[Fe（H2O）m（OH）n]^x配合物电子结构的理论研究  

Theoretical study of the electronic structures of [Fe（H2O）m （OH）n ] ^x

作　　者：李华锋[1] 蒲敏[1] 郭玉华[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《北京化工大学学报（自然科学版）》2007年第3期263-266,共4页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：国家自然科学基金(20573009)

摘　　要：在B3PW91/6-31G(d,p)计算水平上,对铁离子配合物[Fe(H2O)m(OH)n]x(m+n=4;x=3+,2+,1+,0,1-)的5种可能构型进行优化计算,分析比较了优化结果的几何构型、电荷布居以及能量。计算结果表明:这5种配合物在理论上都有可能稳定存在,配体以氧原子与铁离子配位并形成四面体构型,有部分电荷从氧原子转移到铁离子,OH-与Fe3+的配位作用较强。铁离子的d电子以高自旋的形式排布,形成开壳层的电子结构,其中Fe(OH)4-的d电子最难以发生跃迁。比较具有相同数量Fe3+、H2O和OH-的[Fe(H2O)m(OH)n+jH2O+kOH-]体系的能量,发现随着[Fe(H2O)m(OH)n]x中OH-数量的增加,H2O数量的减少,体系的能量逐渐降低。所以,[Fe(OH)4-+6H2O+2OH-]体系最稳定,与布居分析中OH-与Fe3+的配位作用较强的结果相一致。The structures of [Fe（H2O）m （OH）n ]^x（ m ＋ n = 4; x = 3 ＋, 2 ＋, 1 ＋, 0, 1 - ） have been optimized by the Density Functional Theory （DFT） method at the B3PW91/6-31G（d, p） level. The geometric parameters, charge distribution and total energies of the complexes have been analyzed. The computational results show that all five structures are energetically stable. The structures involve Fe-O tetrahedra in which four oxygen atoms are directly bonded to Fe^3 ＋ with charge transfer from oxygen atoms to Fe^3 ＋ . The complexation of OH^- with Fe^3 ＋ is stronger than that of H2O. The complexes are high spin, and the electronic transition of Fe（OH）4^- requires the largest amount of energy. The total energy of [Fe（H2O）m （OH）n ＋ jH2O ＋ kOH^- ] （ m ＋ j = 6; n ＋ k = 6） systems with the same number of Fe^3＋, H2O and OH^- groups decreases gradually with increasing number of coordinated OH^- groups. Therefore, [Fe（OH）4^- ＋ 6H2O ＋ 2OH^-] is energetically most stable, which is consistent with the conclusion that the complexation of OH^- with Fe^3 ＋ is stronger than that of H2O according to population analysis.

关 键 词：铁离子配合物 密度泛函理论 类水滑石 电子结构 布居分析 

分 类 号：O641[理学—物理化学]