bluuebunny/crossref_metadata_2025 huggingface dataset:
Darstellung und Kristallstruktur von endo-2-Dimethylphospliono-exo-2-liydroxy-(—)-camphan zur Bestimmung von 3J(CCCP)-Vicinalkopplungen / Synthesis and Crystal Structure of endo-2-Dimethylphosphono-exo-2-hydroxy-(—)-camphane for the Determination of 3J(CCCP) Vicinal Coupling Constants
Authors: Adiwidjaja Gunadi , Meyer Bernd , Thiem Joachim
Published: August 2018

endo-2-Dimethylphosphono-exo-2-hydroxy-(-)-camphane (2) is prepared and the structure confirmed by X-ray data. The complete assignment of the 13C NMR spectrum of this conformationally rigid derivative leads to a Karplus-type function for the vicinal 3J(CCCP) coupling constant in α-hydroxy phosphonates.
Zur Struktur des Enols von Benzoylaceton / On the Structure of the Enol of Benzoylacetone
Authors: Winter W. , Zeller K.-P. , Berger S.
Published: August 2018

A low temperature X-ray study of the enol of benzoylacetone indicates fixed positions of the C and O atoms within the enolic ring system and an extensive bond delocalisation over these atoms. The distribution of electron density between the two oxygen atoms shows that the enolic hydrogen is spread over a wide range. This is in accordance with a structural model proposed by de la Vega, whereupon the C and O atoms are kept fixed in their average positions during a tunneling process of the hydrogen between the two oxygen atoms. With this conception, the chemical shifts in the 17O and 13C NMR spectra, the 13C13C spin coupling constants and the temperature independance of these values can be explained.
Complexes of 1,2,4-Triazoles, Part XVI Binuclear Complexes of Transition Metal(II)thiocyanates with 4-Ethyl-1,2,4-triazole
Authors: Vos Ger , Haasnoot Jaap G. , Groeneveld Willem L.
Published: August 2018

Coordination compounds of 4-ethyl-1,2,4-triazole (Ettrz) with Mn, Fe, Co, Ni, Cu and Zn are reported. The compounds have been identified and characterized by chemical analyses, infrared and ligand field spectra, electron paramagnetic resonance (e.p.r.) measurements, magnetic susceptibility measurements and thermoanalytical experiments. Except for the Cu compound, which is polynuclear, all compounds appear to be binuclear, with both bridging bidentate and non-bridging triazole ligands. The overall formula is M(Ettrz)2(NCS)2(H2O)3/2 for Mn, Fe, Co and Ni. The copper and zinc compounds have the formula Cu(Ettrz)2(NCS)2 and Zn(Ettrz)3/2(NCS)2.
Zur Verbindungsbildung von MeO :M2O3· V Neue metastabile Verbindungen: BaSr2Y6O12, BaSr2Er6O12 und BaSr2Tm6O12/ About Compounds in Systems MeO:M2CO3· V New Metastable Compounds: BaSr2Y6O12, BaSr2Er6O12 and BaSr2Tm6O12
Authors: Schulze A.-R. , Müller-Buschbaum Hk.
Published: August 2018

The new metastable compounds BaSr2Y6O12 (I), BaSr2Er6O12 (II) and BaSr2Tm6O12 (III) could be prepared with high temperature reactions (CO2-Laser). The X-ray single crystal investigations lead to hexagonal symmetry, space group Ch-P2
6h-P63/m; lattice constants:

I: a= 1029.9 c = 340.9 pm

II: a = 1027.7 c = 338.5 pm

III: a = 1021.5 c = 337.6 pm

The crystal structure the formation of the compounds and the range of stability are discussed.
Reaktionen von Übergangsmetall-Verbindungen mit primären Aminen und Schwefelkohlenstoff: Dithiocarbimato- und Dithiocarbamato-Komplexe von Palladium, Platin, Nickel, Cobalt und Gold. Röntgenstruktur von (Et3P)2MS2CNCH2Ph (M = Pd, Pt) / Reactions of Transition Metal Compounds with Primary Amines and Carbon Disulfide: Dithiocarbimato and Dithiocarbamato Complexes of Palladium, Platinum, Nickel, Cobalt and Gold. X-Ray Structure of (Et3P)2MS2CNCH2Ph (M = Pd, Pt)
Authors: Schierl Rudolf , Nagel Ulrich , Beck Wolfgang
Published: August 2018

A series of dithiocarbimato complexes (R3P)2M(S2CNR′) (1, 2) has been obtained by reaction of (R3P)2MCl2 (M = Pd, Pt) with primary amines and carbon disulfide. The dithiocarbimato complexes 1 and 2 can be reversibly protonated to give the dithiocarbamato compounds (R3P)2M[S2CN(H)R′]+Cl-.

The X-ray structures of the dithiocarbimato complexes (Et3P)2M (S2CNCH2Ph) (M = Pd, Pt) have been determined and the spectroscopic data (IR, 1H-, 13C-, 31P-, 195Pt-NMR) of the complexes are reported. The dithiocarbamato complexes (Ph3P)2M[S2CN(H)CH2Ph]Cl (M = Co, Ni). Ph3PAuS2CN(H)CH2Ph, Cl2Pt[S2CN(H)CH2Ph)2 are formed from the corresponding chloro compounds, primary amine and CS2
Gasphasen-Reaktionen, 71 PE-Spektren und Pyrolysen stickstoffreicher Kohlenstoff-Verbindungen: CN4, C2N4, C2H2N4, C4H6N4 und C5H4N4 Gasphase Reactions, 72 PE Spectra and Pyrolyses of Nitrogen-Rich Carbon Compounds: CN4, C2N4, C2H2N4, C4H6N4 and C5H4N4
Authors: Bock Hans , Dammel Ralph
Published: August 2018

The PE spectra of the nitrogen-rich title compounds cyanogen azide NC-N3, azodicarbonitrile

NC - N = N - CN, azidoacetonitrile NC - H2C - N3, tetrazolo[1,5-a]pyridine (H4C5N)(N )3 and

trimethylenetetrazole (H2C)3(CN4) are presented and assigned by radical cation state comparison

with related compounds or by Koopmans’ correlation with MNDO eigenvalues. In a low pressure

flow system the compounds decompose at higher temperatures, with elimination of the thermodynamically

favorable N2 molecule. PE-spectroscopic real-time analysis reveals as further products:

NC - N3 → C∞, NC - N = N - CN → NC - CN , NC - H2C - N3 → 2HCN (+ traces NC - HC = NH?)

and (H2C)3(CN4) → H2C = N - CN + H2C = CH2. For tetrazolo[1,5-a]pyridine, a preceding ring

opening to the corresponding 2-azidopyridine is observed.
Ligand Substitution Reactions of the Nickel-Sulphur Cluster [Ni3(μ3-S)2(PEt3)6]2+. X-Ray Crystal Structure of [Ni3(μ3-S)2(PEt3)2(S2CNEt2)2]
Authors: Cecconi Franco , Ghilardi Carlo A. , Midollini Stefano , Orlandini Annabella
Published: August 2018

Compounds of the type [Ni3S2(PR3)6]X2 (R = Me, Et; X = BPh4, ClO4) react with dithiocarbamate and diphosphine ligands to yield products [Ni3S2(PEt3)2(S2CNEt2)2] (1), [Ni3S2(PMe3)2(S2CNEt2)2] (2), and [Ni3S2(PMe3)2(dppe)2][BPh4]2 (3). The molecular structure of 1 has been established by single crystal X-ray diffraction. Space group C2/c, a = 25.137(3), b = 9.084(1), c = 18.333(2) Å, β = 123.41(2)°, Ζ = 4, 1128 observed unique reflections, R = 0.041. The inner core of 1 consists of a triangle of nickel atoms capped by two triply bridging sulphur ligands.
Synthese von 5-Methylthio-2-thioxo-1,3-dithiol-4-carbonsäureamiden und -thiolestern, 3-Alkyl-5-bis(alkylthio)methylen-2-thioxo-1,3-thiazol-4(5 H)-onen sowie Röntgenkristallstrukturanalyse des 5-Methylthio-2-thioxo-1,3-dithiol-4-carbonsäure-(N-methyl-anilids) / Synthesis of 5-Methylthio-2-thioxo-1,3-dithiole-4-carboxamides and -thiolesters, 3-Alkyl-5-bis(alkylthio)methylene-2-thioxo-1,3-thiazole-4(5 H)-ones, and X-ray Analysis of 5-Methylthio-2-thioxo-1,3-dithiole-4-carboxyl N-methyl-anilide
Authors: Dölling Wolfgang , Friedemann Kerstin , Heinemann Frank , Hartung Helmut
Published: August 2018

5-Methylthio-2-thioxo-1,3-dithiole-4-carboxamides (2a–e), the methyl 5-methylthio-2-thioxo-1,3-dithiole-4-carboxythiolate (9), and 3-alkyl-5-bis(alkylthio)methylene-2-thioxo-1,3-thiazole-4(5 H)-ones (4a–f) are obtained by reaction of the corresponding N-substituted ethylxanthogen-acetamides (1, 3, 6) with carbon disulfide under basic conditions followed by alkylation.

5-Methylthio-2-thioxo-1,3-dithiole-4-carboxyl N-methyl-anilide (2d) was characterized by an X-ray crystal structure determination (space group P 1̄, a = 877.3(1), b = 1111.1(2), c = 837.6(1) pm, α = 104.22(2), β = 110.41(1), γ = 69.64(2)°, Ζ = 2, R = 0.039 for 1746 observed unique reflections).

The α-oxoketene dithioacetal moiety of the molecule exhibits a noticeable derivation from planarity by a twist of the carbonyl group out of the ethylene plane and shows a short intramolecular S ··· O contact of 277.1 (3) pm.
Notizen: Synthese und Charakterisierung von 3 H-2,1,3-Thiaselenaborolen und eines Carbimino-1,3,2-selenazaborins / Synthesis and Characterization of 3 H-2,1,3-Thiaselenaboroles and a Carbimino-1,3,2-selenazaborine
Authors: Habben Carl D.
Published: August 2018

The reaction of 1,2,3-diselenaboroles with N–thiosulfinyl-tert-butylamine leads to the 2,1,3-thiaselenaboroles 2 a, b. By insertion of di-iso-propylcarbodiimide the novel six-membered ring 3 is formed. NMR (1H, 11B, 13C) and mass spectra are reported and discussed.
Molekül- und Kristallstrukturen zweier einkerniger Ruthenium(II)-Komplexe mit dem starken π·Akzeptorliganden 2,2'-Azobis(pyridin) (abpy): [mer-Ru(abpy)3](PF6)2 und Ru(abpy)2Cl2 (ctc-Isomer) / Molecular and Crystal Structures of Two Mononuclear Ruthenium(II) Complexes with the Strongly π Accepting Ligand 2,2'-Azobis(pyridine) (abpy): [mer-Ru(abpy)3](PF6)2 and Ru(abpy)2Cl2 (ctc Isomer)
Authors: Fees Jörg , Hausen H.-D. , Kaim Wolfgang
Published: August 2018

Crystal structure analyses of the title complexes have been carried out in order to establish their molecular configurations. The tris(chelate) complex dication in (1)(PF6)2 exhibits a mer configuration of pyridine and azo nitrogen atoms in an approximately octahedral arrangement at the metal. The dichlororuthenium bis(chelate) compound 2 has the halide ligands and the coordinated azo nitrogen centers in an equatorial cis arrangement whereas two pyridyl groups (one of each abpy ligand) occupy the axial positions. The bond distances from the metal to the nitrogen donor centers are systematically smaller for the stronger π accepting azo functions than for the more basic but less π acidic pyridyl groups, a result which differs from that obtained for Mo(0) and Cu(I) complexes of abpy. All Ru—N distances are shorter in the neutral dichloro complex 2. The non-coordinated pyridyl rings of the potentially tetradentate abpy ligands are tilted into approximate s-cis/(NN-trans)/s-trans positions (dihedral angle ω ≈ 145°) as to minimize steric repulsion, however, they do not coordinate to the metal (dRu-N > 327 pm). While there are no significant intermolecular interactions, the observed conformation implies that considerable structural reorganization is necessary for the formation of oligonuclear complexes.
K34[Zn20In85]: Eine ternäre Auffüllungsvariante des β-rhomboedrischen Bors / K34[Zn20In85]: A Ternary Filled Variant of β-Rhombohedral Boron
Authors: Cordier Gerhard , Müller Volker
Published: August 2018

In the crystal structure of K34[Zn20In85] (a = 1827.7(5) pm, c = 3980.5(8) pm, R3̅m, Nr. 166, Z = 3, R1 = 0.056, wR2 = 0.124) the In and Zn atoms form the β-rhombohedral boron structure. The structure contains In84 Samson polyhedra, and clusters of 18 In and 10 Zn atoms, forming three In12 icosahedra sharing two common triangular faces. The potassium atoms occupy the centres of truncated tetrahedra – forming the Samson polyhedra – and Kasper polyhedra.
Eine synthetische Spezies zum Mineral Howardevansit mit Eisen anstelle von Kupfer: NaFe3V3O12 / A Synthetic Species of the Mineral Howardevansite with Copper Displacing Iron: NaFe3V3O12
Authors: Martin F.-D. , Müller-Buschbaum Hk.
Published: August 2018

Single crystals of NaFe3V3O12 have been prepared by solid state reaction below the melting point of the reaction mixture. This compound is isotypic to the mineral Howardevansite but shows lower triclinic symmetry, space group C1
1–P1, a = 6.757(2), b = 8.155(2), c = 9.816(3) Å, α = 106.05(2), β = 104.401(9), γ = 102.09(2)°, Z = 2. The acentric space group is caused by the sodium positions, all other atoms comply with the space group P̄ of Howardevansite. The different ions are coordinated by O2- forming VO4 tetrahedra, FeO6 octahedra, trigonal FeO5 bipyramids and irregular NaO5 and NaO7 polyhedra, respectively. The crystal chemistry is discussed with respect to Howardevansite.
Synthese und Röntgenstrukturanalyse von Ba4LiCuO4(CO3)2 / Synthesis and X-Ray Analysis of Ba4LiCuO4(CO3)2
Authors: Tams G. , Müller-Buschbaum Hk.
Published: August 2018

Single crystals of Ba4LiCuO4(CO3)2 have been prepared by CO2—LASER technique and investigated by single crystal X-ray diffraction. The compound crystallizes in the tetragonal space group D11
2d—I4̄2m (No. 121), a = 5.767(1), c = 15.2614(7) Å, Z = 2. It is isotypic with Ba4NaCuO4(CO3)2 and shows Li+ with octahedral and Cu3+ with square planar coordination by O2-. The crystal structure are discussed with respect to the related compounds Ba4NaAuO4(O2)2 and Ba4KAuO4(C2)2.
Preparation and Crystal Structure Determination of [(C2Η5)4N]2Hg3Cl8
Authors: Pabst Inge , Sondergeld Peter , Czjzek Mirjam , Fuess Hartmut
Published: August 2018

The title compound has been prepared in two different ways: First, by boiling single crystals of [(C2H5)4N]HgCl3 in a mixture of n-hexane/n-octane [4:1] at T = 350 K, and second, in a synthesis from stoichiometric quantities of the components. X-ray structure analysis gave the stoichiometry [(C2H5)4N]2Hg3Cl8, monoclinic, space group P21, a = 7.538(3), b = 19.909(6), c = 10.274(3) Å, β = 95.13(1)°, V = 1535.7(9) A3, Z = 2. The basic [Hg3Cl8]2--units form broken zig-zag chains along [100]. The Hg–Cl distances within the [Hg3Cl8]2- clusters range from 2.315(3) to 2.755(4) Å. This is a new coordination type for halomercurates.
Strukturuntersuchungen an Perchlortriazaphosphininen (ClCN)n(Cl2PN)3-n
Authors: Chen Shan-Jia , Brychcy Klaus , Behrens Ulrich , Stohrer Wolf-Dieter , Mews Rüdiger
Published: August 2018

The crystal structures of (ClCN)2(Cl2PN) (1) and (ClCN)(Cl2PN)2 (2) are reported. A general bonding model for heterotriazines (XCN)n(XAN)3-n (X = 2, 1) is discussed.
The Crystal Structures of Et2Sn(O2PMe2)2 and Ph2Sn(O2PMe2)2; Synthesis and Spectral Studies of Ph2Sn(O2PMe2)2
Authors: Shihada Abdel-Fattah , Weller Frank
Published: August 2018

Ph2Sn(O2PMe2)2 has been synthesized by the reaction of HO2PMe2 with Ph2SnO in toluene or by treating HO2PMe2 with Ph2SnCl2 in methanol. X-ray diffraction studies of Et2Sn(O2PMe2)2 and Ph2Sn(O2PMe2)2 show that the O2PMe2 ligands function as bidentate bridges between the tin atoms. The ethyl and the phenyl groups are in trans-position in the resulting octahedral environment around tin. Et2Sn(O2PMe2)2 crystallizes in the monoclinic space group P21/n (a = 817.11(9), b = 974.1(1), c = 970.1(1) pm, β = 113.749(6)°, Z = 2 and R = 0.032) and con­sists of a polymeric layer structure with centrosymmetric (SnOPO)4 sixteen-membered rings. Ph2Sn(O2PMe2)2 also crystallizes monoclinically in the space group P21/n (a= 1060.9(1), b = 999.4 (1), c = 1768.9(2) pm, β = 90.93(1)°, Z = 4 and R = 0.057) and has a polymeric ring-chain structure with centrosymmetric (SnOPO)2 eight-membered rings. The IR and Raman spectra of Ph2Sn(O2PMe2)2 have been assigned and discussed in the light of structural information. The Sn(O2PMe2)+ ion represents the base peak in the mass spectrum of Ph2Sn(O2Me2)2.
Substituierte 1,2,4-Thiadiazolium-dichloroaurate(I) und -tetra- chloroaurate(III) als Reaktionsprodukte von N-Thiocarbamoyl- benzamidinen mit TetrachIorogold(III)-Verbindungen / Substituted 1,2,4-Thiadiazolium dichloroaurates(I) and -tetrachloroaurates(III) as Products o f the Reaction o f N -Thiocarbam oyl-benzamidines with Tetrachlorogold(III) Compounds
Authors: Schröder Uwe , Richter Rainer , Hartung Jürgen , Abram Ulrich , Beyer Lothar
Published: August 2018

The reactions of N-diethylaminothiocarbonyl-benzamidines Et2N-C(S)-N=C(NHR)-Ph (1: R = Ph, 2: R = C3H7, 3: R = H) with gold(III) compounds were studied. Treatment of 1 and 2 with equivalent amounts of tetrachlorogold acid gives 2,3-substituted 5-diethylamino-1,2,4- thiadiazoliumdichloroaurates(I) (1a, 2a). With tetrachlorogold acid in excess 1 yields 2,3-diphenyl- 5-diethylamino-l,2,4-thiadiazolium-tetrachloroaurate(III) 1b. With 3 and Na[AuCl4] bis(3-phenyl-5- diethylamino-1,2,4-thiadiazolium)-chloride-tetrachloroaurate(III) 3b is produced. The structures of la, 2a and 3b were investigated by X-ray structure analysis. In la and 2a the dichloroaurate(I) ions are linear. In the 1,2,4-thiadiazolium cations the N-C-bond lengths alternate characteristically. In 3b the tetrachloroaurate(III) ion is square planar. The 1,2,4-thiadiazolium cation shows a different alternation of N-C bond lengths in comparison with la and 2a which suggests changes in the thiadiazolium ring in 3b to a tautomeric form as confirmed by the localization of the H atom at the N atom in ring position 4 instead of ring position 2. The structures of 1a, 1b, 2a and 3b were confirmed by elemental analysis, ES-MS, FAB-MS, 1H and 13C NMR and IR spectroscopy.
Übergangsmetall-substituierte Acylphosphane und Phosphaalkene, XXXIY [1] Methylendiyl(thioxo)- und MethyIendiyl(selenoxo)-λ5,σ3-phosphorane als μ-Liganden in [(η5-C5H5)2Fe2(CO)3]-Komplexen. Synthese und Struktur von / Transition Metal Substituted Acylphosphanes and Phosphaalkenes, XXXIV [1] Methylenediyl(thioxo)- and M ethylenediyl(selenoxo)-λ5 ,σ3-phosphoranes as μ-Ligands in [(η5-C5H5)2Fe2(CO)3] Complexes. Synthesis and Structure of
Authors: Weber Lothar , Schumann Iris , Scheffer Matthias H. , Stammler Hans-Georg , Neumann Beate
Published: August 2018

The isophosphaalkyne complex (η5-C5H5)2(CO)2Fe2 (μ-CO)(μ-C=PMes) (2a) was converted into the methylenediyl(thioxo)- and methylenediyl(selenoxo)- λ5, σ3-phosphorane complexes (η5-C5H5)2(CO)2Fe2(μ-CO)(μ-C=P(E)Mes) (5a: E = S; 5b E = Se) by oxidation with sulfur or selenium . Reaction of the μ-carbyne complex [(μ75-C5H5)2(CO)2Fe2(μ-CO)(μ- CSMe)]+SO3CF3 (1) with tBuP(H)SiMe3 in the presence of DBU afforded the μ-phosphinocarbyne complex (η5-C5H5)2(CO)2Fe2

(μ-CP(H)tBu] (μ -SMe] (12). μ-Carbene complex

(11) was isolated as an initial product of this conversion and fully characterized by single crystal X-ray analysis.
Introduction of Functional Silyl Groups into Tris(dialkylamino)phosphonium Methylides
Authors: Dreihäupl Karl-Heinz , Schmidbaur Hubert
Published: August 2018

Starting from tris(dialkylamino)phosphonium methylides(R2N)3PCH2 [1a: R = Me; 1b: R = Et] a series of silylated ylides with functional groups at the silicon substituents have been prepared (2 - 8 ). In the general formula X3Si-CH = P(NR2)3 the group SiX 3 represents examples for X = Me, Cl, Br, OMe, iPrO, NMe2, but also for X3 = PhH2 , etc. The compounds are prepared either via the transylidation reaction of 1a, b with reaction components X3SiY [Y = Cl, OTf], or through action of a base on the corresponding silylated phosphonium salts, following methods of preparation for non-functional silylated ylides. Bis(ylides) (9 - 12) are available along the same sequence of reactions, but employing difunctional silanes X2SiY2. Products of the type X2Si[CH = P(NR2)3]2 were investigated with X = Me, OMe, OEt, and NMe2. All ylides are thermally stable, distillable liquids, which have been identified via conventional spectroscopic methods. The ylides are versatile synthons in trans-silylation, trans-ylidation, and de-silylation reactions.
Notizen: Synthese und Strukturuntersuchungen von Iodocupraten(I), XVIII. Darstellung und Kristallstruktur von PbCu2I4 ·2CH3CN/Synthesis and Structure Investigations of Iodocuprates(I), XVIII. Preparation and Crystal Structure of PbCu2I4 · 2CH3CN
Authors: Hartl Hans , Hoyer Michael
Published: August 2018

Single crystals of PbCu2I4·2(CH3CN) are formed by reaction of Pbl2 with Cul in acetonitril. The compound crystallizes in the mono­clinic space group C2/m; a = 1625.8(3), b = 436.6(1), c = 1025.8(2)pm; β = 94.77(3)°; V = 725.7 pm3 106; Z = 2. The crystal structure is built up by chains of trans-edge sharing 1
∞[PbI6/3] octahedra and corner sharing 1
∞[CuI3/3CH3CN)] tetra­hedra connected by common I-I edges.
Chlormethylchlorphosphane mit sperrigen Substituenten -Synthese und reduktive Enthalogenierung mit Fe2(CO)9 / Bulky Chloromethylchlorophosphines -Syntheses and Reductive Dehalogenation with Fe2 (CO)9
Authors: Fischer Jörg , Machnitzki Peter , Stelzer Othmar
Published: August 2018

Chloromethylchlorophosphines R(Cl)P-CH2-Cl (R = C6H11, sec-C4H9, 2,4,6-R′3C6H2; R′ = tBu, iPr) with bulky substituents (1a - 1d) have been prepared by treatment of Cl2P-CH2-Cl with organolithium compounds RLi (R = 2,4,6-R′3C6H2) or Grignard reagents RMgX (R = C6H11, sec-C4H9). For the less bulky phenyl derivative Ph(Cl)P-CH2-Cl (1i) a protected group two stage synthesis has been developed employing Et2N(Cl)P-CH2-Cl as an intermediate. Si-N cleavage reactions between Cl2P-CH2-Cl and R2N-SiMe3 or nucleophilic substitution with Ph2NH yield the amino derivatives R′2N(Cl)P-CH2-Cl (R′ = Ph, Et, iPr) (1e, 1g, 1h). The chloromethylbromophosphines R(Br)P-CH2-Cl (R = Br, C6H11) have been obtained by halogen exchange in 1 and 1a with MgBr2 etherate. 1a, 1e, 1g and 1h exist preferably in an antiperiplanar conformation with respect to the P-C(H2) bond as inferred from the analysis of the 1H(CH2)-NMR spectra. Temperature dependent 1H and 13C {1H} NMR spectra indicate restricted rotational processes in 1h. On reaction of 2a with Fe2(CO)9 the η2,μ3-phosphaalkene cluster 3 is obtained, while with 2b (R = 2,4,6-iPr3C6H2) the μ3-phosphinidene cluster 4 is formed. Reductive dehalogenation of 1c (R = 2,4,6-tBu3C6H2) affords the phosphaalkene complex 6 in addition to the 2,3-dihydrobenzo[b]phosphole complex 5. Treatment of the iron carbonyl complex 7c with Fe2(CO)9 in a 1:1 molar ratio at elevated temperatures leads to a novel μ2-phosphido complex 7b with an ortho-metallated Ph2N substituent.
Synthesis and Crystal Structure of a Caesium Hydrogen Benzoylcyanoximate Complex with 18-Crown-6: Cs(18-Crown-6){H(L)2}
Authors: Ponomareva Vera V , Skopenko Victor V , Domasevitch Konstantin V , Sieler Joachim , Gelbrich Thomas
Published: August 2018

The caesium hydrogen benzoylcyanoximate (L-) complex with 18-crown-6 of composition Cs(18-crown-6){H(L)2} has been prepared and studied by means of X-ray diffraction [monoclinic, space group P21/n, with a = 9.906(1), b = 18.387(3), c = 18.855(3)Å, β = 90.13(1)°, V = 3434.3(9) Å, Z = 4; final R1 = 0.043 for the 6431 independent reflections used. The lattice consists of Cs(18-crown-6)+ cations and complex hydrogen oximate anions {H(L)2}-, formed via strong hydrogen bonding between the oxygen atoms of nitroso-groups [O - - - O ca. 2.456(5)Å]. The caesium atom deviates by 1.492(3) Å from the mean plane of the oxygen atoms of the macrocyclic ether (dominant orientation of disordered ligand, 60%) and adopts a typical “sunrise coordination” [Cs-O (ether) 3.040(9)-3.312(7) Å]. The hydrogen oximate groups are bonded to the metal center only on one side of the crown ether plane via the oxygen atoms of nitroso-groups and the nitrogen atoms of cyano groups (Cs-O ca. 3.040(9), 3.312(7) Å; Cs-N ca. 3.469(5), 3.679(6) Å). The coordination polyhedron of Cs+ can be described as a distorted bicapped tetragonal prism.
A New Method for the Preparation of Ifosfamide and Cyclophosphamide
Authors: Neda I , Sonnenburg R , Schmutzler R , Niemeyer U , Kutscher B , Engel J , Kleemann A
Published: August 2018

The reaction of 2-chloro-3-(2-chloroethyl)-tetrahydro-2H-1,3,2-oxazaphosphorin-2-oxide 1 and 2-chloro-tetrahydro-2H-1,3,2-oxazaphosphorin-2-oxide 2 with 2-(trimethylsilyloxy)ethylamine 3 and bis-[2-(trimethylsiloxy)ethyl]amine 4, respectively, yielded the trimethylsilylated compounds 5 and 6, analogous to ifosfamide and cyclophosphamide. The reaction of 5 and 6 with 2-chloro-1,3,5-trimethyl-1,3,5-triaza-2-phosphorin-4,6-dione 7 led to the diphosphorus compounds 8 and 9 which could be transformed to ifosfamide 11 and cyclophosphamide 12 by treatment with sulfuryl chloride. This synthesis shows that the alkylating agents 2- chloroethylammonium chloride and bis-(2-chloroethyl)ammonium chloride can be avoided and the chlorine atom can be introduced in the final reaction step of the synthesis of 11 and 12.
Synthesis and Crystal Structure of Tetraphenylarsonium Pentachlorocarbonylosmate(IV), (Ph4As)[OsCl5(CO)]
Authors: Höhling M , Preetz W
Published: August 2018

The structure of tetraphenylarsonium pentachlorocarbonylosmate(IV), (Ph4As)[OsCl5(CO)], the first example of a halogenocarbonyl complex with osmium in the oxidation state +IV, has been determined at 208 K by single crystal X-ray diffraction: tetragonal, space group P4/n with a = 12.821 , c = 8.084 Å, Z = 2. There are short intermolecular contacts between neighbouring anions along the tetragonal axis c and unusually large displacement ellipsoids of the carbonyl group and the four equatorial Cl ligands arising from a positional disorder of the complex anion. By analogy with a variety of reported structures of the (Ph4As)[RuNCl4] structure type this is attributed to the close packing of the cation sublattice. Compared to other monocarbonylosmates the Os-C bond of 1.94(2) Å is extraordinaryly long while the bond between Os and the trans coordinated Cl ligand of 2.286(3) Å is rather short.
Crystal Structure and Conformation of 2-{(2′-Aminobenzyl)iminoethyl}- 5-methoxyphenol
Authors: Dey D. K. , Dey S. P. , Elmali A. , Elerman Y.
Published: August 2018

The Schiff base, 2-{(2′-aminobenzyl)iminoethyl}-5-methoxyphenol, 1,2 -C6H4[NH2-2 ʹ]-CH2N=CHC6H3(OMe-5)OH (I), has been prepared by the reaction of 2 -amino-1-benzylamine and 2-hydroxy-4-methoxyacetophenone in methanol. The molecular structure has been con­firmed by single crystal X-ray crystallography (triclinic, space group P 1̄, a = 7.201(2), b = 9.802(2), c = 9.993(2) Å, α = 83.09(2), β = 73.49(2), γ = 84.09(2)°, R = 0.0415 for 2611 independent reflections). The 1H and 13C NMR spectra in CDCI3 solution indicate the forma­tion of some other minor conformations or dissociation in solution. The title compoundois not planar. Intramolecular hydrogen bonding occurs between O(1) and N(1) atoms [2.528(2) Å], the hydrogen atom essentially being bonded to the nitrogen atom. Minimum energy conformations from AMI were calculated as a function of four torsion angles. The optimized geometry of the molecular structure corresponding to the non-planar conformation is the most stable conformation in all calculations. The results strongly indicate that the minimum energy conformation is primarily determined by non-bonded hydrogen-hydrogen repulsions.
The Chemical Evolution of a Nitrogenase Model, XXIII. The Nature of the Active Site and the Role of Homocitric Acid in MoFe-Nitrogenase
Authors: Palmer John G. , Doemeny Paul A. , Schrauzer Gerhard N.
Published: August 2018

The iron-molybdenum cofactor (FeMo-co) of bacterial nitrogenase is a heterometallic cluster of composition MoFe7S9 that is attached to the apoprotein by a coordinative Mo-N bond to the imidazole group of hisα442, and by a Fe-S bond to cysα215. The molybdenum atom of FeMo-co in the enzyme in addition is coordinated to one molecule of homocitrate (hc), which is required for maximal N2 reducing activity. The molybdenum atom in the enzyme-bound FeMo-co thus is hexacoordinated and cannot react with substrates unless free coordination sites are made available. It is proposed that the reactions of the substrates o f nitrogenase occur at a molybdenum active site consisting of a mononuclear molybdenum homocitrate complex attached to hisα442 of the apoprotein that in the functional enzyme is generated from FeMo-co by a reversible, redox-linked dissociation of the Fe7S9-cys cluster. Studies with catalytic model systems consisting of complexes of molybdenum with imidazole and hydroxocarboxylate ligands support this proposal and provide a rationale for the specific activating effect of homocitrate in nitrogenase.
New Dinuclear Transition Metal Complexes with the [M2(μ-dhbq)]n+ Core and 2-(2′-Pyridyl)quinoxaline (L) as a Terminal Ligand: Preparation and Characterization (dhbq2-= the Dianion of 2,5-Dihydroxy -1,4- benzoquinone; M = AgI, MnII, CoII, NiII, CuII, RuII, PdII, FeIII, RhIII; n = 0, 2, 4)
Authors: Mostafa Sahar I. , Perlepes Spyros P. , Hadjiliadis Nick
Published: August 2018

Synthetic procedures are described that allow access to the new complexes [Mn2(dhbq)L2(H2O)4 (1), [Fe2(dhbq)L2(H2O)4](NO3)4 · 6H2O (2), [Co2(dhbq)Cl2L2(H2O)2] (3), [Ni2(dhbq)Cl2L2(H2O)2] (4), [Cu2(dhbq)Cl2L2(H2O)2] (5), [Ru2(dhbq)L2(H2O)4](ClO4)2 (6), [Rh2(dhbq)Cl2L2(H2O)2]Cl2·2H2O (7), [Pd2(dhbq)L2]Cl2·5H2O (8) and [Ag2(dhbq)L2] (9), where dhbq2- is the dianion of 2,5-dihydroxy-1,4-benzoquinone and L is the biheteroaromatic ligand 2-(2′-pyridyl)quinoxaline. The new complexes were characterized by elemental analyses and by a variety of physical and spectroscopic techniques. Dinuclear structures are assigned for the complexes in the solid state. The two metal ions are bridged by the bischelating dhbq2- ion, while L behaves as a bidentate chelate with the 2′-pyridyl nitrogen and the nearest quinoxaline nitrogen atom as the ligand atoms. The metal ion coordination geometries are octahedral, tetrahedral or square planar.
peri-Interactions in Naphthalenes, 6 [1]. On Hypercoordination of Phosphorus in 8-Dialkylamino-naphth-1-yl Phosphonium Salts
Authors: Schiemenza Günter Paulus , Pörksen Simon , Dominiak Paulina M. , Wozniak Krzysztof
Published: August 2018

Under favourable conditions, the phosphorus centres in tetraorganophosphonium cations are sufficiently electrophilic to become hypercoordinate by reaction with strong nucleophiles. However, as a peri substituent at the naphthalene system, such a centre proved to be unable to induce the nitrogen of a peri-bound dialkylamino group to bond formation. The distortion of the naphthalene skeleton revealed by X-ray structure determination of four 8-dialkylaminonaphth- 1-yl phosphonium salts does not exhibit the criteria of N-P bond formation but rather those of intersubstituent repulsion.
Synthesis, Properties and Dimerization Study of Isocyanic Acid
Authors: Fischer Gerd , Geith Janna , Klapötke Thomas M. , Krumm Burkhard
Published: August 2018

Isocyanic acid was prepared in pure form by reaction of KOCN or NaOCN with stearic or oxalic acid in good yield. Identification, characterization and investigation of the thermal stability of HNCO and evidence for a possible existence of “dicyanic acid” have been studied in gas phase, liquid and solid state by vibrational and NMR spectroscopy and mass spectrometry.
Polysulfonylamine, CL [1]. Wasserstoffbrücken in kristallinen Oniumdimesylamiden: Ein robustes Achtring-Synthon in den Strukturen von Methyluronium- und 1,1-Dimethyluronium-dimesylamid./Polysulfonylamines, CL [1]. Hydrogen Bonding in Crystalline Onium Dimesylamides: A Robust Eight-Membered Ring Synthon in the Structures of Methyluronium and 1,1-Dimethyluronium Dimesylamide
Authors: Henschel Dagmar , Hamann Thomas , Moers Oliver , Blaschette Armand , Jones Peter G.
Published: August 2018

Methyluronium dimesylamide (1) and 1,1-dimethyluronium dimesylamide (2) have been prepared by proton transfer reactions of the strong nitrogen acid HN(SO2Me)2 with the corresponding ureas and characterized by low-temperature X-ray diffraction (1: orthorhombic, space group P212121, Z′ = 1; 2: orthorhombic, Pna21, Z′ = 2). Compound 2 appears to be the first crystallographically established 1,1-dimethyluronium salt. As a common feature, the three independent formula units consist of ion pairs held together by an eight-membered ring synthon [N2 = R2
2(8), antidromic] constructed from a syn,syn-sequence H-O-C(sp2)-N-H ofthe cation and a V-shaped O-S(sp3)-N fragment of the anion via homonuclear two-centre hydrogen bonds. The surplus N-H donors form hydrogen bonds to O=S acceptors in adjacent formula units, leading to a three-dimensional network (1) or a pseudo-21 symmetric helical catemer ofalternatingly inequivalent formula units (2). In both structures, the activated methyl groups give rise to numerous short interionic C-H···O contacts, the more prominent of which are analyzed in terms ofweak hydrogen bonding [cut-off criteria: d(H···O) ≤ 270 pm, θ(C-H···O) ≥130°].
Crystal and Molecular Structure of 1,2,4-Triazolium Chloride and its Salt with Antimony Trichloride - Bis(1,2,4-triazolium) pentachloroantimonate(III)-1,2,4-triazolium Chloride
Authors: Bujak Maciej , Zaleski Jacek
Published: August 2018

The structures of 1,2,4-triazolium chloride (C2H4N3)Cl and its derivative with antimony trichloride - (C2H4N3)2[SbCl5] · (C2H4N3)Cl containing unsubstituted 1,2,4-triazolium cations were determined. (C2H4N3)Cl crystallizes in the monoclinic system, space group P21/n with the unit cell dimensions at 86 K: a = 9.425(2), b = 8.557(2), c = 11.158(2)Å , β = 95.87(3)°; V = 895.2(3)Å3, Z=8, dc = 1.566, dm = 1.56(2) g·cm-3.At roomtemperature, crystals of (C2H4N3)2- [SbCl5] · (C2H4N3)Cl are orthorhombic, space group P212121, a = 8.318(2), b = 11.381(2), c = 19.931(4) Å, V = 1886.8(7) Å3, Z = 4, dc = 1.917, dm = 1.91(2) g·cm-3. In both crystals the 1,2,4-triazole rings are planar. The anionic sublattice of (C2H4N3)2[SbCl5]·(C2H4N3)Cl consists of polymeric [SbCl5]n
2- zig-zag chains composed of distorted [SbCl6]3- octahedra connected via their vertices and the single Cl- anions. The cavities between the inorganic chains are filled by 1,2,4-triazolium cations. The nature of the distortion of the [SbCl6]3- polyhedra has been studied by examining correlations between the Sb-Cl bond lengths and the strength of hydrogen bonds, which join the anionic sublattice and the organic cations. This study confirms that the deformation of the [SbCl6]3- octahedra is caused by hydrogen bonds.
The Molecular Structures of the Three Disilylbenzenes Determined in the Gas Phase, the Solid State and by ab initio Calculations
Authors: Mitzel Norbert W. , Brain Paul T. , Hofmann Michael A. , Rankin David W. H. , Schröck Robert , Schmidbaur Hubert
Published: August 2018

The molecular structures of four silylbenzenes (benzenes with H3Si-substituents), viz. silylbenzene, 1,2-, 1,3- and 1,4-disilylbenzene, were studied by electron diffraction in the gas phase and by ab initio calculations. The structures of 1,2- and 1,4-disilylbenzene were also determined by X-ray diffraction experiments on single crystals grown in situ. The results are compared and discussed with the focus on the evaluation of the SARACEN method for the analysis of gas-phase data, and particularly on its ability to deal with small structural distortions. Important experimental structural parameters are the Si-C bond lengths [Å] and the ipso C-C-C angles [deg], which are 1.863(3) / 118.2(2) for gaseous silylbenzene (rα), 1.875(2) / 119.9(2) for gaseous and 1.870(2) / 118.7(av) for solid 1,2-disilylbenzene, 1.871(1) / 119.4(3) for gaseous 1,3-disilylbenzene, 1.870(2) / 119.0(2) for gaseous and 1.866(3) / 117.4(2) for solid 1,4-disilylbenzene. The angle distortions in the benzene ring geometries are analysed and interpreted in terms of an additivity rule of the distortion caused by each of the silyl substituents. This additivity scheme predicts excellently the observed structures of the silylbenzenes and is in best agreement with the structures calculated ab initio. The slight distortion of molecular symmetry in the crystal structures makes a detailed comparison of the solid-state values impossible, but on average they are in good agreement with theory and predictions of the additivity model. The gas-phase values obtained by the SARACEN method show less pronounced distortions of the benzene ring geometries than observed or predicted by the other methods, but the trends of distortion are fully consistent.
peri-Interactions in Naphthalenes, 7 [1]. A Hetera-naphthalene as a Model Compound for 8-Dimethylaminonaphth- 1-yl Silicon and Phosphorus Compounds
Authors: Schiemenz Günter Paulus , Näther Christian
Published: August 2018

In a 4-isopropyl-1-oxa-3-oxonia-2-borata-naphthalene the isopropyl group exhibits the same conformational phenomena as the Me2N group in 8-dimethylamino-naphth-1-yl-silanes and related phosphorus compounds. Since the details can be fully rationalized on the basis of the steric situation and electronic factors are excluded, the common features cannot serve to infer dative interaction from nitrogen to silicon / phosphorus resulting in hypercoordination of the third period element atoms in the reference compounds.
Polysulfonylamine, CLIII [1]. Schwache Wasserstoffbrücken mit aktivierten Methyldonoren: Kristallstrukturen von Cholinium-, Betainium- und Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamid Polysulfonylamines, CLIII [1]. Weak Hydrogen Bonding with Activated Methyl Donors: Crystal Structures of Cholinium, Betainium and Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamide
Authors: Henschel Dagmar , Moers Oliver , Wijaya Karna , Wirth Andreas , Blaschette Armand , Jones Peter G.
Published: August 2018

In order to study weak hydrogen bonds originating from inductively activated C(sp3)-H donor groups, low-temperature X-ray structures are reported for three onium salts of general formula BH+(MeSO2)2N-, where BH+ is Me3N+CH2CH2OH (1; orthorhombic, space group P212121, Z′ = 1), Me3N+CH2C(O)OH (2; orthorhombic, P212121, Z′ = 1), or Me2HN+CH2CH2NMe2 (3; monoclinic, P21/c, Z′ = 1). The asymmetric units consist of cationanion pairs assembled by an O-H···O=S hydrogen bond in 1, an O-H···N- bond in 2, and an N+-H ··· N- bond in 3. The packings display a plethora of short interionic C(sp3)-H···O/N contacts that are geometrically consistent with weak hydrogen bonding; those taken into consideration have normalized parameters d(H ··· O) ≤ 269 pm, d(H···N) ≤ 257 pm and θ(C-H···O/N) ≥ 127°. The roles of the weak hydrogen bonds are as follows: In structures 1 and 3, the anions are associated into corrugated layers, which intercalate catemers of cations (1) or stacks of discrete cations (3), whereas structure 2 involves cation catemers surrounded by four anion catemers and vice versa; moreover, all cations are linked to adjacent anions by several weak hydrogen bonds (and to one anion in particular by the strong H bond). Among the cation-anion interactions, the N+(CH2-H···)3O tripod pattern arising in 1 and 2 is of special interest.
Synthesis and Tautomeric Structure of 1,2-Bis-(7-arylhydrazono-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanes
Authors: Shawali Ahmad S. , Abdallah Magda A. , Mosselhi Mosselhi A. , Mohamed Yasin F.
Published: August 2018

Two series of the title compounds were prepared by reaction of 1,2-bis(4-amino-5-mercapto- 4H-1,2,4-triazol-3-yl)ethane with N-aryl-2-oxopropane-hydrazonoyl chlorides. The spectral data of such compounds indicated that they exist predominantly in the bis-hydrazone tautomeric form.
Structure of Diastereomeric 10-Bromo-10,11-dihydroquinines
Authors: Borowiak Teresa , Dutkiewicz Grzegorz , Thiel Jacek
Published: August 2018

The absolute configurations of new chiral centers in the side chains of diastereomeric 10,11-dihydroquinines, C20H25BrN2O2, have been determined. Both diastereomers with either 10R or 10S configuration adopt the conformations in which quinuclidine nitrogen atom points away from the quinoline ring (open conformations). The bulky C3-side chain in the 10R diastereomer hinders intermolecular hydrogen bond formation to the quinuclidinic, more basic nitrogen atom. Instead, the hydrogen bond to the quinolinic N atom is formed which is an unusual case for Cinchona alkaloid crystal packing. The same bulky C3-substituent in the 10S diastereomer does not hinder the common packing mode via intermolecular hydrogen bonding to the quinuclidinic N-atom.
Zur Alkylierung von 2,3-Dihydro-1,3-diisopropyl-4,5- dimethylimidazol-2-yliden [1] / On the Alkylation of 2,3-Dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene [1]
Authors: Kuhn Norbert , Göhner Martin , Steimann Manfred
Published: August 2018

The reaction of 2,3-dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (7, Im) and alkyl iodides has been investigated. With MeI, 7 forms a 1/1 mixture of [ImH]I (10) and [ImEt]I (11a) while from the reaction of 7 with EtI an 1/1/1 mixture of 10, 11a and [ImCH(Me)Et]I (11b) is obtained. The mechanism of the reactions is discussed, and the crystal structures of 10 and 11a are reported.
Crystal Structure and Conformation of N-(5-Chlorosalicylidene)- 2-hydroxy-5-chloroaniline
Authors: Elerman Yalçün , Kabak Mehmet , Elmali Ayhan
Published: August 2018

N-(5-Chlorosalicylidene)-2-hydroxy-5-chloroaniline was synthesized and its crystal structure determined. It crystallizes in the orthorhombic space group Pna21 with a = 14.668(4), b = 6.084(3), c = 27.980(4) Å , R = 0.051 for 4788 independent reflections). There are two independent nearly planar molecules in the asymmetric unit. The intramolecular hydrogen bonds occur between the pairs of atoms N1 and O1 [2.553(6) Å], N1 and O2 [2.585(5) Å], N2 and O3 [2.567(6) Å], N2 and O4 [2.620(5) Å], the hydrogen atoms essentially being bonded to the nitrogen atoms. The neighboring molecules are linked via an intermolecular O-H···O hydrogen bond [2.557(5) Å ]. Conformations of the title compound were investigated by semi-empirical quantum mechanical AM1 calculations. The optimized geometry of the molecular structure corresponding to the nearly planar conformation is the most stable conformation in the calculations. The results strongly indicate that the minimum energy conformation is primarily determined by non-bonded steric interactions.
Thermochemische Untersuchungen zu den Systemen SE2O3-SeO2 IV. Lösungskalorimetrie der SE2SexO3+2x-Phasen (SE = Nd, Sm, Y) / Thermochemical Investigations on the Systems RE2O3-SeO2 IV. Solution Calorimetry of the Phases RE2SexO3+2x(RE =Nd, Sm, Y)
Authors: Zhang-Preße M. , Oppermann H.
Published: August 2018

The solution enthalpies have been determined for the ternary phases RE2SexO3+2x existing on the pseudo-binary section RE2O3-SeO2 and for RE2O3 and SeO2 in 4n HCl (RE =Nd, Sm, Y). From these date the enthalpies of formation of the ternary phases have been derived via suitable solution schemes on the basis of the known enthalpies of formation of RE2O3 and SeO2.
Synthesis, Spectroscopic Studies, Crystal Structure and Conformation Analysis of N-(2-Fluoro-3-methoxy)-salicylaldimine
Authors: Ünver H. , Kendi E. , Güven K. , Durlu T. Nuri
Published: August 2018

The new Schiff base ligand N-(2-fluoro-3-methoxy)-salicylaldimine (C14H12NO2F) (1) has been synthesised and studied by using, IR, 1H NMR, 13C NMR, UV-visible, GC-MS techniques, X-ray structure analysis and AM1 semi-empirical quantum mechanical methods. Compound 1 crystallises in the orthorhombic space group P212121 with a =12.5461(1), b =18.0495(1), c =5.2615(1) Å . An intramolecular hydrogen bond connects O1 and N1 [2.575(2)Å], the hydrogen atom being bonded essentially to the oxygen atom. Minimum energy conformations were calculated as a function of two torsion angles θ1 (C6-C7-C8-N1) and θ2 (C7-C8-N1-C9), varied every 10 degrees. The optimized geometry of the crystal structure corresponding to the non-planar conformation is the most stable conformation in all calculations. The results strongly indicate that the minimum energy conformation is primarily determined by hydrogen-hydrogen repulsions between the ortho-hydrogen atoms on the aldehyde rings. Complementary IR, 1H NMR and UV measurements in solution and in the solid state were carried out.
Wechselwirkungen in Molekülkristallen, 179 [1, 2]. σ-Donator/Akzeptor-Komplexe {I2C=CI2···X⊖ } (X⊖ = Cl⊖ , Br⊖ , I⊖ , SCN⊖ ) von Tetraiodethen in Tetra(n-butyl)ammoniumhalogenid-Salzen / Interaction in Molecular Crystals, 179 [1, 2]. σ-Donor/Acceptor Complexes {I2C=CI2···X⊖} (X⊖= Cl⊖, Br⊖, I⊖, SCN⊖) of Tetraiodoethene in Tetra(n-butyl)ammonium Halide Salts
Authors: Bock Hans , Holl Sven
Published: August 2018

Four donor/acceptor complexes between halide anion donors and the tetraiodoethene acceptor molecule with tetra(n-butyl)ammoniumcountercations, {(H9C4)4N⊕X⊖···I2C=CI2)} (X⊖ = Cl⊖, Br⊖, I⊖, SCN⊖) could be crystallized from acetone solutions of the components R4N⊕X⊖ and I2C=CI2 by using low gradient techniques, and their structures determined at low temperature. Their molecule packing motif are layers of halide anion/tetraiodoethene patterns, which are penetrated by one of the four R4N⊕ n-butyl chains. The structure comparison, including analogous ones from an extensive Cambridge Structural Database search, discusses the geminal or vicinal addition to dimer subunits {X⊖···I2C=CI2}2 as well as their ribbon formation via additional contacts X⊖···I, and the effects of the voluminous R4N⊕ countercations. Altogether some light is shedded on essential facets of the fascinating self-assembly comprising an electron-rich halide anion and a polyiodo acceptor molecule.
1,1-Ethylborationof Diethynyl(dimethyl)silane: Formation of a Silole Followed by [4+2]Cycloadditions to 7-Silanorbornadienes and 7-Silanorbornenes
Authors: Wrackmeyer Bernd , Süß Jürgen
Published: August 2018

Diethynyl(dimethyl)silane, Me2Si(C≡C-H)2 2, reacts with triethylborane, Et3B 1, by 1,1- ethylboration to give a silole, 3-diethylboryl-4-ethyl-1,1-dimethyl-sila-2,4-cyclopentadiene 3, as a short-lived intermediate which reacts further with 2 or dimerises via [4+2]cycloadditions to the 7-silanorbornadiene 4 or the 7-silanorbornene derivatives 5, respectively. Since the silole 3 was not detected by NMR, the analogous reactions were studied using 1-alkynyl(ethynyl)- dimethylsilanes, Me2Si(C≡C-H)C≡C-R 6 [R = Bu (a), iPent (b), tBu (c)]. In these cases, 1,1-ethylboration gave the siloles 7a,b,c and 7'a,b, now detected in the reaction solutions, and also 7-silanorbornadienes as [4+2]cycloaddition products. Major products were identified, and the progress of the reactions was monitored by NMR spectroscopy (1H, 11B, 13C and 29Si NMR).
Structure of N-Methylisatin N(4)-Dimethylthiosemicarbazone and its Electrochemically Synthesized 6-Coordinate Cadmium(II) Complex
Authors: Labisbal Elena , Sousa-Pedrares Antonio , Kaminsky Werner , West Douglas X.
Published: August 2018

N-Methylisatin N(4)-dimethylthiosemicarbazone, HMIs4DM, prepared by condensation of N-methylisatin and N(4)-dimethylthiosemicarbazide crystallizes in the orthorhombic space group Pbc21, with a = 7.539(1), b = 11.566(4), c = 29.320(1) Å, V = 2556.6(9) Å3 and Z = 8. Cadmium metal was oxidized in the presence of HMIs4DM in an acetonitrile solution, which produced a complex of the formula [Cd(MIs4DM)2]. [Cd(MIs4DM)2] crystallizes in the orthorhombic space group Pbcn with a = 15.529(5), b = 10.672(4), c = 16.247(3) Å , V = 2692.7(14) Å3 and Z = 8. [Cd(MIs4DM)2] is symmetrical with two identical MIs4DM ligands that are at an angle of about 80°.
Synthesen und Kristallstrukturen von Bis(N-lithiumtrimethylsilylamino)- bis(dimethylamino)silan und 1,1-Dichloro-2,4-bis(trimethylsilylamino)- 3,3-bis(dimethylamino)siladiazatitanacyclobutan / Syntheses and Crystal Structures of Bis(N-lithio-trimethylsilylamino)bis(dimethylamino)- silane and 1,1-Dichloro-2,4-bis(trimethylsilylamino)-3,3-bis(dimethylamino)siladiazatitanacyclobutane
Authors: Engering Josef , Peters Eva-Maria , Jansen Martin
Published: August 2018

Bis(N-lithio-trimethylsilylamino)bis(dimethylamino)silane (1) is formed in the reaction of silicon tetrachloride with excess hexamethyldisilazane, followed by halogen substitution using two equivalents of LiN(CH3)2, and treatment with two equivalents of n-butyllithium in hexane. 1, found to be dimeric in the solid state, was characterised by single crystal X-ray diffraction (monoclinic, C2/c, a = 1925.2(4), b = 1501.7(2), c = 1389.7(3) pm, β= 101.98(2), Z = 4, C20H60Li4N8Si6), and by solid state and solution NMR spectroscopy and mass spectrometry. Further reaction with titanium tetrachloride (molar ratio 1:1) yields orange crystals of the dimer [TiClf(μ2-NSi(CH3)3)2Si(N(CH3)2)μ2-Cl]2 (2) characterised by single crystal X-ray diffraction (triclinic, P1, a = 942.1(4), b = 991.7(4), c = 1222.6(5) pm, α= 90.12(1), β= 94.42(2), γ= 107.64(1)°, Z = 1, C20H60Cl4N8Si6Ti2)
Die Kristallstruktur von Bis-[methylammonium]-hexafluorosilikat, (MeNH3)2SiF6 / The Crystal Structure of Bis-[methylammonium]-hexafluorosilicate, (MeNH3)2SiF6
Authors: Graulich Jens , Babel Dietrich
Published: August 2018

The results of a single crystal X-ray structure determination of monoclinic (MeNH3)2SiF6 are reported: a = 962.3(5), b = 964.4(1), c = 966.4(5) pm, " = 100.03(3)°; V = 883.2(7) Å3, Z = 4, space group C2/c; wR2 = 0.0999 based on F0
2 of 1291 independent reflections (including H refinement without restrictions). The structure is related to that of (NH4)2SiF6, but contains the dumb-bells of the cations well oriented along the greater cell diagonals and fixed by one nearly linear and two bi-furcated hydrogen bonds (N...F: 281 and 293 - 305 pm, resp.). The [SiF6]2- octahedron is nearly undistorted with average bond length Si-F: 167.7 pm (169.9 pm corrected for thermal motion)