.5(5) pm, β = 91.48(3)°; R = 0.07 for 2895 unique observed reflexions. [Na-15-crown-5]2[NiCl4]: triclinic, space group P1̄, Z = 2, a = 987.6(1), b = 998.0(1), c = 1779.9(2) pm, α = 104.17(1), β = 95.43(1), γ = 109.95(1)°; R = 0.090 for 4155 unique observed reflexions. In both cases, the [NiCl4]2- ions have distorted tetrahedral structures. With PPh4
+ as the cation the distortion corresponds to a twisted tetrahedron which fulfils the point symmetry D2, the deviation from a flattened D2d-tetrahedron being small. In (PPh4)2[NiCl4] cations and anions alternate in layers parallel to (001). In [Na-15-crown-5]2[NiCl4] two of the Cl atoms of the anion are coordinated to sodium ions; one of the crown ether molecules shows positional disorder.
Iod-dotiertes Lithium-Poly(ketenenolat) / Iodine Doped Lithium Poly(ketene-enolate)
Authors: Fritz Heinz P. , David Peter
Published: March 2015

Lithium poly(ketene-enolate) (1) was prepared from polyketene and LiOH. The resulting polymer salt was doped with varying amounts of iodine. The polymers show mixed ionic and electronic conductivity with a maximum at an iodine content of 47%.
Organophosphorus Chemistry, 18
Authors: Abdou W. M. , Abd El Monem H. A. , Mahran M. R.
Published: March 2015

Trialkyl phosphites (2a—c) react with 1,8-naphthosultam (6) to give the respective N-alkylated products 7 a—c. Compounds 7a—c were also prepared by the action of dialkyl phosphites on 6 in the presence of p-TsOH. Moreover, 7 a could be obtained by treating 6 with DMMP (8). On the other hand, chlorinated phosphorus reagents (11) condense with 6 to give products of type 12. Structures of the new products were assigned according to consistent analytical and spectroscopic measurements.
The Kinetics and Mechanism of Addition of Water and Alcohols to p-Nitrophenyl Isothiocyanate. The Effects of Added Dimethyl Sulphoxide
Authors: Satchell Derek P. N. , Satchell Rosemary S. , Wassef Wasfy N.
Published: March 2015

The second order-rate constants for the addition of water and ethanol to p-nitrophenyl isothiocyanate are larger in dimethyl sulphoxide solution than in pure water or ethanol. The detailed behaviour over a wide composition range suggests that H-bonding by the hydroxylic reactant to the solvent favours reaction, whereas H-bonding to this reactant retards reaction. The behaviour and relative reactivities of isocyanates and isothiocyanates suggest that protontransfer concurrent with nucleophilic attack at carbon, is less important in additions of hydroxylic compounds to isothiocyanates than to isocyanates. Branched-chain alcohols react more slowly with isothiocyanates than do primary alcohols. An excess of ethoxide ions reacts relatively rapidly with p-nitrophenyl isothiocyanate in ethanol to give the ionized thiourethane. The kinetics of this process, and the equilibrium constant for proton transfer between thiourethane and ethoxide ions, have been determined.
Thermal Behaviour, 1H, 13C NMR, and MS Studies of 1,4-Diaryl-2,3-dimethyl-1,4-diazabutadiene Tin Tetrachloride Complexes
Authors: Alvarez-Valdés Amparo , Camazón M. José , Navarro-Ranninger M. Carmen , Torres Tomás
Published: March 2015

1,4-Diaryl-2,3-dimethyl-1,4-diazabutadiene tin tetrachloride complexes 1 · SnCl4 and 2 · SnCl4 have been prepared and characterized by thermal properties, IR and Raman spectroscopy and mass spectrometry. A study on their behaviour in solvents with different donor ability by 1H and 13C NMR spectroscopy is also described.
Synthesis and Plane Selective Spin Trapping of a Novel Trap 5,5-Dimethyl-3-(2-ethoxycarbonylethyl)-1-pyrroline N-oxide
Authors: Zhang Yong-Kang , Lu Dao-Hui , Xu Guang-Zhi
Published: March 2015

A novel cyclic nitrone spin trap 5,5-dimethyl-3-(2-ethoxycarbonylethyl)-1-pyrroline N-oxide has been prepared and its ability to trap a series of transient free radicals has been investigated. This nitrone scavenges free radicals to give persistent nitroxides, e.g., the half life-times of hydroxyl radical adducts and tert-butoxy radical adducts in benzene >30 min, and the life-time of acetyl adducts >60 min. The EPR spectrum of 2,2-dimethyl-4-(3-hydroxypropyl)pyrrolidinyl-1-oxyl aminoxyl shows that the hyperfine splitting constants of two

β-hydrogens are equal to 14.58 G and 23.29 G respectively, i.e., the two β-hydrogens are not magnetically equivalent. Radical addition to the nitrone is probably plane selective affording only one of the two possible geometric isomer pairs of the spin adduct nitroxides. The trans approach mechanism is proposed through configuration and conformation analysis.
Inosose-Flüssigkristalle / Inosose Liquid Crystals
Authors: Praefcke Klaus , Kohne Bernd , Eckert Andreas , Hempel Joachim
Published: March 2015

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.
Notizen: Regioselectivity Control of Thiocyanate Benzylation by the Structure of Phase Transfer Catalysts [1]
Authors: Dehmlow Eckehard V. , Torossian Gagik O.
Published: March 2015

Solid/liquid phase transfer catalytic conversions of KSCN and benzyl chloride at 180 °C give thiocyanate/isothiocyanate ratios depending on catalyst structure. Liquid/liquid PTC at 100 °C yields thiocyanate exclusively.
Notizen: Molekülstruktur von Re3Cl6(Acac)3 im Feststoff / Molecular Structure of Re3Cl6(Acac)3 in the Solid State
Authors: Irmler Manfred , Meyer Gerd
Published: March 2015

Dark red single crystals of Re3Cl6(Acac)3 are obtained from a solution of “ReCl3·2H2O” in acetylacetone by slow evaporation. The unit cell (monoclinic, P21/c, a = 1687.3(9), b = 963.4(5), c = 1664.3(9) pm, β = 108.97(4)°) contains four molecules of Re3Cl6(Acac)3. Each of the bidentate Acac(—) ligands substitutes one of the in-plane terminal and one of the out-of-plane terminal ligands with respect to the Re3 triangle.
Notizen: Elektroreduktion organischer Verbindungen, XV [1] / Electroreduction of Organic Compounds, XV [1]
Authors: Petersen Dirk , Lemmrich Martina , Altrogge Matthias , Voss Jürgen
Published: March 2015

The twelve possible chlorinated benzenes and the three isomeric monochlorobiphenyls are electrochemically reduced in a divided cell in methanol at a lead cathode. Chlorobenzene and benzene or biphenyl, respectively, are formed with acceptable current yields and very good chemical yields.
Darstellung und 11B-NMR-Spektren perhalogenierter closo-Hexaborate Β6ΧnY6-n
2-, n=0-6; X ≠ Y= Cl, Br, I / Preparation and 11B NMR Spectra of the Perhalogenated closo-Hexaborates B6XnY6-n
2-,n = 0-6; Χ ≠ Υ = Cl, Br, I
Authors: Preetz W. , Stallbaum M.
Published: March 2015

The mixed halogenohexaborates B6XnY6-n
2-, n = 1-5; Χ ≠ Υ = Cl, Br, I, including most of the pure stereoisomers for n = 2—4, are prepared for the first time by treatment of the halohydrohexaborates B6XnH6-n
2-, X = Cl, Br in aqueous alkaline solution with bromine and iodine or with halogenosuccinimides. The point symmetry is determined from the "B NMR spectra, which show characteristic features for homologous isostructural compounds. In the systems B6XnY6-n
2- a considerable dispersion of the 11B signals is observed, for B(X) atoms to lower, for B(Y) atoms to higher field compared with B6X6
2- and B6Y6
2- (electronegativity X > Y), respectively. An additional chemical shift is caused by the mutual antipodal effect between pairs of opposite B atoms carrying different substituents. From the systematic influences on the chemical shifts the 11B NMR spectra of the missing species fac-B6X3Y3
2- are calculated.
Tetra-n-butylammoniumdicyanoaurat(I), (n-C4H9)4NAu(CN)2 / Tetra-n-butylammonium Dicyanoaurate(I), (n-C4H9)4NAu(CN)2
Authors: Schubert R. J. , Range K.-J.
Published: March 2015

Single crystals of (n-C4H9)4NAu(CN)2 were obtained by crystallization using the temperature decreasing method in a newly developed computer-controlled apparatus. The colourless crystals are monoclinic, space group A2/n, with a = 20.216(2) Å, b = 13.130(1) Å, c = 9.328(1) Å, and β = 109.69(1)°. The measured density is 1.45 g/cm3, which agrees with the calculated density of 1.40 g/cm3 for Ζ = 4. The structure was solved by Direct Methods using 674 independent reflections and refined by least-squares procedures to conventional and weighted R factors of 0.068 and 0.058, respectively. The nearly linear [Au(CN)2]--anions form pseudohexagonal layers, in which they are arranged parallel to each other. The shortest Au—Au distance is 8.05 A. The stacking of the layers produces pseudo-trigonal channels, occupied by the cations. The tetra-n-butylammonium cation has four ordered trans chains with idealized D2d symmetry (4̄2 m).
Synthese und Kristallstruktur von (PPh4)4[Cu2Se14] / Synthesis and Crystal Structure of (PPh4)4[Cu2Se14]
Authors: Müller Ulrich , Ha-Eierdanz My-Linh , Kräuter Gertrud , Dehnicke Kurt
Published: March 2015

(PPh4)4[Cu2Se14] has been prepared by the reaction of a lithium polyselenide solution in DMF with CuCl at 120 °C in the presence of PPh4Br. The compound forms black crystals, which were characterized by IR spectroscopy as well as by an X-ray structure determination. Space group P 21, Z = 2, 2690 observed unique reflexions, R = 0.095. Lattice dimensions at 19 °C: a = 2139.5(9), b = 1611.7(3), c = 1365.1(3) pm, β = 93.54(3)°. The compound consists of PPh4
+ and [Cu2Se14]4- ions, in which the two copper atoms are bridged by an Se5
2- chain. One of the Cu atoms is a member of a CuSe4 ring, the other one of a CuSe5 ring; the coordination at each Cu atom is trigonal-planar.
Schwingungsspektroskopische Untersuchung einiger gemischter Calcium/Cadmium-Hydroxylapatite / Vibrational-Spectroscopic Investigation on Some Mixed Calcium/Cadmium-Hydroxylapatites
Authors: Narda G. E. , Pedregosa J. C. , Etcheverry S. B. , Baran E. J.
Published: March 2015

The infrared spectra of a series of cadmium substituted calcium hydroxylapatites of the type Ca10-xCdx(PO4)6(OH)2, were investigated in order to obtain insight on the effect of the Cd(II) ion on the vibrational properties of the PO4
3- and OH- groups. The effect of the substitutional process on the strength of the P–O bonds was also checked by Raman Spectroscopy and an analysis of the behaviour of the deuterated Ca5Cd5(PO4)6(OD)2 phase was undertaken. The strength of the P–O bonds shows a linear dependence on the Cd(II) content, whereas the OH-vibrational modes present a more complex behaviour.
Darstellung perhalogenierter Mesylsulfene, X3C — SO2 — C(X) = SO2, und ihre Stabilisierung durch Chinuclidin / Preparation of Perhalogenated Mesylsulfenes, X3C —SO2— C(X) = SO2, and their Stabilization with Chinuclidin
Authors: Pritzkow Hans , Rall Klaus , Sundermeyer Wolfgang
Published: March 2015

Perhalogeno disulfenes (dimeric thione-S,S-dioxides) (2 a, b) are singly cleaved by TAS–fluoride forming the intermediate salts 3a and 3b. From both anions a fluoride ion can be abstracted by silicon tetrafluoride and the perhalogenated mesylsulfenes X3C — SO2— C(X)= SO2 (4 a) (X = Cl) and (4b) (X = Br) could be obtained, which are stabilized by S-coordinated quinuclidine. Hydrolysis occurs to 4 a, b forming the sulfonium salts 7a, b, which are the structural isomers to the sulfonium salts 5 a, b achieved from direct hydrolysis of 2 a, b in the presence of quinuclidine.
Formation and Structure of [Cp2Zr(CH3)OAl(CH3)2]2 — a Neutral Dimethylzirconocene/Alumoxane Adduct
Authors: Erker Gerhard , Albrecht Markus , Werner Stefan , Krüger Carl
Published: March 2015

Trimethylaluminum adds to cyclotrimeric zirconocene oxide [Cp2ZrO]3 to give the cyclodimeric mixed metal complex [Cp2Zr(CH3)OAl(CH3)2]2 (3a-dimer) featuring a central Al2O2 containing four-membered ring system. Complex 3a-dimer crystallizes in space group P21/c with cell parameters a = 8.3974(8), b = 8.6509(7), c = 19.718(1) Å, β = 97.36(1)°, Ζ = 2, R = 0.029, Rw = 0.038. With methylalumoxane 3a-dimer gives an active catalyst (Zr: Al ≈1:8) for ethylene polymerization.
121Sb-Mössbauer-spektroskopische und strukturchemische Untersuchungen an Kronenetherkomplexen SbX3(15-Krone-5) mit X = F, Cl, Br, I. Eine Analyse der Orbitalbesetzungszahlen / 121Sb-Mössbauer-Spectroscopic and Structural Investigations on Crown Ether Complexes SbX3(15-Crown-5) with X = F, Cl, Br, I. A Population Analysis
Authors: Schäfer Michael , Pebler Jürgen , Borgsen Beatrice , Weller Frank , Dehnicke Kurt
Published: March 2015

The crown ether complexes SbX3(15-crown-5) with X = F, Cl, Br, and I have been prepared by reactions of 15-crown-5 with the corresponding antimony trihalides in acetonitrile solutions. The compounds were characterized by IR spectroscopy as well as by 121Sb-Mössbauer spectroscopy. A method of orbital population analysis utilizing both Mössbauer isomer shifts and quadrupole coupling has been developed for Sb(III) antimony halides and their crown ether complexes.

SbF3(15-crown-5) was also characterized by an X-ray structure determination: Space group P21/n, Z = 4, 3628 observed unique reflexions, R = 0.032. Lattice dimensions at 19 °C: a = 891.54(6), b = 1277.26(6), c = 1277.66(7) pm, β = 95.029(4)°. The complex has a molecular structure in which the antimony atom is surrounded by three F-atoms with mean bond lengths of 192.4 pm and by the five oxygen atoms of the crown ether molecule with mean bond lengths of 293.9 pm.
Zn2(Zn1-xFex)FeIII(PO4)3 · 2 H2O: Darstellung, Kristallstruktur und Mößbauer-Untersuchung / Zn2(Zn1-xFex)FeIII(PO4)3 · 2 H2O: Preparation, Crystal Structure and Mössbauer Investigation
Authors: Schmidt Roswitha , Eisenmann Brigitte , Kniep Rüdiger , Ensling Jürgen , Gütlich Philip , Seidel Reinhard
Published: March 2015

Single crystals of the mixed valency phase Zn2(Zn1-xFex)FeIII(PO4)3 · 2 H2O were grown by hydrothermal treatment of phosphophyllite (Zn2Fe(PO4)2 · 4 H2O) at 160 °C in 1 M H3PO4. The crystal structure (tricl., P 1̅; a = 641.5(4) pm, b = 914.4(4) pm, c = 983.4(4) pm, α = 70.79(5)°, β = 78.32(5)°, γ = 73.69(5)°; Ζ = 2) contains PO4 tetrahedra, connected via vertices shared with coordination polyhedra of the metal ions. Cation coordination polyhedra (FeIII(Op)5Ow octahedra, (Zn1
-xFex)(Op)5Ow octahedra and Zn(Op)5 trigonal bipyramids) are connected to centrosymmetrical six-membered chains by sharing common Op-edges. These short chains are interconnected by common vertices of Zn(Op)4 tetrahedra to form infinitive ribbons of cation coordination polyhedra. The x-values observed for the substitutional position (Zn1
-xFex) varied from x = 0.5 (single crystal determination) to x = 1 (Mössbauer investigation). The Mössbauer parameters are consistent with high-spin iron in a slightly distorted octahedral environment and valence states (II) and (III).
A New Example of Edge-to-Face Interaction of Aromatic Rings in Oligopeptides: Cyclolinopeptide A
Authors: Siemion Ignacy Z.
Published: March 2015

The analysis of the aromatic region of 1H and 13C NMR spectra of cyclolinopeptide A (cyclic nonapeptide with the sequence c—(Pro— Pro— Phe—Phe—Leu— Ile— Ile— Leu— Val— ), (CLA)) shows that Phe-3 and Phe-4 aromatic rings are oriented nearly perpendicularly to each other, forming edge-to-face pair. It signifies the strong limitation of the free rotation of aromatic residues, probably because of the steric hindrance exerted by proximal aliphatic side chains of CLA.
Notizen: Na2LiAu3, eine ternäre Laves-Phase vom MgZn2-Typ / Na2LiAu3, a Ternary Laves Phase with MgZn2-Type Structure
Authors: Range Klaus-Jürgen , Rau Franz , Klement Ulrich
Published: March 2015

The intermetallic compound Na2LiAu3 could be synthesized from the elements at 20 kbar, 700 °C in a modified Belt-type apparatus. The structure (P63/mmc, a = 5.5302(9), c = 8.674(2) Å, c/a = 1.568, Z = 2) is a ternary variant of the MgZn2-type structure. As a consequence of the rather low c/a value the CN 12 and CN 16 polyhedra are considerably distorted. The shortest interatomic distances are Au– Li = 2.701 Å, Au– Au = 2.742 Å and Au–Na = 3.180 Å.
Topotaktische Entwässerung von Cs2MnF5 · H2O zu Cs2MnF5 und die Kristallstrukturen beider Verbindungen / Topotactical Dehydration of Cs2MnF5 · H2O to Cs2MnF5 and the Crystal Structures of Both Compounds
Authors: Hahn Friedemann , Massa Werner
Published: March 2015

Redetermination of the crystal structure of Cs2MnF5 · H2O (space group Cmm 2, Z = 2, a = 974.0(2), b = 867.4(1), c = 426.0(1) pm, R = 0.026 for 478 reflections) revealed ordered instead of disordered positions of water molecules indicating ferroelectric properties. The dehydration of a twinned crystal gave an untwinned single crystal of Cs2MnF5 by a topotactical reaction. The crystal structure of Cs2MnF5 (space group P4/mmm, Z = 1, a = 642.0(1), c = 422.9(1) pm, R = 0.034 for 175 reflections) shows trans-connected octahedral chains [MnF5]∞
2- with 180° Mn-F-Mn bridge angles like in the monohydrate. The bridging bonds in Cs2MnF5 · H2O and in Cs2MnF5 resp. are elongated by the Jahn-Teller effect (mean values Mn-Fbridge 213/211, Mn-Fterm 184/186 pm). Cs2MnF5 represents the “aristotype” of the so- called Tl2AlF5 type structure family
ESR Spectra and Reactivity towards Catechol of Iron(III) Complexes with 2-(2-Benzimidazolyl)phenol and its Benzoxazole Derivative
Authors: Nishida Yuzo , Yamada Kasumi , Furuhashi Akiko
Published: March 2015

The iron(III) complex with 2-(2-benzimidazolyl)phenol (abbreviated as H(L2)), Fe(L2)2(NO3), and its benzoxazole derivative, exhibit highly anisotropic ESR signals in the range g = 3.6-7.2; these spectral properties differ from those of regular six-coordinate iron(III) species, but are very similar to those observed for the enzyme-competitive inhibitor complexes in protocatechuate 3,4-dioxygenase. These iron(III) compounds show negligible activity for oxidative cleavage of 3,5-di-tert-butylcatechol
Notizen: Die Reaktion von (Butadien)zirconocen mit Iminoboran / The Reaction of (Butadiene)zirconocene with Iminoborane
Authors: Braunschweig Holger , Manners Ian , Paetzold Peter
Published: March 2015

The azoniaboratacyclopentene [-N(tBu)=B{N(tBu)SiMe3}-CH2-CH(C2H3)-ZrCp2-] (1) is formed from the iminoborane Me3Si(tBu)N··̲·B··̳· NtBu and (butadiene)zirconocene Cp2Zr(C4H6)
Notizen: (Pyridinium)[(1,2-dithioquadratato)-cuprat(I)]hydrat, eine Verbindung mit einer CuI···CuI-Zickzackkette / (Pyridinium)[( 1,2-dithiosquarato)-cuprate(I)]hydrate, a Compound with a CuI···CuI-Zigzag Chain
Authors: Krause Ralf , Mattes Rainer
Published: March 2015

Red crystals of the title compound have been prepared from pyridine, potassium dithiosquarate and copper(II) sulfate in water at pH 5. 1 contains an infinite zigzag chain of CuI atoms, which extends orthogonally through a stacked structure formed by pyridinium and dithiosquarate ions. The CuI atoms are tetrahedrally and trigonally coordinated by sulfur atoms. The Cu···Cu distances are 257.3(8), 262.1(8) and 276.4(8) pm. Crystal data: triclinic, space group P 1̄, a = 7.92(2), b = 10.52(2), c = 14.39(2) pm, α = 102.5(2), β = 104.1 (2), γ = 100.6(2)°, V = 1100.34 nm3, Ζ = 4; 3102 reflections, R = 0.103
Notizen: Tricyclische Phosphorane aus den Phosphonigsäuredichloriden RPCl2 (R = Ph, CH2Ph) und dem (Z)-Ketoenol CF3C(O)CH = C(OH)CF3 / Tricyclic Phosphoranes from the Phosphonous Dichlorides RPCl2 (R = Ph, CH2Ph) and the (Z)-Ketoenol CF3C(O)CH=C(OH)CF3
Authors: Bekiaris Georgios , Röschenthaler Gerd-Volker
Published: March 2015

The phosphonous dichlorides, PhPCl2 and PhCH2PCl2, react with the (Z)-ketoenol CF3C(O)CH=C(OH)CF3 to yield tricyclic trialkoxyphosphoranes, whose structures were determined on the basis of the 1JPC values and “through-space” F···F coupling
Elektronenreiche Ruthenium-Thiolat-Komplexe, Synthese und Reaktionen mit Elektrophilen / Electron-Rich Ruthenium Thiolate Complexes, Synthesis and Reactions with Electrophiles
Authors: Schenk Wolfdieter A. , Stur Thomas
Published: March 2015

Ruthenium thiolates [cpRu(PR′3)2(SR)] (PR′3 = PPh3,1/2 dppe, 1/2 dppm, R = Me, CH2Ph) are obtained from the corresponding chlorides and NaSR. PPh3 is readily exchanged for CO to give the chiral complexes [cpRu(PPh3)(CO)(SR)]. Alkylation with methyl tosylate yields the cations [cpRu(dppe)(SMeR)]+ and [cpRu(PPh3)(CO)(SMeR)]+, which were isolated as their PF6
- salts. The neutral carbonyls add dimethyl acetylenedicarboxylate giving five-membered metallocycles.
Caridiene: A New Sesquiterpene from Pseudoterogorgia americana
Authors: Rivero R. Baluja , Pérez A. Rosado , Castro H. Vélez , Argilagos C. Sedeño , Henriquez R. D.
Published: March 2015

Research on the chemical composition of gorgonian Pseudoterogorgia americana, which grows in the coasts of Havana, has led to the isolation of a new sesquiterpene hydrocarbon, 1,1-dimethyl-7-isopropylidene-1,2,3,4,5,6,7,8-octahydronaphthalene, named caridiene. This compound not previously reported, was found to be a major constituent of the volatile fraction. The proposed structure was confirmed by spectroscopical data (UV, IR, Raman, MS, 1H and 13C NMR techniques).
Synthese und Röntgenstrukturanalyse einer Dibenzo[c,f]oxocanspiroverbindung / Synthesis and X-Ray Structural Analysis of a Dibenzo[c,f]oxocanespiro Derivative
Authors: Neidlein Richard , Krämer Bettina , Krieger Claus
Published: March 2015

X-ray analysis of the reaction product — dibenzo[c,f]oxocane derivative — between benzocyclopropene and diphenylcyclopropenones.
Methanstibonsäure / Methanestibonic Acid
Authors: Wieber Markus , Walz Josef
Published: March 2015

Methanestibonic acid is obtained by hydrolysis of tetraalkoxymethylstiborane or by oxidation of dimethoxymethylstibine with H2O, in a mixture of methylenchloride and alcohol at 0 °C as a white amorphous powder. Reaction of the acid with 2,3-dimethyl-butane-2,3-diol yields MeSb[OC(Me),C(Me)2O]2, and with sodium hydroxide a sodium salt Na2[MeSb(OH)3O]2 · 6 H2O is obtained.
Synthese und Struktur von Ni(2,6-iPr2C6H3N = CH – CH =NC6H3-2,6-iPr2)2. Synthesis and Structure of Ni(2,6-iPr2C6H3N=CH–CH = NC6H3-2,6-iPr2)2
Authors: Bonrath Werner , Pörschke Klaus R. , Mynott Richard , Krüger Carl
Published: March 2015

Ni(cdt)** reacts with two equivalents of the sterically highly demanding 1,4-diazadiene 2,6-iPr2C6H3N =CH –CH =NC6H3-2,6-iPr, to yield the red-brown, crystalline title compound Ni(2,6-iPr2Ph-dad)2 (3). The existence of this compound was previously uncertain. 1H and 13C NMR, MS, and UV/VIS spectra of 3 are reported. The X-ray structure analysis of 3 revealed a strongly distorted tetrahedral coordination of the nickel center with a dihedral angle of 51 between the planes of the chelate rings and mean bond lengths Ni-Ν 1.965(4) Å and N=CH 1.308(5) Å. The poorly soluble compound appears to be rather unreactive because of the bulk of the ligands.
Highly Efficient Camphor-Derived Oxaziridines for the Asymmetric Oxidation of Sulfides to Chiral Sulfoxides
Authors: Meladinis Vassilios , Verfürth Uwe , Herrmann Rudolf
Published: March 2015

Chiral N-sulfonyl-oxaziridines derived from 8-camphorsulfonic acid and fenchone have been evaluated as asymmetric oxidizing agents for the conversion of sulfides to chiral sulfoxides. There is no correlation between the redox potentials nor the 17O NMR chemical shifts of the oxaziridines and their relative oxidation rates, nor with the enantiomeric excesses achieved, indicating that steric effects are responsible for their behaviour. The results are consistent with an attack of one sulfur lone pair at the oxaziridine oxygen in such a way that both sulfur lone pairs lie in the plane of the oxaziridine ring. The most efficient oxaziridines, the camphorlactone-sulfonyloxaziridine [(4aS,9 aR)-10,10-dimethyl-6,7-dihydro-4 H-4 a,7-methano-oxazirino[3,2-j]oxepino[3,4-c]isothiazol-9(5H)-one 3,3-dioxide] and the 3-endo-bromocamphorsulfonyloxaziridine [(4aS,8 S,8 aR)-8-bromo-9,9-dimethyl-5,6,7,8-tetrahydro-4 H- 4a,7-methano-oxazirino-2,1-benzisothiazole 3,3-dioxide] allow the preparation of chiral sulfoxides with up to 85% enantiomeric excess.
Äußerst selektive und schonende Abspaltung von β-Halogenalkyl-Gruppen mittels Cobalt(I)phthalocyanin-anion bei Semisynthesen von β Lactam-Antibiotika / Extremely Selective and Mild Cleavage of β-Haloalkyl Groups by Cobalt(I)phthalocyanine Anion in Semisyntheses of β-Lactam Antibiotics
Authors: Eckert Heiner
Published: March 2015

Cleavage of β-haloalkyl groups can be performed extremely selectively by cobalt(I)phthalocyanine anion under very mild conditions, qualifying it best in the chemistry of highly sensitive β-lactam antibiotics. This is demonstrated in penicillin and cephalosporin semisyntheses.
Syntheses of Phospholipids via Oxazaphospholanes
Authors: Stumpf Renate , Lemmen Peter
Published: March 2015

A method for the synthesis of the head group of phospholipids is described. It is formed by ring opening of oxazaphospholanes, either by mild tetrazole mediated hydrolysis of λ3-oxazaphospholanes or by methylating ring cleavage of λ5-oxazaphospholanes. Oxidation can be performed by means of an oxaziridine.
Redetermination of the Crystal and Molecular Structure of Bis(pentafluorophenyl)mercury
Authors: Wilkinson Dallas L. , Riede Jürgen , Müller Gerhard
Published: March 2015

The crystal and molecular structure of Bis(pentafluorophenyl)mercury, Hg(C6F5)2, was redetermined from diffractometer data yielding greatly improved structural parameters. The geometry at mercury is virtually linear (C—Hg—C 178.8(3)°), with mercury carbon bond lengths of 2.047(6) and 2.052(6) Å.
Elektronentransfer und Ionenpaar-Bildung, 18 [1 -3] / Electron Transfer and Ion Pairing, 18 [ 1 - 3]
Authors: Bock H. , Dickmann P. , Herrmann H.-F.
Published: March 2015

The redox behaviour of aza-substituted naphtho- and anthraquinones, which offer O=C–C=N– chelate tongs for an advantageous five-membered ring metal cation complexation, is investigated by a combination of cyclovoltammetric and ESR/ENDOR spectroscopic measurements. The formation of paramagnetic contact ion pairs like [(quinoline-5,8-semiquinone)·⊖Me⨁]·, with Me⨁ = Li⨁, Na⨁, Tl⨁, or of triple ion radical cations like [(1,4-diazo-9,10-anthrasemiquinone)eMe⨁]·⨁, with Me⨁ = Li⨁, Na⨁ is corroborated both by shifts of the second reduction potential of up to 0,67 V for e.g. quinoline 5,8-quinone upon addition of Li⨁[B(C6H5)4]⊖ to its DMF solution and by the observation of ESR/ENDOR metal couplings.
Neue Strategien zur Synthese von 3,3,3-Trifluoralanin, 2-Deutero-3,3,3-trifluoralanin und ihren Derivaten [1,2] / New Synthetic Pathways to 3,3,3-Trifluoroalanine, 2-Deutero-3,3,3-trifluoroalanine and their Derivatives
Authors: Burger Klaus , Höß Eva , Gaa Karl , Sewald Norbert , Schierlinger Christian
Published: March 2015

New synthetic pathways to 3,3,3-trifluoroalanine, 2-deutero-3,3,3-trifluoroalanine, their esters, amides, and thioamides are described, starting from hexafluoroacetone, and trifluoropyruvates, respectively.
Alkoxigermanate(II), -stannate(II) und -plumbate(II) zweiwertiger Metallionen, I [1] / Alkoxigermanates(II), -stannates(II) and -plumbates(II) of Two-Valent Metal Ions, I [1]
Authors: Veith Michael , Hans Johannes , Stahl Lothar , May Peter , Huch Volker , Sebald Angelika
Published: March 2015

Bis(tri-tert-butoxigermanates), -stannates and -plumbates of Mg (1a), Ca (1b, 2b, 3b), Sr (1c, 2c, 3c), Ba (1d, 2d, 3d), Cd (le, 2e, 3e), Eu (1f, 2f, 3f) and Pb (1g, 2g, 3g) have been synthesized by various procedures from starting materials such as sodium tri-tert-butoxigermanate (5) and -plumbate (6) and other analogous compounds. While in 1 g and 2g the lead atom is situated in the middle of the molecule, it can also occupy two different coordination sites as in Pb(OtBu)3Pb(OtBu)3Pb (3g) and in Ge(OtBu)3Pb(OtBu)3Pb (7). X-ray structure investigations on 1a, 1b, 1e, 1f, 1g, 2b, 2e, 2g, 3c, 3d and 3g reveal that all these molecules have a common ElO3MO3El cage unit. This cage unit can be visualized as two ElO3M trigonal bipyramids sharing the central metal M. Consequently in all structures the central element M is sixfold coordinated by oxygen while the outer metals (El) have three oxygen neighbours. The oxygen atoms are further bonded to tert-butyl-groups, which surround the whole ElO3MO3El frame. Four different structure types have been found to exist: a monoclinic type α (1a), an orthorhombic type β (1b, le, 2b, 2e), a rhombohedral type γ (1f, 1g, 3c, 3d, 3g) and a monoclinic type δ (2g). In the β-structure type the molecules are found to exist as three different isomers, depending on the arrangement of the alkoxy groups in a right- or left-handed manner within the El(OtBu)3 groups (RR, SS and RS). Solution equilibria between these isomers are observed by NMR. In the case of 1e a more detailed picture of this intramolecular motion, attributed to the inversion of the trigonal-pyramidally coordinated oxygen atoms, can be given. CP-MAS-NMR-spectra as well as solution spectra have been obtained for le (13C, 113Cd), 2e (13C, 113Cd, 119Sn), 2g (119Sn, 207Pb), 3g (13C). While δ113Cd values of 2e in solution and in the solid are comparable (92.8 vs 73.7 ppm), the 2J(119Sn/113Cd) values rise from 39 Hz to 295 Hz. Detailed comparison of bond lengths and angles in the different derivatives shows that the “softness” of the El(OtBu)3 groups (or the ability of the groups to accommodate a metal atom with respect to its size) follows the order Sn(OtBu)3 < Ge(OtBu)3 < Pb(OtBu)3. From these findings it can be explained, why the lead derivative 2g shows stereochemical activity of the lone pair, while 1g and 3g do not show this effect at room temperature. All compounds except the lead derivatives 1g, 2g, 3g and 7 are colourless.
Synthesis, Characterization and Crystal Structure of {N-(2-Mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diaminato } oxotechnetium(V)
Authors: Abram Ulrich , Abram Sonja , Hiller Wolfgang , Morgan Gillian F. , Thornback John R. , Deblaton Marcel , Stach Joachim
Published: March 2015

{ N-(2-Mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diaminato} oxotechnetium(V) has been prepared by the reaction of (Bu4N)TcOX4 complexes (X = Cl, Br) with N-(mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diamine in methanolic solution. The compound forms dark red crystals which were characterized by elemental analysis, IR and 1H NMR spectroscopy, mass spectrometry, as well as an X-ray structure determination. The compound crystallizes triclinic in the centrosymmetric space group PĪ with a = 776.50(3), b = 819.69(6), c = 1040.43(7) pm, α = 92.944(6)°, β = 110.805(5)° and γ = 109.957(5)°. The final R value is 0.023. In the monomeric complex the five coordinate technetium atom exhibits a square pyramidal environment with the donors of the tetradentate ligand in the basal plane and the oxo ligand in the apical position. The bond length Tc–O = 165.7(2) is within the normal range of Tc=O double bonds.