bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Reactivity of Cyclopentadienyl and Indenyl Ligands Bearing ω-Fluorinated Pendant Groups. Crystal Structure of (ortho-F-C6H4)-CPh2-C5H4SiMe3
Authors: Khvorost A. , Lemenovskii D. , Ustynyuk N. , Rufanov K. , Kipke J.
Published: August 2018

A series of cyclopentadienes and indenes with ω-fluorinated pendant groups have been synthesised and their reactivity towards metallating agents n-BuLi, NaH, TlOEt, Me3SiCl, Me3SnCl, TiHal4, ZrX4 (X = Cl, NMe2) has been investigated. The crystal structure of 1-trimethylsilyl- 3-(diphenyl-ortho-fluorophenyl-methyl)-cyclopentadiene (3) was determined.
K1.10Zr2Se6, Rb0.86Zr2Se6 and Cs0.80Zr2Se6. The First Intercalation Compounds of Zirconium Triselenide
Authors: Klepp Kurt O. , Harringer Norbert A. , Kolb Andreas
Published: August 2018

Single crystals of K1.10Zr2Se6, Rb0.86Zr2Se6 and Cs0.80Zr2Se6 were obtained by reacting powdered mixtures of A2Se (A = K, Rb, Cs), Zr and Se at 850 °C. K1.10Zr2Se6 and Rb0.86Zr2Se6 crystallize in space group Immm (Z = 2), with a = 3.746(3), b = 5.354(8), c = 21.929(3) Å and a = 3.756(1), b = 5.354(8), c = 22.81(1) Å , respectively. Cs0.80Zr2Se6 crystallizes in space group Cmc21 (Z = 2), with a = 3.747(1), b = 24.102(5), c = 5.332(2) Å. The compounds are characterized by complex anionic layers 2
∞[Zr2Se6]x- with intercalated alkali cations. As in ZrSe3, the layers are built from columns of trigonal prisms 1
∞[ZrSe3], connected by additional waist contacts, yielding an eightfold coordination for the Zr atoms. The mean Zr-Se bond lengths correspond to those found in the binary compound. The Se-Se bond lengths are significantly altered, however, indicating a reduction of the Se-Se bond order due to the electron transfer from the alkali metal.
Kinetic Studies of Condensation of Aromatic Aldehydes with Meldrum’s Acid
Authors: Medien H. A. A.
Published: August 2018

The condensation reaction of Meldrum’s acid with aromatic aldehydes in the presence of a catalyst has been investigated spectrophotometrically at 25-50 °C. The reaction follows overall second order kinetics, first order in each of the reactants. Electron-withdrawing groups accelerate and electron-releasing groups retard the rate of condensation. From the dependence of the rate constants on temperature, the activation parameters have been calculated and also the isokinetic temperature with a value of 403.5 K. Based on this reaction, determination of eight aromatic aldehydes in a concentration range of 1.49 - 91 μg/ml is proposed. On the other hand, determination of some aromatic aldehydes with Meldrum’s acid is performed in water at 75 °C for 2 h, without adding any catalyst.
Synthesis and Crystal Structure of Zr5Rh2In4 and Hf5Rh2In4 – New Ternary Indides with Lu5Ni2In4 Type Structure
Authors: Lukachuk Mar’yana , Pöttgen Rainer
Published: August 2018

The ternary indides Zr5Rh2In4 and Hf5Rh2In2 were synthesized by high-frequency melting of the elements in glassy carbon crucibles in a water-cooled sample chamber. Both compounds have been investigated by X-ray diffraction on powders and single crystals: Lu5Ni2In4 type, Pbam, a = 1739.8(2), b = 758.3(1), c = 337.42(5) pm, wR2 = 0.0420, 1015 F2 values for Zr5Rh2In4, and a = 1732.1(3), b = 757.5(2), c = 333.36(7) pm, wR2 = 0.0534, 739 F2 values for Hf5Rh2In4 with 36 variables per refinement. The structures contain three crystallographically different zirconium(hafnium) siteswith coordination numbers 12, 14, and 16. Striking structural motifs are distorted rhodium-centered trigonal prisms formed by the zirconium(hafnium) atoms and CuAu related distorted cubes of zirconium (hafnium) and indium atoms. The shortest interatomic distances occur for Zr-Rh and Hf-Rh followed by Rh-In. Chemical bonding in these intermetallics is briefly discussed.
Crystal Structure of the Ternary Arsenide CeNi1.91As1.94
Authors: Babizhetskyy V. , Le Für E. , Pivan J. Y. , Guérin R.
Published: August 2018

A new ternary intermetallic has been obtained in the Ce-Ni-As system, the composition of which is CeNi1.91As1.94 from X-ray single crystal structure determination. The structure is derived from the CaBe2Ge2 type with the following relations between the vectors a, b, and c of the cell and a0, b0, and c0 of the subcell: a = 2a0 - 2b0; b = 2a0 + 2b0 and c = 2c0 (V = 16 V0). The structure takes its origin from compositional and displacive mechanisms. The major structural modifications occur in the nickel-arsenic layers (two per cell) where the nickel atoms are in “square” pyramidal As sites. Moreover, the slight atomic displacements in these layers that develop in the ab plane, lead to As8 clusters, each formed by a central part As4 linked by four apical As ligands. These clusters constrain arsenic to adopt a valence state higher than -3 which in turn involves the lowering of the counterbalancing charge from the nickel substructure. The structure of CeNi1.91As1.94 is compared in details with that of the previously reported URh1.6As1.9.
Kristallstrukturen und elektronische Eigenschaften von Ge1/3NbS2 und Ge1/4NbS2 / Crystal Structures and Electronic Properties of Ge1/3NbS2 and Ge1/4NbS2
Authors: Pocha Regina , Johrendt Dirk
Published: August 2018

Single crystals of the intercalation compounds Ge1/3NbS2 andGe1/4NbS2 have been prepared by heating of the elements at 1073 K and by chemical transport with iodine at 923 to 1073 K. Their crystal structures were determined by single crystal X-ray methods.Ge1/3NbS2 (P63/mcm, a=5.767(1), c=13.518(3) Å, Z = 6) crystallizes with a superstructureof 2H-NbS2, characterized by layers of edge-sharing NbS6 trigonal prisms. The Ge atoms in the octahedral voids of the van der Waals gap are sixfold coordinated by sulfur. The NbS2-sublattice of Ge1/4NbS2 (P63/mmc, a = 3.339(1), c = 37.326(7) Å , Z = 6) represents a new 6H-polymorph. Herein, the Ge atoms are located either in the centers of the octahedral voids (c. n. = 6) or shifted from this position along [001] (c. n. = 3 + 3). The unusual electronic state and the bonding situation of germanium in the van der Waal gaps of NbS2 and the metal-metal bonding are studied in detail by using DFT band structure calculations.
New Ternary Phosphide La7Pd17P12: Preparation and Crystal Structure
Authors: Budnyk S. , Prots Yu. , Kuz’ma Yu. , Grin Yu.
Published: August 2018

The title compound was prepared from elements by sintering in the temperature region between 1073 and 1473 K. The monoclinic structure of La7Pd17P12 was solved and refined from X-ray single crystal data: space group C2/m, a = 24.519(1), b = 4.0859(5), c = 13.6106(8)Å , β = 112.129(3)°, Z = 2, RF = 0.025 for 1065 unique of 4877 measured reflections and 112 refined parameters. Main structural motif of the new phosphide are condensed blocks of trigonal prisms around phosphorus atoms connected to infinite chains via lanthanum atoms. The structural features of La7Pd17P12 are discussed in comparison with some representatives of a large family of structures with metal / non-metal ratio close to 2 : 1.
Ca(SCN)2 and Ca(SCN)2 · 2 H2O: Crystal Structure, Thermal Behavior and Vibrational Spectroscopy
Authors: Wickleder Claudia , Larsen Patrick
Published: August 2018

The dehydration of Ca(SCN)2∙4H2O yields single crystals of Ca(SCN)2 ∙ 2 H2O as well as of Ca(SCN)2. Ca(SCN)2 ∙ 2 H2O crystallizes with a hitherto unknown structure (orthorhombic, Pnma, Z = 4, a = 1280.1(2), b = 790.3(1), c = 726.9(1) pm, Rall = 0.0430). The Ca2+ ions are surrounded by four SCN− ions and four water molecules. The polyhedra are connected to chains along [010] via common oxygen atoms. The SCN− ions connect these chains to a three-dimensional network so that each thiocyanate group is linked to two Ca2+ ions. Hydrogen bonding with sulfur atoms as acceptors is observed. The crystal structure of Ca(SCN)2 (monoclinic, C2/c, Z = 4, a = 961.7(2), b = 642.4(2), c = 787.2(2) pm, Rall = 0.0673) consists of alternating layers of Ca2+ and SCN− ions. The cations are surrounded by four sulfur and four nitrogen atoms in form of a square antiprism. According to 3
∞[Ca(SCN)8/4] each SCN− ion connects four Ca2+ ions with each other. Thermal investigations show a phase transition of Ca(SCN)2 ∙ 4 H2O followed by dehydration to Ca(SCN)2 which finally decomposes yielding CaS. IR and Raman measurements have been performed and the resulting frequencies assigned and discussed.
Sulfidisch derivatisierte Oxodisilicate der schweren Lanthanide vom Formeltyp M4S3[Si2O7] (M = Gd - Tm) / Sulfide Derivatized Oxodisilicates of the Heavy Lanthanides with the Formula M4S3[Si2O7] (M = Gd - Tm)
Authors: Sieke Corinna , Hartenbach Ingo , Schleid Thomas
Published: August 2018

The sulfide derivatized oxodisilicates M4S3[Si2O7] of the heavy lanthanides (M = Gd - Tm) have been synthesized by reaction of M, M2O3, S, and SiO2 using MCl3 as flux in evacuated silica tubes at 850 °C for 7 d. The title compounds crystallize tetragonally in the space group I41/amd with 8 formula units per unit cell. Their crystal structure contains isolated [Si2O7]6− pyroanions of two vertex-sharing [SiO4] tetrahedra in eclipsed conformation with Si-O-Si bridging angles of about 130°. The two crystallographically independent lanthanide cations (M3+) both reside in tricapped trigonal prismatic environments of chalcogen ligands. In the case of M1 five S2− and three plus one O2− anions (CN = 8+1), for M2 three S2− and six O2− anions (CN = 9) fill the coordination spheres. Two of the three different sulfide anions are surrounded by four M3+ cations forming a seesaw (S2) and a square (S3), respectively. The third one (S1) is coordinated by six lanthanide cations in the form of a distorted octahedron. The whole structure is basically built up of cationic lanthanide silicate layers which are threaded by sulfide anions.
Novel Thioborates of Cesium: Cs3BS3 and Li2CsBS3
Authors: Kuchinke J. , Küper J. , Krebs B.
Published: August 2018

The new compounds Li2CsBS3 and Cs3BS3 were prepared from the metal sulfide(s), amorphous boron and sulfur in solid state reactions at high temperatures. The crystal structures were determined by single crystal X-ray diffraction experiments. The purity of the products was proved by powder diffraction. Li2CsBS3 crystallizes in the orthorhombic space group Pnma (no. 62) with a = 10.004(2), b = 8.000(2), c = 8.082(2) Å , and Z = 4, while Cs3BS3 is isotypic to Rb3BS3 in the monoclinic space group P21/c (no. 14) with a = 10.397(1), b = 6.660(1), c = 13.618(1) Å , β = 101.31(1) °, and Z = 4. Both compounds contain isolated [BS3]3− anions with boron in a trigonal-planar coordination.
Untersuchungen im System ScCl3 / K2CO3 / H2O: Synthese und Kristallstrukturen von K5[Sc(CO3)4] · 5 H2O und K7[Sc(CO3)4]CO3 · 9 H2O / Investigations on the System ScCl3 / K2CO3 / H2O: Synthesis and Crystal Structures of K5[Sc(CO3)4] · 5 H2O and K7[Sc(CO3)4] CO3 · 9 H2O
Authors: Dahm Matthias , Adam Arnold
Published: August 2018

Both title compounds were found to crystallize from the system ScCl3 / K2CO3 / H2O and their crystal structures have been determined: K5[Sc(CO3)4] ∙ 5 H2O is monoclinic, space group P21/n with a = 883,06(13), b = 1826,2(2), c = 1113,2(2) pm, β = 93,28(2)°, V = 1792,3(4) ∙ 106 pm3, Z = 4), while K7[Sc(CO3)4]CO3 ∙ 9 H2O is monoclinic, space group C2 with a = 1395,98(13), b = 1081,35(7), c = 3378,1(4) pm, β = 93,76(1)°, VEZ = 5088,4(8) ∙ 106 pm3, Z = 8). Both compounds contain discrete [Sc(CO3)4] anions.
Synthesis and Reactivity of Bromo-Mer-Tricarbonyl-Trans-Bis[Tri(1-Cyclohepta- 2,4,6-Trienyl)Phosphane]-Manganese, Mnbr(CO)3[P(C7H7)3]2
Authors: Herberhold Max , Milius Wolfgang , Pfeifer Andreas
Published: August 2018

The reaction of Mn(X)(CO)5 (X = Cl, Br, I) with 2 equivalents of tri(1-cyclohepta-2,4,6- trienyl)phosphane, P(C7H7)3 ((1); [P] if coordinated to a metal) led stepwise first to cis- {Mn(X)(CO)4[P]} (X = Cl (4a), Br (4b), I (4c)) and then to mer,trans-{Mn(X)(CO)3[P]2} (X = Cl (5a), Br (5b), I (5c)). Nucleophilic displacement of the bromo ligand from (5b) by one-, threeor five-electron ligands gave the pseudohalide complexes mer,trans-{Mn(X)(CO)3[P]2} (X = NCO (5d) and NCS (5e)), the acetylacetonate derivative Mn(acac)(CO)2[P]2 (6) and the halfsandwich complexes CpMn(CO)2[P] (7) or TpMn(CO)3 (8). According to the X-ray structure determination of 5e the thiocyanate ligand is N-coordinated.
Synthesis, Thermal and X-Ray Investigations of the High-Temperature Phase of Copper(I) Cyanide
Authors: Reckeweg Olaf , Lind Cora , Simon Arndt , Salvo J.
Published: August 2018

CuCN was investigated by chemical analysis, IR spectroscopy and powder X-ray diffraction. A high-temperature phase of CuCN was identified and structurally characterized by Rietveld refinement. HT-CuCN is isotypic to AgCN (R3m (No. 166), Z = 3, a = 597.109(8), c = 484.33(5) pm, Cu (3a), C/N (6c), z = 0.3915(10) at 77 K) with head-tail disorder of the cyanide anions.
β-CaB4O7: A New Polymorph Synthesized under High-Pressure/High-Temperature Conditions
Authors: Huppertz Hubert
Published: August 2018

A new oxoborate β -CaB4O7 has been synthesized under high-pressure/high-temperature conditions from calcium oxide and boron oxide with a Walker-type multianvil apparatus at 7.7 GPa and 1100 °C. Single crystal X-ray structure determination of β -CaB4O7 revealed: Pmn21, a = 1058.4(1), b = 436.9(1), c = 419.4(1) pm, Z = 2, R1 = 0.0305, wR2 = 0.0587 (all data). The compound is isotypic to the known oxoborates SrB4O7, PbB4O7, and EuB4O7 exhibiting a network structure of linked BO4 tetrahedra. As a prominent feature of the tetrahedral network an oxygen atom is coordinated to three boron atoms. The relation of the crystal structure of the high-pressure phase β -CaB4O7 to the normalpressure phase α-CaB4O7 as well as the relation to the isotypic phases MB4O7 (M = Sr, Pb, Eu) are discussed. The results of IR-spectroscopic investigations on β -CaB4O7 are also presented.
New Dinuclear Mn(II) Phenanthroline Adipato Complex: Synthesis and Structural and Thermal Characterization of Mn2(phen)2(H2O)2(C6H8O4)2
Authors: Zheng Yue-Qing , Zheng Ming-Fang
Published: August 2018

Reaction of freshly precipitated Mn(OH)2−2x(CO3)x · yH2O, adipic acid and phenanthroline in CH3OH/H2O afforded a new dinuclear Mn(II) complex, Mn2(phen)2(H2O)2(C6H8O4)2 1, aside the known [Mn(phen)2(H2O)(C6H8O4)]·7H2O 2. Single crystal X-ray analyses showed that complex 1 consists of the centrosymmetric dinuclear molecules resulting from two [Mn(phen)(H2O)]2+ moities bridged by two twisted tridentate adipato ligands. The Mn atoms are each in severely distorted octahedral geometry defined by two N atoms of one phen ligand, three carboxyl O atoms of two adipato ligands and one H2O molecule with d(Mn-N) = 2.246 and 2.296 Å and d(Mn-O) = 2.066 - 2.339 Å . The complex molecules are assembled via π-π stacking interactions into 2D layers, which are held together by both strong O-H ··· O and weak C- H ··· O hydrogen bonds. The thermal behavior of 1 and 2 upon heating in argon stream is discussed.
Methoxyabietane Diterpenoid from the Root of Salvia phlomoides and Structural Correction of Another Diterpene from Cryptomeria japonica
Authors: Rodríguez Benjamín
Published: August 2018

A reinvestigation of the acetone extract of the root of Salvia phlomoides (Labiatae) allowed the isolation of a new abietane diterpenoid whose structure (6,11-dihydroxy-12-methoxy-5,8,11,13-abietatetraen- 7-one) was established by exhaustive NMR spectroscopic studies and by partial synthesis from 14-deoxycoleon U, another abietane constituent of the same extract. The physical and spectroscopic data of the methoxyabietane isolated from S. phlomoides were identical to those reported for another diterpenoid previously found in Cryptomeria japonica (Taxodiaceae), to which the regioisomeric structure 6,12-dihydroxy-11-methoxy-5,8,11,13-abietatetraen-7-one had been erroneously attributed by other authors.
Synthesis and Molecular Structure of [Fe2Cl2(μ-S-tBu)2(η1-η1-μ-dppe)] (dppe = Ph2P(CH2)2PPh2)
Authors: Huynh Han Vinh , Fröhlich Roland , Hahn F. Ekkehardt
Published: August 2018

The red title compound was synthesized by the metathesis reaction of [FeCl2(dppe)] (dppe = Ph2PCH2)2PPh2) and NaS-tBu in THF. The X-ray structure analysis revealed a dinuclear complex with two iron(II) centers coordinated in a distorted tetrahedral fashion by two bridging thiolates, one bridging dppe molecule and one terminal chloro ligand.
Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs2 and LnAuAs2 with Ln = La–Nd, Sm, Gd, and Tb
Authors: Eschen Marcus , Jeitschko Wolfgang
Published: August 2018

The 14 arsenides LnAgAs2 and LnAuAs2 (Ln = La-Nd, Sm, Gd, Tb) were prepared by reaction of stoichiometric mixtures of the elemental components at high temperatures and characterized by Xray diffractometry. The silver compounds LaAgAs2 and CeAgAs2 and the gold compounds LnAuAs2 (Ln = Ce-Nd, Sm, Gd, Tb) crystallize with HfCuSi2 type structure (P4/nmm, Z = 2). Of these, the structures of CeAgAs2 (a = 408.5(1), c = 1048.2(1) pm, conventional residual R = 0.017 for 261 structure factors and 12 variable parameters) and CeAuAs2 (a = 411.4(1), c = 1015.3(2) pm, R = 0.030 for 428 F values) were refined from four-circle diffractometer data. The silver compounds LnAgAs2 (Ln = Pr, Nd, Sm, Gd, Tb) are isotypic with the antimonide SrZnSb2 (Pnma, Z = 4) as demonstrated by a single-crystal structure refinement of PrAgAs2 (a = 2107.3(4), b = 401.7(1), c = 407.8(1) pm, R = 0.042 for 746 F values and 26 variables). The gold compound LaAuAs2 (I4/mmm, Z = 4, a = 416.9(1), c = 2059.5(3) pm, R = 0.038 for 303 F values and 13 variables) was found to be isotypic with the bismuthide SrZnBi2, again by a refinement from single-crystal diffractometer data. In the structures of CeAgAs2, LaAuAs2, and CeAuAs2 large displacement parameters perpendicular to the four-fold axes were found for one of the two arsenic positions. These structures could also be refined with split positions for these arsenic atoms, which allow for considerable As-As bonding, resulting in a formal charge of −1 for these atoms. Chemical bonding in these compounds can thus be rationalized by a simple model corresponding to the formula Ln+3T+1As−1As−3 (T = Ag, Au), where the superscripts indicate oxidation numbers.
Synthese, Kristallstruktur und spektroskopische Charakterisierung von Bis(dimethylammonium)hexachlorotitanat [Me2NH2]2[TiCl6]/ Synthesis, Crystal Structure, and Spectroscopic Characterization of Bis(dimethylammonium) Hexachlorotitanate [Me2NH2]2[TiCl6]
Authors: Rannabauer Stefan , Schnick Wolfgang
Published: August 2018

By the reaction of (Me3SiNH)2SiClNMe2 with TiCl4 the by-product [Me2NH2]2[TiCl6] was obtained in form of crystals suitable for single-crystal XRD (Pnnm, Z = 2, a = 722.01(3), b = 1428.36(5), c = 703.31(3) pm, T = 200 K, 901 independent reflections, 57 variables, R1 = 0.0636). The product was also synthesized in higher yield by the stoichiometric reaction of two equivalents of [Me2NH2]Cl with TiCl4 in CHCl3 at room temperature as a yellow crystalline powder. Bis(dimethylammonium) hexachlorotitanate is built up from [TiCl6]2- anions forming elongated octahedra and [Me2NH2]+ ions. The [TiCl6]2- ions are connected by the [Me2NH2]+ ions through N-H···Cl hydrogen bridges forming an arrangement which resembles that of an expanded rutile structure type. The elongation of the [TiCl6]2- octahedra was also verified by IR and Raman spectroscopy, confirming a local symmetry reduction from Oh to D4h. The solubility of [Me2NH2]2[TiCl6] in MeNO2 and MeCN was determined by means of 14N-NMR to be about 0.1 mol% and 0.3 mol%, respectively.
seco-Dolastanes from the Marine Brown Alga Dictyota dichotoma (Huds.) Lamour
Authors: Shaiq Ali Muhammad , Kashif Pervez Muhammad
Published: August 2018

Brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new seco-dolastanes (diterpenoids) named: dichotone and dichotodione along with isolinearol acetate of the same skeleton as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques.
C-Substituierte Cyclame aus Cyclotetrapeptiden [1]/ C-Substituted Cyclams from Cyclotetrapeptides [1]
Authors: Lang Markus A. , Beck Wolfgang
Published: August 2018

The reduction of cyclotetrapeptides cyclo(X-β -Ala-X-β -Ala) (X = Gly, (S)-Ala, (S)-Leu, (S)-Val, (S)-Phe) 1a - 1e with LiAlH4 in THF gives the C-substituted cyclams 2a - 2e.
Magnetic Properties of Compounds RE2Cu2Mg (RE = Y, La, Pr, Nd)
Authors: Kotzybaa Gunter , Mishrab Ratikanta , Pöttgena Rainer
Published: August 2018

The Mo2FeB2 type magnesium intermetallics RE2Cu2Mg (RE = Y, La, Pr, Nd) were synthesized from the elements by reactions in sealed tantalum tubes in a high-frequency furnace. Temperature-dependent magnetic susceptibility measurements of Y2Cu2Mg and La2Cu2Mg indicate Pauli paramagnetism. Pr2Cu2Mg and Nd2Cu2Mg show Curie-Weiss behaviour with experimental magnetic moments of 3.67(2) μB/Pr and 3.47(2) μB/Nd, respectively. Both compounds are ordered ferromagnetically at Curie temperatures of 12.0(5) (Pr2Cu2Mg) and 43.0(5) K (Nd2Cu2Mg). Pr2Cu2Mg shows a very complex magnetization behavior with an additional magnetic transition around 2.5 T. The neodymium compound shows a pronounced square loop behavior in the magnetization at 4.5 K with a high remanent magnetization of 1.55(1) μB/Nd atom and a coercive field of 0.31(1) T.
Magnetic and Spectroscopic Properties of LiAuSn
Authors: Wu Zhiyun , Eckertb Hellmut , Moselb Bernd D. , Möllera Manfred H. , Pöttgena Rainer
Published: August 2018

The stannide LiAuSn was synthesized by reaction of the elements in a sealed tantalum tube. Magnetic susceptibility measurements reveal Pauli paramagnetism. LiAuSn shows a single 119Sn Mössbauer signal at an isomer shift of 2.12(3) mm/s subject to a quadrupole splitting of 1.51(2) mm/s. The 119Sn MAS NMR spectrum reveals a strong Knight shift of 5183 ppm, The unique lithium site present in the crystal structure is reflected by a single 7Li NMR signal at 9.8 ppm. While a significant shift of this resonance towards larger frequencies at higher temperature indicates that the s-spin density at the lithium sites increases with increasing temperatures, no motional narrowing occurs up to 470 K. This result indicates that the lithium ions are immobile on the NMR timescale within the temperature range observed.
Electrochemistry of Acetate-, Carbonate-, Sulfate-, and Dihydrogenphosphate-Bridged Dirhodium(II) Complexes
Authors: Yaman Ș. Özalp , Önal A. M. , Isci H.
Published: August 2018

Complexes, [Rh2(B-B)4L2]n (B-B = CH3COD2 , L = CH3CN, H2O, Cl-, Br-, SCN-; B-B = CO2-
3 , SO2-
4 , H2PO4̄, L =H2O, Cl-, Br-, SCN-) were prepared and their cyclic voltammograms (CV) and electronic absorption spectra were measured in solution. The CV of the complexes exhibits a reversible one-electron transfer from a metal-based orbital. Constant potential electrolysis at the oxidation peak potential of [Rh2(O2CCH3)4(NCCH3)2] in acetonitrile yielded [Rh2(O2CCH3)4(NCCH3)2]+, a mixed valent Rh(II)DRh(III) cation complex. The formation of the mixed valent complex was monitored by measuring electronic absorption spectra of the solution in situ during the oxidative electrolysis. The reductive electrolysis of the mixed valent complex solution, in the same electrolysis cell, yielded the original electronic absorption spectrum of the starting complex. The changes in the oxidation and reduction potentials of the complexes with different axial ligands, L = H2O, Cl-, Br-, SCN-, are correlated to the relative energy changes of HOMO and LUMO of the complexes, which indicates the metal-axial ligand σ- and π-bonding interactions. Spectroscopic and CV data indicate that the degree of σ-interaction is Cl- > Br- > SCN-, and that of π-interaction is Br- > SCN- > Cl-.
Two Atropisomeric N-Methyldioncophyllines A and N-Methylphylline, their Naphthalene-Free Heterocyclic Moiety, from Ancistrocladus barteri
Authors: Bringmann Gerhard , Schneider Christoph , Möhler Ulrike , Pfeifer Robert-Michael , Götz Roland , Assi Laurent Aké , Peters Eva-Maria , Peters Karl
Published: August 2018

The West African plant Ancistrocladus barteri (Ancistrocladaceae) was investigated chemically for the first time. Besides the known naphthylisoquinoline alkaloids N-methyldioncophylline A and 7-epi-N-methyldioncophylline A (i.e. its atropo-diastereomer), a new naphthalene-free alkaloid, belonging to the ‘Dioncophyllaceae type’, was isolated. Its structure was elucidated by spectroscopic and degradative methods and confirmed by total synthesis. The new compound, named N-methylphylline, is exactly the isoquinoline “half” of both, N-methyldioncophylline A and its atropisomer. Furthermore, the related tetrahydroisoquinoline O,N-dimethylphylline, an intermediate in the chemical synthesis of N-methylphylline, was detected as a new natural product in crude extracts of A. barteri.
Die neuen Oxoarsenate(III) AAsO2 (A = Na, K, Rb) und Cs3As5O9. Darstellung, Kristallstrukturen und Raman-Spektren / The New Oxoarsenates(III) AAsO2 (A = Na, K, Rb) and Cs3As5O9. Synthesis, Crystal Structures and Raman Spectra
Authors: Emmerling Franziska , Röhr Caroline
Published: August 2018

The new alkaline metal arsenates(III) were synthesized at a temperature of 500 °C via reaction of stoichiometric mixtures of the elemental alkali metals A and As2O3. In the crystal structures of the four title compounds, which have been determined by single crystal x-ray diffraction, the As(III) atoms are in ψ-tetrahedral coordination by oxygen exclusively. In NaAsO2 (orthorhombic, space group Pbcm, a = 1429.6(9), b = 677.3(3), c = 509.1(2) pm, Z = 8) and the compounds AAsO2 (A = K/Rb, orthorhombic, space group Pbcm, a = 715.1(2)/729.7(5), b =748.0(1)/775.2(5), c = 539.20(17)/541.1(3) pm, Z = 4) the AsO3 ψ-tetrahedra are condensed to form zig-zag chains [AsOO2/2]−. In the Cs phase Cs3As5O9 with a lower alkaline metal content (trigonal, space group P31m, a = 845.5(3), c = 602.6(2) pm, Z = 1) the two crystallographically independent ψ-tetrahedra AsO3/2 and AsOO2/2 are connected in a 2:3 ratio to give polar sheets [As5O9]3−.
peri-Interactions in Naphthalenes, 10 [1]. In Search of Independent Criteria for N→P Bonding: Protonation Studies on (8-Diethylamino-naphth-1-yl)-diphenyl-phosphine
Authors: Schiemenz Güter Paulus , Näther Christian , Pörksen Simon
Published: August 2018

Enhancement of the basicity of the amino group in (8-dialkylamino-naphth-1-yl)-diphenylphosphines diverts protonation from the P to the N atom. Thus the cation 8-Et2N+(H)-C10H6-PPh2 becomes available whose 1H and 31P NMR spectra provide arguments against dative N→P interactions in the phosphines and their quaternary phosphonium salts. Likewise, the X-ray structure of 8-Et2N-C10H6-PPh2 does not indicate such interactions.
Synthesis of Novel 2-Alkoxy-5H-benzo[6,7]cyclohepta[1,2-b]pyridine-3-carbonitriles
Authors: Girgis Adel S. , Ahmed-Farag I. S.
Published: August 2018

Reaction of 6-arylmethylene-6,7,8,9-tetrahydro-5H-benzocyclo-hepten-5-ones (1) with malononitrile in the appropriate alcohol in the presence of sodium afforded the corresponding 2-alkoxy-4-aryl- 6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-b]pyridine-3-carbonitriles (2) and not their isomeric forms 2-alkoxy-4-aryl-6,7-dihydro-5H-benzo[3,4]-cyclohepta[1,2-c]pyridine-1-carbonitriles (3). The proposed structure was confirmed via independent synthesis of (2) through the reaction of 6,7,8,9- tetrahydro-5-benzocycloheptenone (4) with the appropriate ylidenemalononitriles 5 under the same reaction conditions. Single crystal X-ray diffraction proves the structures of 2a,b.
Photodisproportionation of (1,5-Cyclooctadiene) copper(I) Hexafluoroacetylacetonate Induced by Metal-to-Ligand Charge Transfer Excitation
Authors: Kunkely Horst , Vogler Arnd
Published: August 2018

The complex CuI(COD)(hfac) with COD = 1,5- cyclooctadiene and hfac = hexafluoroacetyl-acetonate shows two long-wavelength absorptions at λmax = 308 and 241 nm which are assigned to hfac intraligand (IL) and CuI →COD metal-to-ligand charge transfer (MLCT) transitions, respectively. The photolysis of CuI(COD)(hfac) in hexane leads to the release of the olefin and the subsequent disproportionation of CuI(hfac) to elemental copper and CuII(hfac)2 with the quantum yields Φ = 10−3 at λirr =313 nm and Φ = 3×10−3 at λirr = 254 nm. It is suggested that the reactive excited state is of the MLCT type.
The Crystal Structures of Chlorodimethyl( dimethylamino)silane and Dimethyl-bis-(dimethylamino)silane
Authors: Mitzel Norbert W. , Vojinović Krunoslav
Published: August 2018

Single crystals of chlorodimethyl(dimethylamino)silane, Me2NSiMe2Cl, and dimethyl-bis-(dimethylamino)silane, (Me2N)2SiMe2, have been grown in situ from the melt at low temperatures and their structures determined by X-ray diffraction. Important structural parameters (Å / °): Me2NSiMe2Cl (C2/m) Si-N 1.686(2), Si-C 1.851(1), Si- Cl 2.109(1), N-Si-Cl 111.7(1), C-Si-Cl 105.1(1), C-N-C 112.8(2), Si-N-C 123.4(1); (Me2N)2SiMe2 (P21/c) Si-N(1) 1.725(1), Si-C(1) 1.868(1), N(1)-Si-N(2) 105.7(1), C(3)- N(1)-C(4) 111.6(1), Si-N(1)-C(3) 122.4(1), Si-N(1)-C(4) 120.0(1).
Synthesis and Radiosynthesis of 17α-[p-(Iodophenylethynyl)]estra-3,17β-diols
Authors: Wanga Jian , Watanabe Masataka , Mataka Shuntaro , Thiemann Thies , Morais Goreti Ribeiro , Roleira Fernanda , Silva Elisiario Tavares da , Silva Cristina Melo e
Published: August 2018

Estrones have been subjected to an addition reaction with [(4-ethynylphenyl)azo]pyrrolidine to provide 17 α-{4-[(pyrrolidin-1-yl)-azo]phenylethynyl}estra-3,17 β -diols. A subsequent iodination with iodotrimethylsilane, produced in situ from chlorotrimethylsilane and NaI, leads to 17α-(piodophenylethynyl) estra-3,17 β -diols. This reaction can also be carried out with Na125 I to give radiolabelled estra-3,17 β -diols, which are potentially useful radiodiagnostic agents for the detection of estrogen positive breast cancer. The stability of the radiolabelled compounds is exemplified in a stability study of 3-O-methyl 17 α-(p-[125 I]iodophenylethynyl)estra-1,3,5(10),6-tetraene-17 β -ol in acetonitrile.
Ternary Gallides REMgGa (RE = Y, La, Pr, Nd, Sm–Tm, Lu) – Synthesis and Crystal Chemistry
Authors: Kraft Rainer , Valldor Martin , Pöttgen Rainer
Published: August 2018

The title compounds have been synthesized by reacting the elements in sealed niobium or tantalum tubes in a high-frequency furnace. They crystallize with the hexagonal ZrNiAl type structure, space group P62m. All gallides have been characterized through their X-ray powder diffractogram. The cell volume decreases from the lanthanum to the lutetium compound as expected from the lanthanoid contraction. The structures of LaMgGa, PrMgGa, NdMgGa, SmMgGa and TmMgGa have been refined from single crystal diffractometer data. The structures contain two crystallographically independent gallium sites which both have a trigonal prismatic coordination: Ga1 by six RE and Ga2 by six Mg atoms. These trigonal prisms are capped on the rectangular sites by three Mg (RE) atoms, leading to coordination number 9 for each gallium atom. Together, the gallium and magnesium atoms form a three-dimensional [MgGa] network in which the rare earth atoms fill distorted hexagonal channels. Within the network the magnesium atoms have short Mg-Mg contacts, i. e. 312 pm in SmMgGa. The Mg-Ga distances in that gallide range from 284 to 287 pm. Bonding in the network is thus governed by strong Mg-Ga and Mg-Mg bonding. EuMgGa crystallizes with the orthorhombic TiNiSi type: Pnma, a = 783.1(2), b = 472.8(1), c = 829.8(2) pm.
Organometallic Compounds of the Lanthanides 169. Lanthanidocene Complexes Containing Chiral Nitrogen-Functionalized Cyclopentadienyl Ligands
Authors: Schumann Herbert , Herrmann Katja , Erbstein Frank
Published: August 2018

SmCl3 reacts with equimolar amounts of K[(S)-C5H4CHPhCH2NMe2] and Na[C5Me5] yielding [(S)-C5H4CHPhCH2NMe2](C5Me5)SmCl(1). The methylation of complex 1 with LiMe and the reactions of the known analogues of 1, [(S)-C5H4CHPhCH2NMe2](C5Me5)LnCl (Ln = Y (2), Lu (3)) with LiCH2SiMe3 afford [(S)-C5H4CHPhCH2NMe2](C5Me5)SmMe (4) and [(S)-C5H4CHPhCH2NMe2](C5Me5)LnCH2SiMe3 (Ln = Y (5), Lu (6)), respectively. The reactions of ScCl3 and LuCl3 with 1 equivalent of K[(S)-C5H4CHPhCH2NMe2] or K[C5H4CH2CH2NMe2] followed by 2 equivalents of Me3SiCH2Li yield the complexes [(S)-C5H4CHPhCH2NMe2] Ln(CH2SiMe3)2 (Ln = Sc (7a), Lu (7b)) or (C5H4CH2CH2NMe2)Ln(CH2SiMe3)2 (Ln = Sc (8a), Lu (8b)), respectively.
Structural Features of a Sulfur-Containing Group 4 Metalla[11]-crown-4 Derivative
Authors: Snell Alexander , Kehr Gerald , Wibbeling Birgit , Frönlich Roland , Erker Gerhard
Published: August 2018

Treatment of the ligand system (ο-C6H4OH)-S-CH2-CH2-S-(ο-C6H4-OH) (2a) with TiCl4 gave the metalla-crown ether derivative [(-S-CH2-CH2-S-)(ο-C6H4O)2]TiCl2 (5a). Complex 5a was characterized by an X-ray crystal structure analysis. It showed a pseudo-octahedral structure with both sulfur atoms being cis-coordinated to the metal center. The chloride ligands are also cispositioned, whereas the remaining two Ti−oxygen bonds are trans to each other to complete the distorted octahedral coordination geometry. The reaction of 2a with ZrCl4 gave the analogous complex 5c. The related ligand system (ο-C6H4OH)-O-CH2-CH2-O-(ο-C6H4OH) (2b) was doubly deprotonated by treatment with butyl lithium and then reacted with TiCl4 to yield the complex [(-O-CH2-CH2-O-)(ο-C6H4O)2]TiCl2 (5b).
Synthesis and One-Electron Oxidation Chemistry of Stable β,β-Dimesityl Enols with Heteroaryl Substituents
Authors: Schmittel Michael , Lal Mukul , Schenk Wolfdieter A. , Hagel Michael , Burzlaff Nicolai , Langels Anja
Published: August 2018

Four novel stable enols (one characterized by X-ray crystal structure analysis) were synthesized and investigated under oxidative conditions to yield benzofurans. Depending on the donor qualities of the heteroaryl substituent the reaction following the one-electron oxidation could be stopped on the stage of the cyclohexadienyl cation whose lifetime was measured. Oxidation potentials were determined for the enols, the enolates and the α-carbonyl radicals. Oxidation of benzofurans yielded dimeric species or intramolecular cyclization products.
Crystal Structure of B-Type Tm2Si2O7 (≡Tm4[Si3O10][SiO4])
Authors: Hartenbach Ingo , Lissner Falk , Schleid Thomas
Published: August 2018

Single crystals of B-type thulium oxodisilicate Tm2Si2O7 were obtained by the reaction of Tm, S and RbCl with the wall of a silica tube in an attempt to synthesize ternary alkalimetal thulium sulfides (e.g. Rb3Tm7S12). It crystallizes triclinically in space group P1̄(a = 655.91(5), b = 659.04(5), c = 1195.32(9) pm, α = 94.361(8), β = 91.102(8), γ = 92.005(8)◦), with four formula units of Tm2Si2O7 per unit cell. Instead of pyro-anionic [Si2O7]6− groups the title compound contains both ortho-silicate tetrahedra [SiO4]4− and catena-trisilicate units [Si3O10]8−. Therefore the formula Tm4[Si3O10][SiO4] (Z = 2) appears more adequate. The four crystallographically independent Tm3+ cations show coordination numbers from six to eight with distorted octahedral, bicapped trigonal prismatic and square antiprismatic oxygen coordination spheres.
Generation and Structural Characterization of an [(Imidazol-2-ylidene)HfCl5]-Anion/Imidazolium Cation Salt
Authors: Niehues Martin , Kehr Gerald , Fröhlich Roland , Erker Gerhard
Published: August 2018

The reaction of 1,3-diisopropylimidazolium chloride (3) with benzylpotassium in d5-bromobenzene generates the stable carbene 1,3-diisopropylimidazol-2-ylidene that is trapped by hafnium tetrachloride. A chloride anion is subsequently added to the Hf atom of the resulting intermediate to yield the salt [(1,3-diisopropylimidazol-2-ylidene)HfCl₅−][1,3-diisopropylimidazolium+] 6 that was characterized by an X-ray crystal structure analysis.
Synthesis of Microscale Particles of Ternary Sulphides via an Adjusted Polyol-Route
Authors: Blöß Stephan , Jansen Martin
Published: August 2018

The chalcocuprites Roquesite (CuInS2), Mohite (Cu2SnS3) and Famatinite (Cu3SbS4) have been synthesised from metal chlorides and thiourea in form of microscale particles via an adjusted polyolroute. The samples were characterised by means of SEM/EDX and XRD. The as prepared chalcocuprites were found to crystallise in metastable, cation disordered cubic structures. The particle sizes vary in the range of 0.2 to 3 micrometers. Thermal annealing transforms the samples into the thermodynamically stable polymorphs with ordered cationic substructures.
Investigations in the Systems Ag-Hg-X-O (X = AsV, SeIV, SeVI): Hydrothermal Single Crystal Growth of Ag3AsO4, AgHgI
2AsO4, AgHgIIAsO4, Ag2SeO4 and the Crystal Structure of Ag2HgII(SeO3)2
Authors: Weil Matthias
Published: August 2018

Single crystals of the already known phases Ag3AsO4, AgHgI
2AsO4, AgHgIIAsO4, Ag2SeO4 and of the hitherto unknown compound Ag2HgII(SeO3)2 were obtained under hydrothermal conditions (250 °C, 5d) from starting mixtures of the metal nitrates and the respective acids. Both Ag3AsO4 and AgHgI
2AsO4 are isotypic with the corresponding phosphates, Ag3PO4 and AgHgI
2PO4, whereas AgHgIIAsO4 and Ag2SeO4 crystallize in the thenardite (Na2SO4 (V)) structure. All crystal structures were refined by means of single crystal X-ray data. The crystal structure of Ag2HgII(SeO3)2 [Pbca, Z = 8, a = 6.8206(11), b = 11.237(3), c = 16.876(2) Å , 1677 structure factors, 101 parameters, R[F2 > 2σ (F2)] = 0.0193, wR(F2 all) =0.0394] consists of considerably distorted [AgO6] and [HgO6] octahedra, and trigonal SeIVO3 pyramids as the main building units. The [MO6] octahedra build a complex framework by sharing common edges and corners, and the SeIVO3 pyramids are located in the vacancies of this arrangement. The average Hg-O distance of 2.399 Å is significantly shorter than the average Ag-O distance of 2.551Å . The geometries of the two crysta̱llographically independent SeIVO3 pyramids are very similar and the average distance and angle (d(Se-O) = 1.709 Å , ∠(O-S-O) = 100.1°) lie in the characteristic range for a selenite(IV) group. A short comparative structural discussion between the various compounds obtained during the hydrothermal experiments is given.
Synthesis, Thermal Properties and Crystal Structure of Twinned Crystals of the New Coordination Polymer Poly[(CuBr)2(μ2-pyrimidine-N,N’)]
Authors: Näther Christian , Jeß Inke , Bolte Michael
Published: August 2018

Reaction of copper(I) bromide with pyrimidine in acetonitrile leads to the formation of crystals of the new coordination polymer poly[(CuBr)2(μ2-pyrimidine-N,N’)]. Indexing of the reflections yields a monoclinic primitive cell with a = 3.9119(2), b = 13.525(1), c = 15.346(1)Å , β = 97.29(1)° and V =805.4(1) Å3. Inspection of the reciprocal space shows weak reflections which might be indicative of a superstructure leading to a doubling of the crystallographic c-axis. The structure can be solved in space group P21/m but the refinement leads to very poor reliability factors (wR2 for all refl.: 62.57%, R1 for all Fo > 4σ (Fo) = 27.84%). A twin refinement assuming merohedral twinning drastically reduces the R-values (wR2 for all refl.: 7.27%, R1 for all Fo > 4σ (Fo) = 2.64%) and a structure model is obtained which consists of two crystallographically independent copper and bromine atoms and two pyrimidine ligands in the asymmetric unit. However, carefull inspection of this structure shows that the two crystallographically independent layers formed by the connection of the building blocks are very similar and that they are related by a translation by half of the crystallographic c-axis. As a result of that, the crystal is just a partial merohedral twin and the reflections which led to the assumption that the c-axis is twice as long are generated by the second twin domain. The structure was refined with the correct twin law (wR2 for all refl.: 6.70%, R1 for all Fo > 4σ (Fo) = 2.57%). By this procedure a reasonable structure model is obtained which consists of one crystallographically independent copper and bromine atom and one pyrimidine ligand. In the crystal structure CuBr double chains are formed which are connected into layers via μ-N,N’ coordination by the N-donor ligands. On heating, the compound loses all of the ligands and transforms into CuBr within only one single step in an exothermic reaction.
Ca10V5.2Fe0.8O24, a Novel Oxometalate with Discrete Complex Anions
Authors: Kleppa Kurt O. , Harringer Norbert A. , Preßlinger Hubert
Published: August 2018

Lustrous needle shaped prismatic single crystals of the new compound Ca10V5.2Fe0.8O24 were obtained out of a sample with nominal composition Ca2Fe1.6V0.4O5 prepared at 1400 °C. The crystals are opaque and stable to humid air. Ca10V5.2Fe0.8O24 crystallizes with a new structure type, space group Pnma with a = 6.803(3), b = 16.015(8), c = 10.418(7)Å , Z = 2, R = 0.041. The crystal structure is characterized by two mononuclear tetrahedral species, MO4, which differ significantly from each other with respect to their M-O bond lengths. One with an average bond distance of 1.709(8)Å represents an orthovanadate ion. The other with a significantly larger value d(M-O) = 1.744(6) Å corresponds to a mixed occupation of its centre according to [V0.8Fe0.2O4]3.5−. In the crystal structure the complex anions are arranged in separate sheets parallel to the (010) plane. They are separated from each other by three crystallographically independent Ca2+ ions which are each coordinated by 7 oxygen atoms in distorted pentagonal bipyramidal and trigonal prismatic configurations, respectively.
Atomvolumen, Packungsdichte undWertigkeit von Caesium unter Druck Atomic Volume, Packing Density and Valence of Cesium under Pressure
Authors: Trömel Martin , Hübner Sven , Taxer Karlheinz
Published: August 2018

The volume changes of cesium under pressure are discussed with respect to the packing density of the atoms and valence. The element is univalent in densely packed Cs I and Cs II. Valence increases in Cs III (packing density q = 0.973), in Cs IV (q = 0.943), in Cs V (q ≈ 0.99), and in close packed Cs VI. The diminuition of volume beyond ≈15 GPa is caused by this increase only which implies that electrons of the fifth shell act as valence electrons.
Dinuclear Nickel(II) and Palladium(II) Complexes in Combination with Different Co-Catalysts as Highly Active Catalysts for the Vinyl/Addition Polymerization of Norbornene
Authors: Lozana Vasile , Lassahn Paul-Gerhard , Zhang Cungen , Wu Biao , Janiak Christoph , Rheinwald Gerd , Lang Heinrich
Published: August 2018

Dinuclear nickel(II) and palladium(II) complexes with Schiff-base ligands (derived form salicylaldehyde condensed with 2-amino-1-alcohols or from 2-hydroxy-5-methylisophthaldialdehyde and pyridine-2-carboxaldehyde condensed with semicarbazide, thiosemicarbazide, carbonodihydrazide, or thiocarbonodihydrazide) can be activated with the co-catalysts methylalumoxane (MAO) or tris(pentafluorophenyl)borane/triethylaluminium, B(C6F5)3/AlEt3 for the vinyl/addition polymerization of norbornene to reach activities of up to 2.4 · 107 gpolymer/mol(metal)·h (molar ratios metal:AlMAO = 1:100, metal:borane:AlEt3 = 1:9:10). Polymer characterization by GPC gave molar mass distributions of Mw/Mn ≈ 2, thereby indicating a coordination polymerization with a single-site character of the active species.
New Isoflavonoid from Dipterix odorata
Authors: Socorro Maria P. , Pinto Angelo C. , Kaiser Carlos R.
Published: August 2018

The isoflavonol 7,8,3’-trihydroxy-6,4’-dimethoxy-isoflavone (1) was isolated from the methanol extract of the bark of the trunk of Dipterix odorata. The structure was determined from spectral data and with aid of his acetylation to obtain 1a as a strategy to help the assignments of the 2D NMR experiments.
Titanyl Acetylacetonate as an Efficient Catalyst for a Mild and Convenient Reduction of Carbonyl Compounds with NaBH4 under Aprotic Condition
Authors: Zeynizadeh Behzad
Published: August 2018

Titanyl acetylacetonate, TiO(acac)2, is used as an efficient catalyst for the reduction of carbonyl compounds with sodium borohydride under aprotic condition. Reduction reactions are performed in CH3CN and THF. The corresponding alcohols are obtained in high to excellent yields and the chemoselective reduction of aldehydes over ketones is achieved successfully.
A Convenient Synthesis of New Pentaazacyclopentanaphthalene and Pentaazaphenanthrene Derivates
Authors: Issac Yvette A. , Aly Aly A.
Published: August 2018

Reaction of N-{3-cyano-6-[4(5-oxo-2-phenylhydrazono-4,5-dihydroimidazol-1-yl)phenyl]-4-phenylpyridin- 2-yl}formimidic ethyl ester (3) and 3-[4-(3-amino-4-imino-5-phenyl-3,4-dihydropyrido[ 2,3-d]pyrimidin-7-yl)phenyl]-2-phenyl-5-phenylhydrazono-3,5-dihydroimidazol-4-one (4) with different reagents has been investigated and discussed. Some of the obtained compounds were tested for their antimicrobial activity.
Synthesis of Some New Furocoumarins and their Usage in Peptide Synthesis
Authors: Keshk Eman M. , El-Telbani Emad M. , Abdel-Rahman H.
Published: August 2018

1,5-Benzodiazepin-2-ones (3a - d) were obtained fromω-carbethoxy visnaginone or ω-carbethoxy khellinone and substituted 1,2-phenylenediamines. Reactions of active nitriles such as malononitrile and ethyl cyanoacetate with substituted 6-dimethylaminomethylene furocoumarins (4a,b) are described. Additionally, reaction of substituted 6-dimethylaminomethylene furocoumarins with different amino acids gave furochromen-6-ylidenemethyl amino acids (7 - 9). Compound 7 was coupled with glycine ethyl ester to form amino acetic acid ethyl ester (10).
Access to Unsymmetric Binaphthols through Oxidative Coupling of Silicon Bisnaphtholates
Authors: Schmittel Michael , Haeuseler Andreas
Published: August 2018

The oxidative coupling of various symmetric (5 -7) as well as unsymmetric silicon bisnaphtholates (11, 12), initiated by different oxidants (iron(III), cerium(IV), copper(II) or hypervalent iodine), furnishes the corresponding symmetric and unsymmetric binaphthols 13 - 17. The coupling reaction of the substrates follows strictly an intramolecular pathway.
The Low-Temperature Polymorph of Tetramethyldiphosphinebis( monoborane): Insight into the Stabilization of Different Rotational Isomers in the Solid State
Authors: Müller Gerhard , Brand Jörg
Published: August 2018

The low-temperature (LT) polymorph of tetramethyldiphosphine-bis(monoborane), Me2(H3B)PP( BH3)Me2, was obtained by crystallization from diethyl ether at 4 °C. It crystallizes in the monoclinic space group P21/c, a = 6.464(1), b = 7.605(1), c = 11.867(2) Å , β = 119.99(1)° (at 153 K) with 2 molecules per unit cell. This implies that the individual molecules have crystallographic inversion symmetry and a strict anti arrangement with respect to the central B-P-P-B skeleton. At 87.6 °C (DTA) the LT polymorph transforms to the high-temperature (HT) modification which contains the anti and gauche conformers in a 1:2 ratio (P21/c, Z = 6; H. L. Carrell, J. Donohue, Acta Crystallogr. B24, 699 (1968)). This strongly suggests that the gauche conformer is higher in energy and stabilized by the crystal packing of the HT modification. The P-P-B angle in the anti LT form (113.91(6)°) ascertains the value of the anti conformer in the HT form (114.4(6)°) which was found to be significantly different from the gauche conformer which centered around 110 °C.
ScOH(CH3SO3)2, a Basic Methanesulfonate of Scandium with Chain Structure
Authors: Wickleder Mathias S. , Müller Ingrid
Published: August 2018

Single crystals of ScOH(CH3SO3)2 were obtained from a solution of Sc2(CO3)3 in methanesulfonic acid at pH 7. According to the X-ray single crystal structure determination, the compound crystallizes with the non-centrosymmetric orthorhombic space group Pmc21 (Z = 8, a = 743.92(8), b = 1497.7(3), c = 1540.1(2) pm, Rall = 0.0925) and contains the Sc3+ ions in octahedral coordination of oxygen atoms which belong to two OH− and four CH3SO3 − ions. The linkage of the Sc3+ ions leads to chains according to the formulation 1
∞[Sc(CH3SO3)4/2(OH)2/2] which are oriented along the [100] direction and connected via hydrogen bonds. The IR spectrum of the compound shows the typical bands of the CH3SO3 − ion.