离聚体的结构表征 Ⅲ.EXAFS法测定含氟的铜离聚体的精细结构

CHARACTERIZATION OF IONOMERS

本文报道了用先进的EXAFS及ESR等方法研究了羧酸型含氟的铜(Ⅱ)离聚体离子微区的内部精细结构,结果表明,铜离聚体的离子微区主要由羧酸根桥键的双核配位结构单元及平面四方形的配位结构单元等聚集而成。在双核配位结构单元中第一层为Cu^(2+)—O配位,配位数为4,配位键键长为1.96A,第二配位层为Gu^(2+)—Cu^(2+)配位,Cu^(2+)—Gu^(2+)间距为2.64A。平面四方形的配位结构单元Cu^(2+)—O的配位数为4,配位键键长为1.96A。共聚物中羧基含量对离聚体的基本配位结构单元和离子微区的精细结构影响较小,但对微区大小有影响。

The fine structures of ionic domains in the fluorine-containing copper (II) ionomers were examined by the Extended X-ray Absorption Fine-Structure (EXAFS) and Electron Spin Resonance (ESR). The results indicate that there are two basic coordination structure units in the ionomers. The first is a square planar coordination structure of Cu2+ ion with oxygen atoms which come from two carboxylate groups. The coordination number of Cu2+ is four and the bond distance of Cu2+-O is about 1.96A. The second is a binuclear coordination structure of Cu2+-Cu2+ ionic pairs with eight oxygen atoms which come from four carboxylate groups. In this structure, the coordination number of 1st coordination shell is four and the bond distance of Cu!+-O is about 1.96A. The 2nd shell is coordination of Cu2+-Cu2+ and the bond distance of Cu2+-Cu2+ is about 2.64A.