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991.
992.
Meso-四(对-磺基苯基)卟啉光度法测定螺旋藻中的痕量锌 总被引:6,自引:0,他引:6
在pH=4.5的乙酸-乙酸钠缓冲介质中,锌和meso-四-(对磺基苯基)卟啉生成1:l的黄色配合物,λmax=421nm,ε=4.34×105L·mol-1·cm-1。该法可不经分离直接测定螺旋藻中的锌,结果满意。 相似文献
993.
994.
995.
Four new stationary phases for HPLC were prepared by modifying silica gel with a trifrnctional aminoalkyl silane. A conjugated π-electron system was linked to the amino group either directly or with a carboxylic anhydride as a spacer in between. Characterization and dynamic measurements of the new stationary phases were performed by solid state NMR spectroscopy. The results of the 29si and 13C CP/MAS techniques were compared with the recently developed 1H MAS-only technique. Despite strong homonuclear dipole-dipole interactions it was possible to obtain well resolved 1H MAS spectra of those stationaru phases with a high degree of crosslinking. Limited mobility of the aromatic ligand fragments is common for all examined stationaryu phases. The chromatographic properties of the new phases were tested by their ability tio sepatate a mixture of eight PAHS. It could be shown that the π-π interaction mechanism is responsible for the separation of the eight PAHs, because the elution order of the PAHs did not changem despite the use of both a nonpolar mobile phase (n-heptane) and a polar mobile phase (methanol/ water mixture). 相似文献
996.
F. Preuss M. Steidel M. Vogel G. Overhoff G. Hornung W. Towae W. Frank G. Reiß S. Müller-Becker 《无机化学与普通化学杂志》1997,623(8):1220-1228
Phosphane, Phosphite, Phosphido, Complexes of Vanadium(V) Complex formation of tert-butylimidovanadium(V)trichloride ( 1 ) with phosphanes und phosphites has been studied. Syntheses of phosphidovanadium(V) compounds tC4H9N?VCp(NHtC4H9)[P(SiMe3)2] and tC4H9N?VCp(NiProp2)(PR2) (R?SiMe3, Ph) are described starting from the corresponding chlorovanadium(V) complexes. The reaction of 1 with silver hexafluorophosphate yields a bis(fluoro)phosphidovanadium(IV complex [(μ-PF2)2V2Cl2)(NtC4H9)2]; as primary intermediate product of the unknown redox reaction a cationic vanadium(V) complex [tC4H9N?VCl2 · PPh3]+PF6? has been isolated. 1 reacts with an excess of diisopropylamine forming tC4H9N?V(NiProp2)Cl2 ( 16 ); in addition the following diisopropylamido-tert-butylimidovanadium(V) compounds tC4H9N?VCp(NiProp2)Cl ( 3 ) and tC4H9N?V(NiProp2)X2 (X?CH2CMe3, OtC4H9, CH3COO) has been prepared. All compounds obtained are characterized by 1H, 51V, 31P NMR spectroscopy. The X-ray diffraction analysis of 16 and 3 indicate a planar coordination sphere of the amido nitrogen atom. 相似文献
997.
998.
正已醇-邻、间、对二甲苯二元系固液相平衡 总被引:1,自引:0,他引:1
Melting temperatures have been measured and the solid-liquid phase diagrams constructed for 1-hexanol+o-xylene, 1-hexanol+m-xylene and 1-hexanol+p-xylene. They are simple eutectic systems. Excess mole Gibbs free energies were calculated at 298.15K, showing larger positive deviations from ideal-solution behavior. The largest values of GmE are 711、 650 and 800 J•mol-1 for {o-C6H4(CH3)2+C6H13OH}、 {m-C6H4(CH3)2 + C6H13OH} and {p-C6H4(CH3)2+C6H13OH} respectively. 相似文献
999.
1000.
The aim of this study is to establish a new representation for the dynamic algebra of the Morse oscillator and to establish the raising and lowering operators based on the properties of the confluent hypergeometric functions. Using the representation we have obtained a recurrent analytic method for the calculus of the Franck–Condon factors. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 64 : 655–660, 1997 相似文献