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81.
Paul Schaffer James F. Britten Alan Davison Alun G. Jones John F. Valliant 《Journal of organometallic chemistry》2003,680(1-2):323-328
Two homoleptic Re(I) complexes of ortho and para-carborane isocyanide ligands were prepared as the first examples of a new class of metal-based BNCT and BNCS agents. The target compounds were prepared in low yield through the reaction of [Re2(O2CPh)4Cl2] and [Re2(OAc)4Cl2] with 3-isocyano-1,2-dicarba-closo-dodecaborane and a para-carborane azetidine derivative respectively. The desired product from the latter reaction was characterized crystallographically and is only the second reported molecular structure of a homoleptic Re(I) isonitrile complex. 相似文献
82.
The crystal structures of α-UF5 and U2F9 were refined with high-resolution neutron powder diffraction data from an mixture. Refinement was achieved by a multiphase Rietveld profile refinement technique. The results are compared with previous X-ray and neutron powder studies. 相似文献
83.
Thomas Bally Peter Diehl Edwin Haselbach Alan S. Tracey 《Helvetica chimica acta》1975,58(8):2398-2402
The NMR. spectrum of guanidinium ion 1 is studied in anisotropic liquid crystalline nematic solution. Assuming an HNH-angle of 120°, the distance ratio NH /NC = 0.784 is obtained, from which using NC = 1.330 Å (from X-ray data) NH = 1.043 Å results. An upper bound for the free energy of activation for bond rotation of ΔG+ ≤ 13 kcal/mol is deduced. The bondrotational mobility of 1 is also investigated using the MINDO/3-SCF-procedure. The results obtained for the three conceivable consecutive activation energies for bond-rotation indicate that the observed bond-rotational mobility of 1 does not involve cooperative two- or three-bond rotations. The ‘conjugative stabilization’ of 1 has been estimated to be of the order of 24–26 kcal/mol. 相似文献
84.
Gábor Blaskó S.Fazal Hussain Alan J. Freyer Maurice Shamma 《Tetrahedron letters》1981,22(33):3127-3130
The dark yellow indenobenzazepine alkaloids lahorine () and lahoramine () have been found in Lam. (Fumariaceae). In a transformation with biogenetic implications, treatment of the spirobenzylisoquinolines dihydrofumariline () and dihydroparfumidine () with methanesulfonyl chloride and triethylamine in dry THF, followed by iodine oxidation, provided and , respectively. 相似文献
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We report the first high pressure129I Mössbauer measurements with elemental iodine at pressures to 30 GPa. A 20 mg/cm2
129I2 absorber was mounted in a diamond anvil cell with an effective diameter of 0.21 mm. The source used was Mg3
129mTeO6. Experiments were performed mainly at 4 K and the pressure was monitored by the ruby fluorescence method. With increasing pressure we observe a gradual decrease in ¦e2qQ¦ and an increase in IS and values of the low pressure, molecular phase; at 16 GPa a new phase (HP1) is detected characterized by a change in sign of e2qQ and a smaller value of ¦e2qQ¦, and a substantial increase in . At 24 GPa a new phase (HP2) is formed that is characterized by a smaller value of . In general the population of the molecular phase decreases from 1.0 near 15 GPa to a value of 0.4 at 30 GPa. The fraction of the high pressure phase (HP1 + HP2) increases at the expense of the molecular phase and that of the HP2 at the expense of the HP1 phase. These observations are discussed in relation to the onset of a metallic phase near 16 GPa and recent x-ray diffraction studies.Work performed under the auspices of the U.S. Department of Energy. 相似文献
90.
N-Alkoxycarbonyl- and N-carboxamido-oxaziridines are shown to react with aromatic alkenes to give epoxide, aziridine or hydro-oxidation products, in ratios depending on the oxaziridine structure. Chiral oxaziridines can effect epoxidation and hydro-oxidation with promising levels of asymmetric induction. 相似文献