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首页> 外文学位 >Synthesis, spectroscopy, structure, and reactivity of a neutral iridathiabenzene and thiapentadienyl-rhodium-phosphine chemistry.
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Synthesis, spectroscopy, structure, and reactivity of a neutral iridathiabenzene and thiapentadienyl-rhodium-phosphine chemistry.

机译：合成，光谱学，结构和反应性的中性铱和噻吩二烯基-铑-膦化学。

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摘要

A stable neutral iridathiabenzene was synthesized by the treatment of cationic iridathiabenzene with a bulky anionic reagent, sodium tert-butylthiolate. The NMR spectroscopic data and solid state structure of the neutral iridathiabenzene strongly suggested aromaticity in the molecule. In the solution phase, the neutral iridathiabenzene existed as an equilibrating mixture of two square pyramidal isomers. The reactivity of the neutral iridathiabenzene was tested toward a variety of nucleophiles, electrophiles, and coordinating metal fragments. The iridium metal center in the molecule was found to be susceptible to attack by two-electron donors such as acetonitrile and trimethylphosphine ligands, and led to the formation of six-coordinate iridathiacyclohexa-1,3-diene compounds. Reaction with trifluoromethanesulfonic acid led to protonation at the sulfur atom of the thiolate ligand, causing the loss of thiol, and production of a sulfur-bridged dimeric product. The neutral iridathiabenzene also underwent reaction with a cationic coordinating metal fragment to give a sandwich compound in which it coordinated to the new metal fragment in an eta5 fashion. Overall, the reaction chemistry of the neutral iridathiabenzene demonstrated the fragile nature of its metalloaromaticity.;The synthesis and reaction chemistry of novel thiapentadienyl-rhodium-phosphine complexes was systematically carried out. The study demonstrated that the thiapentadienyl ligands in these species could adopt a variety of bonding modes and that interconversions between those modes were facile. The synthetic strategy included the reactions of (Cl)Rh(PR3)3 (R=Me and Et) with the anionic reagent, lithium 2,3-dimethyl-5-thiapentadienide. This reaction initially led to the formation of products in which the sulfur end of the thiapentadienyl chain was sigma-bonded to the rhodium center (1,2,5-eta3 or 5-eta1) and the carbon end of the chain was pi-bound to rhodium. However, ligand rearrangement yielded more stable isomers in which the carbon end of the thiapentadienyl chain was sigma-bonded to the rhodium center and sulfur end was pi-bound. The thiapentadienyl ligands in both the isomers of the rhodium-trimethylphosphine complexes were reactive toward simple electrophiles and the site of electrophilic addition changed with the electrophile. Specifically, treatment with HBF4OEt 2 resulted in proton addition to the terminal thiapentadienyl carbon C1 and production of a sulfur bridged dimer while treatment with CH3 O3SCF3 led to methylation at the nucleophilic sulfur center. The recurring theme in the thiapentadienyl-rhodium- triethylphosphine complexes was the formation of dimers through the agency of thiapentadienyl sulfur bridges.
机译：通过用大体积的阴离子试剂叔丁基硫代硫酸钠处理阳离子铱并合成出稳定的中性铱并噻吩。 NMR光谱数据和中性铱碳杂苯的固态结构强烈暗示了分子中的芳香性。在溶液相中，中性铱硫杂苯以两种方形金字塔形异构体的平衡混合物形式存在。测试了中性铱噻吩苯对各种亲核试剂，亲电试剂和配位金属片段的反应性。发现分子中的铱金属中心易于受到二电子供体（如乙腈和三甲基膦配体）的攻击，并导致形成六配位的iridathiacyclohexa-1,3-diene化合物。与三氟甲磺酸的反应导致硫醇盐配体的硫原子处的质子化，导致硫醇的损失，并产生了硫桥联的二聚产物。中性铱硫杂苯还与阳离子配位金属片段发生反应，生成一种三明治化合物，其中该化合物以eta5方式与新的金属片段配位。总的来说，中性铱硫杂苯的反应化学表现出其金属芳香性的脆弱性质。；系统地进行了新型噻戊二烯基-铑-膦配合物的合成和反应化学。研究表明，这些物种中的噻戊二烯基配体可以采用多种键合模式，并且这些模式之间的相互转化是容易的。合成策略包括（Cl）Rh（PR3）3（R = Me和Et）与阴离子试剂2,3-二甲基-5-噻吩二烯化锂的反应。该反应最初导致形成这样的产物，其中噻戊二烯基链的硫端被σ键合到铑中心（1,2,5-eta3或5-eta1），而链的碳端被π键结合铑。然而，配体重排产生更稳定的异构体，其中噻戊二烯基链的碳末端被σ-键合到铑中心，而硫末端被π-键合。铑-三甲基膦配合物的两个异构体中的噻戊二烯基配体均对简单的亲电试剂具有反应性，并且亲电试剂的加成位点随亲电试剂而变化。具体而言，用HBF4OEt 2处理会导致质子添加到末端的噻吩二烯基碳C1上，并生成硫桥连的二聚体，而用CH3 O3SCF3处理会导致亲核硫中心的甲基化。噻戊二烯基-铑-三乙基膦配合物中的重复主题是通过噻戊二烯基硫桥的作用形成二聚体。

著录项

  • 作者

    Shokeen, Monica.;

  • 作者单位

    Washington University in St. Louis.;

  • 授予单位 Washington University in St. Louis.;
  • 学科 Inorganic chemistry.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 404 p.
  • 总页数 404
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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