bluuebunny/crossref_metadata_2025 huggingface dataset:
EPR of VO2+ in KTiOPO4 Single Crystals
Authors: Vassilikou-Dova A. B. , Jansen S. , Wallrafen F. , Lehmann G.
Published: February 2015

KTiOPO4 single crystals doped with V2O4 were grown from fluxes between 1323 and 1123 K with dimensions up to (10x5x5) mm3. Two crystallographically inequivalent centers of VO2+ in the occupation ratio of 10:1 were detected by EPR at room temperature. Their z axes of largest hyperfine splitting are oriented close to the directions of the very short Ti-O bonds of the two Ti in the structure. An energy difference for incorporation of VO2+ into these two sites of -9.4+ 1.7 kJ/mol per pm difference in bond lengths was obtained from the occupation ratio, the large limits of error being mainly due to uncertainties in the bond lengths. Additional hyperfine splitting caused by 31P nuclei as next-nearest neighbors was also resolved in most orientations.
Mößbauer-Untersuchung der Modifikationen von Li2FeCl4
Authors: Lutz H. D. , Pfitzner A. , Schmidt W. , Riedel E. , Prick D.
Published: February 2015

The room temperature Mössbauer spectrum of the high-temperature polymorph of Li2FeCl4 is in agreement with an inverse spinel structure and a disordered distribution of the cations on the octahedral sites. Mössbauer spectra of the orthorhombic room-temperature modification of Li2FeCl4 correspond to a 1:1 ordering of Li+ -and Fe2+ -ions on the octahedral sites.
A Formula Periodic Table for Benzenoid Hydrocarbons and the Aufbau and Excised Internal Structure Concepts in Benzenoid Enumerations
Authors: Dias Jerry Ray
Published: February 2015

The genesis of two concepts of recent importance to isomeric polyhex enumeration is traced. As it will become evident from this review, the philosophy of our approach stresses the enumeration of select benzenoid groups of practical interest to chemists. These concepts were pivotal to the first published enumerations of the strictly peri-condensed, non-Kekulean, and essentially strain-free total resonant sextet benzenoid groups.
Allende Xenolith AF: Undisturbed Record of Condensation and Aggregation of Matter in the Solar Nebula
Authors: Kurat G. , Palme H. , Brandstätter F. , Huth J.
Published: February 2015

Allende-AF (All-AF) is chemically similar to bulk Allende, its texture is. however, completely different. It consists mainly of highly porous silicate-rich aggregates embedded in a largely opaque matrix. Occasionally olivine-sulfide-metal aggregates and large sulfide-andradite objects are found. Chondrules are absent and grain size in matrix and aggregates is the same, quite different from normal Allende.

The main mineral in All-AF is olivine (22-41 wt% FeO). low Ca-pyroxene is absent, but a variety of clinopyroxenes were encountered. Rare phases found throughout All-AF are refractory metal nuggets (Ir, Os, Ru etc.), HgS, and Ca-phosphate. Associated with sulfide-andradite objects are native-Cu, Ti-magnetite, perovskite, barite, and calcite.

Morphology, crystalline state and minor element contents of olivine strongly suggest an origin by condensation from a gas. Al20 3-contents, for example, range from 0.5 to 3% and Cr2O3-contents reach 2.5%.

Texture of All-AF indicates that condensation of olivine continued during formation of aggregates. Relictic low-Fe aluminous diopsides suggest that olivine was initially FeO-poor. Before final accretion into a solid rock exchange reactions between condensed phases and an (increasingly oxidized) vapor established the high FeO-content of olivine. A similar process led to sulfurization of most of the original metal. The exotic sulfide-andradite objects are probably alteration products of unusual, metal-rich calcium-aluminium-rich inclusions.

It appears that All-AF has preserved a unique record of condensation, hierarchical aggregation, and metasomatic exchange reactions in the solar nebula.
Allende Whole Rock and CAI Studies: Thermal Equilibration History and Noble Metal (Re)distributions in Mineral Phases*
Authors: Jovanovic S. , Reed G. W.
Published: February 2015

Ru, Os, and Ir in Allende whole rock and coarse grained CAIs are present in amounts up to 80% in phases other than inert Pt-metal alloys. Selective chemical dissolution was used to dissolve sulfides by ascorbic acid-H2O2 and metal (NiFe)-silicate-oxides by HF/HCl. Carbon-rich, spinel-chromite residues were left from the demineralization procedures and scavenged inert material such as Pt-metal alloy particles. The Pt-metal contents in sulfide phases from the Allende whole rock sample and the total Pt-metal contents of the CAI samples give near-cosmic to cosmic interelement ratios. Pt-metal ratios in all the other separated phases are fractionated. The Fe/Co ratio in the carbon-rich residue from the CAI and in the sulfide fractions from Allende whole rock and CAI-bulk samples is 230, the same as is reported for sulfides in the Zelda fremdlinge. A scheme for mixing aggregates from different regions of “Allende-space” in the solar nebula is proposed to account for the Pt-metal and Fe-Co distributions observed here.

Chemical alteration processes in condensed material may have required moderate to high temperatures in the nebula to have caused the interelement relationships observed. We determined the final equilibration temperatures to which components of Allende were subjected. Temperatures are based on the distribution of Hg between labile (low T) and retentive (high T) sites in silicate rocks. Compositionally and texturally different CAI clasts and the matrix associated with one of the clasts were equilibrated at 778-975 °C. The averaged thermal equilibration temperature for seven bulk (matrix) Allende samples reported previously was 670 °C. The final thermal equilibrations of the clasts probably occurred before Allende was assembled.
Structural Phase Transitions and Cationic Motions in Pvridinium Dichloroiodate(I) as Studied by 1H NMR, Differential Thermal Analysis, and Powder X-Ray Diffraction
Authors: Watanabe Reiko , Asaji Tetsuo , Furukawa Yoshihiro , Nakamura Daiyu , Ikeda Ryuichi
Published: February 2015

For crystals of pyridinium dichloroiodate (I), (pyH)ICl2, the temperature dependences of the 1H NMR spin-lattice relaxation time T1 and the 1H second moment M2 were determined. M2 was found to be small (~ 1 G2) above room temperature, indicating that the cations perform rapid reorientational motion about their pseudohexad axis perpendicular to the cationic plane. 1H T1 at its minimum was unusually long, indicating this motion occurring in the low symmetry local environments. Phase transitions between stable solid phases were revealed at 282 and 373 K by the 1H NMR measurements and differential thermal analysis. The highest-temperature phase was easily supercooled and transformed reversibly into another metastable phase and back on cooling and warming at almost the same temperature of 138 K. The kinetics of the phase transition from the supercooled to the stable phase at room temperature was analyzed using an Avrami type relation. The growth time of the stable phase was estimated to be about 14 h at room temperature
Cationic Dynamics in the Crystalline Phases of (CH3NH3)PbX3 (X: Cl, Br) as Studied by Proton Magnetic Resonance Techniques
Authors: Furukawa Yoshihiro , Nakamura Daiyu
Published: February 2015

The temperature dependences of the 1H spin-lattice relaxation time T1, the linewidth parameter T2*. and the second moment M2 of 1H NMR absorption were measured for solid (CH3NH3)PbX3 (X: CI. Br). In the room-temperature cubic phases of both salts, and also in the high-temperature tetragonal phase of (CH3NH3)PbBr3, the cations undergo rapid overall rotation or reorientation. In the lowest-temperature phase of both salts the orientation of the cations is fixed but rapid C3 reorientation of the CH3 and NH+
3 groups of the cations about their C - N bond axes takes place. From the M2 measurements, a precessional motion of the cations in the intermediate-temperature phase of both complexes is suggested. Above room temperature, 1H T1 of both salts can be explained by assuming spin-rotational relaxation operative due to the rapid rotation of the cations. An anomalous behavior of 1H T1, attributable to cross relaxation between 1H and 81Br nuclei, was detected for (CH3NH3) PbBr3 when T1 was measured at 42 MHz
High Resolution Microwave Spectra of Pyridine-N-oxideanda-Picoline-N-oxide
Authors: Heineking N. , Dreizler H. , Endo K. , Kamura Y.
Published: February 2015

The rotational spectra of pyridine-N-oxide and x-picoline-N-oxide ( = 2-methvlpyridine-N-oxide) have been observed by means of pulsed microwave spectroscopy. For both molecules, the 14N quadrupole coupling constants have been obtained. For α-picoline-N-oxide. in addition the parameters of the internal rotation motion and the centrifugal distortion constants have been determined.
Metal Tetrahydroborates and Tetrahydroboratometalates, 18 [1] Studies on the Formation of Cadmium(II)-tetrahydroborates with Tetrahydroborate and Iodide
Authors: Nöth Heinrich , Thomann Martina
Published: February 2015

The structure of cadmium tetrahydroborate in THF solution is fluxional on the NMR time scale and best described as Cd[(µ-H)2BH2]2•nTHF as indicated by IR data. Reactions of LiBH4 with Cd(BH4)2 in THF yield the monoanion [Cd(BH4)3]- exclusively, while a dilithium salt Li2[Cd(BH4)4] • 4 diglyme precipitates from diglyme solutions. Equilibria involving ICd(BH4), Cdl2, Cdl3
-, [Cd(BH4)3]-and/or [ICd(BH4)2]- result from Cd(BH4)2 and LiI in THF or diglyme. The solvent as well as the cation of the iodide (Cd2+ or Li+) influence the equilibria. This can be explained in terms of the different polarity and chelating ability of the solvents.
The New Laves Phase Na2Ba
Authors: Snyder G. Jeffrey , Simon Arndt
Published: February 2015

The crystal structure of Na2Ba was determined from single crystal X-ray diffraction data. It is isostructural with the hexagonal Laves phase Zn2Mg; P63/mmc, a = 739.3(4) pm, c = 1199.9(9) pm. The compound Na4Ba reported in the phase diagram literature is actually Na2Ba. Comparisons are made with other Laves phases using a strain parameter diagram.
Synthese und Kristallstruktur eines Alkali-Erdalkali-Kupfer-Halogeno-Oxovanadats: KBaCuV2O7Cl / Synthesis and Crystal Structure of an Alkaline Alkaline-Earth Halide Oxide of Copper and Vanadium: KBaCuV2O7Cl
Authors: Martin F.-D. , Müller-Buschbaum H.
Published: February 2015

Single crystals of KBaCuV2O7Cl have been prepared by a flux technique and investigated by X-ray analysis. The compound crystallizes with tetragonal symmetry, space group C2
4v-P4 bm, a = 8.8581, c = 5.4711 Å, Z = 2. The crystal structure shows Cu2+ within a one sided strongly distorted CuO4Cl2 octahedron. The copper ion is shifted towards the nearer Cl- neighbour to form a CuO4Cl square pyramid. Two VO4 tetrahedra are connected to give stretched V2O7 double tetrahedra, and linked in planes via the oxygen corners of the CuO4Cl pyramids. The crystal structure and the structure of the complex BaO8Cl2 polyhedron are discussed.
New Dimeric Tetrapeptide Enkephalin AnaloguesHydrophilic Spacer Length and Configuration Affects Potency and Receptor Selectivity
Authors: Stępiński Janusz , Tam S. William
Published: February 2015

Three new bivalent opioid peptide analogues, 1,3-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-2-propanol, 1,4-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-(2R, 3S)-butanediol and 1,4-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-(2R,3R)-butanediol, were synthesized and tested in vitro for μ, δ and ϰ receptor affinities. They were found to have potent opioid receptor binding activity. The (2S,3S)-butanediol bridge configuration yielded selectivity and high potency for μ and ϰ receptors, while the (2R,3R)-butanediol bridge configuration yielded high potency and selectivity for δ receptors. It thus appears that changes in the length and configuration of the polyhydroxyl bridge in dimeric enkephalin analogues can produce a shift in receptor selectivity profiles and therefore suggest the possibility of developing more selective drugs.
The Direct Synthesis of Secondary Amides from Aldehydes; A Novel General Redox Procedure Mediated by Iodotrichlorosilane (ITCS)
Authors: Elmorsy Saad S. , Badawy Doria S. , Nour Mohamed A. , Kandeel Ezzat M.
Published: February 2015

A unique, general redox process for the preparation of secondary amides by the interaction, of aldehydes with nitriles in the presence of two equivalents of iodotrichlorosilane (ITCS) is described and possible pathways are discussed.
Synthese und Kristallstruktur von [Na(12-Crown-4)2]2[Fe4Se4Cl4] / Synthesis and Crystal Structure of [Na(12-Crown-4)2]2[Fe4Se4Cl4]
Authors: Ahle Andreas , Dehnicke Kurt , Maichle-Mössmer Cäcilia , Strähle Joachim
Published: February 2015

[Na(12-crown-4)2]2[Fe4Se4Cl4] has been prepared by the reaction of FeCl2 with Na2Se4 in dimethylformamide solution in the presence of 12-crown-4 as dark red crystals, which were characterized by a crystal structure determination. Space group P1̄, Z = 2, 6295 observed unique reflections, R = 0.085. Lattice dimensions at 20 °C: a = 1397.3(3), b = 1501.8(4), c = 1570.1(4) pm, α = 85.86(2)°, β = 64.06(2)°, γ = 65.01(2)°. The structure consists of [Na(12-crown-4)2]+ cations and cuban-like anions [Fe4Se4Cl4]2+ with Fe ··· Fe contacts o f 282.8(3) pm.
Die Kristallstruktur von trans-1,3,5-Trichloro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazin (β-Sulfanurchlorid) / The Crystal Structure of /trans-1,3,5-Trichloro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazin (β-Sulfanuric Chloride)
Authors: Lork Enno , Behrens Ulrich , Steinke Günter , Mews Rüdiger
Published: February 2015

The crystal structure of β-(NS(O)Cl)3 is reported.
μ2-Halogenokomplexe von N-Bromsuccinimid und N-Bromphthalimid. Die Kristallstrukturen von PPh4[X(N-Bromsuccinimid)2] und von PPh4[X(N-Bromphthalimid)2] mit X = CI und Br / μ2-Halogeno Complexes of N-Bromosuccinimide and N-Bromophthalimide. The Crystal Structures of PPh4 [X(N-Bromosuccinimide)2] and PPh4 [X(N-Brom ophthalimide)2] with X = Cl and Br
Authors: Ghassemzadeh Mitra , Harms Klaus , Dehnicke Kurt , Fenske Dieter
Published: February 2015

The μ2-halogeno complexes PPh4[X(N-bromosuccinimide)2] and PPh4[X(N-bromophthali- mide)2] with X = Cl and Br have been prepared by reactions of N-bromosuccinimide and N-bromophthalimide, respectively, with the corresponding tetraphenylphosphonium halides PPh4X in acetonitrile solutions. The compounds form pale yellow crystal needles, which were characterized by IR spectroscopy and by crystal structure determinations.

PPh4[Cl(N-Bromosuccinimide)2] (1): Space group P21/n, Z = 4, structure solution with 2516 observed unique reflections, R = 0.040. Lattice dimensions at -25 °C: a = 1775.9(1), b = 764.3(1), c = 2341.7(2) pm, β = 101.84(1)°.

PPh4[Br(N-Bromosuccinimide)2] (2): Space group P21/n, Z = 4, structure solution with 5620 observed unique reflections, R = 0.061. Lattice dimensions at 20 °C: a = 1776.9(9), b = 762.2(3), c = 2331(1) pm, β = 103.02(3)°.

PPh4[Cl(N-Bromophthalimide)2] (3): Space group P1̅, Z = 4, structure solution with 3812 observed unique reflections, R = 0.039. Lattice dimensions at -50 °C: a = 918.5(2), b = 1115.0(3), c = 2584.4(5) pm, α = 88.22(3)°, β = 83.20(3)°, γ = 85.10(3)°.

PPh4[Br(N-Bromophthalimide)2] (4): Space group P1̅, Z = 2, structure solution with 3413 observed unique reflections, R = 0.044. Lattice dimensions at -50 °C: a = 1120.2(2), b = 1308.6(3), c = 1343.2(3) pm, α = 105.10(3)°, β = 104.16(3)°, γ = 92.99(3)°.

The structures of 1-4 consist of PPh4
+ ions, anions [X(N-bromosuccinimide)2]- and [X(N-bromophthalimide)2]-, respectively, in which the halide ions X- are coordinated by the bromine atoms of N-bromosuccinimide and N-bromophthalimide molecules, respectively. The bond angles Br···X···Br are 86.48(5)° for 1, 85.1(1)° for 2, 102.31(6)° and 93.61(6)° for 3, and 91.86(4)° for 4. The bond angles N-Br···X are nearly linear.
Neue Synthesen für homonukleare Cobalthydrid-Clusterverbindungen / New Synthetic Routes to Homonuclear Cobalt Hydride Clusters
Authors: Schneider Jörg J.
Published: February 2015

Several homonuclear cobalt hydride clusters are accessible by reacting the complexes (η5-CpR)Co(η2-ethene)2 (R = H5, Me5) 3, 4 with (C2H5)2AlH followed by alcoholysis of the crude reaction mixtures. Depending on the degree of alkyl substitution, different nuclearities of the resulting clusters have been observed. In the case of the pentamethyl substituted derivative (η5-Cp*)Co(η2-ethene) 4 a mixture of di-, tri- and tetranuclear cobalt hydride clusters namely [(η5-Cp*)Co]2H3 1, [(η5-Cp*)Co]3H4 2 and [(η5-Cp*)Co]4H4 7 were form­ed and separated by repeated crystallization. When reacting the parent compound (η5-Cp)Co(η2-ethene) 3 with (C2H5)2AlH and quenching the reaction mixture with alcohol at low temperature, the tetranuclear cobalt cluster [(η5-Cp)Co]4H4 5 is the main product. Aside from this, trace amounts of the cobalt alkylidine cluster [(η5-Cp)Co]4μ-[C(CH3)]H 6 were formed as detected by mass spectrometry. For the first time a direct synthesis of [(η5-Cp**)Co]3H4 10 and [(η5-Cp**)Co]4H4 11 was achieved by reaction of cobalt atoms with tetramethyl-ethyl-1,3-cyclopentadiene (mixture of isomers) in methylcyclohexane at -120 °C. However, the main product of this metal atom reaction is the mononuclear cobalt sandwich compound (η5-Cp**)Co(η4-tetramethyl-ethyl-1,3-cyclopentadiene) 9 as a mixture of isomers. The trinuclear cobalt alkylidine cluster [(η5-Cp*)Co]3μ3-[C(CH3)]2 8 is formed when reacting (η5-CpR)Co(η2-ethene)2 3 with equimolar amounts of di-isobutyl-aluminium- hydride or the borabicyclus 9-BBN.
Covalent Adducts from 2-Substituted 5-Arylazotropones and Nucleophiles and their Fate
Authors: Cavazza Marino , Pietra Francesco
Published: February 2015

Working in (CD3)2SO/MeOH 98:2, 2-methoxy-5-[(4-methylphenyl)azo]-2,4,6-cyclohepta- trien-1-one (1a) was found to add either MeO-, giving the stablegcw-dimethoxy α-adduct 2a, or EtS-, to give initially to the C-2 α-adduct 4 a; on neutralization, the latter gave ipso (C-2) replacement of OMe by SEt, while the former returned to the starting material, via the neutral α-adduct 3a. In contrast, in the same medium, 2-ethylthio-5-[(4-methylphenyl)azo]-2,4,6-cy- cloheptatrien-1-one (5 a) was found to add EtS- at both C-2 and C-7; on neutralization prod­ucts of both ipso substitution (5 a) and ipso- plus tele-substitution (C-7) (8) were isolated.
Darstellung, schwingungsspektren und Normalkoordinatenanalyse der Bromo-Iodo-Rhenate(IV), [ReRrnI6-n]2-, n = 0-6 / Preparation, vibrational spectra, and normal coordinate analysis of bromo-iodo-rhenates(iv), [ReRrnI6-n]2-, n = 0-6
Authors: Prillwitz P. , Preetz W.
Published: February 2015

The IR and Raman spectra of the ten bromo-iodo-rhenates(IV) [ReBrnI6-n]2-, n = 0 -6 , including the geometrical isomers for n - 2,3,4, have been recorded at 80 K. The vibrational spectra are completely assigned according to point groups Oh, D4h, C4v, C3v, and C2v, as supported by normal coordinate analyses based on a general valence force field. Due to the different mms-influences Br < I in asymmetric axes Br•-Re-I', the Re-I' bonds are strengthened and the Re-Br• bonds are weakened, as indicated by valence force constants, for Re-I' on average 8,5% higher and for Os-Br• 8,3% lower, as compared with the values calculated for symmetric I-Re-I and Br-Re-Br axes, respectively
Beiträge zur Chemie des 4,5-Benzo-3-methyl-1,3,2-oxazaphosphorinan- 6-on Ringsystems: Röntgenstrukturanalysen an einem Bis(2-chlorethyl)amino- und einem Acetamido-substituierten Derivat / Chemistry of the 4,5-Benzo-3-methyl-1,3,2-oxazaphosphorinan-6-one Ring System: X-Ray Crystal Structure Analysis of a Bis(2-chloroethyl)amino- and of an Acetamido-Substituted Derivative
Authors: Fischer Axel , Neda Ion , Kaukorat Thomas , Sonnenburg Ralf , Jones Peter G. , Schmutzler Reinhard
Published: February 2015

The reaction of 4,5-benzo-2-chloro-3-methyl-1,3,2-oxazaphosphorinan-6-one 1 with 1,2-bis- (trimethylsiloxy)ethane led to the bisphosphoryl species 2a and to the isomeric bisphosphite derivative 2b. The reaction of 1 with heptamethyldisilazane furnished the expected diphos­phorus compound 3, with two λ3P(III) atoms linked by a methylamino group. Substitution of the chlorine atom of 1 by the 2-chloroethylamino and bis(2-chloroethyl)amino group led to the oxazaphosphorinanones 4 and 6. By oxidation of 4 with the hydrogen peroxide/urea 1:1-adduct, the phosphoryl compound 5 was formed. Oxidation of 4,5-benzo-2-diethyl- amino-3-methyl-1,3,2-oxazaphosphorinan-6-one 7 [1] with hydrogen peroxide, sulfur and se­lenium led to the corresponding phosphoryl, thiophosphoryl and selenophosphoryl com­pounds 8-10. Analogously, the reaction of the dimethylamino- and acetamido-substituted derivatives 11 and 13 [1] with elemental sulfur furnished the thiophosphoryl compounds 12 and 14. X-ray crystal structure determinations of 4 and 14 confirmed the molecular structures, proposed in accord with NMR spectroscopic and mass spectrometric data. The heterocyclic rings are essentially planar. In 14 a hydrogen bond N-H···O (amide) is observed.
Isolierung von Venturicidin X, dem Aglycon der Venturicidine A und B aus Streptomyceten / Isolation of Venturicidin X, the Aglycon of Venturicidines A and B from Streptopyces sp
Authors: Laatsch Hartmut , Kellner Michael , Lee Yong-Se , Wolf Gerhard
Published: February 2015

Venturicidin X (la ), the aglycon of the venturicidins A (1b) and B (1c) was isolated for the first time as a natural product from an unidentified Streptomyces sp. Venturicidin X (1a) is highly active against a broad spectrum of plant pathogenic fungi.
Schwingungsspektren und Kraftkonstanten von linearen Anionen [MIIP2]4- und [MIX2]5- (MII = Zn, Cd, Hg; MI = Cu, Ag; X = E 15) in den kaliumverbindungen und in Na4[HgP2] / Vibrational spectra and force constants of the linear anions [MIIP2]4- and [MIX2]5- (MII = Zn, Cd, Hg; MI = Cu, Ag; X = E 15) in Potassium Compounds and in Na4[HgP2]
Authors: Somer Mehmet
Published: February 2015

The vibrational spectra of the title compounds have been recorded and interpreted based on the symmetry Dooh of the isolated linear anions [MX2]n- (M = Cu, Ag, Zn, Cd. Hg; X = P, As, Sb). The calculated stretching force constants are: f(MII-P) = 1.89 {MII = Zn}, 1.66 {Cd}, 1.83 {Hg} Ncm-1 and f(Cu-X ) = 1.27 {X = P}, 0.99 {Sb} and f(Ag-As ) = 0.93 Ncm-1 respectively. These are compared with those of the isoelectronic molecules MIIY2 and [MIY2]- in relation to charge effects (MII = Zn, Cd, Hg; MI = Cu, Ag; Y = Cl, Br)
Ein neues Carbonat mit Baylissit-Struktur: Rb2[Mg(CO3)2(H2O)4] / A New Carbonate with Baylissite Structure: Rb2[Mg(CO3)2(H2O)4]
Authors: Zheng Yue Qing , Adam Arnold
Published: February 2015

The new complex carbonate Rb2[Mg(CO3)2(H2O))4] crystallizes in the Baylissite-type structure with a = 1130,4(3), b = 641,9(1), c = 703,3(2) pm, β = 99,62(1)°, VEZ = 503,2(2), space group P21/n (No. 14) and Z = 2. In comparison with the isostructural potassium compound the cell dimensions increase in b- and c- and decrease in a-direction. This effect depends on the greater coordination number of Rb+ and the rigidity of strong hydrogen bonds. The carbonate anion exhibits significant deviations from D3h-symmetry (C -O: 127,1(5)-130,2(5) pm, ∠ O - C - O: 117,9(4)-121,1(3)°).
Zum Redoxverhalten von elementarem Quecksilber und Diorganyldisulfiden / The Redox Behaviour of Elemental Mercury and Diorganyl Disulphides
Authors: Steinfatt Ingeborg , Hoffmann Gerhard G.
Published: February 2015

The thermal reaction of elemental mercury with diorganvl disulphides (RSSR: R = CH3 and C6H5) has been studied. The corresponding mercury dithiolates (CH3S)2Hg (1) and (C6H5S)2Hg (2) are formed under redox conditions. Heating of 2 in n-octanethiol leads to the formation of the corresponding mercury di-n-octanethiolate (3). Compounds 1, 2, and 3 have been characterized by means of 1H NMR. IR. DSC and DTG methods.
Heterometallische Verbindungen. Darstellung und Strukturen einiger Co(III)-Komplexe mit CrO4
2--Liganden / Heterometallic Compounds. Preparation and Structures of Some Co(III) Complexes with CrO4
2- Ligands
Authors: Brüggemann Ricardo Catasus y , Thewalt Ulf
Published: February 2015

Heteronuclear complexes containing Co(III) and Cr(VI) are formed on reaction of [Co(en)2(OH)(OH2)]2+or [Co(tren)(OH)(OH2)]2+ cations with CrO4
2- .Two types of com­plexes were isolated:

1.Complexes with two trans chromato ligands at Co; namely Li[Co(en)2(CrO4)2]·5H2O (1a) and K[Co(en)2(CrO4)2](1b).

2.Complexes having a cyclic structure with two CrO4 bridges between two cis-Co(en)2 or Co(tren) units, namely [Co2(en)4(CrO4)2]Cl2 (2a), [Co2(en)4(CrO4)2]Br2 (2b)and [Co2(tren)2(CrO4)2](ClO4)2(3).

The molecular structures have been confirmed by X-ray methods. The molecular confor­mations adopted by the complexes in the solid state are stabilized by intramolecular hydro­gen bonds.
Synthesis of Cross-Linked Polyamines
Authors: Sosnovsky George , Lukszo Jan
Published: February 2015

Several synthetic approaches are explored for the preparation of polyamines which are cross-linked at the central, secondary nitrogen moiety. Diethylenetriamine, norspermidine and spermidine were used as examples.
Darstellung neuartiger 1-Wolframa-2-phospha-3-cyclobuten-4-ol-Verbindungen durch Hydrochlorierung von η3-Phosphinoketenkomplexen / Synthesis of 1-Tungsta-2-phospha-3-cyclobuten-4-ol Complexes by Hydrochlorination of η3-Phosphinoketene Complexes
Authors: Ostermeier Josef , Heckel Max , Hiller Wolfgang , Kreißl Fritz R.
Published: February 2015

η3-Phosphinoketene complexes of tungsten Cp(CO)ClW [η3-P(Ph2)-C(R)=C=O] (R=Me, Ph) react with hydrogen chloride under protonation of the ketene oxygen atom converting the ketene into a new cyclobutenol system. The products have been characterized by 1H, 13C, 31P NMR. IR and mass spectra. 1-Carbonyl-1,1-dichloro-1-(η5-cyclopentadienyl)-2,2-di-phenyl-3-methyl-1-wolframa-2-phospha-3-buten-4-ol crystallized in the monoclinic space group P21/n with a = 9.046(2), b = 7.369(1), c = 30.266(2) Å, β = 96.63(3)° and Z = 4.
Oxidation of Disilenes: Experimental and Theoretical Studies
Authors: McKillop Kirsten L. , West Robert , Clark Timothy , Hofmann Heinz
Published: February 2015

The oxidation of E-1,2-di-tert-butyl-1,2-dimesityl disilene (1) in benzene by gaseous dioxygen to give 2 and 3 has been studied at various temperatures and with rapid or slow addition of oxygen. The effect of various additives (amines, phosphines, THF) on the product distribution was also investigated. Ab initio MO calculations were carried out on the oxidation of H2Si=SiH2 with triplet oxygen. These led to a proposed reaction mechanism for the oxidation of 1, in which the initial intermediate is a disileneperoxy biradical 6′, which can close to give 2 or react with another molecule of disilene to give ultimately 3.
Zur Festphasenpeptidsynthese des Makrophagen-migrationsinhibierenden Faktors der Maus (mMIF): Ein Vergleich verschiedener Syntheseansätze zur Darstellung der schwierigen C-terminalen Sequenz mMIF(93-115)/ Solid Phase Peptide Synthetic Approaches to Mouse Macrophage Migration Inhibitory Factor (mMIF): Comparison of Different Strategies Producing the C-Terminal Difficult Sequence Peptide mMIF (93-115)
Authors: Kaiser Thomas , Voelter Wolfgang
Published: February 2015

From solid phase peptide synthetic approaches of mMIF(93-115) the C-terminal sequence turned out to be a typical „difficult sequence“ peptide. Various stepwise syntheses were performed with different resins and coupling reagents. The Peptide was synthesized in 90% yield by solid phase fragment condensation of protected mMIF(93-108) to mMIF(109-115) ‘2-Chlorotrityl’ resin bound.
Unsymmetrische BN2
3--Ionen in den Strukturen von Ca2ClBN2 und Sr2ClBN2 / Unsymmetric BN2
3--Ions in the Structures of Ca2ClBN2 and Sr2ClBN2
Authors: Reckeweg Olaf , Meyer H.-Jürgen
Published: February 2015

The new compounds Ca2ClBN2 (1) and Sr2ClBN2 (2) were prepared from the respective metal, its dihalide and h-BN in sealed tantalum ampoules at 1200 °C. The crystals obtained were transparent yellow (1) and blue (2), respectively. The crystal structures were determined from single crystal X-ray data. Ca2ClBN2 and Sr2ClBN2 are isotypic and crystallize in the orthorhombic space group Pnma (No. 62), Z = 4 (Ca2ClBN 2: a = 1166.7(2), b = 390.26(4), c = 899.8(1) pm, R1 = 0.043, wR2 = 0.115 for 554 independent reflections; Sr2ClBN2: a = 1242.8(1), b = 416.75(4), c = 920.8(1) pm, R1 = 0.031, wR2 = 0.054 for 662 independent reflections).

The structures contain two different layers of M2+, Cl- and BN2
3- alternating along the [010] direction. The bond angles N-B-N are 177.2(4)° for (1) and 176,6(5)° for (2), the bond distances of the BN2
3- ions are dB_ N1] = 134.6(5) pm for (1), 136,3(7) pm for (2) and dB_N2 = 132.4(5) pm for (1) and 131,3(7) pm for (2). The unsymmetric structure of the BN2
3- ion, as is manifested particularly in the Sr compound (2), is caused by the coordination of N1 to four cations while N2 is coordinated only to three.
Crystal and Molecular Structure of Methylpropylglyoxal Bis(amidinohydrazone) Sulphate Monohydrate
Authors: Koskinen Mikko , Mutikainen Ilpo , Koskinen Jere T. , Elo Hannu
Published: February 2015

A single-crystal X-ray diffraction study was performed on methylpropylglyoxal bis(amidinohydrazone) (M PGBG) sulphate monohydrate. The bis(amidinohydrazone) dication was found to exist exclusively in the form of the anti-anti isomer, with an all-trans configuration of the glyoxal bis(amidinohydrazone) chain, just as do the free base, the monocation and the dication of glyoxal bis(amidinohydrazone) and the dications of all mono-and dialkylglyoxal bis(amidinohydrazones) so far studied. MPGBG sulphate monohydrate crystallizes in the triclinic space group Pl̅ with unit cell parameters a = 8.860(2), b = 9.195(2), c = 10.788(2) Å, α = 73.71(3), β = 77.59(3), γ = 65.28(3)° and with Z = 2. When the structure is compared with that of propylglyoxal bis(amidinohydrazone) (PGBG) sulphate, an analogous compound that is devoid of the methyl group of MPGBG, a distinct difference can be observed regard­ing the conformation of the propyl side chain. In the MPGBG dication, the propyl group is directed away from the glyoxal bis(amidinohydrazone) chain, whilst in the case of the PGBG dication it is tangled around the glyoxal bis(amidinohydrazone) moiety. Whether this difference results from packing effects and related factors, or whether it is a result of a more fundamental difference between MPGBG and PGBG, remains to be studied. The observed difference may contribute to the biochemical differences between the two compounds.
2.4.6-Tri-tert-butylphenylaminofluorsilane und Lithium-bis(2,4,6-tri tert- butylphenyldifluorsilyl)amid - im Kristall ein Polymer / 2.4.6-Tri-tert-butylphenylaminofluorosilanes and Lithium-bis(2,4,6-tri-tert-butylphenyldifluorosilyl) amide - in the Crystal a Polymer
Authors: Herbst-Irmer Regine , Klingebiel Uwe , Noltemeyer Mathias
Published: February 2015

2,4,6-Tri-tert-butylphenyltrifluorosilane (1) reacts with lithium amides to give the aminofluorosilanes (2 - 7); RSiF2NHR′ (R = 2,4,6-Me3CC6H2; R′ = H (2), CMe3 (3), SiMe2CMe3 (4)), (R-SiF2)2NH (5), RSiF(NHR′)2. R′ = CMe3 (6), C6H5 (7). The reaction of 5 with BuLi in THF leads to the formation of the monomeric lithium derivative 8, R-SiF2Li⊕(THF)3-N⊖ -SiF2R. The polymeric lithium derivative 9 [R-SiF2-N⊖-SiRF2Li⊕(THF)2]n is obtained by recrystallisation of 8 in THF. In 8 and 9 lithium is only coordinated to fluorine and THF. Hydrolysis of 8 or 9 lead to the 1,3-disiloxane 10, (RSiF2)2O . 10 shows linearity at the oxygen and short Si-O bond lengths.
Synthesis and Spectroscopic Properties of 1,2-Diiminetricarbonylrhenium( I)chloride Complexes with Aliphatic Diimines (or 1,4-Diaza-1,3-butadienes) as Ligands
Authors: Leirer Markus , Knör Günther , Vogler Amd
Published: February 2015

Re(1,2-diimine)(CO)3Cl complexes with the aliphatic bidentate ligands diiminosuccinodinitrile (DISN), benzilbisanile (BEAN), bisacetylbisanile (BABA), and benzildiimine (BEDIM) are reported. The compounds show Re(I) to π*(diimine) metal-to-ligand charge transfer (MLCT) absorptions in the visible spectral region. The energy of these MLCT-transitions decreases in the series BABA > BEDIM > BEAN > DISN, depending on the π* acceptor properties of the coordinated diimine ligands. The maxima of these CT bands undergo a solvent-dependent shift (negative solvatochromism), which indicates a partial charge redistribution in the excited state. The compounds are not photoluminescent at room temperature and 77 K.
1,3-Diisopropyl-4,5-dimethylimidazolium-2-N,N’-diisopropylamidinat, ein neuartiges Retain [1] / 1,3-Diisopropyl-4,5-dimethylimidazolium-2-N,N'-diisopropylamidinate, a Novel Betaine [1]
Authors: Kuhn Norbert , Steimann Manfred , Weyers Gerd , Henkel Gerald
Published: February 2015

The imidazolium-2-amidinate 6 is obtained from the reaction of 2,3-dihydro-1,3-diisopropyl- 4,5-dimethylimidazol-2-ylidene (4) with diisopropylcarbodiimide (5) as stable solid. Overcrowding causes a lowered symmetry of the amidinate fragment indicated both by structural and NMR data. The strongly basic properties of 6 allow facile protonation with HCl to the cationic amidine derivatives 7 and 8. The ketoamidine 10 is formed by a ring opening reaction of 6 with water. The X-ray structures of 6 and 10 are reported.
Komplexe Chalkogenide der IVa Metalle mit niedrigdimensionalen anionischen Partialstrukturen. Darstellung und Kristallstruktur von K2ZrTe3 und Rb2ZrTe3 / Complex Chalcogenides of the IVa Metals with Low Dimensional Anionic Partial Structures. Preparation and Crystal Structures of K2ZrTe3 and Rb2ZrTe3
Authors: Klepp Kurt O. , Kolb Andreas
Published: February 2015

The isostructural compounds K2ZrTe3 and Rb2ZrTe3 were obtained at 1000°C by reacting K2Te and Rb2Te with stoichiometric amounts of Zr and Te. The compounds are monoclinic, mP24, space group P21/c, Z = 4 with a = 9.089(3), b = 14.148(4), c = 6.986(3) Å, β = 105.90( 1)° and a = 9.735(4), b = 14.300(7), c = 6.952(8) Å, β = 108.61(2)°, respectively. The crystal structure was determined from diffractometer data and refined to R = 0.030 for 1452 Fo's for K2ZrTe3 and R = 0.038 for 1131 Fo's for Rb2ZrTe3. The crystal structure is of a new type, characterized by infinite anionic chains, 1
∞-[ZrTe3]2- built up by octahedra sharing opposite faces which run along [001]. The mean Zr-Te bond lengths are 2.921 and 2.920 Å, respectively. The alkali cations separating the chains are characterized by two different - distorted octahedral and pentagonal bipyramidal - chalcogen environments.
The Crystal Structure of Dimethyl (2Z, 6Z)-2,7-bis-(benzyloxycarbonylamino) octa-2,6-diendioate: A Useful Precursor for Optically Pure 2,7-Diaminosuberic Acid
Authors: Klepp K. O. , Hiebl J. , Kollmann H. , Rovenszky F.
Published: February 2015

Needle shaped single crystals of the dimethyl ester of (2Z, 6Z)-2,7-bis-(benzyloxycarbonylamino)- octa-2,6-diendioic acid (1), C26H28N2O8 were obtained by very slow cooling from methanol/ethylacetate solution 20:1. 1 crystallizes in the anorthic space group Pl̅ (No.2) with a = 4.813(5), b = 12.277(6), c = 12.340(7) Å, α =117.15(3)°, β = 97.52(4)°, γ = 92.02(4)°, Z =1. The crystal structure was determined from diffractometer data (MoKα-radiation). It was solved by direct methods and refined to a conventional R of 0.054 for 1452 Fo's and 178 refined parameters. The molecule is characterized by the presence of an inversion center. In the crystal structure the molecules are stacked along the crystallographic a-axis. In this direction - which coincides with the needle axis of the crystals - each molecule is connected with its neighbors through almost linear N-H···O-hydrogen bonds.
Synthese neuer Pyridin-, Pyrindin- bzw. Isochinolin-substituierter α- und β-C-Nukleoside der 2-Desoxy-D-ribose / Synthesis of Novel Pyridine-, Pyrindine- and Isoquinoline-Substituted α- and β-C-Nucleosides of 2-Deoxy-D-ribose
Authors: Seitz Gunther , Lachmann Jens
Published: February 2015

The novel imido esters of 2-deoxy-α- and -β-D-ribose 8 and 9 have been synthesized and successfully transformed to the protected 1,2,4-triazine-C -nucleosides 11 and 12 using an inverse type Diels-Alder reaction with the 1,2,4,5-tetrazine 10. The electron deficient diazadiene system of both C -nucleosides 11 and 12 proved to be highly reactive in a consecutive [4 + 2] cycloaddition with inverse electron demand towards several electron rich dienophiles yielding after successful deprotection the novel pyridine-, pyrindine- and isoquinoline-C-nucleosides 15, 18 and 21 of 2 -deoxy-α-D-ribose and 23, 25 and 27 of 2-deoxy-β-D-ribose.
Synthesis and Coordination Properties of 6,6'-Dimesityl-2,2'-bipyridine
Authors: Schmittel Michael , Ganz Andrea , Schenk Wolfdieter A. , Hagel Michael
Published: February 2015

A synthetic route to 6,6′-dimesityl-2,2′-bipyridine is presented that involves a Suzuki coupling of 6,6′-dibromo-2,2′-bipyridine with mesityl boronic acid. The new sterically crowded ligand is investigated by X-ray analysis and its coordination behavior in the presence of copper(I) is examined.
Polysulfonylamine, CXII. Neues aus der Festkörperchemie der 2-Pyridone: Isolierung und Röntgenstrukturen von Bis(2-pyridon)hydrogen(I)- und Bis(6-methyl-2-pyridon)hydrogen(I)-dimesylamid / Polysulfonylamines, CXII. A Novel Solid-State Aspect of 2-Pyridones: Isolation and X-Ray Structures of Bis(2-pyridone)hydrogen(I) and Bis(6-methyl-2-pyridone)hydrogen(I) Dimesylamides
Authors: Wijaya Karna , Moers Oliver , Blaschette Armand , Jones Peter G.
Published: February 2015

The compounds (2-pyridone)2H+(MeSO2)2N- (1, monoclinic, space group P21/n ) and (6- methyl-2-pyridone)2H+(MeSO2)2N- (2, triclinic, P1) crystallize selectively and in good yields when the parent 2-pyridones (2-hydroxypyridines) are treated with the strong NH acid dimesylamine in acetonitrile or acetone. The corresponding 2-hydroxypyridinium salts could not be obtained. In the unprecedented crystal structures of 1 and 2, two pyridone units are linked by a proton to form very short and approximately symmetric O⋯H+ ⋯O hydrogen bonds, the adjacent C-O distances being appreciably elongated as compared to “free” pyridones [1: O ⋯ O 241.8(2), C -O 127.8(3) and 129.1(2) pm; 2: O ⋯ O 243.8(2), C -O 128.1(2) and 129.2(2) pm]. In both crystal packings, the homoconjugate cations and the dimesylamide anions are alternately associated into chains by an N - H ⋯ N “ and an N - H ⋯ O hydrogen bond.
A Short and Productive Synthesis of (R)-α-Lipoic Acid
Authors: Bringmann Gerhard , Herzberg Daniela , Adam Geo , Balkenhohl Friedhelm , Paust Joachim
Published: February 2015

(R )-α-Lipoic acid is synthesized in seven steps from the base chemicals methyl acetoacetate or Meldrum’s acid and monomethyl adipate. The key steps are the introduction of the stereogenic center by fermentative or homogeneously catalyzed hydrogenation of 3-oxooctanedioic acid diester to (3S)-3-hydroxyoctanedioic acid diester and its regioselective reduction to (6S)-6 ,8-dihydroxyoctanoic acid ester. The overall yield of (R )-α-lipoic acid, starting from 3-oxooctanedioic acid diester, is 40%.
Fixation o f Neutral Molecules in the Binding Cavity of Nonplanar Porphyrins - A Third Dodecaphenylporphyrin Modification with NH -Solvent Hydrogen Bonding
Authors: Senge Mathias O.
Published: February 2015

A third crystalline modification of dodecaphenylporphyrin is described in which the pyrrole nitrogen atoms are hydrogen-bonded to two ethanol molecules. This is the first crystallographic proof for the accessibility of nitrogen atoms in saddle-distorted free base porphyrins for hydrogen bonding. No such coordination is possible in either planar or ruffled porphyrins. Thus, the possibility exists to utilize conformationally distorted porphyrins for the binding of neutral m olecules
K[B6PO10(OH)4]: Ein Borophosphat mit gestreckten Bändern aus Tetraeder-Vierer-Ringen und offen-zyklischen Verzweigungen über planare B2O3(OH)2-Gruppen / K[B6PO10(OH)4]: A Borophosphate Containing Rods of Tetrahedral Vierer-Rings with Additional Open-Loop Branchings via Planar B2O3(OH)2 Groups
Authors: Boy Insan , Kniep Rüdiger
Published: February 2015

K[B6PO10(OH)4] was prepared under mild hydrothermal conditions (T = 170 °C) from a concentrated solution of K2B4O 7 ∙ 4H2O , KH2PO4, and HCl (18%). The crystal structure of the tetragonal compound was solved by X-ray single crystal methods (space group P 4/ncc, No 130): a = 1209.66(13), c = 759.05(7) pm; Z = 4. The anionic partial structure consists of infinite rods of ∞
1[B6PO10(OH)4]− which are built of vierer-rings of alternating BO4 and PO4 tetrahedra with additional open-loop branchings via planar B2O3(OH )2 groups at the BO4 units by sharing common oxygen functions. Potassium (K+) is located within structural channels running along [001]; the eightfold coordination by oxygen (OH-groups) results in a (slightly) distorted tetragonal antiprism.
Synthesis and Crystal Structure of Mn2(C2H5NH2)2Sb2S5 Exhibiting a Reversible Phase Transition
Authors: Schur Michael , Näther Christian , Bensch Wolfgang
Published: February 2015

Thioantimonates, Solvothermal Synthesis, Chalcogenides The reaction of elemental manganese, antimony and sulfur with ethylamine under mild solvothermal conditions yielded a thioantimonate(III) with composition Mn2(EA)2Sb2S5 (EA = C2H5NH2) that is a new member of a series of polymeric manganese thioantimo-nates(III). The structure of the title compound consists of layers of a neutral mesh-like Mn2Sb2S5 framework. The ethylamino ligands coordinated to the Mn centres separate the sheets and fill the voids within the layers formed by the interconnection of Mn2Sb2S4 hetero-cubane like building blocks. Below 273 K a reversible phase transition occurs, which is accom­panied by a doubling of the crystallographic a-axis.
Dimeres Di(N-lithium–tert–butylamino)bis(dimethylamino)silan - [Si(N(CH3)2)2(NLiC(CH3)3)2]2 – Darstellung und Kristallstruktur / Dimeric Di(N -lithio-tert-butylamino)bis(dimethylamino)silane - [Si(N(CH3)2)2(NLiC(CH3)3)2]2 – Synthesis und Crystal Structure
Authors: Engering Josef , Peters Eva-Maria , Jansen Martin
Published: February 2015

[Si(N(CH3)2)2(NLiC(CH3)3)2]2 results from the reaction of silicon tetrachloride with excess terf-butylamine, followed by halogen substitution with LiN(CH3)2, and treatment with n-butyllithium in hexane. The title compound, found to be dimeric in the solid state, was characterised by single crystal X-ray diffraction (triclinic, Pi , a = 10.208(2), b = 12.140(2), c = 15.658(3) Å , a = 79.02(3), ß = 82.80(3), γ = 67.19(3)°, Z = 2, C24H60Li4N8Si2 ), and by solid state and solution NMR-spectroscopy and mass spectrometry.
Oxovanadium(IV), Nickel(II) and Palladium(II) Complexes of Tridentate Salicylaldiminates Derived from 2,4-Di-ter-butyl-6-aminophenol
Authors: Kasumov Veli T.
Published: February 2015

Several new binuclear nickel(II), oxovanadium(IV) and palladium(II) complexes (MLX) of tridentate salicylaldimines (LXH2) obtained from substituted salicylaldehydes and 2,4-di-tert-butyl-6-aminophenol, as well as mononuclear nickel(II) and oxovanadium(IV), MQx nH2O, complexes with hydrogenated LX H2 ligands (QXH2) have been prepared and their spectroscopic, magnetic and catalytic activity (for PdLx) have been investigated. NiLx and VOLx complexes when dissolved in pyridine, take up three or two pyridine molecules to form six coordinated complexes, respectively. The Ni(II) and VO(IV) complexes obtained from QXH2 can be formu­lated as NiQx-3H2O and VOQx H2O. All VO(IV) complexes have been characterized by ESR parameters. It has been found that some PdLx complexes without any preliminary activation, in EtOH, THF and DMF exhibit high catalytic activity in the hydrogenation of nitrobenzene or cyclohexene at room temperature and at 30 -40 °C under 760 torr H2. When this reaction has been carried out in the ESR cavity at room temperature the triplet of 12 line multiplets due to the nitroxyl type coordinated radical (g = 2.013, AN = 10 G, AH = 0.8 G) was detected.
Quassinoids and Other Constituents from Picrasma crenata
Authors: Krebs H. C. , Schilling P. J. , Wartchow R. , Bolte M.
Published: February 2015

16-β-O-methylneoquassin and 16-β-O-ethylneoquassin, and four known quassi­ noids have been isolated together with coniferyl aldehyde, coniferin, cantin-6-one, 4,5-di-methoxycantin-6-one and (+)-neo-olivil from the wood of Picrasma crenata. Their structures were determined on basis of spectroscopic and X-ray analysis.
α-Dicarbonylmonophenylhydrazone als Nucleophile und Nachbargruppen / α-Dicarbonylmonophenylhydrazones as Nucleophiles and Neighbouring Groups
Authors: Möhrle Hans , Keller Georg
Published: February 2015

The α-dicarbonylmonophenylhydrazones 1 and 8 do not react as simple ,,CH-acidic compounds“ in the Mannich condensation reaction. In a concerted reaction with aminals in absolute dioxane they give rise to the products 5a-e and 10a-e with better practicability and much higher yields compared with the conventional method. The formal Mannich bases 5a/5b/5d and 10a/10b/10d with a cyclic amine part show in the dehydrogenation, using mercury- EDTA , a neighbouring group participation of the phenylhydrazono moiety yielding the corresponding lactams. With 5c only cyclization occurs leading to 1,2,4-triazine 19 in low yield, while 10c shows no dehydrogenation but an amine elimination to the vinyl-azo com pound 21 with consecutive cycloaddition leading to the 1,2-diazine 23.
Ba16Nb5N19 - A Nitridoniobate(V) Containing Isolated [NbN4]7- and [Nb2N7]11- Units
Authors: Höhn Peter , Kniep Rüdiger
Published: February 2015

Ba16NbsN19 was synthesized by reaction of Ba with Nb under nitrogen at ambient pressure at 1223 K. The refined crystal structure was solved in the space group P1̄ (no. 2), Z = 2, with the lattice constants a = 1099.33(3), b = 1140.41(15), c = 1622.06(6) pm, α = 72.197(2)°, β = 59.949(1)°, γ = 82.243(2)° and R1 = 0.058, wR2 = 0.088. The crystal structure contains both isolated [NbN4]7- as well as dimeric units [Nb2N7 ]11- . Together with the Ba2+ ions the compound has to be regarded as Ba16 [NbN4]3[Nb2N7 ].
Dihydroquinol And Quinol Derivatives From Ajuga Parviflora
Authors: Akbar Erum , Nawaz Hafiz Rub , Malik Abdul
Published: February 2015

Dihydroquinol derivative 1, quinol glucopyranoside 2 and quinol derivative 3 have been isolated from the ethyl acetate soluble fraction of Ajuga parviflora and their structures have been elucidated through spectroscopic studies as methyl 2-[2,2-dimethyl-6-oxo-7-dihydro-1,3- benzodioxol-3(6H)-yl]aceate (1), 2-hydroxy-4β-methyl-4a-(β-D-glucopyranoside)-2,5-cyclohexadien- 1-one (2) and (4-oxo-2,5-cyclohexadien-1-yl)acetic acid (3). The known quinol 4 has also been isolated for the first time from this species
New Hydrazinium Salts of 5,5'-Azotetrazolate
Authors: Hammerl Anton , Holl Gerhard , Kaiser M. , Klapötke Thomas M. , Mayer Peter , Nöth Heinrich , Piotrowski Holger , Suter Max
Published: February 2015

Salts of the 5,5′-azotetrazolate dianion with several different hydrazinium cations were pre­ pared. The compounds were characterized by elemental analysis, vibrational spectroscopy (IR, Raman) and multinuclear NMR spectroscopy (1H, 13C, 14 N). The crystal structures of the di-tert-butylhydrazinium, the ethylenedihydrazinium, the diguanidinium and the bis-triamino-guanidinium azotetrazolate were determined. The thermal, shock and friction sensitivities of all compounds were investigated and their explosion products were analysed. For the 5,5′-azotetr-azolate dianion the structure was calculated with density functional theory (B3-LYP). An NBO analysis was performed for the 5,5′-azotetrazolate dianion in order to understand the charge distribution of the dianion.