化学学报 ›› 2001, Vol. 59 ›› Issue (4): 538-543. 上一篇    下一篇

研究论文

二{氧合-二[3-二茂铁基丙烯酸二正丁基锡(Ⅳ)]} 配合物的晶体结构及溶液中的 配位互变平衡机理

陶家洵;李旭宇;卢文贯   

  1. 清华大学化学系.北京(100084);韶关大学化学系
  • 发布日期:2001-04-15

Crystal structure of bis{oxo-bis[3-ferrocenylacrylate di-n-butyltin( Ⅳ)]}and mechanism of coordination tautomeric equilibrium in solution

Tao Jiaxun;Li Xuyu;Lu Wenguan   

  1. Tsing Hua Univ, Dept Chem.Beijing(100084)
  • Published:2001-04-15

测定了配合物{[(n-Bu)2Sn(FcCH=CHCO2)]2O}2(Fc=Ferrocenyl)晶体结构,它属三斜晶系,空间群P1,晶胞参数a=1.3943(3)nm,b=1.4635(3)m,c=1.2792(3)nm,α=94.32(3)°,β=116.27(3)°,γ=109.08(3)°,Z=2,V=2.1362(8)nm^3,Dc=1.542g/cm^3,F(000)=1004。最终偏差因子R=0.0401,Rw=0.1076。该分子中存在着内环锡和外环锡配位单元,锡原子均形成具有假六配位的单加帽畸变三角双锥配位构型。Sn2O2中心内环与丙烯酸酯基茂环等共轭体系之间相互未能共平面。配合物中四个羧基配体划分为两类:两个为桥式双齿配位(μ-COO),跨接于一个内环锡和一个外环锡;另两个仅以单齿配位方式各连接一个外环锡。根据核磁共振谱信息表明分子在溶液中存在着配位互变异构体之间的快交换。我们提出振动模式的假说,认为可能是羧酸酯基氧在其平面内快速摇摆建立了动态平衡之故。

关键词: 二茂铁P, 丙烯酸P, 有机锡化合物, 晶体结构, 配位化学

The crystal structure of the title complex has been determined. The crystal is space P1 with parameters: a=1.3943(3)nm,b=1.4635(3)m,c=1. 2792(3)nm, α=94.32(3)°,β=116.27(3)°,γ=109.08(3)°,Z=2, V=2. 1362(8)nm^3, Dc=1.542g/cm^3,F(000)=1004, and the structure is refined to final R=0.0401,Rw=0.1076. Four carboxylate ligands are divided into two types. Two of the carboxylate ligands are bidentate (μ-COO) and bridging each pair of endo-and exo-cyclic tin atoms by using both oxygen atoms. The others are monodentate and coordinate each exo cyclic tin atom. Both endo-and exo-cyclic tin atoms are all five- coordination with coordination geometry of monocapped distorted trigonal bipyramid. Two conjugate systems (acryloxy group and Cp ring) can not be coplanar with the central endo-cyclic Sn2O2 unit. The NMR data indicate the existence of a dynamic process of the carboxylic coordination tautomers. Comparing the crystal {[(n-Bu)2Sn(FcCO2)]2O}2 ·4C6H6 (A) with {[(n-Bu)2Sn(FcCO2)]2O}2 (B), we put forward a waggling mechanism to explain this phenomenon, namely, the oxygen atoms of carboxylic groups vacillate quickly within the plane of their carboxylic groups. This is owing to the fluctuations of electron cloud to result in re-distribution or re-adjustment of Sn— O bonds considering completely both the strong and weak interactions between Sn atoms and O atoms rather than the internal rotation about the Sn— O(carboxylic) bonds.

Key words: FERROCENE P, ACRYLIC ACID P, ORGANO TIN COMPOUNDS, CRYSTAL STRUCTURE, COORDINATE CHEMISTRY

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