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41.
Silver J Marsh PJ Symons MC Svistunenko DA Frampton CS Fern GR 《Inorganic chemistry》2000,39(13):2874-2881
The crystal structure of the title compound is presented and shown to be one of a class of low-spin iron porphyrin complexes having a ground-state electronic configuration of (dxy)2(dxz)2(dyz)1. If their Fe-N bond lengths (average N-porphyrin plotted against average N-axial) are considered, this class of low-spin iron(III) porphyrins of general formula [Fe(III)Por(L)2]+X- and of 2B ground state is shown to be distinctly different crystallographically from a similar class of compounds with the same general formula but with a 2E or a (dxy)2(dxz,dyz)3 ground state. A third group of compounds with the same general formula have a (dxz,dyz)4(d)1 ground state and again are in a different region of the plot. Compounds showing intermediate properties can be forecast from the simple relationship presented in this work. The electron paramagenetic resonance data are shown to be dependent on the ground state, and those of configuration (dxy)2(dxz,dyz)3 and the 2B ground state obey a correlation previously suggested in the literature. 相似文献
42.
The lead compounds are extracted into aqueous iodine monochloride, converted to lead nitrate by digestion with nitric acid, and determined by atomic absorption spectrometry against aqueous lead nitrate standards. The procedure is accurate, precise and rapid. 相似文献
43.
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45.
Martyn C. R. Symons 《Chemical physics letters》1979,60(3):418-420
Exposure of a dilute solution of SiCl4 in adamantane to 60Co γ-rays at 77 K gave anisotropic ESR features which are shown to be characteristic of SiCl−4 anions with a trigonal bipyramidal structure. 相似文献
46.
47.
G. Reza Bebahani David Dunnion Patrick Falvey Kenneth Hickey Mary Meade Yvonne McCarthy Martyn C. R. Symons W. Earle Waghorne 《Journal of solution chemistry》2000,29(6):521-539
We report enthalpies of solution of formamide, N,N-dimethylformamide,N,N-dimethylacetamide, acetic acid, methyl acetate, and acetonitrile in water +dimethylsulfoxide mixed solvents. These, along with literature data for additional solutes,are analyzed in terms of the extended coordination model of solvation. We alsoanalyze infrared data for several of these solutes. These analyses show thatN,N-dimethylformamide and N,N-dimethylacetamide are preferentially hydrated,while the other solutes appear to be preferentially solvated by dimethylsulfoxide.In all cases, the extent of preferential solvation is relatively small. It is also foundthat the degrees of preferential solvation recovered from analyses of the enthalpydata correspond closely to those recovered from the infrared data, although thelatter refer only to the polar chromophores on the solute molecules. It is foundthat the extent to which the solutes disrupt the solvent-solvent interactions variessystematically with the area of the nonpolar surfaces of the solute molecules. 相似文献
48.
Martyn C. R. Symons 《Hyperfine Interactions》1984,19(1-4):771-783
High energy muons induce radiation damage when they interact with molecules or ions. The chemical reactions expected to occur are summarised, and attention is then given to events likely to give rise to radicals exhibiting muon-electron hyperfine coupling. Addition of muonium atoms to double or treble bonds, which is one example of the way this can occur is considered, and, in particular, the resulting proton-muon hyperfine isotope effect is discussed. Finally, possible chemical models for paramagnetic muon centres in carbon and silicon are outlined.I thank Dr. S. Cox and Dr. A. Hill for helpful discussions. 相似文献
49.
S. F. J. Cox E. A. Davis W. Hayes M. C. R. Symons A. Wright A. Singh F. L. Pratt T. A. Claxton F. Jansen 《Hyperfine Interactions》1991,64(1-4):551-560
A study of muons implanted into amorphous hydrogenated silicon (a-Si: H), using both transverse and longitudinal field μSR,
is presented. Particular use is made of the muon repolarization curves in longitudinal fields. By comparison with the results
of similar measurements on polycrystalline silicon, both the diamagnetic and Mu* fractions are found to be substantially increased. We postulate that weak strained bonds in the amorphous structure are responsible.
Little evidence has been found from longitudinal field measurements for isotropic muonium Mu', and a transverse field experiment
on a-Si: D suggests that this state might not exist in the amorphous material. 相似文献
50.
M. Mihara K. Matsuta D. Nishimura T. Nagatomo R. Matsumiya S. Momota T. Ohtsubo T. Izumikawa D. M. Zhou Y. N. Zheng M. Ogura H. Akai J. Komurasaki M. Fukuda D. Ishikawa Y. Nojiri H. Hirano S. Takahashi R. Watanabe T. Kubo S. Y. Zhu A. Kitagawa M. Kanazawa S. Sato M. Torikoshi T. Sumikama T. Minamisono J. R. Alonso G. F. Krebs T. J. M. Symons 《Hyperfine Interactions》2007,178(1-3):83-86
The spin-lattice relaxation times T 1 for short-lived β emitters 25Al(I?=?5/2, T 1/2?= 7.2 s) and 28P(I?=?3, T 1/2?= 270 ms) in Pt were measured by means of the β-NMR technique. As a result, T 1[25Al in Pt] = (1.1 $^{+\ 0.7}_{-\ 0.3})$ s and T 1[28P in Pt] >0.5 s were obtained at temperatures of 17 and 20 K, respectively. The Knight shifts were estimated from the Korringa relation, which were evaluated by comparing to the first principle calculations. 相似文献