bluuebunny/crossref_metadata_2025 huggingface dataset:
α-Dicarbonylmonohydrazone und ihre Acylderivate als Nucleophile und Nachbargruppen/α-Dicarbonylmonohydrazones and their Acylderivatives as Nucleophiles and Neighbouring Groups
Authors: Möhrle Hans , Keller Georg
Published: August 2018

The aminomethylation of the α-carbonylhydrazones 1 and 14 with N,N,N′,N′-tetralkylaminals yields only N,N- or C,N-bis-aminomethyl products, but no C-mono-aminomethyl compounds. Phenylglyoxal N-methylhydrazone (24) yields the Mannich bases 27, while anilinocarbonyl hydrazone 29 dependent on the conditions gives rise to the N-aminomethyl derivatives 30 or to the Mannich bases 31. From benzoylhydrazone 33 and semicarbazone 35 the Mannich bases 34 and 36, respectively, are available. Mercury-EDTA reacts with 27 and 31 by twofold dehydrogenation and cyclization to form the lactams 46 and 47, respectively, whose treatment with perchloric acid yields the triazinium salts 45 and 51. When Mannich base 34 is exposed to the same oxidation conditions, the products of both dehydrogenation steps, 54 and 55, may be isolated. From the semicarbazones 36 only the triazines 56 are produced after a single dehydrogenation step.
Synthesis of Some New (Nα-Dipicolinoyl)-bis-L-leucyl-DL-norvalyl Linear tetra and Cyclic octa Bridged Peptides as New Antiinflammatory Agents
Authors: Abo-Ghalia Mohamed H. , Amr Abd El-Galil E. , Abdalah Mohamed M.
Published: August 2018

In continuation to our search for new amino acid and peptide based anti-inflammatory agents, the suggestion, synthesis, structure elucidation of some Nα -bis-dipicolinoyl amino acids, linear tetra and cyclic octa bridged peptides 1-9, of which four are new compounds 6-9, were herein realized. Accordingly, Nα -bis-dipicolinoyl-L-leucine methyl ester 1, the corresponding acid 2, its bis-DL-norvalyl methyl ester homologue 3, the acid 4 and hydrazide 5 analogues were conventionally prepared.

The tetrachlorophthalic acid hydrazine conjugate 6, anisaldehyde hydrazone 7, the benzenetetracarboxylic acid and naphthalenetetracarboxylic acid bis-L-leucyl-DL-norvalyl cyclic octa bridged peptides 8 and 9 respectively, were newly synthesized via condensation of the hydrazide 5 with the corresponding aldehyde or anhydride.

The chromatographic, IR, NMR and mass spectral analysis confirmed the identities of the synthesized compounds.

Comparable to the two reference antiinflammatory drugs indomethacin® and voltaren® (100%), the determined antiinflammatory potency of the candidates (carrageenan® induced paw edema in rats) revealed a general significant activity (66 - 94%), except for the practically inactive 6 (∼1.5 % activity).

In particular, the potency of the (Nα -dipicolinoyl)-bis-L-leucyl-DL-norvalyl anisaldehyde hydrazone 7 was of 94 and 87%, comparable to the reference drugs. However, 7 also showed 58% protection against ulcer formation, comparable to null for indomethacin®. Additionally, an acceptable acute toxicity was observed (LD50: 2833 mg/kg, comparable to 2700 and 2850 for indomethacin® and voltaren® respectively).
Darstellung und 51V-NMR-spektroskopische Untersuchungen von η5-Cyclopentadienyl-tert-butylimidovanadium(III)-Komplexen mit σ-Donator, π-Akzeptor-Liganden / Synthesis and 51V NMR Spectroscopic Studies of η5 -Cyclopentadienyl-tert-butylimidovanadium( III) Complexes with σ -Donor, π -Acceptor Ligands
Authors: Billen Martin , Hornung Gabriele , Preuss Fritz
Published: August 2018

The imidovanadium(III) complexes [tBuN=VCp(PR3)2], [tBuN=VCp{P(OR)3}2] and [tBuN= VCp(CO)2] have been prepared starting from tBuN=VCpCl2 by reductive dehalogenation with magnesium. The reaction of [tBuN=VCp(PMe3)2] (2a) with carbon monoxide, alkynes, alkenes, tert-butylphosphaalkyne, nitriles, ketones and carbon disulfide furnished the complexes [tBuN=VCp(PMe3) (L)], while the vanadium(V) compound tBuN=VCp(O2C2Ph2) is formed with benzil. All vanadium(III) complexes obtained are diamagnetic (d2, low-spin configuration) and have been characterized by spectroscopic methods (MS; 1H, 13C, 31P, 51V NMR).
Conformations and Structures of N,N’-Bis(2-methoxybenzylidene)- 1,3-diamino-propanol and N,N’-Bis(3-methoxybenzylidene)-1,3- diamino-propanol
Authors: Kabak Mehmet , Elmali Ayhan , Elerman Yalçin , Svoboda Ingrid
Published: August 2018

N,N’-bis(2-methoxybenzylidene)-1,3-diamino-propanol (C19H22N2O4) 1 and N,N’-bis(3-methoxybenzylidene)- 1,3-diamino-propanol (C19H22N2O4) 2 have been investigated by X-ray analysis and AM1 semi-empirical quantum mechanical method. 1 is in the monoclinic space group C2/c with a = 33.694(6), b = 6.735(1), c = 17.681(3) Å , β = 114.72(2)°, V = 3645(1) Å3, Z = 8, Dc = 1.248 mg cm−3 and μ(Mo-Kα ) = 0.088 mm−1. 2 is in the monoclinic space group C2/c with a = 19.173(4), b = 7.626(2), c = 11.788(2) Å , β = 91.72(2)°, V = 1722.8(6) Å3, Z = 4, Dc = 1.320 mg cm−3 and μ(Mo-Kα ) = 0.093 mm−1. The crystal structures of 1 and 2 were solved by direct methods and refined to R = 0.053 for 1 and R = 0.041 for 2. Both molecules are not planar and 2 has twofold axes on C9 atom. Intramolecular hydrogen bonds occur between O1 and N1 [2.541(3) Å ] and between O3 and N2 [2.573(4) Å ] atoms for 1 and between O1 and N1 [2.631(2) Å ] atoms for 2. The optimized geometries of the crystal structures of 1 and 2 corresponding to non-planar conformation are the most stable conformation in all calculations. The results strongly indicate that the minimum energy conformation is primarily determined by non-bonded hydrogen-hydrogen and hydrogen-carbon repulsions.
Frankiamide: A Structural Revision to Demethyl (C-11) Cezomycin
Authors: Klika Karel D. , Haansuu J. Pasi , Ovcharenko Vladimir V. , Haahtela Kielo K. , Vuorela Pia M. , Sillanpää Reijo
Published: August 2018

A compound (née frankiamide) isolated from Frankia was initially structurally elucidated on the basis of NMR and MS. However, X-ray analysis provided a structure that is in discord with this structure and in light of this the structure has now been revised and the compound renamed as demethyl (C-11) cezomycin.
Xyloccensin M and N, Two New B, D-seco Limonoids from Xylocarpus granatum
Authors: Wu Jun , Zhang Si , Xiao Qiang , Li Qingxin , Huang Jianshe , Xiao Zhihui , Long Lijuan
Published: August 2018

Two new mexicanolide-type B, D-seco limonoids named xyloccensin M(1) and N (2) were isolated from the stem bark of Xylocarpus granatum. Their structures were elucidated with the help of modern spectroscopic techniques.
A Study of Substituent Effect on the Oxidative Strengths of N-Chloroarenesulphonamides: Kinetics of Oxidation of Leucine and Isoleucine in Aqueous Acid Medium
Authors: Shetty Mahesha , Gowda B. Thimme
Published: August 2018

To study the variation of oxidative strengths of N-chloro-arenesulphonamides with substitution in the benzene ring, six mono- and five di-substituted N-chloro-arenesulphonamides are employed as oxidants for studying the kinetics of oxidation of two neutral amino acids, L-leucine and Lisoleucine in aqueous acid medium. The N-chloro-arenesulphonamides studied are of the constitution: ArSO2NaNCl·H2O (where Ar = C6H5, 4-CH3C6H4, 4-C2H5C6H4, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 2,3-(CH3)2C6H3, 2,4-(CH3)2C6H3, 2-CH3-4-ClC6H3, 2,4-Cl2C6H3, and 3,4-Cl2C6H3). The reactions show second order kinetics in [oxidant], fractional order in [amino acid] and inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. A two-pathway mechanism is considered to explain the experimental results. Effective oxidizing species of the oxidants is Cl+ in different forms. Therefore the oxidising strengths of N-chloro-arenesulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of substituent in the benzene ring of the oxidant affects both the kinetic and thermodynamic data for the oxidations The electron releasing groups such as CH3 generally inhibit the rates, while electron-withdrawing groups such as Cl enhance this ability, as the electron withdrawing groups ease the release of Cl+ from the reagents and hence increase the oxidising strengths. The on Ea and logA and validity of the Hammett and isokinetic relationships for the oxidations are also analysed.
Boron Trifluoride Mediated Addition of Nucleophiles to endo- and exo-Substituted Norbornene Derivatives
Authors: İşleyen Alper , Sayraç Tuğmac , Doğan Özdemir
Published: August 2018

Remote substituent effects on the regioselectivity and stereoselectivity in the boron trifluoride mediated addition of nucleophiles (iodide and bromide) to endo- and exo-2-substituted norbornene derivatives have been investigated. The main products of the reactions resulted from the regioselective addition of nucleophiles to the double bond of norbornene derivatives. Products resulting from the Wagner-Meerwein type rearrangement were also isolated in considerable amounts. All of the reactions gave the addition products in reasonably good yields with high regioselectivity. The endo/exo selectivity, on the other hand, changed depending on the nucleophile and the substrate.
Crystal Structures of the Supramolecular Aggregates of the Methyl and Chloro Substituted Gallanes MexGaCl3-x
Authors: Lustig Christian , Mitzel Norbert W
Published: August 2018

The crystal structures of the complete series of compounds of the general formula MexGaCl3−x have been determined. New polymorphs of GaCl3 and MeGaCl2 were found. All chloro compounds MexGaCl3−x (x = 0, 1, 2) are dimers with Ga2Cl2 four-membered rings. (GaCl3)2 and (MeGaCl2)2 are aggregated into layers with the same aggregation motif (each molecule connected to four neighbouring molecules), (Me2GaCl)2 is associated in a ladder-like structure (each molecule connected to two neighbouring molecules), GaMe3 forms weakly Ga···C bound pseudo-tetramers aggregated into layers by further Ga···C contacts (each molecule has two shorter Ga···C’ and C···Ga’ and two weaker Ga···C’ and C···Ga’ contacts).
Synthese und Struktur der Nitridokomplexe (Ph3Sb)2Cl3Os≡N-RhCl(COD), (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5), [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3][OsCl3(CO)3] und [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3][OsCl4(CO)2] / Synthesis and Structure of the Nitrido Complexes (Ph3Sb)2Cl3Os≡N-RhCl(COD), (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5), [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3][OsCl3(CO)3], and [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3][OsCl4(CO)2]
Authors: Schwarz Simon , Mestres Montserrat Galceran , Niquet Elke , Barboza da Silva Carlos F , Strähle Joachim
Published: August 2018

The reaction of (Ph3Sb)2Cl3OsN with [Rh(μ-Cl)(COD)]2 in benzonitrile yields the heteronuclear nitrido complex (Ph3Sb)2Cl3Os≡N-RhCl(COD) (1). It crystallizes as dark brown blocks in the triclinic space group P1 with a = 1080.09(5), b = 1173.15(5), c = 1702.28(9) pm, α = 101.214(4), β = 92.923(8), γ = 92.836(5)֯, and Z = 2. The complex fragment RhCl(COD) is coordinated to the osmium nitrido complex via a linear nitrido bridge Os≡N-Rh, with a bond angle Os-N-Rh = 175.3(5)° and distances Os-N = 168.6(6) and Rh-N = 184.6(6) pm. The heteronuclear complexes (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5) (2) and [(Me2PhP)3(PhCN)ClRe≡NOsCl2( CO)3][OsCl3(CO)3] (3) are obtained by the reaction of (Me2PhP)3Cl2ReN with [RhCl(μ- Cl)(C5Me5)]2 and [OsCl(μ-Cl)(CO)3]2, respectively, in benzonitrile. 2 forms orange red crystals with the composition 2・C6H5CN in the monoclinic space group P21/c and a =910.23(7), b =1255.4(1), c = 3761.5(3) pm, β = 95.617(9)° and Z = 4. The nitrido bridge Re≡N-Rh to the complex fragment [RhCl2(C5Me5)] has a bond angle Re-N-Rh of 171.9(3)° and distances Re-N = 169.4(5) and Rh-N = 201.9(5) pm. 3 forms yellow orange plates with the monoclinic space group P21/c and a = 1113.74(5), b = 2038.5(2), c = 2130.1(1) pm, β = 90.298(6)° and Z = 4. The nitrido bridge within the complex cation [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3]+ is characterized by a bond angle Re-N-Os of 167.7(4)° and distances Re-N = 169.5(8) and Os-N = 206.1(8) pm. The ligands of the octahedral anion [OsCl3(CO)3]− are in a facial arrangement. The synthesis of 3 yields [{(Me2PhP)3(PhCN)ClRe≡N}2ReCl4][OsCl4(CO)2] (4) as a byproduct. It crystallizes as red brown blocks with the composition 4·CH2Cl2 in the space group P1 and a = 1444.2(1), b = 1536.3(1), c = 2150.5(2) pm, α =87.41(1), β =88.54(1), γ =62.453(8)° and Z =2. In the two symmetry independent, centrosymmetric cations [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3]2+ of 4 two nitrido complexes [(Me2PhP)3(PhCN)ClReN]+ coordinate with their terminal nitrido ligands a central, square planar ReCl4 unit. The resulting nitrido bridges with bond angles Re(1)-N(1)- Re(2) = 167.0(4)° and Re(3)-N(2)-Re(4) = 168.9(4)°, respectively, exhibit distances Re(1)-N(1) = 172.4(7) and Re(2)-N(1) = 197.1(7) or Re(3)-N(2) = 171.4(6) and Re(4)-N(2) = 197.1(6) pm. The two carbonyl ligands of the anion [OsCl4(CO)2]2− are in cis position.
High-Pressure Synthesis, Crystal Structure, and Properties of the New Orthorhombic Rare-Earth meta-Oxoborates RE(BO2)3 (RE = Dy – Lu)
Authors: Emme Holger , Nikelski Tanja , Schleid Thomas , Pöttgen Rainer , Möller Manfred Heinrich , Huppertz Hubert
Published: August 2018

The new orthorhombic meta-oxoborates RE(BO2)3 (≡REB3O6) (RE = Dy-Lu) have been synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 °C. They are isotypic to the known ambient pressure phase Tb(BO2)3, space group Pnma. In contrast to Dy(BO2)3, which was also obtained in small amounts under high-temperature conditions, the preparation of the higher orthorhombic homologues RE(BO2)3 (RE = Ho-Lu) was only possible using high-pressure. The meta-oxoborates RE(BO2)3 (RE = Dy-Er) were synthesized as pure products, whereas the orthorhombic phases with RE = Tm-Lu were only obtained as byproducts. With the exception of Yb(BO2)3 it was possible to establish single crystal data for all compounds. The results of temperature-resolved in-situ powder-diffraction measurements, DTA, IR-spectroscopic investigations, and magnetic properties are also presented.
Synthesis and Structure of an Aluminium-Nitrogen Heteronorbornane with Bulky tButyl Substituents and the Crystal Structure of Tri(tbutyl)aluminium
Authors: Woski Markus , Mitzel Norbert W.
Published: August 2018

The reaction of bis(lithiomethyl-methylamino)methane with ditbutylaluminium chloride leads to the formation of 3,3,6,6-tetra-tbutyl-1,4-dimethyl-3,6-dialumina-1,4-diaza-norbornane by simultaneous formation of two metal-carbon and two metal nitrogen bonds accompanied by two ring closure reactions. The compound was identified by an NMR analysis (1H, 13C, 27Al) and by determination of its crystal structure. Despite the high steric demand of the tbutyl groups, the norbornane-basket structure is favoured over potential isomers containing three-membered rings and over polymeric aggregation. The crystal structure of tri(tbutyl)aluminium has been determined. tBu3Al crystallizes as a monomer, with the molecules interconnected by weak secondary Al···C contacts (2.95 Å) leading to a slight deviation of the AlC3 units from a planar coordination geometry at the Al atoms
Supersilylated Tetrachlorodigermane (tBu3Si)Cl2GeGeCl2(SitBu3) and Trigermoxetane (tBu3Si)3Ge3Cl3O
Authors: Lerner Hans-Wolfram , Schödel Frauke , Sänger Inge , Wagner Matthias , Bolte Michael
Published: August 2018

In contrast to the tetrachlorodigermane (tBu3Si)Cl2Ge-GeCl2(SitBu3), the cis,transcyclotrigermane (tBu3SiGeCl)3 is sensitive to oxygen. Its treatment with O2 at ambient temperature leads to the trigermoxetane (tBu3Si)3Ge3Cl3O. According to an X-ray structure analysis of single crystals consisting of cocrystallized (tBu3Si)3Ge3Cl3O and (tBu3Si)Cl2Ge-GeCl2(SitBu3) the trigermaoxetane contains an almost planar Ge3O-ring while the tetrachlorodigermane (tBu3Si)Cl2Ge- GeCl2(SitBu3) possesses a Si-Ge-Ge-Si chain which is exactly all trans
The Ti(IV) Complex of a Benzannulated N-Heterocyclic Carbene
Authors: Hahn F. Ekkehardt , Fehren Thorsten von , Fröhlich Roland
Published: August 2018

The yellow titanium(IV) carbene complex [TiCl4(1)], 2 (1 = N,N’-bis(2,2-dimethylpropyl)benzimidazol-2-ylidene) was synthesized by reaction of TiCl4 and the benzannulated carbene 1 in toluene. The X-ray structure analysis revealed a mononuclear complex with a titanium(IV) center coordinated in a distorted trigonal-bipyramidal fashion by the carbene ligand in an equatorial position and four chloro ligands
1,4,5,8-Tetraazafulvalene – Darstellung schwefelhaltiger Derivate und Zuordnung des Chromophors / 1,4,5,8-Tetraazafulvalenes – Synthesis of Sulfur-Containing Derivatives and Classification of the Chromophor
Authors: Kühn Christiane , Beckert R. , Grummt U.-W. , Käpplinger C. , Birckner E.
Published: August 2018

In order to obtain sulfur-containing tetraazafulvalenes the derivatives 1 - 3 were cross-coupled with different types of acetylenes via palladium-catalyzed reactions. Starting from the tetrabromoaryl derivative 3a, four bromine atoms could be replaced by 2-ethynylthiophene. Under analogous conditions, the methylsulfanyl esters 7 -11 could be obtained by employing 4-ethynylbenzoic acid 4-(methylsulfanyl)butylester 6. Lipoic acid could be integrated into tetraazafulvalenes successfully in a two step reaction. First, the Sonogashira coupling method yielded the compound 12 possessing two (4-anilino)ethynyl residues which were then condensed with lipoic acid to give derivative 13.

Whereas the NMR data suggest the predominance of prototropic form A, UV/vis spectra of the deeply colored tetraazafulvalenes are in favor with structure B rather than with structure A. DFT calculations at the B3LYP/6-31G(d) level showed that tautomeric form B is about 60 kJ/mol more stable than A. In addition, time-dependent density functional theory calculations support the substructure of two crossed diazaheptamethinemerocyanines.
Ternary Indides REMgIn (RE = Y, La–Nd, Sm, Gd–Tm, Lu). Synthesis, Structure and Magnetic Properties
Authors: Kraft Rainer , Valldor Martin , Kurowski Daniel , Hoffmann Rolf-Dieter , Pöttgen Rainer
Published: August 2018

The equiatomic rare earth-magnesium-indium compounds REMgIn (RE = Y, La-Nd, Sm, Gd- Tm, Lu) were prepared from the elements in sealed tantalum tubes inside a water-cooled sample chamber of an induction furnace. All compounds were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P6̄̄2m, with three formula units per cell. The structure of SmMgIn was refined from X-ray single crystal diffractometer data: a = 761.3(2), c = 470.3(1) pm, wR2 = 0.0429, 380 F2 values and 14 variable parameters. The DyMgIn, HoMgIn, and TmMgIn structures have been analyzed using the Rietveld technique. The REMgIn structures contain two cystallographically independent indium sites, both with tri-capped trigonal prismatic coordination: In1Sm6Mg3 and In2Mg6Sm3. Together the magnesium and indium atoms form a three-dimensional [MgIn] network with Mg-Mg distances of 320 and Mg-In distances in the range 294 - 299 pm. Temperature dependent magnetic susceptibility data show Curie-Weiss behavior for DyMgIn, HoMgIn, and TmMgIn with experimental magnetic moments of 11.0(1) μB/Dy atom, 10.9(1) μB/Ho atom, and 7.5(1) μB/Tm atom. The three compounds order antiferromagnetically at TN = 22(2) K (DyMgIn), 12(1) K (HoMgIn), and 3(1) K (TmMgIn).
Synthese und Struktur von Meldrums Olefin/Synthesis and Structure of Meldrum’s Olefin
Authors: Kuhn Norbert , Al-Sheikh Ahmed , Kolb Hans-Jürgen , Richter Markus
Published: August 2018

Diisopropylidene ethylenetetracarboxylate, Meldrum’s olefin (4, Mel2) has been prepared from [HNEt3][(Mel)2CSMe] (8) and Meldrum’s acid (1, MelH2) in moderate yield. The X-ray analysis of 4 reveals a centrosymmetrical structure in which the two six-membered rings are folded along their carboxylate carbon axes by 34.9°) and linked by a conventional C-C double bond [1.3501(19) Å ]. The “unsymmetrical” structure of 8 is also discussed.
Dimethyl-, Disilyl- and Digermylsulfide: Different Intermolecular Contacts in the Solid State
Authors: Mitzel Norbert W. , Losehand Udo
Published: August 2018

The compounds (H3C)2S, (H3Si)2S and (H3Ge)2S have been crystallised in situ on a diffractometer and their crystal structures determined by low-temperature X-ray diffraction. The molecules are present as monomers in the crystals. The aggregation of the molecules through secondary intermolecular contacts in the crystal is different: (H3C)2S is weakly associated into dimers by S···S contacts, whereas (H3Si)2S and (H3Ge)2S form Si···S and Ge···S contacts in an ice-analogous aggregation motif. Important geometry parameters are (H3C)2S: C-S 1.794(av) Å , C-S-C 99.2(1)°; (H3Si)2S: Si- S 2.143(1) Å , Si-S-Si 98.4°; (H3Ge)2S Ge-S 2.223(2) and 2.230(2) Å , Ge-S-Ge 98.2(1)◦.
The Hexagonal Laves Phase MgIr2
Authors: Hlukhyy Viktor , Pöttgen Rainer
Published: August 2018

The hexagonal Laves phase MgIr2 was synthesized from the elements in a sealed tantalum tube in an induction furnace. MgIr2 was investigated by powder and single crystal X-ray data: P63/mmc, a = 516.9(1), c = 838.5(2) pm, wR2 = 0.0771, 135 F2 values, and 11 variable parameters. The magnesium atoms have coordination number (CN) 16 (12 Ir + 4 Mg), while the smaller iridium atoms, Ir1 and Ir2, both have CN 12 (6 Ir + 6 Mg). The Ir-Ir distances within the three-dimensional network of face- and corner-sharing Ir4/2 tetrahedra range from 250 to 267 pm. The magnesium atoms have one shorter (306 pm) and three longer (319 pm) magnesium contacts. The crystal chemistry of MgIr2 is briefly discussed and compared with the other binary Mg-Ir intermetallics.
Solvothermal Syntheses, Crystal Structures of Two New Thioantimonates(III) of the Mn2(L)Sb2S5 Family with L = Diethylenetriamine and N-Methyl-1,3-Diaminopropane and a Study of the Magnetic Properties of Four Compounds of the Series
Authors: Engelke L. , Stähler R. , Schur M. , Näther C. , Bensch W. , Pöttgen R. , Möller M. H.
Published: August 2018

The two new compounds Mn2(L)Sb2S5 (L = diethylenetriamine = DIEN, N-methyl-1,3- diaminopropane = MDAP) were prepared under solvothermal conditions using the elements as starting materials. Both compounds crystallise in the monoclinic space group P21/c with the lattice parameters a=10.669(7), b=12.805(2), c=12.072(1)Å , β =115.786(7)°,V =1485.1(4) Å3 for L = DIEN and a = 10.1859(7), b = 12.7806(6), c = 12.1256(8)Å , β = 110.173(8)°, V = 1481.7(2) Å3 for L = MDAP and Z = 4. The primary building units are SbS3 pyramids, MnS6 and MnS4N2 distorted octahedra. These primary building blocks are interconnected to form Mn2Sb2S4 hetero-cubane units. The hetero-cubanes share common corners, edges and faces thus forming a second heterocubane. These secondary building units are joined to form layers within the (100) plane. The connection mode yields ellipsoidal pores within the layers. The amines are exclusively bound to one of the two crystallographically independent Mn2+ cations and they point into the pores and between the layers separating the layers from each other. The interlayer separation and the size of the pores depend on the sterical requirements of the amine incorporated into the network. A pronounced distortion of the MnS4N2 octahedron results from a significant elongation of one Mn-S distance from 2.866 Å (L = methylamine, MA) to 3.185 Å for L = MDAP. The magnetic susceptibility curves are typical for low-dimensional antiferromagnetic materials and the large negative values for the Weiss constant Θ indicate strong antiferromagnetic exchange interactions. The magnetic properties are significantly influenced by the change of the Mn-S bonds introduced by the different amines. The compounds decompose at elevated temperatures with a two step reaction for L = MA and ethylenediamine and in a one step reaction for the bidentate acting amine molecules.
Crystal and Molecular Structure of [(η5-C5H4SiMe3)2LuCl]2: A Precursor for the Production of Lu2O3 Films
Authors: Schumanna Herbert , Fedushkin Igor L. , Hummert Markus , Scarel Giovanna , Bonera Emiliano , Fanciulli Marco
Published: August 2018

The single crystal X-ray diffraction study of [(η5-C5H4SiMe3)2LuCl]2, prepared from LuCl3 and Na[C5H4SiMe3], shows the compound to be a centrosymmetric dimer with two η5-bonded cyclopentadienyl rings and two symmetrically bridging chlorine atoms coordinated to each of the two metal centers. The coordination geometry around the lutetium atoms is that of a distorted pseudo tetrahedron. The Lu-C(Cp) distances lie within the narrow range of 2.571 - 2.608 Å . The Lu-Cl bond lengths are 2.639(1) and 2.653(1) Å . The crystal structure shows no significant intermolecular contacts.
Syntheses and Characterization of Two New Lead(II) Acetate Complexes, Pb(L)(CH3COO)2, L = 2,2':6',2''-Terpyridine (tpy) and 2,4,6-Tris(2-pyridyl)- 1,3,5-Triazine (trz), Crystal Structure of Pb(tpy)(CH3COO)2
Authors: Morsali Ali
Published: August 2018

Lead(II) complexes with 2,2':6',2''-terpyridine (tpy) and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (trz) ligands, [Pb(tpy)(CH3COO)2] and [Pb(trz)(CH3COO)2], have been synthesized and characterized by IR, CHN elemental analysis and 207Pb NMR. The structure of Pb(tpy)(CH3COO)2 was confirmed by single crystal X-ray data. The complex is monomeric and the Pb atom has an unsymmetrical seven-coordinate geometry, being coordinated by three nitrogen atoms of the 2,2’:6’,2”-terpyridine ligand and four oxygen atoms of the CH3COO− ligands. The arrangement of the ligands in the two complexes exhibits a coordination gap around the Pb(II) ion, occupied possibly by a stereoactive lone pair on lead(II). The coordination around lead atoms is hemidirected. The parallel aromatic rings in Pb(tpy)(CH3COO)2 show π − π stacking.
The Pd(II) Complex of a N,N’-Diallylbenzimidazol-2-ylidene Ligand
Authors: Hahn F. Ekkehardt , Pape Tania , Holtgrewe Christian
Published: August 2018

The palladium(II) dicarbene complex trans-[PdBr2(L)2], 2 (L = 1,3-di-(2-propenyl)-benzimidazol- 2-ylidene) was synthesized from 1,3-di-(2-propenyl)-benzimidazolium bromide 1 and Pd(OAc)2 by in situ deprotonation. The X-ray structure analysis revealed a mononuclear complex with a palladium( II) center coordinated in a square-planar fashion by the two carbene functions and two bromo ligands.
Thiakronenether-Metallkomplexe: Komplexe von Silber(I) und Quecksilber(II) mit Tetrathia-12-krone-4, Silber(I) und Cadmium(II) mit Hexathia-18-krone-6 und Silber(I) mit 3,6,9,14-Tetrathiabicyclo[9.2.1]tetradeca-11-13-dien / Thia Crown Ether Metal Complexes: Complexes of Silver(I) and Mercury(II) with Tetrathia-12-crown-4, Silver(I), and Cadmium(II) with Hexathia-18-crown-6, and Silver(I) with 3,6,9,14-Tetrathiabicyclo[9.2.1]tetradeca-11-13-diene
Authors: Pickardt Joachim , Chrzanowski Lars von , Steudel Ralf , Borowski Marina
Published: August 2018

Crystals of 1,4,7,10-tetrathiacyclododecane silver(I) trifluoromethanesulfonate, Ag(C8H16S4)- (CF3SO3), 1,4,7,10-tetrathiacyclododecane iodo mercury(II) hexaiododimercurate(II)methylene chloride [HgI(C8H16S4)][Hg2I6] · CH2Cl2, 1,4,7,10,13,16-hexathiacyclooctadecane silver(I) trifluoromethanesulfonate [Ag(C12H24S6)](CF3SO3), 1,4,7,10,13,16-hexathiacyclooctadecane diiodocadmium, [Cd(C12H24S6)I2], and bis-3,6,9,14-tetrathiabicyclo[9.2.1]tetradeca-11-13-diene silver(I) trifluoromethanesulfonate [Ag(C10H14S4)2](CF3SO3) were obtained by reaction of solutions of the ligands and the appropriate metal salts and their X-ray crystal structures determined.
Cazolobine, a New Sesquiterpene from Isolona hexaloba (Annonaceae)
Authors: Mathouet Hilarion , Cazoulat Isabelle , Oulyadi Hassan , Seguin Elisabeth , Daïch Adam , Elomri Abdelhakim
Published: August 2018

Methyl 7-(5’,5’-dimethyltetrahydrofuran-2’-yl)-3-methylocta-2,6-dieneoate (cazolobine), a new sesquiterpene derivative was isolated from the root of Isolona hexaloba (Annonaceae) collected in Gabon. The structure of cazolobine was elucidated on the basis of its spectral data, mainly MS and multiple-pulse NMR.
Pt-Dumbbells in Ba3Pt2: Interplay of Geometric and Relativistic Effects on Pt–Pt Bonding
Authors: Karpov Andrey , Wedig Ulrich , Jansen Martin
Published: August 2018

Ba3Pt2 has been synthesized by reaction of a 3 : 2 mixture of Ba and Pt at 1223 K in argon, and characterized by single-crystal X-ray structure determination and electrical resistivity measurements. Ba3Pt2 crystallizes in the Er3Ni2 structure type (space group R3̅ with a = 962.40(6), c = 1860.6(1) pm, Z = 9, R(F)N′ = 0.063, N′(hkl) = 777), and is isotypic to Ca3Pt2 and Sr3Pt2. The Pt atoms occur in pairs at a distance of 303 pm. According to the analysis of the Electron Localization Function and the Crystal Orbital Hamilton Population obtained from DFT band structure calculations, covalent bonding can be assumed in the Pt-dumbbells, although it is weaker in Ba3Pt2 than in Ca3Pt2. The peculiarities of the platinum compounds due to relativistic effects are elaborated by a comparison with theoretical results for Ca3Pd2. Ba3Pt2 exhibits metallic conductivity (ρ270 = 0.7 mΩ · cm), which is in accordance with band structure calculations.
Random Interstitial Halide Accommodation in an α,ω-Alkylidene-diammonium Template
Authors: Schneider Daniel , Schier Annette
Published: August 2018

N,N,N′,N′-Tetramethylethylenediammonium diiodide [Me2HNCH2]2I2 (1) as well as a set of I/Br- (2) and Br/Cl-mixed-halide salts (4 and 5) have been prepared, and their structures determined by single crystal X-ray diffraction. The results show the [Me2HNCH2]2
2+ dication to be a highly flexible template for halide inclusion, thereby tolerating the assembly of anions of different size, with phase widths of 0 ≤ x ≤ 2 for a monoclinic form with [Me2HNCH2]2I2−xBrx and 0 ≤ x ≤ 1 for a triclinic form with [Me2HNCH2]2Br2−xClx. The isotypic mixed halide compounds [Me2HNCH2]2IBr (2) and [Me2HNCH2]2BrCl (4) exhibit a statistical distribution of the anions in a structure of space group P21/c which is also found for the pure diiodide [Me2HNCH2]2I2 (1). With an excess of chloride (x>1 for Br2−xClx) this structure is converted into that of the pure dichloride, [Me2HNCH2]2Cl2 (6), with space group P1̅. In all cases the halide anions are trapped in voids between the dications and fixed to the ammonium centers by strong N-H· · ·X and weak C-H· · ·X hydrogen bonding.
Synthesis and Reactivity of Novel Alkali Metal Stannides
Authors: Schollmeier Thorsten , Englich Ulrich , Fischer Roland , Prass Ingo , Ruhlandt Karin , Schürmann Markus , Uhlig Frank
Published: August 2018

Reactivity and side products of reactions of diorganodihydridostannanes (R2SnH2, R = Me, nBu, tBu)) with various alkali metal compounds have been discussed. Alternatively, the synthesis and characterization of a family of novel potassium stannides are described as well. The compounds of type (RR’2Si)R”2SnK (R, R’= Me, Ph; R”= , Me, tBu, Ph) 4 - 9 were synthesized by reaction of potassium hydride with bis(silyl)stannides ((RR’2Si)2SnR”2). All compounds were characterized by multinuclear NMR spectroscopy. In addition, the tri-tert-butyltin compound 3 (LiSntBu3) and the unsymmetrical silyl substituted stannane 10 were characterized by X-ray crystallography.
Polymorphism of Trimeric Perfluoro-ortho-phenylene Mercury, [Hg(o-C6F4)]3
Authors: Haneline Mason R. , Gabbaï François P.
Published: August 2018

Three new modifications of trimeric perfluoro-ortho-phenylene mercury (2) have been investigated by single crystal X-ray diffraction. In each of these modifications, the molecules of 2 form extended stacks. Within each stack, the successive molecules are parallel and separated by approximately 3.3 - 3.4 Å. The packing observed in the different structures is rationalized on the basis of secondary mercury-π interactions, mercuriophilic interactions and electrostatic interactions. Altogether, little preference is given for one particular type of interaction. The packing appears to be dominated by non-directional van der Waals interactions between molecules of 2 which are largely aromatic and whose overall polarizability is magnified by relativistic effects at the mercury(II) centers.
Strukur und Reaktivität von Al2Cp*+ in der Gasphase. Ein experimenteller Beitrag zur Problematik der Aluminium-Aluminium- Doppelbindung / Structure and Reactivity of Al2Cp*+ in the Gas Phase. Experiments on the Problematic Nature of the Aluminum-Aluminum-Multiple Bond
Authors: Koch K. , Schnöckel H.
Published: August 2018

The cation Al2Cp*+ descending from the tetrahedral Al4Cp*4 Cluster after using LDI as ionisation method in an FT-ICR mass spectrometer reacts with Cl2 in the gas phase. The investigation of this reaction together with quantum chemical calculations gives a new approach to the question of existence and stability of an aluminum-aluminum double bond.
Two New Mn(II) and Co(II) Complexes with the Tridentate 2,4,6-Tris(2-pyridyl)-1,3,5-triazine Ligand
Authors: Majumder Arpi , Choudhury Chirantan Roy , Mitra Samiran , Marschner Christoph
Published: August 2018

Two new complexes of manganese(II) and cobalt(II), [Mn(tptz)(OCH3CO)(H2O)2]ClO4 (1) and [Co(tptz) (OSO3) (H2O)2](H2O)2 (2) {where tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine}, have been prepared and characterised by elemental analyses, spectroscopic, electrochemical studies and single crystal X-ray diffraction. Single crystal X-ray analysis reveals complexes of Mn(II) and Co(II), where tptz remains intact and behaves as a tridentate ligand and forms heptacoordinated Mn(II) and hexacoordinated Co(II) complexes for 1 and 2, respectively.
Juglomycins G-J: Isolation from Streptomycetes and Structure Elucidation
Authors: Maskey R. P. , Lessmann H. , Fotso S. , Grün-Wollny I. , Lackner H. , Laatsch H.
Published: August 2018

From the Streptomyces spp. 815 and GW4184, four new 4-juglon-2-ylbutyric acid derivatives, the juglomycins G - J (3a, 4a, 4c, 5c), have been isolated and characterised. The structures were derived from the 1D and 2D NMR data and mass spectra and confirmed by comparison with structurally related compounds. The absolute configuration was deduced from the CD spectra. The new natural products exhibited weak antibacterial activity similar to juglomycin A (5a).
Bioactive Phenylethanoid Glycosides from Buddleia lindleyana
Authors: Lu Jiang-hai , Pu Xiao-ping , Li Yan-yun , Zhao Yu-ying , Tu Guang-zhong
Published: August 2018

Nine phenylethanoid glycosides were isolated from Buddleia lindleyana. On the basis of spectral analyses, their structures were elucidated to be acteoside (1), echinacoside (2), citanoside A (3), leucosceptoside A (4), leucosceptoside B (5), pedicularioside A (6), isoacteoside (7), arenariside (8), and a new compound named buddleoside A (9). The eight known compounds were isolated from this plant for the first time. The neuroprotective effects of compounds 1 (acteoside), 5, 6, 8 and 9 on the 1-methyl-4-phenylpyridinium ion (MPP+)-induced cell death in mesencenphalic neurons were investigated. Mesencenphalic neurons treated with MPP+ underwent cell death as determined by MTT assay. Simultaneous treatment with the phenylethanoid glycosides markedly attenuated MPP+- induced cytotoxicity.
Microwave-Assisted Synthesis of Novel Imidazo- and Pyrimidopyrido[4’,3’:4,5]thieno[2,3-d]pyrimidines
Authors: Ahmed Essam Kh. , Ameen Mohamed A. , Abdel-Latif Fathy F.
Published: August 2018

It is reported on the microwave-assisted synthesis of imidazo- and pyrimidopyrido [4’,3’:4,5]thieno[ 2,3-d]pyrimidines from 2-ethoxymethylene-amino-3-cyano-4,5,6,7-tetrahydrothieno[2,3-c]- pyridine-6-carboxylic acid ethyl ester and 4-chloro-pyridothieno[2,3-d]pyrimidine.
2,2'-Bipyridine Mercury(II) Complexes [Hg(bpy)(NO2)X] (X = NO2 –, SCN– , CH3COO–); Π-Π Stacking In The Crystal Structure Of [Hg(bpy)(NO2)2]
Authors: Ramazani Ali , Morsali Ali , Dolatyari Leila , Ganjeie Bijan
Published: August 2018

The mercury(II) complexes of 2,2′-bipyridine (bpy), [Hg(bpy)(NO2)2], [Hg(bpy)(NO2) (CH3COO)], and [Hg(bpy)(NO2)(NCS)] have been synthesized and characterized by elemental analysis, IR, 1H NMR and 13C NMR spectroscopy. The structure of [Hg(bpy)(NO2)2] has been confirmed by X-ray crystallography. The complex is a monomer and the Hg atom has an unsymmetrical six-coordinate geometry, formed by two nitrogen atoms of the bpy ligand and four oxygen atoms of the two nitrite anions. There is a short intermolecular π-π stacking interaction between parallel aromatic rings
Metallation of Ligands with Biological Activity: Synthesis And X-Ray Characterization of [(SDAZ)2Au2(dppe)] (SDAZ = Sulphadiazinide Anion; dppe = 1,2-Bis(diphenylphosphanyl)ethane)
Authors: Marques Lenice L. , Oliveira Gelson Manzoni , Lang Ernesto Schulz , Burrow Robert A.
Published: August 2018

Sulphadiazine, [4-amino-N-(2-pyrimidinyl)-benzenesulfonamide], reacts with (dppe)Au2Cl2 and triethylamine in methanol to produce [(SDAZ)2Au2(dppe)]. The structure of this novel complex was analyzed by single crystal X-ray diffraction. In [(SDAZ)2Au2(dppe)] the ligands SDAZ− and dppe have approximately the same bond distances and angles as found for the protonated and free ligand, respectively. The compound is assembled essentially of two gold atoms bonded to the phosphorus centers of one 1,2-bis(diphenylphosphanyl)ethane molecule (in an anti conformation). The coordination sphere is completed with a trans sulphadiazine ligand on each gold atom. Because of their fairly high reactivity, the two aromatic amine groups in the SDAZ ligands represent important sites for the chemical modification of the complex with biological purposes
[Bi2O2]2+ Layers in Bi2O2(OH)(NO3): Synthesis And Structure Determination
Authors: Henry Natacha , Evain Michel , Deniard Philippe , Jobic Stéphane , Abraham Francis , Mentré Olivier
Published: August 2018

Bi2O2(OH)(NO3) is the first bismuth oxynitrate containing [Bi2O2]2+ layers for which the crystal structure has been determined. The current study presents its synthesis, formula determination using powder XRD, thermogravimetric analysis and nitrate assay, and finally, crystal structure refinement from twinned crystals. Bi2O2(OH)(NO3) crystallizes in the orthorhombic system, a = 5.3878(11), b = 5.3984(10) and c = 17.136(2) Å , with the space group Cmc21. The structure refinement based on 1257 independent reflections converged to RI (obs) = 0.0321 and RIw (obs) = 0.0765. The Bi2O2(OH)(NO3) structure is based on [Bi2O2]2+ sheets in the (ab) plane. The interlayer space is composed of two slices containing OH− and (NO3)− groups, respectively. Within the nitrate layers, the disorder over two possible NO3- orientations (related by a four fold axis) involves half occupied positions for two of the oxygen atoms. An attempt to lower the symmetry and/or enlarge the unit cell, looking for an (NO3)− ordering, failed
Oxalylierung von N-Phenylanthranilo-O-alkylhydroxamsäuren zu 4-Alkoxy-2,3,4,5-tetrahydro-1H-1,4-benzodiazepin-2,3,5-trionen
Authors: Geffken Detlef , Köllner Maria Anna
Published: August 2018

O-Alkyl (N-phenylanthranilo)hydroxamic acids 2, easily available by condensation of Nphenylanthranilic acid 1 with 1,1’-carbonyldiimidazole and the appropriate hydroxylamine in tetrahydrofuran, are cyclized by oxalyl chloride in the presence of imidazole to give 4-alkoxy-2,3,4,5- tetrahydro-1H-1,4-benzodiazepine-2,3,5-triones (3) in fair to good yields
Enzymes Inhibitory Constituents From Buddleja Crispa
Authors: Ahmad Ijaz , Malik Abdul , Afza Nighat , Anis Itrat , Fatima Itrat , Nawaz Sarfraz Ahmad , Tareen Rasool Bukhsh , Choudhary M. Iqbal
Published: August 2018

Steroidal galactoside 1 and aryl esters 2 and 3 have been isolated from Buddleja crispa, along with ginipin 4, gardiol 5, 1-heptacosanol 6, and methyl benzoate 7, isolated for the first time from this species. The structures of all of the compounds were determined by spectroscopic techniques and chemical studies. The steroidal galactoside 1 is an inhibitor of lipoxygenase. Compounds 1- 3 displayed inhibitory activity against butyrylcholinesterse, while compounds 2 and 3 further showed inhibition against acetylcholinesterase
Prenylated Flavonoids From Pongamia Pinnata
Authors: Yin Hao , Zhang Si , Wu Jun
Published: August 2018

Two new prenylated flavonoids (1, 2), together with five known compounds, were isolated from the stem bark of Pongamia pinnata. Their structures were characterized on the basis of spectral data
Metallkomplexe von 2,2’-Dipyridyldisulfid mit Quecksilber(II)-, Cadmium(II)- und Zink(II)-Halogeniden und mit Cadmium(II)- Trifluormethansulfonat / Metal Complexes of 2,2’-Dipyridyldisulfide with Mercury(II), Cadmium(II), and Zinc(II) Halides and with Cadmium(II) Trifluoromethanesulfonate
Authors: Pickardt Joachim , Chrzanowski Lars von , Steudel Ralf , Borowski Marina , Beck Sebastian
Published: August 2018

Crystals of diiodo-2,2’-dipyridyldisulfide mercury(II) [HgI2(C5H4N)2S2], dichloro-2,2’-dipyridyldisulfide zinc(II) [ZnCl2(C5H4N)2S2], dibromo-2,2’-dipyridyldisulfide cadmium(II) [CdBr2 (C5H4N)2S2], diiodo-2,2’-dipyridyldisulfide cadmium(II) [CdI2(C5H4N)2S2], and diaquo 2,2’-dipyridyldisulfide cadmium(II) trifluoromethanesulfonate [Cd(H2O)2(C5H4N)2S2](CF3SO3)2, were obtained by evaporation of solutions of the ligand and the appropriate metal salts, and their X-ray crystal structures determined
Zwitterionische Imidazolium- und Phosphonium-Derivate der Methylenmeldrumsäure [1,2] / Zwitterionic Imidazolium and Phosphonium Derivatives of Methylene-Meldrum’s Acid [1,2]
Authors: Kuhn Norbert , Al-Sheikh Ahmad , Schwarz Simon , Steimann Manfred
Published: August 2018

2,2-Dimethyl-4,6-dioxo-5-pyridinomethyl-1,3-dioxan-5-yl-pyridinium ylide (9) reacts with 2,3-dihydro- 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1; R1 = iPr, R2 = Me) to give the zwitterionic imidazolium derivative 2,2-dimethyl-4,6-dioxo-5-(1,3-diisopropyl-4,5-dimethylimidazoliomethyl)- 1,3-dioxan-5-yl-imidazolium ylide (4) in good yield. Similarly, the phosphonium compound 2,2-dimethyl-4,6-dioxo-5-triphenylphosphoniomethyl-1,3-dioxan-5-yl-phosphonium ylide (5) is obtained from 9 and PPh3. The crystal structures of 4 and 5 are reported
Tumor Necrosis Factor-α Production-Enhancing Properties of Novel Adamantylalkylthio Derivatives of Some Heterocyclic Compounds
Authors: Orzeszko Barbara , Świtaj Tomasz , Jakubowska-Mućka Anna B. , Lasek Witold , Orzeszko Andrzej , Kazimierczuk Zygmunt
Published: August 2018

Certain adamantylated heterocycles were previously shown to enhance the secretion of tumor necrosis factor alpha (TNF-α) by murine melanoma cells that have been transduced with the gene for human TNF-α and constitutively expressed this cytokine. The stimulatory potency of those compounds depended, among other factors, on the structure of the linker between the adamantyl residue and the heterocyclic core. In the present study, a series of (1-adamantyl)alkylsulfanyl derivatives of heterocyclic compounds was prepared by alkylation of the corresponding thioheterocyles. Of the novel adamantylalkylthio compounds tested in the aforementioned cell line, 2-(2-adamantan-1-ylethylsulfanyl)- 4-methyl-pyrimidine was found to be the most active
A Novel Method for Synthesizing Crystalline Copper Carbodiimide, CuNCN. Structure Determination by X-Ray Rietveld Refinement
Authors: Liu Xiaohui , Wankeu Martial Aime , Lueken Heiko , Dronskowski Richard
Published: August 2018

Well-crystallized copper carbodiimide, CuNCN, was synthesized by the slow oxidation of a copper(I) cyanamide precursor under aqueous conditions. The X-ray powder data evidence the orthorhombic system and space group Cmcm with a = 2.9921(1), b = 6.1782(1), c = 9.4003(2) Å , V = 173.769(5) Å3 and Z = 4. There is a strongly distorted octahedral Cu2+ coordination reflecting a typical first-order Jahn-Teller effect, with interatomic distances of 4×Cu-N = 2.001(2) Å and 2×Cu-N = 2.613(3) Å ; the NCN2− unit adopts the carbodiimide shape with C-N = 1.227(4) Å . Despite the formal d9 electron count of Cu2+, CuNCN exhibits a small temperature-independent paramagnetism and is likely to be a metallic conductor.
Fragmentable Heterogeneous Cocatalysts for the Metallocene-Catalyzed Polymerization of Olefins, II [1]. Preparation, Characterization and Testing of the Cocatalysts and Microscopic Evaluation of the Polyethylene
Authors: Schumann Herbert , Widmaier Ralf , Lange Katharina C. H. , Wassermann Birgit C.
Published: August 2018

Surface modified silica were reacted with different aluminiumalkyls AlR2R’ (R = Me, Et, i-Bu, R’ = H, Me, Et, i-Bu), oligomeric methylaluminoxane (MAO) and combinations of both, to yield heterogeneous cocatalysts. These cocatalyts were employed to polymerize ethylene using zirconocene dichloride as the catalyst. The polymerization activity profiles have been recorded and compared with the information gained from the scanning electron microscopy (SEM) images of the polymers. The fragmentation of the heterogeneous cocatalyts upon polymerization has been demonstrated. The degree of fragmentation and the polymerization activity depend on the preparation of the silica supports and on the preparation of the heterogeneous cocatalysts using these supports. The most reactive, fragmentable heterogeneous cocatalysts show polymerization activities slightly higher than MAO in homogeneous solution and almost 1.5 times higher than commercially available MAO on silica (=MAO on Sylopol).
Polysulfonylamine, CLXXIII [1]. Intermolekulare Wechselwirkungen in kristallinen Di(organosulfonyl)aminen. – Teil 2 [2]. Strukturvergleich f ¨ur Di(4-X-benzolsulfonyl)amine mit X = Fluor, Chlor, Brom oder Methyl / Polysulfonylamines, CLXXIII [1]. Intermolecular Interactions in Crystalline Di(organosulfonyl) amines. Part 2 [2]. Comparing the Stuctures of Di(4-X-benzenesulfonyl)amines, where X is Fluorine, Chlorine, Bromine, or Methyl
Authors: Henschel Dagmar , Hamann Thomas , Moers Oliver , Jones Peter G. , Blaschette Armand
Published: August 2018

Low-temperature X-ray structures of the following di(4-X-benzenesulfonyl)amines, HN(SO2-C6H4-X)2, are compared in order to study the effects of the 4-substituents on the molecular packings: X = F (1, monoclinic, C2/c, Z′ = 1), X = Cl (2, monoclinic, C2/c, Z′ = 1/2, N-H bonds lying on twofold rotation axes), X = Me (3, orthorhombic, Pbca, Z′ = 1), X = Br (4A, monoclinic, P21/c, Z′ = 1), X = Br (4B, monoclinic, P21/c, Z′ = 2). As a common feature, the molecules of the halogen compounds, including two polymorphs of 4, are associated into catemers by strong hydrogen bonds of the type N-H···O in 1, 4A and 4B or N-H(···O)2 in 2. These molecular chains are assembled in the crystal structures via different packing modes, which underline the well-known correlation between the atomic number of halogen atoms and their propensity to form halogen bonds. Thus, the structure of 1 is devoid of short C-F···O/N contacts, but close F···F contacts are tolerated, whereas in 2 each catemer is connected to four parallel congeners by long and bifurcated C-Cl(···O)2 bonds, and both polymorphs of 4 display layers in which the molecules are connected by N-H···O bonds in one and by relatively short and approximately linear C-Br···O interactions in the other dimension. Despite the alleged steric equivalence of methyl and chloro substituents (“chloro-methyl exchange rule”), the packing architecture of the methyl compound 3 is not related to any of the preceding structures. In this case, the N-H···O bonding leads to centrosymmetric cyclodimers, which pack in such a way that each methyl group is located between two oxygen atoms and above the face of an aromatic ring in a topology consistent with C-H···O and C-H···C(π) bonding. All the structures are pervaded by weak Car-H···O hydrogen bonds; moreover, 1 displays a short C-H···F hydrogen bond and a C-F···C(π) interaction, and π-stacking of aromatic rings is observed in 1, 3 and 4B