共查询到20条相似文献,搜索用时 31 毫秒
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Silvana Guilardi Ruggiero Maria Teresa do Prado Gambardella Marcelo Cardoso Branco Antonio Jacinto Demuner Luis Claudio A. Barbosa Dorila Pil‐Veloso 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):868-869
The crystal structure of 21α‐fluoro‐7‐norvouacapane‐17β,21α‐lactone, C20H25FO3, a new synthetic derivative of the diterpenoid 6α,7β‐dihydroxyvouacapan‐17β‐oic acid isolated from Pterodon polygalaeflorus Benth fruits, is described. 相似文献
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The addition of reactive carbanions to (η4‐1,3‐diene)Fe(CO)3 complexes at ?78 °C and 25 °C produced putative homoallyl and allyl anion complexes, respectively. Reaction of the reactive intermediates with 2‐(phenylsulfonyl)‐3‐phenyloxaziridine afforded nucleophilic substituted (η4‐1,3‐diene)Fe(CO)3 complexes. 相似文献
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Masood Parvez Oliver E. Edwards Zdzisaw Paryzek 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(4):o249-o251
The structures of 3β‐acetoxy‐9α,11α‐epoxy‐5α‐lanost‐9(11)‐en‐7‐one and 3β‐acetoxy‐9β,11β‐epoxy‐5α‐lanost‐9(11)‐en‐7‐one, C32H52O4, differ in their respective substituted cyclohexanone rings but adopt similar conformations in the other three rings. In both of the crystal structures, weak intermolecular C—H⋯O interactions are present. 相似文献
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Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR3 Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η2‐tBu2P–P}Pt(PR3)2] and [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)] (R3P)2PtCl2 and C2H4 yield the compounds [{η2‐C2H4}Pt(PR3)2] (PR3 = PMe3, PEt3, PPhEt2, PPh2Et, PPh2Me, PPh2iPr, PPh2tBu and P(p‐Tol)3); which react with tBu2P–P=PMetBu2 to give the phosphinophosphinidene complexes [{η2‐tBu2P–P}Pt(PMe3)2], [{η2‐tBu2P–P}Pt(PEt3)2], [{η2‐tBu2P–P}Pt(PPhEt2)2], [{η2‐tBu2P–P}Pt(PPh2Et)2], [{η2‐tBu2P–P}Pt(PPh2Me)2], [{η2‐tBu2P–P}Pt(PPh2iPr], [{η2‐tBu2P–P}Pt(PPh2tBu)2] and [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2]. [{η2‐tBu2P–P}Pt(PPh3)2] reacts with PMe3 and PEt3 as well as with tBu2PMe, PiPr3 and P(c‐Hex)3 by substituting one PPh3 ligand to give [{η2‐tBu2P1–P2}Pt(P3Me3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3Ph3)(P4Me3)], [{η2‐tBu2P1–P2}Pt(P3Et3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3iPr3)(P4Ph3)] and [{η2‐tBu2P1–P2}Pt(P3(c‐Hex)3)(P4Ph3)]. With tBu2PMe, [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2] forms [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4(p‐Tol)3)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR3 ligands. 相似文献
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J. I. F. Paixo J. A. R. Salvador J. A. Paixo A. Matos Beja M. Ramos Silva A. M. d'A. Rocha Gonsalves 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o630-o632
In the title compound, C21H31N3O4, a potential inhibitor of aromatase, all rings are fused trans. Rings A, B and C have chair conformations which are slightly flattened. Ring D has a 14α‐envelope conformation. The steroid nucleus has a small twist, as shown by the C19—C10⋯C13—C18 torsion angle of 6.6 (2)°. Ab initio calculations of the equilibrium geometry of the molecule reproduce this small twist, which appears to be due to the steric effect of the 6β‐azide substituent rather than to packing effects. 相似文献
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The polysulfides α‐ and β‐P2S7 are synthesized by heating stoichiometric mixtures of P4S3 and sulfur in the presence of catalytic amounts of anhydrous FeCl3 as mineralizer (evacuated silica tube, 250 °C, 10 d). 相似文献
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Lanthanoid Peroxo Complexes with μ3‐η2:η2:η2‐(O22—) Coordination. Crystal Structures of [Ln4(O2)2Cl8(Py)10] · Py mit Ln = Sm, Eu, Gd The four‐nuclear peroxo complexes [Ln4(O2)2Cl8(Py)10]·py (py = pyridine) with Ln = Sm ( 1 ·py), Eu ( 2 ·py) und Gd ( 3 ·py) are formed as pale yellow ( 1 ·py) and colourless ( 2 ·py and 3 ·py) crystals by action of atmospheric oxygen on heated solutions of the anhydrous trichlorides LnCl3 in pyridine/ diacetone alcohol (4‐hydroxy‐4‐methyl‐2‐pentanone). According to the X‐ray structural analyses the three complexes crystallize isostructural in the triclinic space group PP1¯ with two formula units per unit cell. 1—3 form centrosymmetrical molecular structures, in which the four lanthanoid atoms in coplanar array are linked via the two peroxo groups in a hitherto unobserved μ3‐η2:η2:η2 coordination. Additionally, they are bonded by four �μchloro bridges. Two of the Ln atoms complete their coordination sphere by three pyridine molecules each, the other two by two chlorine atoms and two pyridine molecules. The gadolinium compound is additionally characterized by its complete vibrational spectrum (i.r. and Raman). 相似文献
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L. C. R. Andrade J. A. Paixo M. J. M. de Almeida E. J. Tavares da Silva M. L. S e Melo F. M. Fernandes Roleira 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o82-o83
The title compound, alternatively called 24‐nor‐5β‐chol‐22‐ene‐3β,7α,12α‐triyl triformate, C26H38O6, has a cis junction between two of the six‐membered rings. All three of the six‐membered rings have chair conformations that are slightly flattened and the five‐membered ring has a 13β,14α‐half‐chair conformation. The 3β, 7α and 12α ring substituents are axial and the 17β group is equatorial. The 3β‐formyloxy group is involved in one weak intermolecular C—H⋯O bond, which links the molecules into dimers in a head‐to‐head fashion. 相似文献
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Masahiro Nagaoka Hiroyuki Tsuruda Dr. Masa‐aki Amako Prof. Dr. Hiroharu Suzuki Prof. Dr. Toshiro Takao 《Angewandte Chemie (International ed. in English)》2015,54(49):14871-14874
A μ3‐η2:η2:η2‐silane complex, [(Cp*Ru)3(μ3‐η2:η2:η2‐H3SitBu)(μ‐H)3] ( 2 a ; Cp*=η5‐C5Me5), was synthesized from the reaction of [{Cp*Ru(μ‐H)}3(μ3‐H)2] ( 1 ) with tBuSiH3. Complex 2 a is the first example of a silane ligand adopting a μ3‐η2:η2:η2 coordination mode. This unprecedented coordination mode was established by NMR and IR spectroscopy as well as X‐ray diffraction analysis and supported by a density functional study. Variable‐temperature NMR analysis implied that 2 a equilibrates with a tautomeric μ3‐silyl complex ( 3 a ). Although 3 a was not isolated, the corresponding μ3‐silyl complex, [(Cp*Ru)3(μ3‐η2:η2‐H2SiPh)(H)(μ‐H)3] ( 3 b ), was obtained from the reaction of 1 with PhSiH3. Treatment of 2 a with PhSiH3 resulted in a silane exchange reaction, leading to the formation of 3 b accompanied by the elimination of tBuSiH3. This result indicates that the μ3‐silane complex can be regarded as an “arrested” intermediate for the oxidative addition/reductive elimination of a primary silane to a trinuclear site. 相似文献
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Hsiao‐Fen Wang Kuang‐Hway Yih Weng‐Feng Zeng Shou.‐Ling Huang Gene‐Hsiang Lee 《中国化学会会志》2012,59(8):989-994
Reactions of the thiocarbamoyl‐molybdenum complex [Mo(CO)2(η2‐SCNMe2)(PPh3)2Cl] 1 , and ammonium diethyldithiophosphate, NH4S2P(OEt)2, and potassium tris(pyrazoyl‐1‐yl)borate, KTp, in dichloromethane at room temperature yielded the seven coordinated diethyldithiophosphate thiocarbamoyl‐molybdenum complexe [Mo(CO)2{η2‐S2P(OEt)2}(η2‐SCNMe2)(PPh3)] β‐3 , and tris(pyrazoyl‐1‐yl)borate thiocabamoyl‐molybdenum complex [Mo(CO)2(η3‐Tp)(η2‐SCNMe2)(PPh3)] 4 , respectively. The geometry around the metal atom of compounds β‐3 and 4 are capped octahedrons. The α‐ and β‐isomers are defined to the dithio‐ligand and one of the carbonyl ligands in the trans position in former and two carbonyl ligands in the trans position in later. The thiocabamoyl and diethyldithiophosphate or tris(pyrazoyl‐1‐yl)borate ligands coordinate to the molybdenum metal center through the carbon and sulfur and two sulfur atoms, or three nitrogen atoms, respectively. Complexes β‐3 and 4 are characterized by X‐ray diffraction analyses. 相似文献