bluuebunny/crossref_metadata_2025 huggingface dataset:
Ligand vs. Metal Basicity: Reactions of 2-(Diphenylphosphanyl)anilido and 2-(Diphenylphosphanyl)phenolato Complexes of Rhodium(I) and Iridium(I) with HBF4
Authors: Dahlenburg Lutz , Herbst Konrad
Published: February 2015

Treatment of [M(CO)(PPh3)(2-Ph2PC6H4NR-κN,κP)], where M/NR = Rh/NH (1), Rh/NCH3 (2), Ir/NH (3), and Ir/NCH3 (4), with Et2O・HBF4 in CH2Cl2 resulted in protonation at nitrogen with formation of [M(CO)(PPh3)(2-Ph2PC6H4NHR-κN,κP)]BF4 [M/NHR = Rh/NH2 (7), Rh/NHCH3 (8), Ir/NH2 (9), Ir/NHCH3 (10)]. Similar protonation of [Rh(CO)(PPh3)(2-Ph2PC6H4O-κO,κP)] (5) in CH2Cl2 afforded [Rh(CO)(PPh3)(2-Ph2PC6H4OH-κO,κP)]BF4 (11), but furnished [Rh(CO)(PPh3)- (NCCH3)(2-Ph2PC6H4OH-κP)]BF4 (12) if carried out in CH3CN. [Ir(CO)(PPh3)(2-Ph2PC6H4O- κO,κP)] (6) reacted with HBF4 by protonation at the central metal atom and oxidative addition to give [IrH(FBF3)(CO)(PPh3)(2-Ph2PC6H4O-κO,κP)] (13), the substitutionally labile BF4 − ligand of which underwent smooth exchange with neutral donors L producing [IrH(CO)(L)(PPh3)(2- Ph2PC6H4O-κO,κP)]BF4 with L = H2O (14), CH3CN (15) and PPh3 (16). The structures of 6 and 15 were determined by single-crystal X-ray crystallography.
Syntheses and Palladium, Platinum, and Borane Adducts of Symmetrical Trialkylphosphines with Three Terminal Vinyl Groups, P((CH2)mCH=CH2)3
Authors: Nawara-Hultzsch Agnieszka J. , Skopek Katrin , Shima Takanori , Barbasiewicz Michał , Hess Gisela D , Skaper Dirk , Gladysz John A
Published: February 2015

Reactions of Br(CH2)mCH=CH2 with Mg powder and then PCl3 (0.33 equiv.) afford P((CH2)m- CH=CH2)3 (1; m = a, 4; b, 5; c, 6; d, 7; e, 8; f, 9; 52 - 87%). Reactions of 1a - c, e with PdX2(COD) (X = Cl, Br) give trans-PdX2(P((CH2)mCH=CH2)3)2 (35 - 92%). Reactions of 1b - e with PtCl2 in benzene give mainly trans-PtCl2(P((CH2)mCH=CH2)3)2 (trans-5b-e; 52 - 75%), whereas those with K2PtCl4 in water give mainly cis-5b-e (33 - 70%). The reaction of equimolar quantities of 1c and H3B・S(CH3)2 gives the 1 : 1 adduct H3B・P((CH2)6CH=CH2)3 (85%). In none of these transformations are by-products derived from the C=C linkages observed
Metal Complexes of Biologically Important Ligands, CLXXIV [1]. Palladium(II) and Platinum(II) Complexes with Schiff Bases from 2-(Diphenylphosphino)benzaldehyde and α-Amino Acid Esters
Authors: Schreiner Bernhard , Robl Christian , Wagner-Schuh Barbara , Beck Wolfgang
Published: February 2015

A series of palladium(II) and platinum(II) complexes Cl2M(P-N-O) (M = Pd, Pt) with bidentate Schiff bases (P-N-O) from 2-(diphenylphosphino)benzaldehyde and α-amino acid esters has been synthesized, using PdCl2 or K[PtCl3(C2H4)], respectively. Abstraction of chloride from Cl2M(P-N-O) (using AgBF4) has afforded the cationic complexes [(P-N-O)M(Cl)]+BF4
− in which the Schiff bases function as tridentate ligands with coordination of the ester group. The structures of Cl2Pd(Ph2PC6H4C(H)=N-CH2CO2Et) and of [(Cl)Pd(Ph2PC6H4C(H)=NC(H)(CH2CH=CH2)CO2Me)]+BF4
− have been determined by X-ray diffraction. Complexes (L)MCl2 and [(L)MCl]+BF4 (M = Pd, Pt) have also been prepared with the reduced Schiff base Ph2PC6H4CH2NHC(H)(CH2Ph)CO2Me.
Synthesis, Crystal Structure and Luminescence Properties of a Cyclometalated Ir(III) Complex of 3,4-Diphenylcinnoline
Authors: Tong Bi-Hai , Wu Fang-Hui , Mei Qun-Bo , Zhang Qian-Feng
Published: February 2015

An iridium(III) complex, [(dpci-H)2Ir(dafo)](PF6) (dpci-H = deprotonated 3,4-diphenylcinnoline, dpci; dafo = 4,5-diazafluoren-9-one), was synthesized from the reaction of the iridium complex [Ir(dpci-H)2(Cl)]2 and dafo in methanol, and characterized by single-crystal X-ray diffraction along with FT-IR, UV/Vis, 1H NMR and mass spectroscopy. The luminescence properties and the decay of the cyclometalated iridium(III) complex were also investigated. Excitation at the absorption wavelength (469 nm) resulted in a strong emission band centered at 591 nm with a lifetime of 0.9 μs.
Terpenoids from Clerodendrum formicarum Gürke (Lamiaceae) of Cameroon
Authors: Ali Muhammad Shaiq , Ahmed Zeeshan , Ngoupayo Joseph , Ali Muhammad Imran
Published: February 2015

The ethanolic extract of the leaves of Clerodendrum formicarum, a Lameacious plant of Cameroon, afforded a new abeo-abietane diterpenoid named formidiol (1) together with some known diand triterpenoids. They include 12,16-epoxy-11,14-dihydroxy-6-methoxy-17(15→16)-abeo-abieta- 5,8,11,13,15-pentanene-3,7-dione (2), trans-phytol, friedelin and friedlan-3β -ol. Structures of all the isolated constituents have been characterized with the aid of 1D NMR spectroscopy while the structure of a new metabolite was elucidated via 2D NMR spectroscopic techniques.
Ab initio Molecular and Solid-state Studies of the Spin Crossover System [Fe(phen)2(NCS)2]
Authors: Matar Samir F. , Létard Jean-François
Published: February 2015

Ab initio computations are reported for both the isolated molecule and the extended solid within the density functional theory to assess the electronic structure and derived physical properties of [Fe(phen)2(NCS)2] inwhich FeII is characterized by either one of two spin states, i. e. high spin (HS, t2g
4eg
2) and low spin (LS, t2g
6eg
0). For molecular HS and LS configurations, the characteristic IR and Raman spectra have been computed with vibrational frequencies magnitudes and their assignments in relative agreement with the experiment. For the extended solid, the equilibrium total energies reproduce the correct LS ground state. From the calculated equations of state for the two forms, a pressure-induced HS→LS transition is proposed.
Structural and Computational Studies of 1-Methyl-2-thiocytosine and its Coordination Mode in a Dinuclear Platinum(IV) Complex [(PtMe3)2(μ-1-MeSCy-1κN3,1:2κ2S)2][BF4]2
Authors: Vetter Cornelia , Wagner Christoph , Kluge Ralph , Steinborn Dirk
Published: February 2015

X-Ray diffraction analysis of 1-methyl-2-thiocytosine (1-MeSCy, 1) revealed that its crystals contain two structurally very similar independent molecules (A, B). These molecules are connected through a complex network of hydrogen bonds. Centrosymmetric di- and tetrameric units AAʹ and BAAʹBʹ, respectively, are formed through N-H...N hydrogen bonds (N4a...N3aʹ 3.019(4) Å , AAʹ; N4a...N3b 2.988(4) Å, BAAʹBʹ), and the tetrameric units are connected through N-H...S hydrogen bonds. The arrangement of A and B molecules found in crystals of 1 was confirmed by DFT calculations up to tetrameric BAAʹBʹ units, yielding similar equilibrium structures, and the energies of the N-H...N hydrogen bonds between A and Aʹ and A and B were calculated to be about 10 kcal mol−1. Reaction of 1-MeSCy (1) with [PtMe3(Me2CO)3][BF4] (2) led to the formation of the ionic dinuclear complex [(PtMe3)2(μ-1-MeSCy-1κN3,1:2κ2S)2][BF4]2 (3) which was fully characterized by NMR (1H, 13C, 195Pt) and IR spectroscopy, ESI mass spectrometry and microanalysis. A singlecrystal X-ray diffraction analysis of 3 confirmed the dinuclear structure of the complex. The complex cation consists of a central [Pt2(μ-S)2] core having bound the 1-methyl-2-thiocytosine ligands in a 1κN3,1:2κ2S coordination mode in a face-to-face arrangement, the thionucleobase ligands being present as the amino-thione tautomer.
Crystal Structures of SomeN-substituted 2,5-Dimethylpyrrole Derivatives
Authors: Jones Peter G. , Kuś Piotr , Łannik Mariusz , Kozik Violetta
Published: February 2015

The crystal and molecular structures of five di-(2,5-dimethylpyrrole) and one tri-(2,5-dimethylpyrrole) derivatives have been determined. These compounds were synthesized from the respective diamino derivatives and hexane-2,5-dione in direct and simple reactions. The molecular packings are largely based on C-H...π interactions.
Crystal Structure of the Arsenate(V) NaTi2[AsO4]3
Authors: Ben Yahia Hamdi , Rodewald Ute Ch. , Pöttgen Rainer
Published: February 2015

The arsenate(V) NaTi2[AsO4]3 has been synthesized by a solid-state reaction route using a salt flux. Its structure has been solved and refined from single-crystal X-ray data: NASICON- type, R3̄c, a = 8.8057(5), c = 22.2406(15) Å, Z = 6, wR(F2) = 0.0617 for 576 unique reflections and 30 variables. The NaTi2[AsO4]3 structure consists of a three-dimensional framework of corner-sharing AsO4 tetrahedra and TiO6 octahedra. The negatively charged [Ti2As3O12] framework gives rise to two different interstices. The Na+ cation is located on the 6b position with a trigonal antiprismatic coordination and enhanced anisotropic displacement parameters.
Hydrothermal Synthesis, Crystal Structure and Properties of a 1DMetal- Organic Coordination Polymer {[Zn2(2,2´,3,3´-odpa)(py)3(H2O)]·H2O}n
Authors: Li Qi-Yao , Zang Shang-Quan , Li Jia-Bin , Hou Hong-Wei
Published: February 2015

Hydrothermal reaction of Zn(NO3)2·6H2O with 2,2´,3,3´-oxydiphthalic acid (H4odpa) and pyridine (py) at 120 °C yielded a one-dimensional metal-organic coordination polymer {[Zn2(2,2´,3,3´- odpa)(py)3(H2O)]·H2O}n (1), which is further connected together through hydrogen bonds, π· · ·π and C−H· · ·π interactions to give a three-dimensional supramolecular network. The thermal stability of complex 1 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Compound 1 exhibits photoluminescence with an emission maximum at ca. 430 nm upon excitation at 350 nm.
N-Heterocyclic Carbene (NHC) Derivatives of 1,3-Di(benzyloxy)imidazolium Salts
Authors: Laus Gerhard , Wurst Klaus , Kahlenberg Volker , Kopacka Holger , Kreutz Christoph , Schottenberger Herwig
Published: February 2015

1-Hydroxyimidazole-3-oxide (1) was alkylated with benzyl bromide in the presence of NaHCO3 to give the new 1,3-di(benzyloxy)imidazolium bromide 2a which was converted to the hexafluorophosphate 2b and bis(trifluoromethylsulfonyl)imide 2c. From this cation, pyridine generated a carbene which was trapped by sulfur or selenium to yield the respective 2-thione 3 or 2-selone 4. Bromination afforded the 2-bromo derivative 5. Reaction of the hexafluorophosphate 2b with silver oxide gave the silver-N-heterocyclic carbene complex 6 which was transmetallated with Au(Me2S)Cl to the gold-carbene complex 7. A rhodium-carbene complex 8 was obtained by reaction of the hexafluorophosphate 2b with [Rh(cod)Cl]2 in the presence of triethylamine. Eight crystal structures were determined by X-ray diffraction. The N-benzyloxy groups are twisted out of the plane of the imidazole ring in the solid state. They adopt syn conformations in the cation of the hexafluorophosphate 2b and in the metal-carbene complexes 6 - 8, but anti conformations in the thione 3 and selone 4. Both conformations were observed in two polymorphs of the 2-bromo compound 5.
Metal-doped Zeolites as Green Catalysts for Organic Synthesis
Authors: Chassaing Stefan , Alix Aurélien , Olmos Andrea , Keller Muriel , Sommer Jean , Pale Patrick
Published: February 2015

Metal-doped zeolites prepared by vapor diffusion are excellent heterogeneous catalysts. Copper(I)- exchanged zeolites catalyze for example 1,3-dipolar reactions or Mannich condensation, whereas scandium(III)-exchanged zeolites catalyze the Mukaiyama-type aldolization. These catalysts are easily prepared, stable for months, conveniently recovered by filtration and recyclable. They can be used in safe solvents and even without solvent, and thus fully comply with the Green Chemistry principles. Their ease of handling and their large scope of applications enabled us to introduce the “zeo-click” concept for organic synthesis catalyzed by such green heterogeneous catalysts.
Empirical Polarity Parameters for Hexaalkylguanidinium-based Room-temperature Ionic Liquids
Authors: Bogdanov Milen G. , Svinyarov Ivan , Kunkel Helene , Steinle Christine , Arkhipova Maria , Kantlehner Willi , Maas Gerhard
Published: February 2015

The polarity of a series of 36 hexaalkylguanidinium-based room-temperature ionic liquids (RTILs), featuring different unbranched alkyl substituents in the cation and eight different anions, has been determined by means of Reichardt’s solvatochromic betaine dye; ET(30) and the corresponding normalized EN
T values are presented. The positively solvatochromic probe 5-dimethylamino-5´-nitro-2,2´-bithiophene was used to characterize unspecific solvent/solute interactions (effects of dipolarity/polarizability) of ten hexaalkylguanidinium and, for comparison, two 1-alkyl-3-methylimidazolium ionic liquids.
Neue Bisguanidin-Kupfer-Komplexe und ihre Anwendung in der ATRP/ New Bisguanidine-Copper Complexes and their Application in ATRP
Authors: Bienemann Olga , Haase Roxana , Flörke Ulrich , Döring Artjom , Kuckling Dirk , Herres-Pawlis Sonja
Published: February 2015

The ligands TMG2e [bis(N,N,N´,N´-tetramethylguanidino)ethane] and DMEG2e [N1,N2-bis(1,3-dimethylimidazolin-2-ylidene)ethane-1,2-diamine] were used in the complexation of copper cations to give the new complexes [Cu(TMG2e)2][Cu2I4], [Cu(TMG2e)Cl2] and [Cu(DMEG2e)2]-[CuCl2]. Single-crystal structure determination shows that the complexes [Cu(TMG2e)Cl2] and [Cu(DMEG2e)2][CuCl2] both crystallise in the monoclinic space group C2/c, the complex [Cu(TMG2e)2][Cu2I4] in the orthorhombic space group Pbca. The copper atoms in all complex cations reside in a coordination environment between tetrahedral and square-planar geometry. The application of copper complexes with TMG2e and DMEG2e as ligands in atom transfer radical polymerisation (ATRP) was investigated with styrene as monomer. The polymerisation process with both ligand systems shows even at low temperature unexpected high conversions and molecular weight distributions that are evidence of a well controlled ATRP. These first results in the application of guanidine ligands in ATRP show that these ligands have high potential, but that further process optimisations and ligand tuning are necessary to develop highly active catalysts for ATRP.
Solvothermal/ Hydrothermal Synthesis of Metal Oxides and Metal Powders with and without Microwaves
Authors: Komarneni Sridhar , Noh Young Dong , Kim Joo Young , Kim Seok Han , Katsuki Hiroaki
Published: February 2015

Anatase and Ca, Sr and Ca0.5Sr0.5 hydroxyapatites were synthesized by conventional-hydrothermal (C-H) as well asmicrowave-hydrothermal (M-H)methods.Microwave-assisted reactions led to accelerated syntheses of anatase but no such acceleration of reactions could be detected with the syntheses of hydroxyapatites because the crystallization of the latter materials occurred at very low temperature. Cu and Au metal powders were produced by using glucose, fructose or sucrose as reducing agents under C-H conditions at 160 ℃, where fructose and sucrose were found to be stronger reducing agents than glucose. The crystallinity of all the powders was characterized by powder X-ray diffraction, and morphology and particle sizes were determined by scanning or transmission electron microscopy
Dissolving Silicides: Syntheses and Crystal Structures of New Ammoniates Containing Si5
2– and Si9
4– Polyanions and the Role of Ammonia of Crystallisation
Authors: Joseph Stefanie , Suchentrunk Christof , Korber Nikolaus
Published: February 2015

The dissolution of the ternary material K6Rb6Si17 in liquid ammonia yields the solvate compound Rb4Si9 ・ 5NH3, which contains fourfold negatively charged nine atom silicon clusters Si9
4−. Using additionally the [2.2.2] cryptand during the dissolution results in the solvate [K(2.2.2- crypt)]2Si5 ・ 4NH3 , in which the Si5
2− anion is present in the crystal structure. The Si5
2− anion has the shape of a nearly ideal trigonal bipyramid. The starting material K6Rb6Si17 contains both Si4
4− and Si9
4− Zintl anions. In ammoniate crystal structures, Si9
4− anions are accessible independently of Si4
4− anions, and ammonia of crystallisation plays a major role in the observed crystal symmetry. For the cryptate structures of Si5
2− and Ge5
2− anions ammonia of crystallisation is obligatory despite the loss of crystal symmetry compared to the crystal structures of the heavier homologues Pb5
2− and Sn5
2−.
Cyanoplatinate Halides – Synthesis, Crystal Structure Analyses and Vibrational Spectroscopy of Compounds A2[Pt(CN)4X2] (A = Rb, Cs; X = Cl, Br, I)
Authors: Mühle Claus , Nuss Jürgen , Dinnebier Robert E. , Jansen Martin
Published: February 2015

Crystal structures of the cyanoplatinates A2[Pt(CN)4X2] (A = Rb, Cs; X = Cl, Br, I) have been determined by single-crystal analysis and X-ray powder diffraction. The compounds were synthesized by metathesis from Ba[Pt(CN)4] ·4 H2O and alkali metal sulfates, and by subsequent oxidation with the respective halogens. The crystals were grown by slowly concentrating respective aqueous solutions. The PtIV cations are octahedrally coordinated by four cyanide ligands and two halogen atoms, the latter being located in trans positions. Rb2[Pt(CN)4Cl2]: triclinic, P¯1 (Z = 2), a = 6.7779(2), b = 9.3149(3), c = 9.6707(3) Å , α = 89.37(0), β = 76.05(0), γ = 72.98(0)◦, V = 565.42(2) Å3, N` hkl= 5616, R(F)N` = 0.0273; Rb2[Pt(CN)4I2]: monoclinic, P21/c (Z = 2), a = 7.4239(2), b = 9.2486(2), c = 9.1189(2) Å , β = 107.22(3)◦, V = 598.04(6) Å3, N` hkl = 2917, R(F)N` = 0.0295; Cs2[Pt(CN)4I2]: monoclinic, P21/c (Z = 2), a = 7.6740(4), b = 9.5397(5), c = 9.3474(5) Å , β = 106.46(0)◦, V = 656.3(2) Å3, Z = 2, N` hkl = 2738, R(F)N` = 0.0283; Cs2[Pt(CN)4Cl2]: monoclinic, C2/c (Z = 4), a = 17.947(4), b = 7.395(2), c = 12.031(3) Å , β = 131.904(1)◦, V = 1188.4(5) Å3, R-wp = 2.77; Cs2[Pt(CN)4Br2]: monoclinic, C2/c (Z = 4), a = 18.404(1), b = 7.2819(5), c = 12.4156(8) Å , β = 132.156(1)◦, V = 1233.5(1) Å3, N` hkl = 2566, R(F)N` = 0.0268. All compounds were characterized by differential thermal analysis, thermogravimetry, and infrared and Raman spectroscopy.
Synthesis and Radiofluorination of Iodophenyl Esters as Tool for the Traceless Staudinger Ligation
Authors: Pretze Marc , Flemming Anke , Kockerling Martin , Mamat Constantin
Published: February 2015

A new synthetic pathway for the preparation of ω-functionalized 2-iodophenyl esters as starting materials for the synthesis of substituted phosphanes is described. A radiolabeling of these esters with fluorine-18 has led to building blocks which were reacted with HPPh2 in a Pd-catalyzed P-C cross coupling to establish new phosphanes. These compounds can be applied as mild and bioorthogonal radiolabeling agents by means of the traceless Staudinger ligation. A route to access this class of compounds has been established.
Synthesis of 2,2`-(1,4-Phenylene)bis-3,4-dihydro-2H-1,3-thiazin-4-ones and their Facile Recyclization to 2,2`-(1,4-Phenylene)bis(pyrimidin-4-one) and/or 2,2`-(1,4-Phenylene)-bis-(thieno[2,3-d]pyrimidin-4(1H)-one) Derivatives
Authors: Shaker Raafat M. , Ibrahim Yusria R. , Abdel-Latif Fathy F. , Hamoda Asmaa
Published: February 2015

An efficient and direct procedure for the synthesis of 2,2`-(1,4-phenylene)bis-3,4-dihydro-2H-1,3- thiazin-4-one derivatives is described. Oxidation of the latter and their base-catalyzed recyclization has been studied. The products were characterized by elemental analyses, and IR, 1H NMR, and 13C NMR spectra.
Intermediate-valent Cerium in CeRu2Mg5
Authors: Linsinger Stefan , Eul Matthias , Rodewald Ute Ch. , Pöttgen Rainer
Published: February 2015

The magnesium-rich compound CeRu2Mg5 was synthesized by high-frequency melting of the elements in a sealed tantalum ampoule. CeRu2Mg5 crystallizes with a new tetragonal structure type: P42/ncm, a = 961.1(1), c = 723.2(1) pm, wR2 = 0.0284, 481 F2 values and 25 variables. The striking structural motifs in CeRu2Mg5 are short Ce-Ru distances of 232 pm. Each cerium atom is connected to two ruthenium atoms within a three-dimensional [Ru2Mg5] network. CeRu2Mg5 has a pronounced magnesium substructure with short Mg-Mg distances in the range 302 - 341 pm. The short Ce-Ru distances are a consequence of the almost tetravalent character of the cerium atoms. Temperature-dependent magnetic susceptibility data show intermediate-valent behavior of the cerium atoms (0.9(1) μB per formula unit) and no magnetic ordering down to 3 K.
Optical and Magnetic Properties of some REZnPnO (Pn = P, As, Sb) Phases
Authors: Schellenberg Inga , Lincke Hannes , Hermes Wilfried , Dittrich Volker , Glaum Robert , Möller Manfred H. , Pöttgen Rainer
Published: February 2015

Several REZnPnO phases of the ZrCuSiAs type (RE = rare earth element, Pn = P, As, Sb) were synthesized in X-ray-pure form in NaCl/KCl salt fluxes. The structure of PrZnSbO was refined from single-crystal diffractometer data: P4/nmm, a = 418.79(8), c = 946.7(5) pm, wR2 = 0.0349, 192 F2 values, 12 parameters. The REZnPnO pnictide oxides were studied with respect to magnetic susceptibility, 121Sb Mössbauer spectroscopy, and optical properties.
Amine-rich Silver Complexes of rac-trans-1,2-Diaminocyclohexane
Authors: Wölper Christoph , Durán Ibáńez Sara , Jones Peter G.
Published: February 2015

The use of the diamine rac-trans-1,2-diaminocyclohexane (LL) as a major component of the solvent system allows the isolation of crystalline silver complexes with higher ratios of LL to silver (up to 4 : 1, compared to the previously obtained 1 : 1 in ethanolic solution). The complexes obtained and crystallographically characterized were (LL)2AgNO3 (1), (LL)3Ag(OAc)(H2O)2 (2) and (LL)4AgBr(H2O)3 (3). Additionally, the silver-free compounds (LL)・(H2O) (4) and (LL)3・HCl (5) were obtained as by-products. Complex 1 is a chain polymer with one bridging and one terminal LL ligand; the chains are homochiral. Complex 2 contains isolated [(LL)3Ag]+ cations with one chelating and two monodentate ligands. Complex 3 contains dimeric [(LL)2AgBr]2 units; the additional LL molecules are not coordinated to the metal. Compound 5 consists of one diamine with imposed twofold symmetry, one half-protonated diamine in which the acidic hydrogen site is half-occupied (it is involved in a disordered hydrogen bond N-H・ ・ ・N across a twofold axis) and a chloride anion on a twofold axis. In all five structures, the components pack so as to form clearly defined hydrophilic and hydrophobic areas. In the former, classical hydrogen bonds are formed. Except for a few borderline cases of three-center bonds, these are all two-center systems. The appreciable number of these (e. g. 20 for compound 3) renders the layer structures quite complex, but in most cases they can be analyzed in terms of smaller units.
Polysulfonylamine, CLXXXVIII [1]. Kristallstrukturen von drei Dimethylammonium-di(4-halogenbenzolsulfonyl)amiden (Halogen = Cl, Br, I) und von Dimethylammonium-di(4-methylbenzolsulfonyl)amid: Eine isotype Reihe mit strukturbestimmenden starken Wasserstoffbrücken und beiläufigen Halogenbrücken/ Polysulfonylamines, CLXXXVIII. Crystal Structures of Three Dimethylammonium Di(4-halobenzenesulfonyl)amides (Halogen = Cl, Br, I) and of Dimethylammonium Di(4-methylbenzenesulfonyl)amide: An Isotypical Series Featuring Strong Structure-determining Hydrogen Bonds and Incidental Halogen Bonds
Authors: Wölper Christoph , Rodríguez-Gimeno Alejandra , Freytag Matthias , Jones Peter G. , Blaschette Armand
Published: February 2015

The four title compounds, Me2NH2
+·(4-Cl/Br/I/Me-C6H4-SO2)2N-, were obtained by metathesis of dimethylammonium chloride with the corresponding silver di(arenesulfonyl)amides. The products crystallize isotypically in the monoclinic space group Cc (Z = 4, Z´ = 1). In each structure, the ionic entities associate into hydrogen-bonded chains, which propagate along the c axis of the crystals and consist of alternating cations and anions held together by charge-assisted N+-H· · ·N− and N+- H(· · ·O)2 hydrogen bonds. In the three structures containing 4-halobenzenesulfonyl groups, each hydrogen-bonded chain is linked to four neighboring chains by pairs of C-Cl/Br/I· · ·O halogen bonds, which at first sight seem to be the causative factor in the formation of catemeric head-to-tail arrays of anions propagating along the ab face diagonals. On suppressing these halogen bonds by means of halogen-methyl exchange, all essential features of the packing architecture, including the anion headto- tail arrays, are precisely maintained. It may be thus inferred that the halogen bonds occurring in the first three compounds are supportive incidentals, but do not play any structure-determining role.
Synthesis and Characterization of New Palladium(II) Complexes with Ligands Derived from Furan-2-carbaldehyde and Benzaldehyde Thiosemicarbazone and their in vitro Cytotoxic Activities against Various Human Tumor Cell Lines
Authors: Hernández Wilfredo , Paz Juan , Carrasco Fernando , Vaisberg Abraham , Manzur Jorge , Spodine Evgenia , Hennig Lothar , Sieler Joachim , Beyer Lothar
Published: February 2015

With the ligands 4-phenyl-1-(furan-2-carbaldehyde)thiosemicarbazone, HTSC1, (1), 4-phenyl-1- (5´-phenyl-furan-2-carbaldehyde)thiosemicarbazone, HTSC2 (2), o-methoxy-benzaldehydethiosemicarbazone, HTSC3 (3), and o-cyano-benzaldehydethiosemicarbazone, HTSC4 (4), the corresponding palladium(II) complexes, Pd(TSC1)2 (5), Pd(TSC2)2 (6), Pd(TSC3)2 (7), and Pd(TSC4)2 (8) were synthesized and characterized by elemental analysis and spectroscopic techniques. The crystal structure of Pd(TSC3)2 (7) was determined by single-crystal X-ray diffraction. Complex 7 shows a squareplanar geometry, where two deprotonated ligands are coordinated to the PdII center through the nitrogen and sulfur atoms in a trans arrangement. In vitro antitumor studies against different human tumor cell lines have revealed that the palladium(II) complexes 5- 8 are more cytotoxic (IC50 values in the range of 0.21 - 3.79 μM) than their corresponding ligands (1 - 4) (> 60 μM). These results indicate that the antiproliferative activity is enhanced when thiosemicarbazone ligands are coordinated to the metal. Among the studied palladium(II) complexes, 8 exhibits high antitumor activity on K562 chronic myelogenous leukemia cells with a low value of the inhibitory concentration (IC50 = 0.21 μM).
Intermetallic Magnesium Compounds RE2Ni2Mg3 (RE =Gd, Dy–Tm, Lu) with Tb2Ni2Mg3-type Structure
Authors: Linsinger Stefan , Eul Matthias , Yahia Hamdi Ben , Möller Manfred H. , Pöttgen Rainer
Published: February 2015

New intermetallic magnesium compounds RE2Ni2Mg3 (RE = Gd, Dy-Tm, Lu) were synthesized from the elements by induction melting. They are isotypic with Tb2Ni2Mg3. The structure of Gd2Ni2Mg3 was refined from X-ray powder data: Cmmm, a = 398.7(1), b = 2121.9(7), c = 368.39(9) pm, RB = 7.49%, 3800 data points, 23 parameters. The RE2Ni2Mg3 intermetallics are intergrowth variants of AlB2- and CsCl-related slabs. Gd2Ni2Mg3 is a Curie-Weiss paramagnet above 75 K with an experimental magnetic moment of μeff = 8.16(1) μB /Gd atom. Antiferromagnetic ordering sets in at TN = 42.0(5) K.
Synthesis and Crystal Structure of the High-pressure Cobalt Borate HP-CoB2O4
Authors: Neumair Stephanie C. , Kaindl Reinhard , Huppertz Hubert
Published: February 2015

The cobalt borate HP-CoB2O4 was synthesized from Co3O4 and B2O3 under high-pressure / high-temperature conditions of 6.5 GPa and 950 °C. The structure of HP-CoB2O4 is isotypic to HPNiB2O4 and β -FeB2O4, representing the third example of a borate, in which every BO4 tetrahedron shares a common edge with a second one. HP-CoB2O4 crystallizes in the space group C2/c (Z = 4) with the parameters a = 934.6(2), b = 562.0(2), c = 443.3(1) pm, β = 108.2(1)°, V = 0.2212(1) nm3, R1 = 0.0218, and wR2 = 0.0410 (all data). The structure consists of layers of BO4 tetrahedra, that are interconnected via strings of edge-sharing FeO6 octahedra
Reactivity of Tetramethylphosphonium Fluoride in Acetonitrile Solutions
Authors: Hohenstein Christian , Neumann Frank , Kornath Andreas
Published: February 2015

Anhydrous tetramethylphosphonium fluoride dissolved in acetonitrile reacts slowly with the solvent under formation of (E)-2-amino-1-cyano-propene which was characterized by infrared and NMR spectroscopy. An attempted preparation of [Me3PF3]− by addition of Me3PF2 to Me4PF/acetonitrile solutions has shown that the desired reaction does not occur, but prolonged reaction times and small acetonitrile concentrations lead to the formation of the iminophosphorane Me3P=NC(Me)=CH2 and [Me4P]+HF2
−. Me3P=NC(Me)=CH2 was characterized by infrared spectroscopy and a single-crystal structure determination. N-(2-propenyl)trimethyliminophosphorane crystallizes in the monoclinic space group P21/c with a = 1006.8(2), b = 1523.5(3), c =1180.3(2) pm, β = 111.72(6)° and Z = 8. The two independent molecules per unit cell have nearly planar P=NC( C)=C skeletons with torsion angles P-N-C-C of 5.9(3)° and 7.1(4)° and an average P=N distance of 158.1(2) pm. The general ability of Me4PF as a fluoride donor was proven by the reaction with SO2 which results in the formation of [Me4P]+SO2F−. The colorless salt was characterized by infrared, Raman, and NMR spectroscopy.
Synthesis, Crystal Structure and DNA-binding Properties of a Nickel(II) Complex with 2, 6-Bis(2-benzimidazolyl)pyridine
Authors: Wu Huilu , Huang Xingcai , Yuan Jingkun , Kou Fan , Chen Guisheng , Jia Beibei , Yang Yang , Lai Yulin
Published: February 2015

A novel complex of nickel(II) picrate (pic) with the V-shaped ligand 2, 6-bis(2-benzimidazolyl) pyridine (bbp) was synthesized and characterized by elemental analysis, electrical conductivity, and IR and UV/Vis spectral measurements. The crystal structure of the nickel(II) complex ([Ni(bbp)2](pic)2·2DMF) has been determined by single-crystal X-ray diffraction. The Ni(II) cation is bonded to two bbp ligands through six nitrogen atoms, resulting in a distorted octahedral geometry. The DNA-binding properties of the nickel(II) complex were investigated by electronic absorption and fluorescence spectra and by viscosity measurements. The experimental results suggest that the nickel(II) complex binds to DNA in an intercalation mode.
Cyclotrimerization of 3-R-1,2,4-Triazin-5(4H)-ones with Cyclic Ketones
Authors: Egorov Ilya N. , Kovalev Igor S. , Rusinov Vladimir L. , Chupakhin Oleg N.
Published: February 2015

New heterocyclic tetracyclic systems were synthesized. Interaction between 3-R-1,2,4-triazin- 5(4H)-ones and cyclic ketones under acidic conditions leads to the formation of zwitterion derivatives of 5,6,7,8,9,10,11,12-octahydro-[1,2,4]triazino[1,6- ƒ ]phenanthridine and 1,2,3,6,7,8-hexahydro-bicyclopenta[ b,d]pyrido[1,2- ƒ ][1,2,4]triazine.
Polysulfonylamine, CLXXXIX [1]. Weitere Beispiele für die O-Protonierung von Harnstoffen mit Di(organosulfonyl)aminen: Bildung und Kristallstrukturen von 1,1-Dimethyluroniumdi( 4-fluorbenzolsulfonyl)amid und Di(1-methylharnstoff)- hydrogen(I)-di(4-fluorbenzolsulfonyl)amid/ Polysulfonylamines, CLXXXIX. Additional Examples of the O-Protonation of Ureas by Di(organosulfonyl)amines: Formation and Crystal Structures of 1,1-Dimethyluronium Di(4-fluorobenzenesulfonyl)amide and Di(1-methylurea)hydrogen(I)Di(4-fluorobenzenesulfonyl) amide
Authors: Wölper Christoph , Rodríguez-Gimeno Alejandra , Iborra Katherine Chulvi , Jones Peter G. , Blaschette Armand
Published: February 2015

Co-crystallization of N-methyl-substituted ureas with di(organosulfonyl)amines, (RSO2)2NH, leads unpredictably to either molecular co-crystals or, via proton transfer, to uronium salts. As a sequel to former reports, this communication describes the formation and the crystal structures of the new ionic compounds 1,1-dimethyluronium di(4-fluorobenzenesulfonyl)amide (1, monoclinic, space group P21/c, Z´ = 1) and di(1-methylurea)hydrogen(I) di(4-fluorobenzenesulfonyl)amide (2, triclinic, P1̄, Z´ = 1); both salts were obtained from dichloromethane/petroleum ether. In the structure of 2, the urea moieties of the cationic homoconjugate are connected by a very short [O-H· · ·O]+ hydrogen bond [d(O· · ·O) = 244.6(2) pm, θ (O-H· · ·O)≈170°, bridging H atom asymmetrically disordered over two positions]. The O-protonation induces a specific elongation of the C-O bond lengths to 131.2(2) pm in 1 or 129.5(2) and 127.4(2) pm in 2, as compared to literature data of ca. 126 pm for the unprotonated ureas. Both crystal structures are dominated by conventional two- and threecentre hydrogen bonds, which involve the OH and all NH donors and give rise to one-dimensional cation-anion arrays. In particular, the ionic entities of 1 are alternatingly associated into simple chains propagated by glide-plane operations parallel to the c axis, whereas the donor-richer structure of 2 displays inversion symmetric dimers of formula units, which are further hydrogen-bonded into strands propagated by translation parallel to the a axis.
Three New Antiviral Triterpenes from Aster tataricus
Authors: Zhou Wen Bing , Tao Jun Yan , Xu Hui Min , Chen Ke Li , Zeng Guang Zhi , Ji Chang Jiu , Zhang Yu Mei , Tan Ning Hua
Published: February 2015

Three new shionane-type triterpenes, shion-22-methoxy-20(21)-en-3-one (1), shion-22(30)-en- 3,21-dione (2), shion-22-methoxy-20(21)-en-3β -ol (3), were isolated from the rhizomes of Aster tataricus. Their structures have been determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Compounds 1 and 2 show inhibitory activities on HBsAg with IC50 values of 0.89 and 4.49 μgmL−1, respectively, 1 shows inhibitory activity on HBeAg with an IC50 value of 0.83 μgmL−1, and 2 shows inhibitory activity on HA with an IC50 value of 11.18 μgmL−1.
The Transition Metal-rich Orthophosphate Arrojadite with Special Structural Features
Authors: Kallfaß Christoph , Hoch Constantin , Schier Hermann , Simon Arndt , Schuber Helmut
Published: February 2015

The crystal structure of the transition metal-rich orthophosphate mineral arrojadite was reexamined, and the disorder phenomena were analyzed applying modern X-ray single-crystal diffraction and refinement methods on samples from Nickel Plate (USA) and Hagendorf (Germany). As a new feature of the arrojadite structure, two different types of channels oriented along [010] are described. The occupancy of the atomic positions inside these channels have been elucidated.
Synthesis of New 3-Substituted Indole Derivatives
Authors: Hassaneen Huwaida M. E. , Pagni Richard M.
Published: February 2015

Treatment of 3-cyanoacetyl-2-methylindole (1) with phenyl isothiocyanate gave the corresponding thioacetanilide derivative 3. The thioacetanilide 3 was utilized as the key intermediate for the synthesis of some new 1,3,4-thiadiazole (6a, b and 9a - e), thiophene (11a, b), thiazolidin-4-one (4), thiazole (12 and 13), and benzothiazole (15) derivatives. The structures of the new compounds were elucidated on the basis of elemental analyses and spectral data.
Electroreduction of Organic Compounds, 37 [1]. Electroreduction of 1,4-Dichlorobicyclo[2.2.2]octane-2-carboxamides
Authors: Voss Jürgen , Baum Werner , Adiwidjaja Gunadi , Behrens Ulrich
Published: February 2015

Several 1,4-dichlorobicyclo[2.2.2]octanecarboxamides were prepared, which were expected to be suitable precursors for the electrochemical synthesis of [2.2.2]propellanes. Their potentiostatic electroreduction at extremely negative potentials in THF, however, did not lead to the expected [2.2.2]propellanes. Instead, protio-dechlorination to form the corresponding bicyclo[2.2.2]octanecarboxamides occurred, even under rigorous exclusion of moisture and oxygen. Ring-opened olefins were produced as by-products. Polytetrahydrofuran was formed when the supporting electrolyte tetrabutylammonium hexafluorophosphate was electrolyzed at −3.5 V in the absence of an organic chloro compound as depolarizer. The experimental results are interpreted in terms of semi-empirical MO calculations.
The Solid Solutions Gd2Cu2In1–xMgx – Drastic Increase of the Curie Temperature upon In/Mg Substitution
Authors: Hermes Wilfried , Schappacher Falko M. , Pöttgen Rainer
Published: February 2015

The Mo2B2Fe-type intermetallic compounds Gd2Cu2In and Gd2Cu2Mg form a complete set of solid solutions Gd2Cu2In1−xMgx. The a lattice parameter, the Weiss constant and the Curie temperature increase with increasing magnesium content in an almost Vegard-like manner, while the c parameter remains almost constant. All members of the solid solutions show ferromagnetism with TCs between 114 and 80 K.
A New Approach for the Synthesis of Nanostructured Polyurethane-Hydroxylapatite-based Hybrid Materials
Authors: Popescu Laura Mădălina , Piticescu Roxana Mioara , Buruiană Tinca , Vasile Eugeniu , Truşcă Roxana , Bădiliţă Viorel
Published: February 2015

The structural properties of composites prepared by a hydrothermal method in high-pressure conditions and the role of pressure in the formation of hydroxylapatite-polyurethane (HAp-PU) materials with strong interactions between the two components were investigated. X-Ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), FT-IR and NMR analyses were used to characterize the composite powders from a structural, morphological and compositional point of view. Both FT-IR and NMR spectroscopies indicate interactions between hydroxylapatite and acid polyurethane
Synthesis, Crystal Structure and Photoluminescence of 1,2-Bis(phenylselenyl)-1,2-dicarba-closo-dodecaborane(12)
Authors: Miao Jinling , Chen Hongwei , Xu Meiling , Peng Bin , Nie Yong , Sun Daofeng
Published: February 2015

The reaction of dithio-o-carborane with diphenyldiselenide (PhSeSePh) affords the title compound, closo-1,2-(PhSe)2C2B10H10 (1), which has been characterized by IR and NMR (1H, 11B) spectroscopy and by single-crystal X-ray diffraction. The phenylselenyl groups are bonded to the cage carbon atoms of the o-carborane cluster with a Ccage-Ccage distance of 1.751(6) Å and an Se-Ccage- Ccage-Se torsion angle of 10.1(3)°. Compound 1 displays a violet emission on excitation with UV light. For comparison the photoluminescence of the known analog closo-1,2-(PhS)2C2B10H10 (2) was also studied
1,1-Ethylboration of Trimethyl(methoxypropargyl)- and Chloro(dimethyl)methoxypropargylsilane. A Novel 1,2,5-Oxasilaborolane
Authors: Wrackmeyer Bernd , Klimkina Elena V. , Kupcik Tomas , Kupcik Tomas , Lohwasser Ruth
Published: February 2015

Triethylborane reacts with trimethyl(methoxypropargyl)- silane via 1,1-ethylboration to give quantitatively a 90 : 10 mixture of (E)- and (Z)-3-diethylboryl-2-trimethylsilyl-pent- 2-yl-methyl ethers. In contrast, the reaction of triethylborane with chloro(dimethyl)methoxypropargylsilane affords the novel 1,2,5-oxasilaborolane [2,2-dimethyl-5-ethyl-3-(1- ethylpropylidenyl)-1-oxa-2-sila-5-boracyclopentane] by 1,1- ethylboration, rearrangement and ether cleavage
Synthesis, Crystal Structures and Properties of New Barium Thiocyanato Coordination Polymers with trans-1,2-Bis(4-pyridyl)ethylene as Ligand
Authors: Wöhlert Susanne , Jess Inke , Näther Christian
Published: February 2015

Reactions of barium thiocyanate with trans-1,2-bis(4-pyridyl)ethylene (bpe) in acetonitrile/water using different molar ratios always lead to the formation of a new barium coordination polymer of composition {[[Ba(NCS)(H2O)5]2](bpe)}(NCS)2(bpe)3(H2O)2 (1). During the preparation of single crystals of compound 1, three additional new compounds were obtained (2 - 4), of which one crystallizes in two different polymorphic modifications (4I and 4II). In compound 1 the Ba cations are coordinated by six water molecules, two N-bonding thiocyanato anions and one N atom of a bpe ligand within an irregular polyhedron. Two Ba cations are linked by two water molecules and two μ- 1,1-N-bridging thiocyanato anions into centrosymmetric dimers that are further connected by the bpe ligands into chains. The coordination topology in the crystal structure of compound 2 is very similar to that in 1 in that two coordinating water molecules are exchanged by two terminal bpe ligands. As in 1, Ba dimers are observed that are connected by the bpe ligands into chains. In [[Ba(NCS)2]2]- (bpe)3 (3) the barium cations are linked by two μ-1,3-bridging anions and one side-on-bridging thiocyanato anion into chains that are further linked by the bpe ligands into layers. In the first polymorphic modification of composition [Ba(NCS)2(bpe)(H2O)(CH3CN)]CH3CN (4I) each Ba cation is coordinated by one terminal N-bonding and two μ-1,1,3(N,Nʹ ,S)-bridging thiocyanato anions, two bridging water molecules, one acetonitrile molecule and one bpe ligand within an irregular polyhedron. The Ba cations are connected into chains that are further linked via O-H···N hydrogen bonding. The crystal structure of the second form 4II is very similar to that of form 4I, and significant differences are found predominantly in the packing of the complexes. Investigations using simultaneous differential thermoanalysis and thermogravimetry on compound 1 have shown that this compound decomposes in three steps with the formation of compound 3 in the second TG step.
Crystal Chemistry of Uranyl Halides Containing Mixed (UO2)(XmOn)5 Bipyramids (X = Cl, Br): Synthesis and Crystal Structure of Cs2(UO2)(NO3)Cl3
Authors: Nazarchuk Evgeny V. , Siidra Oleg I. , Krivovichev Sergey V.
Published: February 2015

Single crystals of Cs2(UO2)(NO3)Cl3 were prepared by a hydrothermal method at 205 °C. The crystal structure has been solved by Direct Methods: monoclinic, P21/n, a = 10.3748(13), b = 9.4683(13), c = 12.5535(16) Å, β = 110.280(2)◦, V = 1156.7(3) Å3, R1 = 0.029. In the structure, strongly bonded linear uranyl cations UO2
2+ are equatorially coordinated by two O and three Cl atoms to form (UO2)Cl3O2 pentagonal bipyramids. Each bipyramid shares its O-O edge with an adjacent (NO3)− anion to form finite clusters with the chemical composition [(UO2)(NO3)Cl3]2−. The Cs+ cations provide three-dimensional connectivity of the structure by forming Cs-O and Cs-Cl contacts to the uranyl nitrate chloride complexes. Related structures of mixed-ligand uranyl halides are compared.
HF-HNO3-H2SO4/H2O Mixtures for Etching Multicrystalline Silicon Surfaces: Formation of NO2
+, Reaction Rates and Surface Morphologies
Authors: Lippold Marcus , Patzig-Klein Sebastian , Kroke Edwin
Published: February 2015

The reaction behavior of HF-HNO3-H2O etching mixtures, which are frequently used for texturing silicon surfaces, is significantly influenced by the addition of sulfuric acid. For high concentrations of sulfuric acid, nitronium ions NO2
+ ions have been detected by means of 14N NMR spectroscopy, and results of Raman spectroscopic investigation have allowed the quantification of the nitronium ions. Maximum etching rates of 4000 - 5000 nm s−1 are reached for HF (40 %)-HNO3 (65%)-H2SO4 (97%) mixtures with w (40%-HF)/w (65%-HNO3) ratios of 2 to 4 and w (97%-H2SO4)<0.3. For higher concentrations of sulfuric acid, H2SO4 can be considered as a diluent. In order to investigate the influence of the sulfuric acid at constant HF and HNO3 quantities, fuming HNO3 (100 %) was used and the water in the mixtures successively replaced by H2SO4. A sudden increase of etching rates was found for sulfuric acid concentrations around 6 mol L−1 correlating with the characteristic color of the etching solutions. Decreased reaction rates at > 7 molL−1 H2SO4 are attributed to high solution viscosities and the formation of fluorosulfuric acid. Generally, in HF-HNO3-H2SO4/H2O etching mixtures a reduced dissociation of nitric acid, the formation of nitronium ions, the solubility of neutral nitrogen intermediates (e. g. NO2, N2O3), as well as other effects influence the attack of silicon surfaces. The structure of etched silicon surfaces was investigated by means of scanning electron (SEM) and laser scanning microscopy (LSM). The morphologies are influenced most significantly by the relative amounts of sulfuric acid. Unexpectedly, in nitronium ion-containing mixtures rough surfaces with pore-like etching pits are generated.
An Efficient Procedure for the Synthesis of Polysubstituted Pyrroles in an Ionic Liquid
Authors: He Yan-Hong , Wang Gang-Qiang , Xu Ke-Ling , Guan Zhi
Published: February 2015

The ionic liquid 1-butyl-3-methyl-imidazolium hydrogen sulfate, [bmim]HSO4, was used as a catalyst and reaction medium for the pyrrole synthesis, and a wide range of aliphatic, aromatic, heteroaromatic and carboxylic 1,4-diketones easily underwent condensations with aniline and ethylenediamine to form polysubstituted pyrroles. Sequential decarboxylation/Paal-Knorr pyrrole condensation was observed, which provides a new and facile approach to monoester pyrroles from 1,4-diketo-2,3-dicarboxylic acid esters.
ScIrP with ZrNiAl-type Structure
Authors: Pfannenschmidt Ulrike , Rodewald Ute Ch. , Pöttgen Rainer
Published: February 2015

The phosphide ScIrP was synthesized from the elements in a bismuth flux and characterized by powder and singlecrystal X-ray diffraction: ZrNiAl type, P6̄2m, Z = 3, a = 637.2(3), c = 389.2(2) pm, wR2 = 0.0280, 250 F2 values, 15 variables. The two crystallographically independent phosphorus sites have tricapped trigonal-prismatic metal coordination P1Ir3Sc6 and P2Ir6Sc3. The shortest interatomic distances occur for Ir-P (244 - 251 pm) within the 3D [IrP] network in which the scandium atoms fill cavities of coordination number 15 (4 Sc + 6 Ir + 5 P).
CaAl2Si2-type Arsenides RE2/3Zn2As2 (RE = La, Ce, Pr, Nd, Sm)
Authors: Nientiedt André T. , Lincke Hannes , Rodewald Ute Ch. , Pöttgen Rainer , Jeitschko Wolfgang
Published: February 2015

The ternary arsenides RE2/3Zn2As2 (RE = La, Ce, Pr, Nd, Sm) were synthesized from the elements in NaCl/KCl salt fluxes and were characterized by powder X-ray diffraction. The Ce2/3Zn2As2 structure was refined on the basis of single-crystal X-ray diffractometer data: CaAl2Si2 type, P¯3m1, Z = 1, a = 417.17(6), c = 703.7(1) pm, wR2 = 0.0353, 211 F2 values, 11 variables, SOF(Ce) = 62.9(5) %. The zinc and arsenic atoms form a two-dimensional network of edge-sharing ZnAs4/4 tetrahedra with Zn-As distances of 253 pm. These covalently bonded [Zn2As2]2− layers are separated and charge-balanced by the cerium atoms. Each cerium atom has a slightly distorted octahedral arsenic coordination (Ce-As 302 pm). The defect type of the RE2/3Zn2As2 arsenides is discussed with respect to isotypic sulfides RE2/3Cu2S2.
Neue gemischte Zinn-reiche Erdalkalimetall-Stannide – Synthese, Strukturchemie und chemische Bindung / New Mixed Tin-rich Alkaline Earth Stannides – Synthesis, Structural Chemistry and Chemical Bonding
Authors: Wendorff Marco , Röhr Caroline
Published: February 2015

Ternary mixed Ca/Ba-Sr pentastannides AIISn5 (AII = Ca, Sr, Ba) have been synthesized from stoichiometric mixtures of the elements or from tin-rich melts. The crystal structures of two new compounds of overall composition ASn5 (A = Sr, Ba) were determined by means of single-crystal X-ray data. The structures of both Sr0.94Ba0.06Sn5 (monoclinic, space group C2/m, a = 1762.8(11), b = 704.1(3), c = 1986(2) pm, β = 100.31(6)º, Z = 14, R1 = 0.0996) and Sr0.89Ba0.11Sn5 (orthorhombic, space group Cmcm, a = 708.1(2), b = 1770.4(8), c = 2781.6(11) pm, Z = 20 , R1 = 0.0821) are closely related and can be described by different stacking sequences of comparable nets. They both resemble the structural features of the tristannides AIISn3 in forming dimers and trimers of facesharing Sn6-octahedra, which are further connected via common corners. According to the higher tin content, the rods formed of the octahedra are interspersed by additional Sn atoms, which themselves show a bonding situation resembling the structure of elementary tin. The complex tin network formed by the strong Sn-Sn bonds alone can be regarded as a cutout of the hexagonal diamond structure. In this view, the similarities of the title compounds to the known binary stannides BaSn5 and SrSn4 become apparent. The phase widths of the latter have been investigated and shown to reach up to Sr0.37Ba0.63Sn5 (BaSn5 type, hexagonal, space group P6/mmm, a = 536.8(2), c = 695.2(3) pm, R1 = 0.0312) and Sr0.79Ca0.21Sn4 (SrSn4 type, orthorhombic, space group Cmcm, a = 461.7(3), b = 1714.1(14), c = 706.7(4) pm, Z = 4, R1 = 0.0861), respectively. The total density of states calculated for the orthorhombic pentastannide within the FP-LAPW DFT band structure approach shows a broad minimum at the Fermi level, which can be explained using the Zintl and the Wade/Jemmis electron counting rules.