物理化学学报 >> 2007, Vol. 23 >> Issue (12): 1875-1880.doi: 10.1016/S1872-1508(07)60091-6

研究论文 上一篇    下一篇

配合物[Fe(CO)3(PPh2R)2(HgCl2)] (R=pym, fur, py, thi)的Fe—Hg相互作用及31P化学位移

李勤瑜; 许旋   

  1. 华南师范大学化学与环境学院, 广州 510631
  • 收稿日期:2007-05-14 修回日期:2007-09-14 发布日期:2007-11-30
  • 通讯作者: 许旋 E-mail:xuxuan@scnu.edu.cn

Fe—Hg Interactions and 31P Chemical Shifts in [Fe(CO)3(PPh2R)2(HgCl2)] (R=pym, fur, py, thi)

LI Qin-Yu; XU Xuan   

  1. School of Chemistry and Environment, South China Normal University, Guangzhou 510006, P. R. China
  • Received:2007-05-14 Revised:2007-09-14 Published:2007-11-30
  • Contact: XU Xuan E-mail:xuxuan@scnu.edu.cn

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摘要： 用密度泛函理论(DFT)的PBE0方法对单核配合物Fe(CO)3(PPh2R)2 (R=pym: 1, fur: 2, py: 3, thi: 4; pym=pyrimidine, fur=furyl, py=pyridine, thi=thiazole)及异双核配合物[Fe(CO)3(PPh2R)2(HgCl2)] (R=pym: 5, fur: 6, py: 7, thi: 8)进行结构优化及相互作用能的计算, 用DFT(PBE0)-GIAO法计算了化合物1-8的31P化学位移, 研究了基团R对配合物的稳定性、Fe—Hg相互作用及31P化学位移的影响, 并对Fe—Hg相互作用进行了NBO分析. 得到以下结论: (1)双核配合物中含N的R基团的配合物稳定性较高, N原子个数越多, 稳定性越高. (2) Fe—Hg相互作用是双核配合物稳定的主要因素. 5 和6中Hg以6s轨道与Fe的4s、3dz2组成的杂化轨道结合成Fe—Hg的σ键. 7 和8中则以σP—Fe→nHg和σC—Fe→nHg的Fe—Hg间接作用为主. (3) Fe—Hg 互作用拉动电荷由R向P、Fe、Hg 转移, 使双核配合物中P的电子密度增大, 故双核配合物中P核周围的电子密度增大, 其31P化学位移比单核配合物的小.

关键词: DFT(PBE0), GIAO, Fe—Hg 相互作用, 31P NMR, NBO

Abstract: In order to study the effects of R group on Fe—Hg interactions and 31P chemical shifts, the structures of mononuclear complexes Fe(CO)3(PPh2R)2 (R=pym: 1, fur: 2, py: 3, thi: 4; pym=pyrimidine, fur=furyl, py=pyridine, thi=thiazole) and binuclear complexes [Fe(CO)3(PPh2R)2(HgCl2)] (R=pym: 5, fur: 6, py: 7, thi: 8) were studied by using the density functional theory (DFT) PBE0 method. The 31P chemical shifts were calculated by PBE0-GIAO method. Nature bond orbital (NBO) analyseswere also performed to explain the nature of the Fe—Hg interactions. The conclusions can be drawn as follows: (1) The complexes with nitrogen donor atoms are more stable than those with O or S atoms. The more N atom there are, the higher is the stabilitity of the complex. (2) The Fe—Hg interactions play a dominant role in the stabilities of the complexes. In 5 or 6, there is a σ-bond between Fe and Hg atoms, However, in 7 and 8, the Fe—Hg interations act as σP—Fe→nHg and σC—Fe→nHg delocalization. (3) Through Fe邛Hg interactions, there is charge transfer from R groups towards the P, Fe, and Hg atoms, which increases the electron density on P nucleus in binuclear complexes. As a result, compared with their mononuclear complexes, the 31P chemical shifts in binuclear complexes show some reduction.

Key words: DFT (PBE0), GIAO, Fe—Hg Interaction, 31P NMR, NBO