金属有机化合物分析(ⅩⅤ)——稀土-金属双核金属有机化合物的薄层色谱和红外光谱关系的研究

Analysis of Organometallic Compounds(ⅩⅤ)--Study on the Relationship Between the Rf Values of Thin Layer Chromatograph and Infra-Red Spectral Absorption of Some Rare Earth-Metal Binuclear Organometallic Compounds

用薄层色谱法,分离了稀土-金属双核金属有机化合物,该类化合物的薄层色谱R_f值和红外光谱vco波数之间存在一致的变化关系,本文对这种变化关系作了初步解释。

A series of rare earth-metal binuclear organometallic compounds with the general formulae [(C6H_(5)CO)_(2)CH]_(2) Re-Fe (or Mo) (CO)_(2)(π-C_(5)H_(5)), [(C6H_(5)CO)_(2)CH]_(2)Re-Sn(G6H_(5))3 have been separated successfully by TLC using silica-gel as absorbent and xylene-absolute alcohol-petroleum ether (1:1:20, 1:0.4:20 and is 0.5:20) as development. The minimum detectable quantity is 0.01649mg per millitre soluticn of determined binuclear organometallic compounds.The observation of the satisfactory correspondence between the Rf values obtained in the thin-layer chromatograph of the compounds and the IR data(vc-o in cm-1) allows us to make the primary theoretical explanation.For the compounds with the same coordinated metal and organic ligand but different rare earth metals the observed vc-o in cm-1 values vary with the change of dipolar force constant K resulted from the variation of the rare earth metals in these compounds. That is, as the K increases, vc=o in cm-1 increases too. Rf values on TLC also match with the vc-o in cm-1 obtained from IR measurement.The compounds of the same rare earth metal and organic ligand but differing only in coordinated metal, the IR data (vc-o in cm-1) and Rf values on TLC decrease with the increase of their ionic radii and polarities, respectively.