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A. V. Virovets M. Laege B. Krebs O. A. Geras'ko V. E. Fedorov O. V. Shishkin Yu. T. Struchkov 《Journal of Structural Chemistry》1996,37(4):666-673
Crystal structures of (Et4N)2[Mo3S7Br6] (I) and (Et4N)(H9O4)[Mo3S7Cl6] (II) clusters belonging to the class of Mo3S 7 4+ were determined by X-ray diffraction analysis. Crystals I are orthorhombic a=19.106(3), b=12.930(2), c=29.887(5) Å, V=7383(2) Å3, space group Pbca, Z=8, dcalc=2.253 g/cm3, R(F)=0.0402, wR(F2)=0.0587 for 2493 Fhkl>4σ. Crystals II are monoclinic, a=17.106(3), b=18.882(4), c=11.006(2), Å, β=126.13(3)°, V=2871.2(9) Å3, space group Cc, Z=4, dcalc=2.147 g/cm3, R(F)=0.0181, wR(F2)=0.0445 for 2307 Fhkl>4σ. Structure I has an anion dimer with 3Sax…Cl=3.258(4)–3.404(4) Å; the dimer is similar to that observed in the structures of A2[M3X7Hal6], A=Ph4P+, Ph3EtP+, and PPN+. In structure II, infinite chains of anions bonded by 3Sax…Cl contacts of 3.183(3)–3.394(3) Å were found. A similar phenomenon was established earlier for the structure of (Et4N)(H9O4)[Mo3S7Br6] (III), which is not isostructural to II. Compounds II and III also differ in the structure of the H9O4 + cation: infinite helix in II and pyramid in III. 相似文献
24.
Tetrakis(trifluoromethyl) cyclotetraarsane (F3CAs)4 ( 2 ) was used to repeat the UV initiated [4+2]‐cycloaddition reaction of the diarsene F3CAs=AsCF3 ( 1 ) with cyclohexa‐1,3‐diene (CHD) and to isolate single crystals of the cycloadduct 4 for a X‐ray diffraction analysis. 4 crystallizes in the space group and contains the diarsene group in its E‐configuration. 2 was also applied for [2+2]‐cycloaddition reactions of 1 with tBuC≡P and MeC≡CNiPr2, but in contrast to positive results with (F3CP)4 the products were too labile for isolation. However, 2 was successfully used at room temperature as precursor for coordinating 1 as π‐donor ligand to the Pd(PPh3)2 complex fragment yielding η2‐bis(trifluoromethyl)diarsene‐bis(triphenylphosphane)‐palladium(0) 5 , which was characterized by X‐ray diffraction of single crystals and by spectroscopic investigations (NMR, IR, MS). Attempts to prove the existence of the diarsene 1 , generated by different methods, by spectroscopic studies very probably failed due to its extreme reactivity, not allowing the necessary concentrations for detection. Quantum chemical calculations of the stability of 1 with respect to dimerization, the stability of the [2+2]‐cycloadduct with 1‐di(isopropyl)aminopropyne and the energy difference between 4 and the 2,3‐dimethyl‐1,3‐butadiene cycloadduct of 1 were performed to understand the considerable differences between 1 and the related diphosphene F3CP=PCF3. 相似文献
25.
Monolayers with segregated carbon and/or adsorbed acetylene on iron foils were prepared in vacuum and characterized by their C 1s XPS spectra. The subsequent hydrogenation of these layers in 1 bar H2 at 500–560 K produced substantial amounts of higher molecular weight hydrocarbons, up to butane, in support of a chain growth mechanism not involving molecular CO. 相似文献
26.
Die Kristallstruktur der Diphenyldithiophosphinsäure (C6H5)2P(S)SH wurde röntgenographisch bei tiefer Temperatur und Normaltemperatur aus Einkristalldiffraktometerdaten bestimmt und bis zu R-Werten von 0,037 (140 K, (sin Θ)/λ < 0,81 Å?1) und 0,035 (293 K, (sin Θ)/λ < 0,64 Å?1) verfeinert. Die Verbindung kristallisiert in der monoklinen Raumgruppe P21/c mit den bei 140 K (in Klammern: 293 K) gemessenen Gitterkonstanten a = 9,824(3) (9,887), b = 10,061(3) (10,175), c = 14,342(4) (14,433) Å, β = 122,08(3) (121,73)° und V = 1201,1 (1234,9) Å3, Z - 4. Im Kristall sind individuelle Moleküle über fast lineare S? H…?S-Wasserstoffbrückenbindungen zu schraubenförmig gewundenen Ketten verknüpft. Bei 140 K beträgt der S…?S-Abstand innerhalb der Brücke 3,790(1) Å; die weiteren geometrischen Daten der Wasserstoffbrücke sind: d(S? H): 1,25(2), d(S…?H): 2,56(2), d(P? S): 2,077(1), d(P?S): 1,954(1) Å, ? (S? H…?S): 169,5(14), ? (P? S…?S): 98,87(2), ? (P?S…?S): 96,65(2)°. Investigations on Compounds Containing S? H…?S Hydrogen Bonds. Crystal Structure of Diphenyldithiophosphinic Acid at 140 and 293 K The crystal structure of diphenyldithiophosphinic acid (C6H5)2P(S)SH was determined from X-ray diffraction data collected at 140 and 293 K and was refined to R factors of 0.037 (140 K, (sin Θ)/λ < 0.81 Å?1) and 0.035 (293 K, (sin Θ)/λ < 0.64 Å?1) respectively. The compound crystallizes in the monoclinic space group P21/c with unit cell parameters at 140 K (in parentheses: at 293 K): a = 9.824(3) (9.887), b = 10.061(3) (10.175), c = 14.342(4) (14.433) Å, β = 122.08(3) (121.73)° and V = 1201.1 (1234.9) Å3, Z = 4. In the crystalline state individual molecules are linked together by nearly linear S? H…?S hydrogen bonds so that endless helical chains are formed. At 140 K the S…?S distance within the hydrogen bond is 3.790(1) Å; the other distances and angles associated with the bridge are: d(S? H): 1,25(2), d(S…?H): 2,56(2), d(P? S): 2,077(1), d(P?S): 1.954(1) Å, ? (S? H…?S): 169.5(14), ? (P? S…?S): 98.87(2), ? (P? S…?S): 96.65(2)°. 相似文献
27.
Wilfried A. Knig Detlef Icheln Torsten Runge Ingo Pforr Adolf Krebs 《Journal of separation science》1990,13(10):702-707
Transferring the site of specific substitution of dipentylated cyclodextrins with methyl or acyl residues from the secondary 3-hydroxyl group to the primary 6-hydroxyl group was expected to provide new information on the mechanism of chiral recognition. The 3-position points towards and the 6-position points away from the cyclodextrin cavity which via inclusion complex formation is supposed to play a major role in chiral separation. The “inverse” 6-O-acyl-2,3-di-O-pentyl-cyclodextrins displayed almost no enantioselectivity but the corresponding 6-O-methyl derivatives are a versatile supplement to the chiral capillary GC phases nowadays available. Among the compounds that could be enantiomerically resolved are alcohols, amino acids, alkyl halides, bicyclic ethers, acetals, olefins, other hydrocarbons and chiral pharmaceuticals. 相似文献
28.
Herein, we discuss the analyses and quantification of the different components in porphyrin mixtures, prepared from p-anisaldehyde, p-tolualdehyde, and 5-(4-bromophenyl)-dipyrromethane with acid catalysis, using NMR and HPLC. The advantages and disadvantages of these analytical methods are emphasized. Due to the similar size of a bromine atom and a methyl group it was possible to grow crystals suitable for X-ray crystallographic studies from a mixture of porphyrins, where the 4-position of the meso-phenyl rings was either substituted with methyl groups or bromine atoms. We also show that X-ray studies are inferior to NMR analysis for determining the components in a porphyrin mixture. 相似文献
29.
Joseph Grobe Duc Le Van Franz Immel Marianne Hegemann Bernt Krebs Mechtild Lge 《无机化学与普通化学杂志》1996,622(1):24-34
Reactive E = C(pp)π-Systems. XLII [1]. Novel Coordination Compounds of 2-(Diisopropylamino)-1-phosphaethyne: [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}], [(Ph3P)2Pt{η2-(iPr2NCP)}], and [Co2(CO)6{η2-μ2-(iPr2NCP)}] 2-(Diisopropylamino)-phosphaethyne iPr2N? C?P ( 2 ) reacts with the Ni(0)-complexes [Ni(1,5-cyclooctadiene)2] and [Ni(CO)3(1-azabicyclo[2.2.2]octane)], respectively, to give the novel complex [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}] ( 5 ), with the 1,3-diphosphacyclobutadiene derivative and 2 (side-on) as π-ligands. The molecular structure of 5 determined by X-ray diffraction on single crystals proves the spin systems and rotational barriers deduced from NMR-data (1H, 13C-, 31P). The PC distances of the four-membered ring of 1.817(2) and 1.818(2) Å – as expected – are considerably longer than the PC bond of the η2-coordinated phosphaalkyne 2 [1.671(2) Å]. – In the reactions of 2 with [(Ph3P)2Pt(C2H4)] or [Co2(CO)8] the ligand properties of 2 resemble those of alkynes affording the complexes [(Ph3P)2Pt{η2-(iPr2NCP)}] ( 7 ) with side-on coordinated 2 and [Co2(CO)6{η2-μ2-(iPr2NCP)}] with 2 acting as a 4e donor bridge in quantitative yield. In attempts to prepare copper(I) complexes of the aminophosphaalkyne 2 by reaction with CuCl or CuI the only isolable product formed in reasonable amounts under the influence of air and moisture is the 1 λ3, 3 λ5-diphosphetene (iPr2N) ( 10 ) (isolated yield: ca. 20%). The crystal structure analysis of 10 indicates a strong structural relationship to the diamino-2-phosphaallyl cation [Me(iPr2N)]+ ( 12 ), the 1,3-diphosphacyclobutadiene ligand (iPr2NCP)2 in the binuclear complex [{η1, μ2-(iPr2NCP)2}Ni2(CO)6] ( 3a ) as well as to the heterocycles (dme)2LiOE2′ (E′ = S, 11a ; E′ = Se, 11b ) prepared by Becker et al. [11b, 35]. 相似文献
30.
Sarah Fakih Wing Chau Tung Dirk Eierhoff Christian Mock Bernt Krebs 《无机化学与普通化学杂志》2005,631(8):1397-1402
In modern cancer therapy the clinical application of platinum‐based drugs is more and more limited by the occurrence of intrinsic or acquired resistances. In this context the potential use of dinuclear platinum complexes in chemotherapy is increasingly relevant. The novel complexes Pd(Bzdpa)Cl2, Pd2(C4H8(dpa)2)Cl4, and Pt2(C4H8(dpa)2)Cl4 allow a direct comparison of mono‐ and dinuclear palladium and platinum complexes respectively deriving from a 2,2′‐dipyridylamine (Hdpa) ligand system. They were characterized by single crystal X‐ray analysis as well as infrared spectroscopy and elemental analysis. The cisplatin analogous mononuclear palladium complex Pd(Bzdpa)Cl2 ( 1 ) (Bzdpa: (2,2′‐dipyridylbenzyl)amine) belongs to a range of 2,2′‐dipyridylamine‐based compounds which were extensively studied in our laboratories. 1 crystallizes in the orthorhombic space group Pna21 with a = 13.722(3), b = 13.457(3), c = 9.483(2), V = 1751.1(6) Å3, and Z = 4. The metal binding motif of 1 was expanded by a flexible butyl‐linker to form the tetradentate C4H8(dpa)2 ligand. The resulting isotypic dinuclear complexes Pd2(C4H8(dpa)2)Cl4·2CH3CN ( 2 ) and Pt2(C4H8(dpa)2)Cl4·2CH3CN ( 3 ) crystallize in the triclinic space group with a = 7.8427(2), b = 8.7940(2), c = 11.7645 (3), α = 79.219(2)°, β = 84.033(2)°, γ = 87.744(2)°, V = 792.58(3) Å3 ( 2 ) and a = 7.831(5), b = 8.814(5), c = 11.817(5), α = 79.271(5)°, β = 83.571(5)°, γ = 88.063(5)°, V = 796.3(8) Å3 ( 3 ), both with one centrosymmetrical molecule in the unit cell. 相似文献