共查询到20条相似文献,搜索用时 15 毫秒
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Bruce W. Tattershall Julian G. Knight Mark J. Andrews Claire L. Booth 《无机化学与普通化学杂志》2006,632(3):425-432
Reactions of bicyclic α‐P4S3I2 with Hpthiq gave solutions containing α‐P4S3(pthiq)I and α‐P4S3(pthiq)2, where Hpthiq is the conformationally constrained chiral secondary amine 1‐phenyl‐1,2,3,4‐tetrahydroisoquinoline. The expected diastereomers have been characterised by complete analysis of their 31P{1H} NMR spectra. Hindered P–N bond rotation in the amide iodide α‐P4S3(pthiq)I caused greater broadening of peaks in the room‐temperature spectrum of one diastereomer than in that of the other. At 183 K, spectra of two P–N bond rotamers for each diastereomer were observed and analysed. The minor rotamers showed strong evidence for steric crowding, having large diastereomeric differences in 1J(P–P) and 2J(P–S–P) couplings (49 Hz, 16 % of value, and 4.4 Hz, 19 % of value, respectively). 相似文献
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Reaction of bicyclic β‐P4S3I2 with enantiomerically pure (R)‐Hpthiq (1‐phenyl‐1,2,3,4‐tetrahydroisoquinoline) and Et3N gave a solution of a single diastereomer of the unusually stable diamide β‐P4S3(pthiq)2, accounting for 83 % of the phosphorus content. Despite the steric bulk of the substituents, each amide group of this could adopt either of two rotameric positions about their P–N bonds, so that, at 183 K, 31P NMR multiplets for four rotamers could be observed and the spectra of three of them analysed fully. The large 2J(P–P–P) coupling became greater (253, 292, 304 Hz) with decreasing abundance of the individual rotamers. The rotamers were modelled at the ab initio RHF/3–21G* level, and relative NMR chemical shifts predicted by the GIAO method using a locally dense basis set, allowing the observed spectra to be assigned to structures. Calculations at the same level for the model compound α‐P4S3(pthiq)Cl confirmed the assignments of low‐temperature rotamers of α‐P4S3(pthiq)I reported previously. Changes in observed P–P coupling constants and 31P chemical shifts, on rotating a pthiq substituent, could then be compared between β‐P4S3(pthiq)2 and α‐P4S3(pthiq)I, confirming both sets of assignments. The most abundant rotamer of β‐P4S3(pthiq)2 was not the one with the least sterically crowded sides of both pthiq substituents pointing towards the P4S3 cage, because of interaction between the two substituents. Only by using a DFT method could relative abundances of rotamers of β‐P4S3(pthiq)2 be predicted to be in the observed order. Use of racemic Hpthiq gave also the two diastereomers of β‐P4S3(pthiq)2 with Cs symmetry, for which the room temperature 31P{1H} NMR spectra were analysed fully. 相似文献
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The diamide exo, exo‐β‐P4S3(NHCH(Me)Ph)2 has been made in solution using enantiomerically pure or racemic PhCH(Me)NH2, and its three diastereomers characterised by complete analysis of their 31P{1H} NMR spectra.The unsymmetric diastereomer contains phosphorus atoms, made chemically non‐equivalent by the chirality of the substituents, which show a large 2J(P—P—P) coupling to each other (225.2 Hz). 相似文献
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Babett Krauss Clemens Mügge Adolf Zschunke Friedrich Krech Michaela Flock 《无机化学与普通化学杂志》2002,628(3):580-588
1‐Phosphabicyclo[2.2.1]heptanes Exo‐endo‐ and exo‐exo‐2.6‐dimethyl‐1‐phosphabicyclo [2.2.1]heptane have been obtained by cyclization of 2‐methyl‐4‐(2‐propenyl)phospholane in the presence of the complex base, sodium salt of diethylenglycolmonoethylether ‐ sodium amide in THF (NAMEDEG). The bicyclic phosphanes are characterized by reac‐tions with selenium, sulfur, (CH3)2SeO, CH3I and HSO3F, respectively, elemental analysis, X‐ray crystal structure analysis as well as 1H, 13C, 31P NMR spectral measurements. The steric demand of these phosphanes as complex ligands has been estimated from the P, H coupling constants of the phosphonium fluorosulphates according to the Tolman model. The phosphane selenides were found to display the lowest values for the 1J(Se, P) coupling constant, found up to now for alicyclic and cyclic aliphatic tertiary phosphane selenides. The nJ(P, H)‐ and nJ(H, H)n=2, 3 coupling constants have been extracted from the proton spectra at 600 MHz by computerized analysis. 相似文献
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A New Phosphorus Sulfide with Adamantane Structure: δ‐P4S7 By sulfur abstraction from α‐P4S9/P4S10 with triphenylphosphine a new phosphorus sulfide δ‐P4S7 with adamantane skeleton and an additional sulfur in exo‐position was identified in CS2‐solution by 31P‐NMR spectroscopy. Product distribution and 31P‐NMR parameter are given. 相似文献
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Markus Henn Klaus Jurkschat Ralf Ludwig Michael Mehring Katja Peveling Markus Schürmann 《无机化学与普通化学杂志》2002,628(13):2940-2947
The reaction of the organolithium derivative {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu‐C6H2}Li ( 1 ‐Li) with [Ph3C]+[PF6]— gave the substituted biphenyl derivative 4‐[(C6H5)2CH]‐4′‐[tert‐Bu]‐2′, 6′‐[P(O)(OEt)2]2‐1, 1′‐biphenyl ( 5 ) which was characterized by 1H, 13C and 31P NMR spectroscopy and single crystal X‐ray analysis. Ab initio MO‐calculations reveal the intramolecular O···C distances in 5 of 2.952(4) and 2.988(5)Å being shorter than the sum of the van der Waals radii of oxygen and carbon to be the result of crystal packing effects. Also reported are the synthesis and structure of the bromine‐substituted derivative {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu]C6H2}Br ( 9 ) and the structure of the protonated ligand 5‐tert‐Bu‐1, 3‐[P(O)(OEt)2]2C6H3 ( 1 ‐H). The structures of 1 ‐H, 5 , and 9 are compared with those of related metal‐substituted derivatives. 相似文献
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Mayra Cortés‐Hernández Susana Rojas‐Lima Marcos Hernández‐Rodríguez Julián Cruz‐Borbolla Heraclio López‐Ruiz 《Helvetica chimica acta》2016,99(6):416-424
An efficient, simple protocol for the synthesis of a new family of chiral ureas 1 – 4 is described. The binding properties of 1 – 4 toward different anion (acetate, benzoate, fluoride, and chloride) have been studied by 1H‐NMR titration and have been observed in the case of 4 is a selective receptor for acetate. The theoretical calculation M06/6‐311+G(d,p) helped us explain the binding properties observed. The most interesting observation is that this calculated structure is consistent with expected, based on the concept of allylic 1,3‐strain (A1,3 strain). When chiral caboxylates were studied, urea 1 was the best in discriminating between enantiomers. 相似文献
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The crystal and molecular structure of γ‐P4S6 was determined from single‐crystal X‐ray diffraction. It crystallizes monoclinically in the space group P21/m (No. 11) with a = 6.627(3) Å, b = 10.504(7) Å, c = 6.878(3) Å, β = 90.18(4)°, V = 478.8(4) Å3, and Z = 2. The structure consists of cage‐like P4S6 molecules with CS symmetry arranged with the topology of a cubic close packing. 相似文献
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Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XVIII. Syntheses and Structures of [{η2‐tBu2P–P=P–PtBu2}Pt(PR3)2] tBu2P–P=P(Me)tBu2 reacts with [{η2‐C2H4} · Pt(PR3)2] as well as with [{η2‐tBu2P–P}Pt(PR3)2] yielding [{η2‐tBu2P–P=P–PtBu2}Pt(PR3)2]; PR3 = PMe3 3 a , PEtPh2 3 b , 1/2 dppe 3 c , PPh3 3 d , P(p‐Tol)3 3 e . All compounds are characterized by 1H and 31P NMR spectra, for 3 b and 3 d also crystal structure determinations were performed. 3 b crystallizes in the triclinic space group P1 (No. 2) with a = 1212.58(7), b = 1430.74(8), c = 1629.34(11) pm, α = 77.321(6), β = 70.469(5), γ = 87.312(6)°. 3 d crystallizes in the triclinic space group P1 (No. 2) with a = 1122.60(9), b = 1355.88(11), c = 2025.11(14) pm, α = 83.824(9), β = 82.498(9), γ = 67.214(8)°. 相似文献
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Andreas Schnepf Gregor Stßer Duncan Carmichael Franois Mathey Hansgeorg Schnckel 《Angewandte Chemie (International ed. in English)》1999,38(11):1646-1649
Monomeric polyhapto-bound phospholyl compounds were hitherto unknown for the main group elements. Use of a solution of metastable GaBr has allowed the synthesis of monomeric η5-phospholylgallium, which has been characterized by X-ray structure analysis as the Cr(CO)5 complex 1 . 相似文献
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Jinhong Song Prof. Dr. Zhiming Zhou Dan Cao Haifeng Huang Lixuan Liang Kai Wang Jun Zhang 《无机化学与普通化学杂志》2012,638(5):811-820
Energetic salts that contain nitrogen‐rich cations and the 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐1‐ene anion were synthesized in high yield by direct neutralization reactions. The resulting salts were fully characterized by multinuclear NMR spectroscopy (1H and 13C), vibrational spectroscopy (IR), elemental analysis, density and differential scanning calorimetry (DSC), and elemental analysis. Additionally, the structures of the ammonium ( 1 ) and isopropylideneaminoguanidinium ( 9 ) 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐l‐ene salts were confirmed by single‐crystal X‐ray diffraction. Solid‐state 15N NMR spectroscopy was used as an effective technique to further determine the structure of some of the products. The densities of the energetic salts paired with organic cations fell between 1.50 and 1.79 g · cm–3 as measured by a gas pycnometer. Based on the measured densities and calculated heats of formation, detonation pressures and velocities were calculated using Explo 5.05 and found to to be 25.2–35.5 GPa and 7949–9004 m · s–1, respectively, which make them competitive energetic materials. 相似文献
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Dr. Josep M. Anglada Dr. Ramon Crehuet Prof. Joseph S. Francisco 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18092-18100
High‐level ab initio and Born–Oppenheimer molecular dynamic calculations have been carried out on a series of hydroperoxyalkyl (α‐QOOH) radicals with the aim of investigating the stability and unimolecular decomposition mechanism into QO+OH of these species. Dissociation was shown to take place through rotation of the C?O(OH) bond rather than through elongation of the CO?OH bond. Through the C?O(OH) rotation, the unpaired electron of the radical overlaps with the electron density on the O?OH bond, and from this overlap the C=O π bond forms and the O?OH bond breaks spontaneously. The CH2OOH, CH(CH3)OOH, CH(OH)OOH, and α‐hydroperoxycycloheptadienyl radical were found to decompose spontaneously, but the CH(CHO)OOH has a decomposition energy barrier of 5.95 kcal mol?1 owing to its steric and electronic features. The systems studied in this work provide the first insights into how structural and electronic effects govern the stabilizing influence on elusive α‐QOOH radicals. 相似文献
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