α-异丙基、β-异丁基丙烯酸希土配合物的合成和配位性质研究

SYNTHESIS AND COORDINATION PROPERTIES OF THE RARE EARTH COORDINATION COMPOUNDS OF α-ISOPROPYL-β-ISOBUTYL ACRYLIC ACID

本文制备了α-异丙基、β-异丁基丙烯酸的15种希土配合物RE(C_9H_(17)COO)_3,用X射线多晶粉末衍射、电子光谱、红外光谱和热重差热分析方法研究了配合物中RE-O键的成键性能以及羧基的配位性质。配合物中存在两种不同的羧基配位形式,轻中希土配合物(La,Ce,Pr,Nd,Sm,Eu)中羧基具有不对称桥式双齿配位形式,而重希土配合物(Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y)中羧基具有对称螯合双齿配位形式,配位形式的不同使得希土配合物呈现两种不同的多晶衍射图和热分解过程。

The coordination compounds of α-isopropyl-β?-isobutyl acrylic acid with fifteen rare earth (except promethium). RE(C9H17COO)3, were synthesized. The bonding characteristics of RE-O bond and coordination properties of carboxylate were studied by UV-VS, IR spectra, TG-DTA thermal analysis and X-ray powder diffraction analysis. The RE-O bond of coordination compounds is mainly ionic, but with some covalent due to the participation of 4f electrons of lanthanide ions in bonding, There are two different carboxylate coordination modes, for the light and medium rare earth compounds (La, Ce, Pr, Nd, Sm, Eu), the carboxylate coordination is of the unsymmetric bridging bidentate binding mode, for the heavy rare earth compounds (Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y), of the symmetric chelating bidentate binding mode. Thus, the coordination compounds appear in two different X-ray powder diffraction patterns and two different thermal decomposing processes, and the thermal stability of the compounds decreases uncontinually from La to Lu.