bluuebunny/crossref_metadata_2025 huggingface dataset:
Bis(silylation) of Tris(dimethylamino)phosphonium Methylide
Authors: Dreihäupl Karl-Heinz , Bauer Andreas , Schmidbaur Hubert
Published: August 2018

Treatment of (Me2N)3PCHSiMe3 with Me3SiOTf (OTf = triflate) affords the phosphonium salt [(Me2N)3PCH(SiMe3)2]OTf (2a), which can be converted into the correspond­ing ylide (Me2N)3PC(SiMe3)2 (3a) in high yield using NaN(SiMe3)2. The compounds with SiMe2Ph substituents (2, 3b) are obtained following an analogous procedure. The ylide (Me2N)3PC[Si(OMe)3]2 (3c) is available in 50% yield by direct transylidation of (MeO)3SiOTf with (Me2N)3PCH2 in the molar ratio 2:3, with [(Me2N)3PMe]OTf as the by-product. Com­pound 3c is a distillable liquid, but 3a,b are crystalline solids the structure of which has been determined by single crystal X-ray diffraction. Both compounds feature a trigonal planar ylidic carbon atom and short ylidic P-C and Si-C bonds. The nitrogen atoms are also in a planar configuration with non-standard orientations of the NMe2 groups at the phosphorus atoms. These data are in agreement with the results of recent quantum chemical calculations of simple prototypes which show very flat energy profiles for internal motions (rotation, inversion) of dimethylamino groups at the phosphorus atoms in phosphines and phosphoranes.
Laboratory Stopped-Flow XAFS Apparatus. Structure Determination of the Short-Lived Peroxochromium Intermediate Formed during Reduction Process of Chromate(VI) Ion by Hydrogen Peroxide
Authors: Inada Y. , Funahashi S.
Published: August 2018

In order to determine the structure parameters of the reaction intermediate formed during the reduction process of chromate(VI) ion by hydrogen peroxide, a laboratory stopped-flow X-ray absorption fine structure (XAFS ) apparatus, which was constructed by a rotating anode X-ray generator, an energy scanning spectrometer, a stopped-flow assembly, and X-ray detectors, was newly developed. Using the apparatus, the Cr K -edge XAFS spectrum of the reaction intermediate was measured. One oxo group, two peroxo groups, and one water molecule are coordinated to the Cr(VI) center in the intermediate, CrO(O2)2(H2O ) , with Cr - O bond lengths of 157, 168, and 193 pm, respectively. The geometry around the Cr(VI) center is probably 6-coordinate pentagonal pyramidal.
Kristallstruktur von [PMePh3] [Cl - 1 - C≡C - Ph]/Crystal Structure of [PMePh3] [Cl - I - C≡C - Ph]
Authors: Ghassemzadeh Mitra , Harms Klaus , Dehnicke Kurt
Published: August 2018

The donor-acceptor complex [Cl-I-C≡C-Ph]- has been prepared as the methyl-triphenyl-phosphonium salt from 1-iodo-2-phenylacetylene and [PMePh3]N3 in CH2Cl2 solution. It forms co­lourless single crystals which were characterized by a crystal structure determination. Space group Pbca, Z = 8, lattice dimensions at -80 °C: a = 1047.1(1), b = 1700.3(1), c = 2793.2(1) pm, R = 0.035. The chloride ion is coordinated at the io­dine atom of the 1-iodo-2-phenylacetylene molecule in a nearly linear arrangement [CI-I-C≡C-Ph]- with bond lengths I-Cl of 302.4 pm and I-C of 203.1(5) pm.
Darstellung und Kristallstrukturbestimmung von 1,2-Di-t-butyl-1,2-diiodo- diarsan (t-C4H9AsI)2 und Synthese von 1,2,3,4-Tetrakis(t-butyl)tetraarsetan (t-C4H9As)4 über selektive Reduktion von t-Butylarsendiiodid t-C4H9AsI2 Synthesis and Crystal Structure of 1,2-Di-t-butyl-1,2-diiododiarsane (t-C4H9AsI)2 and Synthesis of 1,2,3,4-Tetrakis(t-butyl)tetraarsetane (t-C4H9As)4 via Selective Reduction of t-Butylarsenic Diiodide t-C4H9AsI2
Authors: Megges Klaus , Avtomonov Evgeni V. , Lorberth Jörg
Published: August 2018

1,2,3,4-Tetrakis(t-butyl)tetraarsetane (t-C4H9As)4(4) has been synthesized by reduction of t-butylarsenic (III) diiodide (1) with equivalent quantities of either Mg, Ca, Zn, Li, or CoCp2 in THF at low temperatures in high yields. Treatment of 1 with CoCp2 in a molar ratio 1:1 in n-pentane at -78 °C leads to the formation of 1,2-di-t-butyl-1,2-diiododiarsine (2) (t-C4H9AsI)2 in 69 % yield. The products have been characterized by spectroscopic methods (H, 13C-NMR, EI-MS) and elemental analyses. The crystal structure of 2 has been determined by X-ray diffraction methods.
Strukturen zweier isomerer Gadolinium(III)-Polyaminopolycarboxylate -Argumente für signifikante Unterschiede ihrer 1H-NMR-Relaxation/Structures of Two Isomeric Gadolinium(III) Polyamino Polycarboxylates -Relation to their Significant Differences in 1H NMR Relaxation
Authors: Ruloff Robert , Gelbrich Thomas , Sieler Joachim , Hoyer Eberhard , Beyer Lothar
Published: August 2018

We present preparation and X-ray crystal structures of gadolinium(III) complexes with two isomeric ligands; triethylenetetraminehexaacetic acid, H6ttha, and tris(2-aminoethyl)amine-hexaacetic acid, H6ttaha, respectively. In case of [C(NH2)3]2[Gd(Httha)] · 5 H2O (1) the inner coordination sphere is made up of 9 donor atoms of the ligand and reflects the low efficiency in accelerating 1H NMR relaxation of an aqueous solution. In case of [C(NH2)3]3[Gd(ttaha)] · 3 H2O (2) the coordination number of 9 is realized via 7 donor atoms of the ligand and 2 oxygen atoms of a pending acetate group of the adjacent complex. Luminescence studies in aqueous solution confirm replacement of this acetate group by 2 water molecules. The relaxivity of [Gd(Httaha)]2- is 7.3 ± 0.1 mM -1 s -1 as determined at pH = 7.2, 20 MHz and 40°C.
Mechanismus der Cyclotrimerisierung von Phenylvinylketonen und die Kristallstrukturen von 1-((1R*,2S*,3R*,5S*)-und 1-((1R*,2S*,3R*,5R*)- 3.5-Dibenzoyl-2-hydroxy-2-phenylcyclohexylmethyl)-pyrrolidin-2-on/The Mechanism of Cyclotrimerisation of Phenylvinylketones and theCrystal Structures of 1-((1R*,2S*,3R*,5S*)-and1-((1R*,2S*,3R*,5R*)-3.5-Dibenzoyl-2-hydroxy-2-phenylcyclohexylmethyl)-pyrrolidin-2-on
Authors: Möhrle H. , Wille R. , Middelhauve B. , Mootz D. , Wunderlich H.
Published: August 2018

The cyclotrimerisation of 1-phenyl-2-propyn-1-ol (1) with pyrrolidin-2-one (2) to the tribenzoylcyclohexanes 4 and 5 produced -with modifications of the reaction conditions -the phenylvinylketone adducts 17 and 18 as intermediates and additionally the cyclohexylmethyl-pyrrolidin-2-ones 8 and 9. Obviously the mechanism consists of a primary attack of pyrrolidin-2-onat (2a) to a phenylketone (7) followed by a series of consecutive Michael reactions, which give rise to 4 and 5 as well as to 8 and 9. The latter two have been identified by X-ray crystal structure analyses. They crystallize in the monoclinic space group P21/c, Z=4, with 8: a = 1786,8(6), b = 636.7(2), c = 2280.9(8) pm, β = 102.33(3)°; 9: a = 1119.9(7), b = 1165.1(3), c = 2198.6(5) pm, β = 118.24(4)°.
Acyclo C-Nucleosides Analogues of Condensed 1,2,4-Triazines
Authors: El Ashry El Sayed H. , Rashed Nagwa , Hamid Hamida Abdel , Ramadan El Sayed
Published: August 2018

1-Acyclo C-nucleosides of 7-methyl-10H-1,2,4-triazolo[3’,4’:3,4][1,2,4]triazino[5,6-b]indoles (9) have been prepared by cyclodehydrogenation of the sugar derivatives of 3-hydrazino-8-methyl-5H-1,2,4-triazino[5,6-b]indole (1). The respective linear isomer as 4 has been prepared by a dehydrative cyclization of the amides of 1. Acetylation of the sugar hydrazones and their cyclized products gave the per-N,O-acetyl derivatives. The molecular connectivity of the products was established by 1H, 13C, and 2D H ,H Cosy spectra.
Darstellung und Kristallstruktur von P4O8 / Preparation and Crystal Structure of P4O8
Authors: Strojek Stephan , Jansen Martin
Published: August 2018

P4O8 was synthesized for the first time in a pure state. Its crystal structure has been refined using X-ray diffractometer data (monoclinic, C2/c with a = 970.0(2); b = 1017.9(2); c = 692.3(1) pm; β = 96.95(2)°; V = 678.5 Å3; R1 = 0.033; wR2 = 0.073). Molecular geometry and packing in the solid state are discussed.
Darstellung, 11B-,13C-,1H-NMR- und Schwingungsspektren von Phenylundecahydro-closo-dodecaborat(2-) sowie Kristallstruktur von [As(C6H5)4]2[(C6H5)B12H11] / Preparation, 11B-, 13C-, 1H-NMR- and Vibrational Spectra of Phenylundecahydro-closo-dodecaborate(2-) and Crystal Structure of [As(C6H5)4]2[(C6H5)B12H11]
Authors: Koch T , Preetz W
Published: August 2018

By reaction of [N(C4H9)4]2[B12H12] with chlorotriphenyltin at 170 °C the phenylundecahydro-closo-dodecaborate anion [(C6H5)B12H11]2- is formed which can be isolated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The crystal structure of [As(C6H5)4]2[(C6H5)B12H11] has been determined by single crystal X-ray diffraction analysis; triclinic, space group P1̄

with a = 11,0066(11), b = 11.1371(6), c = 22.236(2) Å, α = 93.040(6), β = 92.981(8), γ = 100.254(6)°, Z = 2. The 11B NMR spectrum reveals the features (1:5:5:1) of a monosubstituated B12 cage with the ipso B atom at - 6.1 and the antipodal B at -17.4 ppm. The 13C and 1H NMR spectra show the characteristic patterns of the phenyl group. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2464 and 2519 cm-1 and the CC stretching vibrations in the range of 1405 to 1592 cm-1.
N-Boryl-Substituted Bis(amino)stannylenes and -plumbylenes
Authors: Wrackmeyer Bernd , Weidinger Jürgen
Published: August 2018

Two equivalents of N-lithio-N-trimethylsilyl-amino-9-borabicyclo[3.3.1]nonane (1) react with tin and lead dichloride by salt elimination to give the corresponding bis(amino)stannylene 2 and -plumbylene 3, respectively. The compounds 2 and 3 are monomers in solution and were characterized by 1H, 13C, 14N, 29Si, 119Sn and 207Pb NMR spectroscopy.
Silyl Derivatives of the Mixed Sandwiches Cyclopentadienyl Manganese Benzene and Cyclopentadienyl Manganese Biphenyl, CpMn(C6H6) and CpMn(C6H5-Ph)
Authors: Herberhold Max , Hofmann Thomas , Weinberger Stefanie , Wrackmeyer Bernd
Published: August 2018

Mixed manganese sandwich complexes containing a silyl-substituted cyclopentadienyl ring, e. g. (η5 - C5H4 - R)Mn(η6- C6H6) (3a - c) and (η5- C5H4 - R)Mn(η6- C6H5 - Ph) (4a - c); (R = SiMe3 (a), Si2Me5 (b) and SiMe2
tBu (c)), were obtained in low yield via intermediates {(η5 - C5H4 - R)MnCl} and their reaction with phenyl Grignard reagents. Use of the 4-trimethylsilyl-phenyl magnesium halide in the reaction with the intermediate {CpMnCl} led to complexes with silylsubstituted arene rings, CpMn(η6 - C6H5 - R′) (5a) and CpMn(η6 -R′ - C6H5 - C6H5 - R′) (6a); (R′ = SiMe3 (a)). Dilithiation of CpMn6H6) (1) and subsequent reaction with a chlorosilane gave (η5-C5H4 - R)Mn(η6 - C6H5 - R′) (7a,b); (R = R′ = SiMe3 (a), Si2Me5 (b)). A cyclophane 8 in which five- and six-membered ring are linked through a -Me2Si-SiMe2- bridge was obtained using 1,2-dichloro-tetramethyldisilane. The mixed manganese sandw ich complexes were thoroughly characterized by 1H , 13C, 29Si and 55Mn NMR spectroscopy. The 55Mn spectra can be used to detect low-yield side-products.
SolvatothermaleDarstellung und Struktur von [Me4N]2[As6S10] und [Me4N]2[As4S7], dem ersten Thioarsenat(III) mit Ψ -AsS4trigonalen Bipyramiden / Solvatothermal Synthesis and Structure of the Thioarsenates(III) [Me4N]2[As6S10] and [Me4N]2[As4S7], the First Thioarsenate(III) with Ψ-AsS4 Trigonal Bipyramids
Authors: Vater Viola , Sheldrick William S.
Published: August 2018

The tetramethylammonium thioarsenate(III) [Me4N]2[As6S10] (1) has been prepared together with the minor product [Me4N]2[As4S7] (2) by reaction of [Me4N]Cl with As2S3 and Na2S in acetonitrile at 115 °C. The polymeric anion of 1 consists of adjacent 1
∞[As3S5
-] chains linked together into a 1
∞[As6S10
2-] double chain through planar As2S2 rings involving As atoms of every second constituent ring-shaped As3S6 building unit. A relatively undistorted Ψ-AsS4 trigonal bipyramidal geometry is observed for the participating As atoms. Individual As3S6 units are linked by bridging AsS3 pyramids into the zweier single chains 1
∞[As4S7
2-] in 2.
Atomvolumen, Atomabstände und chemische Bindung in festen metallischen Elementen/Atomic Volume, Atomic Distances and Chemical Bonding in Solid Metallic Elements
Authors: Trömel Martin , Hübner Sven
Published: August 2018

Relationships between bond lengths and bond numbers and also between atomic volumes and valencies are derived and parameters for their calculation are given for the s-block, p-block, and d-block metals. From the atomic volumes under pressure, the valencies of three solid lanthanoids have been confirmed or redetermined: La 3; Ce 2. 3. and 4; Yb 2 and 3.
Notizen: Crystal Structure of a Lithium Chloride Cubane Cluster Solvated by Diethyl Ether
Authors: Mitzel Norbert W. , Lustig Christian
Published: August 2018

The thermally highly unstable diethyl ether solvate of lithium chloride was crystallised and its crystal structure determined. It consists of a cubic cluster of the composition Li4Cl4 with each of the four Li atoms coordinated to a molecule of diethyl ether.
Spectroelectrochemical Investigation of Pentacarbonyl(pyrazine)metal(0) (Metal = Cr, Mo, W) Complexes of Group 6 Elements
Authors: Yaman Şeniz Özalp , Esentürk Emren , Kayran Ceyhan , Önal Ahmet M.
Published: August 2018

The electrochemical behaviour of pentacarbonyl(pyrazine)metal(0) complexes of the group 6 elements was studied by cyclic voltammetry in dichloromethane-(n-Bu)4NBF4 solventelectrolyte couple at -20°C vs. Ag/Ag+ or SCE reference electrode. Constant potential electrolyses of the complexes were carried out at their first oxidation peak potentials and monitored in situ by UV-Vis spectrometry. Electrolysis of W(CO)5pz produces [W(CO)5pz]+ and a similar electrochemical mechanism is expected both for Cr(CO)5pz and Mo(CO)5pz complexes. In situ low temperature constant current ESR electrolysis also confirmed the production of [W(CO)5pz]+ after the electron transfer.
A Xanthone Dixylopyranoside from Swertia thomsonii
Authors: Ahmad Viqar Uddin , Rahman Inayat-ur- , Khana Murad Ali , Arfan Muhammad , Siddiqui Mohammad Tariq
Published: August 2018

A xanthone dixylopyranoside has been isolated from Swertia thomsonii C. B. Clarke and its structure established as 1,7-dihydroxy-3,8-dimethoxyxanthone 1-O-[β-D-xylopyranosyl- (1→4)D-xylopyranoside on the basis of spectral evidence, particularly 2D NMR studies. Three known compounds, 1,7-dihydroxy-3,8-dimethoxyxanthone, swertianin (1,7,8-trihydroxy- 3-methoxy-xanthone) and ursolic acid were also isolated from this species.
Synthesis and EPR Evaluation of the Nitrone PBN-[tert-13C] for Spin Trapping Competition
Authors: Zhang Yong-Kang , Maples Kirk R.
Published: August 2018

N-[tert-13C]Butyl C-phenyl nitrone (PBN-[tert-13C]) has been synthesized for an EPR spin trapping competition study. The newly synthesized PBN-[tert-13C] shows different 13C-hyperfine splitting constants (a13C) when it traps free radicals as compared to another 13C-labeled PBN analogue, N-tert-butyl C-phenyl [nitronyl-13C]nitrone (PBN-[nitronyl-13C]). The PBN- [tert-13C] hydroxyl adduct gives a larger a13C value (5.14 G) as compared to the PBN-[nitronyl-13C] hydroxyl adduct (4.36 G). This gain ofthe a13C value decreases the chance of EPR signal overlap, thus providing a more resolved EPR spectrum when PBN-[tert-13C] is used as an internal standard for EPR spin trapping competition studies of hydroxyl radical formation.
Crystal Structures and Properties of Eu2GeSe4 and Eu2Ge2Se5
Authors: Tampier M. , Johrendt D. , Pöttgen R. , Kotzyba G. , Rosenhahn C. , Mosel B. D.
Published: August 2018

Europium selenogermanate(IV) and Europium selenogermanate(III) were synthesized by direct reactions of the elements at 1023 K and their crystal structures determined by single crystal methods. α-Eu2GeSe4 (P21, a = 6.964(1), b = 7.055(2), c = 8.400(2) Å , β = 108.12(2)˚, Z = 2) crystallizes as a polar variant of the monoclinic Sr2GeS4-type at room temperature. At 673 K, the structure is centrosymmetric (β-Eu2GeSe4, P21/m, a = 6.969(1), b = 7.059(2), c = 8.516(2)Å , β = 107.99(2)˚, Z = 2), and a phase transition P21→P21/m as known from Eu2GeS4 is highly probable. Eu2Ge2Se5 (P21/n, a = 8.421(4), b = 12.235(4), c = 9.127(3) Å,β = 93.67(4)˚, Z = 4) crystallizes in the Sr2Ge2Se5 type, mainly characterized by complex [Ge4Se10]8- anions with homonuclear Ge-Ge bonds. Both compounds are deep red Zintl phases according to (Eu2+)2Ge4+(Se2-)4 and (Eu2+)2(Ge3+)2(Se2-)5. Magnetic susceptibility measurements show paramagnetic behavior above 20Kwith magnetic moments of 8.00(5) μB/Eu and 8.10(5) μB/Eu, respectively, indicating Eu2+. Eu2Ge2Se5 orders antiferromagnetically at TN = 4.2(2) K and undergoes a metamagnetic transition at 2 K at a critical field of 0.5(3) T. The saturation moment at 2.2 K and 5.5 T is 7.00(2) μB/Eu. Eu2GeSe4 is a ferromagnet with TC = 5.8(2) K and a saturation moment at 2.2 K and 5.5 T of 6.92(2) μB/Eu. 151Eu Mössbauer spectroscopic measurements of Eu2GeSe4 and Eu2Ge2Se5 at 78 K show isomer shifts of -12.43(4) mm/s and -12.69(5) mm/s, respectively, in accordance with divalent europium.
Two New Triterpenes from Fern Adiantum incisum
Authors: Hayat Safdar , Rahman Atta-ur , Choudhary M. Iqbal , Khan Khalid Mohammed , Latif Hamied , Bayer Ernst
Published: August 2018

Two new triterpenes, adininaneone (1) and adininaonol (2) were isolated from Adiantum incisum. Three known triterpenes, adiantone (3), isoadiantone (4) and 23-hydroxyfernene (5) were also isolated for the first time from the methanolic extracts of A. insicum. The structures were elucidated with the help of modern spectroscopic techniques.
Tri(1-cyclohepta-2,4,6-trienyl)- phosphane, P(C7H7)3, as a Tripodal Tetradentate Ligand in Cationic, Five-coordinate Complexes of Platinum(II) and Palladium(II)
Authors: Herberhold Max , Schmalz Thomas , Wrackmeyer Bernd
Published: August 2018

Chloride abstraction, using AgPF6, from tri(1- cyclohepta-2,4,6-trienyl)phosphane platinum and palladium dichloride, [P]MCl2 [M = Pt (1), Pd (2)], affords the complexes {[P]MCl}PF6 [M = Pt (3), Pd (4)] in good yields. The central metal is coordinated by the chloro ligand, the phosphorus atom and by three η2-C=C units, one of each C7H7 ring. This assignment of a highly symmetrical C3v structure is based on a consistent set of NMR data (1H, 13C, 31P, 195Pt NMR), in agreement with NMR data of the corresponding known neutral iridium and rhodium complexes [P]MCl [M = Ir (5), Rh (6)]. The chemical shift δ103Rh of 6 was determined, and a nearly linear relationship δ195Pt / δ103Rh was established.
Magnetic Super-Exchange Mechanism and Crystal Structure of a Binuclear μ-Acetato-Bridged Copper(II) Complex of Pentadentate Binucleating Ligand.An Influence of Overlap Interactions to Magnetic Properties
Authors: Kavlakoglu Ebru , Elmali Ayhan , Elerman Yalçin
Published: August 2018

[Cu2(L)(O2CMe)· 1/2H2O (L = 1,3-bis (2-hydroxy-5-chlorosalicylideneamino)propan-2-ol) was synthesized and its crystal structure determined. (C19H16N2O5Cl2Cu2)· 1/2H2O, monoclinic, space group P 21/c, a = 20.660(10), b = 9.618(2), c = 21.810(10) Å3 , β = 109.3(8)­­°, V = 4090(2) Å3, Z = 8. The crystal contains two independent dicopper(II) complexes and an uncoordinated molecule of water in the asymmetric unit. In both molecules of the asymmetric unit, the two copper(II) ions are bridged by the alkoxo group of the ligand and by an acetato group. Magnetic susceptibilities of the complex in the solid state were measured over the temperature range 4.6 - 308 K. The title compound shows weak antiferromagnetic coupling with a best fit J value of -89.6 cm-1, which is interpreted in terms of a compensation effects of the different bridging ligands which participate in the super-exchange interactions. Ab initio restricted Hartree-Fock calculations have shown that the acetato bridge and the alkoxide bridge contribute to the magnetic interaction countercomplementarily to reduce antiferromagnetic interaction.
Palladium-Cadmium Ordering In Repdcd (Re = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) And Comparison With Isotypic Indium Compounds
Authors: Fickenscher Thomas , Hoffmann Rolf-Dieter , Mishra Ratikanta , Pöttgen Rainer
Published: August 2018

Ternary intermetallic compoundsREPdCd (RE=La, Ce, Pr, Nd, Sm, Eu, Tb)were synthesized by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. All compounds were investigated by X-ray diffraction on powders. Those with RE = La, Ce, Pr, Nd, Sm, and Tb contain trivalent rare earth metals and they crystallize with the hexagonal ZrNiAl type structure. NdPdCd [a = 764.8(3), c = 401.3(2) pm] and TbPdCd [a = 756.5(2), c = 389.0(1) pm] are reported here for the first time as well as EuPdCd. The compounds with La, Ce, Pr, and Sm [J. Alloys Compd. 182, 87 (1992)] are confirmed. The crystal structure of EuPdCd was refined from X-ray single crystal diffractometer data: TiNiSi type, Pnma, a = 745.9(3), b = 439.8(2), c = 863.7(3) pm, wR2 = 0.0405, 683 F2 values, and 20 variable parameters. The three-dimensional [PdCd] substructure consists of strongly puckered, orthorhombically distorted Pd3Cd3 hexagons with Pd-Cd distances ranging from 283 to 285 pm. The europium atoms fill the cavities within the [PdCd] network. Chemical bonding in the series REPdCd and REPdIn is compared.
Optically Active Cyclopentadienyl Ligands from the Chiral Pool, Part 1. The Synthetic Utility of a Camphor-Derived Pentafulvene
Authors: Quindt Valeri , Wallasch Mark , Wolmershäuser Gotthelf , Sitzmann Helmut
Published: August 2018

Starting from (1R)-(+)-camphor, the reaction with cyclopentadienylmagnesium chloride gave the corresponding tertiary alcohol 1, which was transformed into the optically active pentafulvene 5-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)cyclopentadiene (2) by acidcatalyzed water elimination. Deprotonation with tert-butyllithium yielded the corresponding lithium 5-{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl}cyclopentadienide (3), which was converted into the non-racemic 1,1β-bis{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2- yl}ferrocene (4). 4 forms orthorhombic crystals of the space group P212121 with a = 7.7163(4), b = 10.7381(6), and c = 28.804(2) A˚ , which have been subjected to X-ray diffraction.
Mass Spectrometry of Oligomeric Cyanines and Squaraines of the Indole Series: Fast Atom Bombardment-Induced Chemical Reactions
Authors: Dülcks Thomas , Grahn Walter , Johannes Hans-Hermann , Lawrentz Ulf , Rittner Miriam , Schiebel Hans-Martin , Schulze Peter
Published: August 2018

Fast atom bombardment (FAB) has been used for mass spectrometric characterization of oligomeric cyanines and squaraines of the indole series which are linked by different aromatic spacers. Markedly different results were obtained for the oligomers and for the corresponding monomers. In addition to the expected mono-anions and mono-cations, ions of high relative abundance were detected which can only be explained on the basis of FAB-induced chemical reactions of the initial oligomers. Formation of allenes, hydrogenation and dehydrogenation, respectively, is characteristic for this class of compounds under FAB-conditions.
Orthoamide, LVIII . Kondensationsreaktionen von CH2-aciden Verbindungen mit Orthoamiden von Carbonsäuren und Alkincarbonsäuren / Orthoamides, LVIII . Condensation Reactions of CH2-Acidic Compounds with Orthoamides of Carboxylic Acids and Alkyne Carboxylic Acids
Authors: Kantlehner Willi , Haug Erwin , Stieglitz Rüdiger , Frey Wolfgang , Kress Ralf , Mezger Jochen
Published: August 2018

The orthoamide derivatives 1s and 2e were prepared from the guanidinium salt 7a and the appropriate carbanions. Cleavage of the orthoamide 2e with benzoyl chloride affords the amidinium salt 10a, which can be transformed into the amidinium salt 10b by an anion exchange reaction. The enamines 11a-i, 12a-c, 13a, b, 14a-c, 15a, b, 16, 17a, b, 18a, b, 19a, b, 20 were prepared by condensation of CH2-acidic compounds with the carboxylic acid orthoamides 2a-j. The orthoamide 2d reacts with 1-nitropropane to give the amidinium salt 27a which is transformed into the salt 27b. From benzyl cyanide and orthoamides 2g, i the enamines 30 and 32 were obtained. Similar condensation reactions were performed with the orthoamides of alkyne carboxylic acids 1b, 1c, 1d, 1e, 1p, 1s, giving the push-pull-butadiene derivatives 35a-f, 36a-f, 37a-j, 38a, b, 39a, b, 40a, b. Crystal structure analyses of the butadiene derivatives 37a, 39a, b, 40a, b and 42 were performed, showing that in 37a, 39b, 40a, b by far the shortest bond distance is between C-2 and C-3 of the butadiene system. In 39a the bonds between C1-C2, C2-C3 and C3-C4 are nearly of equal length, whereas in the 1,3-diene unit of 42 the shortest bonds are between C1-C2 and C3-C4.
Preparation and Characterisation of Several New N-Disubstituted 2-Aminoselenophene Derivatives
Authors: Zug Ines , Hartmann Horst
Published: August 2018

N,N'-Persubstituted selenoacrylamides (4), easily available by reaction of 1-chlorovinamidinium salts (2) with sodium selenide, were transformed by means of acceptor-substituted halomethyl compounds (9-14) into new 2-aminoselenophene derivatives (15-20).Their UV/ vis data are presented, and the positive solvatochromism of 2-R2N-5-acceptor-substituted selenophenes is reported.
A New Layered Chalcogenide in the System NiIn2S4-NiIn2Se4
Authors: Memo A. , Haeuseler H.
Published: August 2018

The system (1 - x)NiIn2S4 - xNiIn2Se4 has been investigated by X-ray powder methods. The subsolidus phase diagram is constructed in the temperature interval 600 -1000 °C. The spinel type NiIn2S4 exhibits a phase width up to the composition NiIn2S2Se2 at 900 °C and NiIn2S2.8Se1.2 at 600 °C. A new layered compound is formed for 0.7 ≥ x ≥ 0.5 at 600 °C and for x = 0.6 at 900 °C which crystallizes in the MgAl2S4-type with a = 392.4 and c = 3739.6 pm (x = 0.6) for the hexagonal cell.
Polysulfonylamine, CLI [1]. Starke und schwache Wasserstoffbrücken in den Kristallstrukturen von 8-Hydroxychinolinium- und 8-Aminochinolinium-dimesylamid / Polysulfonylamines, CLI [1]. Strong and Weak Hydrogen Bonding in the Crystal Structures of 8-Hydroxyquinolinium and 8-Aminoquinolinium Dimesylamide
Authors: Henschel Dagmar , Moers Oliver , Wijaya Karna , Blaschette Armand , Jones Peter G.
Published: August 2018

In order to study hydrogen bonding networks and packing arrangements in ionic organic crystals, low-temperature X-ray structures were determined for two chemically related onium salts BH+(MeSO2)2ND, where BH+ is 8-hydroxyquinolinium (1; monoclinic, space group P21/ c, Z´ = 1) or 8-aminoquinolinium (2; monoclinic, P21/n, Z´ = 1). The packings are governed by strong hydrogen bonds, π-π stacking interactions and weak hydrogen bonding. In both compounds, hydrogen bonds using the NH/OH donors of the cations and O/N acceptors of the anion result in simple chain polymeric structures, which extend parallel to the y axis and are propagated by translation (1) or 21 transformation (2). Moreover, an intramolecular N- H···O hydrogen bond is present in the 8-hydroxyquinolinium cation. As a common feature, the anion substructures are pervaded by hexagonal channels parallel to y, each one accommodating either two separate stacks of translation related cations (1) or a unique (merged) stack of inversion related cations (2). The crystal cohesion is reinforced by numerous weak hydrogen bonds of the types Car-H···O=S and CH2-H···O=S, the latter creating in each structure a topologically different double-chain ribbon of anions. All C-H···O contacts taken into consideration have normalized parameters d(H···O) ≤ 268 pm and θ(CDH···O) ≥ 126°.
Synthesis of 9-Methoxy and 9-Acetoxy-3-amino-1-(4-methoxyphenyl)- 1H-benzo[f]chromene-2-carbonitriles via 2-(Imino-piperidin-1-yl-methyl)- 3-(4-methoxyphenyl)acrylonitrile as Intermediate
Authors: El-Agrody Ahmed M. , Eid Fathy A. , Emam Hussein A. , Mohamed Hany M. , Bedair Ahmed H.
Published: August 2018

Several new 1H-benzo[f]chromene derivatives (3aÐd) were prepared by the reaction of 7-substituted-2-naphthols (1a,b) with substituted α-cyano-4-methoxycinnamonitriles (2a,b) together with 2-(imino-piperidin-1-yl-methyl)-3-(4-methoxyphenyl)acrylonitrile (4) as intermediate. Also, the reaction of 1a,b with 4 without catalyst afforded 9-methoxy and 9-acetoxy- 3-amino-1-(p-methoxyphenyl)-1H-benzo[f]chromene-2-carbonitrile (3b,e). The reaction of 3a,b with different electrophilic and nucleophilic reagents afforded the 12H-7-oxa-8,10-diazabenzo[ a]anthracene derivatives 5, 9, 10 and 1H-benzo[f]chromene derivatives 6Ð8, 11.
(2S)-1-(4-Methoxyphenyl)-N-[(1R)-2-(4-methoxyphenyl)-1- methylethyl]-2-propanamine in Crude p-Methoxyamphetamine (PMA) Produced by the Leuckart Method
Authors: Błachut Dariusz , Maurin Jan K. , Starosta Wojciech , Wojtasiewicz Krystyna , Czarnocki Zbigniew
Published: August 2018

The synthesis and separation of both diastereoisomers of 1-(4-methoxyphenyl)-N-[2- (4-methoxyphenyl)-1-methylethyl]-2-propanamine as markers of clandestine p-methoxyamphetamine have been described. The stereochemistry of the meso diastereomer was established by crystallographic method.
Crystal Structure of Tetrabutylammonium Carbonyltribromoplatinate(II) [(C4H9)4N][PtBr3(CO)]
Authors: Berkei Michael , Bickley Jamie F. , Heaton Brian T.
Published: August 2018

Tetrabutylammonium carbonyltribromoplatinate(II) [(C4H9)4N][PtBr3(CO)] crystallises in the monoclinic system in the space group P21/n with a = 1487.84(13), b = 897.41(8), c = 1849.6(2) pm, β = 106.558(2)° and four formula units per unit cell. The [PtBr3 (CO)]- anion is symmetrical (C2v) and almost planar with Pt-Br bond lengths of 242.40(12) pm (trans to CO), 243.25(10) pm and 242.99(9) pm (trans to Br), and a Pt-C bond length of 185.6(11) pm.
Die Koordination des [Hg2]2+-Kations in der konjugierten Supersäure HF/SbF5 durch CO oder H2O: Kristallstruktur von [Hg2(OH2)2][SbF6]2 · 4HF / The Co-ordination of the [Hg2]2+ Cation with CO or H2O in the Conjugated Super Acid HF/SbF5:Cryst al Structure of [Hg2 (OH2)2][SbF6]2 · 4HF
Authors: Berkei Michael , Schürmanna Markus , Bernhardt Eduard , Willner Helge
Published: August 2018

In the superacidic system HF/SbF5, the salt [Hg2(CO)2][Sb2F11]2 reacts with traces of water to give the novel salt bis(aqua)dimercury(I) bis(hexafluoroantimonate)tetra(hydrogenfluoride) solvate [Hg2(OH2)2][SbF6]2 · 4HF. It crystallises in the triclinic system in the space group P1̄ with a = 661.47(6), b = 695.11(7), c = 922.29(9) pm, α = 83.428(5)°, β = 84.186(6)°, γ = 71.696(5)°, and one formula unit per unit cell. The four heavy atoms of the [Hg2(OH2)2]2
+ cation are linked symmetrically and almost linear (nearly C2h) with a Hg-Hg bond length of 249.17(11) pm, two terminal Hg-O bonds of 214.8(8) pm, and an O-Hg-Hg bond angle of 177.6(3)°. Final R indices [I > 2σ(I)] are R1 = 0.0405 and wR2 = 0.0714.
Synthesis and Characterization of Tetraphenylphosphonium Tetraazidoborate
Authors: Fraenk Wolfgang , Nöth Heinrich , Klapötke Thomas M. , Suter Max
Published: August 2018

Tetraphenylphosphonium tetraazidoborate, [P(C6H5)4][B(N3)4], was obtained from B(N3)3 - in situ prepared from BH3 · O(C2H5)2 and HN3 - and [P(C6H5)4][N3]. Recrystallization from an acetonitrile / hexane mixture yielded colorless crystals in 60% yield. The molecular structurewas determined by single crystal X-ray diffraction and the [B(N3)4]- anionwas shown to possess S4 symmetry.
Double Porphyrin Platinum Conjugates
Authors: Brunner Henri , Schellerer Karl-Martin
Published: August 2018

Platinum-containing groups and porphyrins in the same molecule not only show additivity of the dark toxicity of the platinum moiety and the phototoxicity of the porphyrin system but also a selective enrichment of porphyrin platinum conjugates in tumor tissues compared to platinum-only drugs. Porphyrin platinum conjugates containing amino-porphyrin non-leaving groups and porphyrin-carboxylate leaving groups were synthesized and tested with the mammary carcinoma cell line MDA-MB-231.
Übergangsmetallorganisch stabilisierte Indate und Germanate: Synthese, Struktur und Eigenschaften der Komplexe [{(CO)5M}EX3]2– (M = Cr, Mo, W; E = In; X = Cl, Br), [(CO5Cr)InBr(μ2-Br)]2
2– sowie [{(CO)5Cr}E(oxinat)2]n– (E = In, n = 2; E = Ge, n = 1) / Organometallically Protected Indates and Germanates: Synthesis, Structure and Properties of [{(CO)5M}EX3]2- (M = Cr, Mo, W; E = In; X = Cl, Br), [(CO5Cr)InBr(μ2-Br)]2
2- and [{(CO)5Cr}E(oxinat)2]n- (E = In, n = 2; E = Ge, n = 1)
Authors: Rutsch Peter , Renner Gerd , Huttner Gottfried , Sandhöfner Steffen
Published: August 2018

A novel route to reactive In(I)-complexes [{(CO)5M}InXּTHF] (M = Cr, X = Cl, Br; M = Mo, X = Cl; M = Mo, X = Cl) is described. With an excess of tetraphenylphosphonium halides [Ph4P]X (X = Cl, Br) these compounds react to give trihaloindate-complexes [Ph4P]2ּ [{(CO)5M}InX3] (M = Cr, X = Cl: 1a, X = Br: 1b; M = Mo, X = Cl: 2; M = W, X = Cl: 3), which contain indium in a formal oxidation state of +I. The reaction of equimolar ammounts of [{(CO)5Cr}InBrּTHF] and bromide ions gives the bridged, dinuclear compound [{(CO)5Cr}InBr(μ2-Br)]2
2- (4). 4 is an intermediate in the reaction of [{(CO)5Cr}InBrּTHF] to [{(CO)5Cr}InBr3]2-, 1b. Reaction of sodium-8-hydoxychinolate and [{(CO)5Cr}InClּTHF] produces the anion [{(CO)5Cr}In(oxinat)2]- (5) which contains In(+I) in a square pyramidal coordination geometry. [{(CO)5Cr}GeI3]-, which is isoelectronic to 1-3, reacts with 8-hydroxyquinoline to produce [{(CO)5Cr}Ge(oxinat)2] (6) which is isoelectronic to 5. All new compounds have been characterized by X-ray analysis and by the usual analytic and spectroscopic techniques. 115In NMR spectra of M(CO)5 substituted indium species (M = Cr, Mo, W) are reported for the first time.
A Homoleptic Zirconium Complex with Four Bulky η2-Pyrazolato Ligands
Authors: Röder Jens C , Meyer Franc , Pritzkow Hans
Published: August 2018

Two new tetrakisη2-pyrazolato) zirconium complexes are prepared from the reaction of Zr(CH2Ph)4 with bulky pyrazolate ligands bearing indenylmethyl (HL1) or fluorenylmethyl (HL2) substituents, respectively. Zr(L2)4 has been analyzed by X-ray crystallography, which represents the first structural characterisation of a homoleptic η2-pyrazolato zirconium compound.
Palladium Complexes with Bidentate P,N Ligands: Synthesis, Characterization and Application in Ethene Oligomerization
Authors: Müller Gabi , Klinga Martti , Osswald Peter , Leskelä Markku , Rieger Bernhard
Published: August 2018

Palladium complexes of two different P,N ligands (a phosphane-pyridine and a phosphane-imine ligand) were synthesized and characterized. Single crystal X-ray structure analyses of the palladium diiodide compounds revealed a square-planar coordination geometry at the metal center with a longer Pd-I bond in trans-position to the phosphorus atom. The chloro-methyl palladium species of the phosphane-pyridine ligand was applied for the oligomerization of ethene using a borate salt as cocatalyst.
2"-Chartreusin-monoacetate, a New Natural Product with Unusual Anisotropy Effects from the Marine Isolate Streptomyces sp. B5525, and its 4"-Isomer
Authors: Maskey R. P , Pusecker K , Speitling M , Monecke P , Helmke E , Laatsch H
Published: August 2018

The marine Streptomycete isolates B5342 and B5525 forms, beside large amounts of the antitumor antibiotic chartreusin (1a), two chartreusin monoacetates as trace components. Whereas the chemical shift of the acetate methyl in 1c is in the normal range, the methyl group of the 2"-acetate residue in 1b and also in the tetra- and pentaacetates shows an extreme upfield shift. The structures of the monoacetates were confirmed by extensive NMR experiments, the anisotropic shift is explained by semi-empirical calculations.
Synthesis and Crystal Structures of Two Monomeric Methylene Bis(diaminoalanes)
Authors: Knabel Klaus , Nöth Heinrich , Seifert Thomas
Published: August 2018

Substitution of the Cl atoms of CH2(AlCl2)2 by 2,2,6,6-tetramethylpiperidino or bis(trimethylsilyl)- amino groups leads to monomeric methylene bis(diaminoalanes). These show a wide Al-C-Al bond angle as determined by X-ray crystallography and asymmetrically bonded amino groups in the piperidino derivative.
Wechselwirkungen in Molekülkristallen, 180 [1, 2]. σ-Donator/Akzeptor-Komplexe {S(CI)4···X⊖ }(X⊖ = I⊖ , SCN⊖ ) von Tetraiodthiophen in Tetra(n-butyl)ammoniumhalogenid-Salzen/Interaction in Molecular Crystals, 180 [1, 2]. -Donor/Acceptor Complexes {S(CI)4···X⊖} (X⊖= I⊖, SCN⊖ of Tetraiodothiophene in Tetra(n-butyl)ammonium Halide Salts
Authors: Bock Hans , Holl Sven
Published: August 2018

Two donor/acceptor complexes between halide anion donors and the tetraiodothiophene acceptor with tetra(n-butyl)ammonium countercations, {(H9C4)4N⊕X⊖···(IC)4Sg (X⊖ = I⊖, SCN⊖) could be crystallized from acetone solutions of the components R4N⊕X$ and (IC)4S by using low-gradient techniques. Low temperature structural studies revealed that the molecule packing motifs are layers of halide anion/tetraiodothiophene patterns penetrated each by one of the four R4N⊕ n-butyl chains. The structure discussion emphasizes observed regularities such as the preferred coordination X⊖···I by the polyiodo acceptor molecules to dimers, followed by the additional aggregation to layers and the inclusion of one n-butyl chain fromeach voluminous R4N⊕ countercation. Especially this effect could be an essential crystallization principle for the fascinating self-assembly comprising a halide anion and a polyiodo acceptor molecule.
Thermochemische Untersuchungen zu den Systemen SE2O3-SeO2. V. Ytterbiumselenoxide auf dem Schnitt Yb2O3-SeO2/Thermochemical Investigations of Systems RE2O3-SeO2. V. Ytterbium Selenium Oxides on the Line Yb2O3-SeO2
Authors: Oppermann H. , Zhang-Preße M. , Schmidt P.
Published: August 2018

The pure ternary phases on the line Yb2O3-SeO2 in thermodynamical equilibrium have been synthesized by solid state reaction and characterized using X-ray powder diffraction and IR-spectroscopy. There exist three phases: Yb2SeO5, Yb2Se3O9 and Yb2Se4O11, the last one with a homogeneiety range extending a higher SeO2-content. The thermal decompositions have been determined by total pressure measurements, and the thermodynamical data of the compounds have been derived. The phase diagram and the phase barogram have been established using the results of thermal analysis and total pressure measurements.
Implications of the Results of a Routine Structure Determination: Tris(triphenylphosphine)gold(I) Chloride Bis(dichloromethane)
Authors: Hamel Armin , Schier Annette , Schmidbaur Hubert
Published: August 2018

Tris(triphenylphosphine)gold(I) chloride was found to form a crystalline phase with two molecules of dichloromethane. In the crystal the chlorine atom is almost fully dissociated from the [(Ph3P)3Au]+ cation. The gold atom shows only a minor displacement from the plane of the phosphorus atoms (sum of the angles P-Au-P 355.35°; d(Au-Cl) 2.7962(6) Å), very similar to the geometry of the solvent-free crystalline phase. The results are discussed in the context of all known structures for compounds [(Ph3P)3MCl], M = Cu, Ag, Au. The variations in structure appear to be dominated by electronic (relativistic) rather than steric effects.
[4 + 2]-Cycloaddition Reactions Involving α-Oxo Thioketone Intermediates
Authors: Hegab Mohamed I. , Amr Abd El-Galil A. , Abdel-Megeid Farouk M. E.
Published: August 2018

α-Chloro β-oxo sulfenyl chlorides 2 were reduced by iodide ions to the corresponding α-oxo thioketones 3 which dimerized in situ in a hetero-[4 + 2] cycloaddition to give the 1,3,4- oxadithiin derivatives 4. The α-oxo thioketones 3, in situ, cyclized also with 2,3-dimethyl-1,3- butadiene to give the corresponding adducts 5 and only in case of the oxo thioketone intermediate 3d two products 4d and 5d were obtained. Also, The α-oxo thioketones 3a,c, underwent in situ, cycloaddition with furan to give the corresponding adducts 6a,c together with the corresponding thioketone dimers 4a,c. When this reaction was carried out in the presence of diethyl acetylenedicarboxylate or chalcone derivative 8, only the oxo thioketone dimers 4a-d were obtained.
New Derivatives of Quinoxaline – Syntheses, Complex Formation and their Application as Controlling Ligands for Zinc Catalyzed Epoxide-CO2–Copolymerization
Authors: Hampel O. , Rode C. , Walther D. , Beckert R. , Görls H.
Published: August 2018

A series of amino-(type 3) as well as hydrazino-substituted quinoxalines (type 8) have been synthesized in order to study their ability to complex with iron(III) and zinc(II) ions. Cyclization of 2,3-dichloroquinoxaline (1) with a bis-amidine 9 leads to ring-fused quinoxalines of type 10. One of these compounds (10a) forms a unique macrocyclic hexameric complex 14 with zinc ions in the presence of 2,6-diisopropyl phenolate. In an analogous manner, the monomeric complexes 12 and 13 could be synthesized. All of these new zinc complexes catalyze the copolymerization of cyclohexene oxide and carbon dioxide with a high degree of selectivity in the resulting polymers.
Alkalimetall-Arsenide A3As7 Und Aas (A = K, Rb, Cs). Synthesen, Kristallstrukturen, Schwingungsspektren / Alkaline Metal Arsenides A3As7 and AAs (A = K, Rb, Cs). Preparation, Crystal Structure, Vibrational Spectroscopy
Authors: Emmerling Franziska , Röhr Caroline
Published: August 2018

The title compounds were synthesized from the elements and characterized via single crystal x-ray studies and Raman spectroscopy. In the Zintl phases A3As7 (A = K, Rb, Cs) the As atoms form nortricyclene-analogous anions As3
7 with As-As distances ranging from 230 to 254 pm. The three compounds crystallizewithdifferent newstructure types containing different packings of theAs7 anions:K3As7 (orthorhombic, Pbca; a=1291.9(8), b = 2544.1(9), c=1537.7(16) pm) shows a double hexagonal close packing (ABAC stacking of planes of hexagonal close packed anions), Rb3 As7 (monoclinic, P21/c, a = 757.3(5), b = 1310.2(8), c = 2692.7(18) pm , β= 91.972(12)°) hows a hexagonal close packing (AB) and the Cs compound (orthorhombic, Pbca, a = 1022.8(5), b = 1317.6(7), c = 2195.2(11) pm) a cubic close packing (ABC) (also present in theHT-forms of the three compounds) respectively. The alkaline metalmonoarsenides AAs (A = K, Rb) crystallize with the NaP structure type (A = K/Rb: orthorhombic, P212121; a = 661.7(5) / 658.1(8), b = 688.8(6) / 691.6(8), c = 1197.3(10) / 1204.7(10) pm, Z = 8) with approximate fourfold screw axes 41 of As$ chains, whereas the crystal structure of CsAs (hexagonal, P¯62m, a = 1219.7(3), c = 1046.3(2) pm, Z = 18) contains three crystallographically independent three membered rings As3
3 with As-As distances of 243.0 to 247.5 pm
Bis[dicarbonyl(cyclopentadienyl)ruthenium(I)] Komplexe / Bis[dicarbonyl(cyclopentadienyl)ruthenium(I)] Complexes
Authors: Schumann Herbert , Stenz Susanne , Girgsdies Frank , Mühle Stefan H.
Published: August 2018

Ru3(CO)12 reacts with 1-tert-butyl-2,4-cyclopentadiene (1), 1-trimethylsilyl-2,4-cyclopentadiene (2), 1-tert-butyl-3-methyl-2,4-cyclopentadiene (3), 1,3-di(tert-butyl)-2,4-cyclopentadiene (4), 1-iso-propyl-2,3,4,5-tetramethyl-2,4-cyclopentadiene (5), 1-tert-butyl-2,3,4,5-tetramethyl- 2,4-cyclopentadiene (6), 1-phenyl-2,3,4,5-tetramethyl-2,4-cyclopentadiene (7), 2,5- diphenyl-2,4-cyclopentadiene (8), or 2,3,4,5-tetraphenyl-2,4-cyclopentadiene (9) with formation of the corresponding bis[dicarbonyl(cyclopentadienyl) ruthenium(I)] complexes [RuCp# (CO)2]2 1a to 9a. The 1H and 13C NMR spectra of the new compounds 3a and 5a to 9a as well as the single crystal X-ray structures of 1a, 4a, 5a, 7a, 8a, and 9a are reported and discussed
New Bioactive Diterpenoid from Euphorbia decipiens
Authors: Ahmad Viqar Uddin , Hussain Hidayat , Hussain Javid , Jassbi Amir Reza , Bukhari Ishfaq A. , Yasin Amsha , Choudhary M. Iqbal , Dar Ahsana
Published: August 2018

One new diterpene ester with a tricyclic lathyrane-or myrsinol-type skeleton has been isolated from Euphorbia decipiens Boiss.&Buhse. In addition to one new, the known constituents β-amyrin, β-amyrin acetate, methyl (2,4-dihydroxy-3-formyl-6-methoxy) phenyl ketone (2), and 1,1-bis (2,6-dihydroxy-3-acetyl-4-methoxyphenyl) methane (3) have been isolated from the same source. The structure elucidation of the isolated compounds was based primarily on 1D and 2D-NMR analysis, including COSY, HMQC, HMBC and NOESY correlations. Compound 1 showed inhibitory activity against prolyl endopeptidase, and also analgesic activity
[3+1]-Cyclisierungen zu Tetraboraporphyrinogenen / [3+1]-Cycloadditions with Formation of Tetraboraporphyrinogenes
Authors: K¨ohler Thomas , Pritzkow Hans , Siebert Walter
Published: August 2018

2,5-Bis(chloro-2,2,6,6-tetramethylpiperidinoboryl)thiophene (1) and 2,5-bis(chloro-diisopropylaminoboryl) pyrrol (4) react with two equivalents of 2-lithiothiophenide to yield the corresponding 2,5-diborylheteroarenes (2,5) in which two boryl groups connect three heteroarenes. After lithiation of the terminal thiophenes of both compounds in 5,5'-position their reactions with the diborylthiophene 1 as well as with diborylpyrrol 4, lead to tetraboraporphyrinogenes (3, 6), the latter being the first tetraboratetraazaporphyrinogene. By silicon / boron exchange of 1-trimethylsilylimidazol with the 2,5-diborylpyrrol 4 the 2,5-bis(imidazolyldiisopropylamino- boryl)pyrrol 7 is formed, which reacts with BH3 and BEt3 to give the N-borane adducts of 7. The spectroscopic data and four X-ray structure analyses are reported.
Self-Assembly of Organo-Sulfur, Selenium and Tellurium Compounds via π-π-Stacking and Hydrogen Bonding Interactions
Authors: Kersting Berthold
Published: August 2018

The crystal structures of 2-isopropyl-benzisothiazol-3-one-7-carboxylicacid isopropyl amide and of the corresponding selenium and tellurium derivatives have been determined. In contrast to the sulfur and selenium compounds, the tellurium derivative has an unprecedented three-dimensional network structure held together via π-π stacking and hydrogen bonding interactions. The cavities in the 3D molecular network are filled with guestwater molecules that are hydrogen bonded to carbonyl oxygen atoms.
The First 6,8-Cycloeudesmane Sesquiterpene from a Marine Organism: The Red Seaweed Laurencia microcladia from the Baia di Calenzana, Elba Island
Authors: Guella Graziano , Skropeta Danielle , Mancini Ines , Pietra Francesco
Published: August 2018

Reported here is the isolation and structural elucidation of a new 6,8-cycloeudesmane sesquiterpene, 5-bromo-1-isopropyl-2,5a-dimethyl-decahydro-cyclopropa[a]inden-2-ol (5), alongside the known sesquiterpenes (-)-δ-cadinene (7) and (+)-α-cadinol (8), from the red seaweed Laurencia microcladia Kützing of the Baia di Calenzana, Elba Island. Other than belonging to a rare sesquiterpene class, 5 is the first 6,8-cycloeudesmane sesquiterpene of marine origin.
Synthesis of Rigid Cyclopropanoid Nucleoside Analogues
Authors: Csuk René , Kern Anja
Published: August 2018

A convenient synthesis has been developed for the synthesis of cyclopropanoid nucleoside analogues that possess no additional spacer groups between the heterocycle and the hydroxylated cyclopropane ring. For some of these compounds the respective enantiomers could be separated on an analytical scale by means of HPLC using chiral phases.
Synthesis of a Dinuclear μ-(η2-Thioaldehyde)zirconocene Cation Complex
Authors: Courtenay Silke , Smith Sarah , Hollink Emily , Blaschke Ulrich , Kehr Gerald , Fröhlich Roland , Erker Gerhard , Stephan Douglas W.
Published: August 2018

Treatment of (butadiene)zirconocene with two molar equivalents of benzylmercaptane results in the formation of Cp2Zr(SCH2Ph)2 (11). Subsequent reaction of 11 with [Cp2ZrCH3
+][CH3B(C6F5)3
-](12) leads to rapid elimination of methane to yield the dinuclear [μ-(η2-thiobenzaldehyde)(μ-SCH2Ph)(ZrCp2)2
+] cation complex 14. A similar reaction is observed upon treatment of Cp2Zr(SC2H5)2 (15) with 12 to yield the thioacetaldehydebridged dinuclear metallocene cation complex Cp2Zr-μ-(η2-MeCHS)-μ-(SEt)ZrCp2 (16).
A Pyrazine-Bridged Ni(II) Coordination Polymer
Authors: Choudhury Chirantan Roy , Dey Subrata Kumar , Sen Sutapa , Bag Bappaditya , Mitra Samiran , Gramlich Volker
Published: August 2018

The single pyrazine-bridged polymeric complex {[Ni(pyz)(H2O)4](NO3)2.2H2O}n has been synthesised and characterised by elemental analyses, IR and UV-vis spectra, and a single-crystal X-ray diffraction study. The coordination around the Ni centre is perfectly octahedral. The Ni(H2O)4 coordination planes are bridged by pyrazine ligands forming an infinite chain structure. Two nitrate anions and two water molecules exist in the lattice and are linked by intermolecular hydrogen bonds to the coordinated water molecules.