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首页> 外文学位 >Investigation of phosphine containing ligands including tridentate diphosphine diazaphospholeniums and their transition metal complexes.
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Investigation of phosphine containing ligands including tridentate diphosphine diazaphospholeniums and their transition metal complexes.

机译：研究含膦配体，包括三齿二膦二氮磷鎓及其过渡金属配合物。

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摘要

Historically, the coordination of N-heterocyclic phosphenium/phosphido (NHP+/NHP-) ligands incorporated into a chelating diphosphine ligand framework (PPP) to late transition metals has revealed a variety of possible binding modes. In continuation of previous work, PPP-nickel coordination compounds and new diphosphine/NHP+ compounds have been synthesized and investigated. Treatment of the chlorophosphine precursor (PPP)Cl with a stoichiometric amount Ni(COD)2 led to the formation (PPP)NiCl which has been described as an NHP-/NiII complex. The NHP--bridged NiII/Ni0/Ni II compound (PPP)2Ni3Cl2, and the reduced NiINiI dimer [(PPP)Ni]2 were synthesized using excess Ni(COD)2 and the (PPP)Cl ligand. An asymmetrically-bridged dication [(PPP)Ni]2[PF6]2, in which two Ni 0 centers are bridged by two NHP+ cations, was synthesized when [PPP][PF6] was used as the ligand precursor. Comproportionation of the reduced, neutral [(PPP)Ni]2 dimer and the dicationic [(PPP)Ni] 2[PF6]2 complex afforded the mixed-valent monocationic dimer [(PPP)Ni]2[PF6]. Examination of the crystal structures as well as density functional theory calculations have been used to assess the electronic structure and bonding in the mono-, bimetallic compounds, and highlight the redox non-innocence of NHP+/- ligands.;The coordination of a Cp- anion to the PPP ligand via the addition of LiCp to the (PPP)Cl precursor resulted in the formation of two eta1 [PPP]Cp compounds including both the vinylic and allylic NHP-Cp isomers, as well as the deprotonated compound [PPP(C5 H4)][Li]. The vinylic PPP(C5H5) compound, in which the eta1 Cp has undergone a [1,5]-hydride shift, was the major product. Using excess LiCp as a base, PPP(C5H 4) can be synthesized independently. Treatment of (PPP)Cl with two equivalents of NiCp2 resulted in the formation of [(micro-PPP)Ni2Cp 2]Cl, which has been described as a NiIINiII system bridged by one NHP- ligand. The addition of PPh 3 to a reaction of (PPP)Cl and NiCp2 was shown to facilitate the migration of a Cp ring from the metal to the PNHP of the ligand resulting in the formation of (PP(C5H5)P)NiCl 2. Again, the C5H5 ring was found to be the vinylic isomer bound to the PNHP in an eta1 fashion. Deprotonation of (PP(C5H5)P)NiCl2 resulted in the formation of the zwitterionic complex (PP(C5H4)P)NiCl. Calculations were used to assess the electronic structure and bonding of the [(microPPP)(NiCp)2]+, (PP(C5H 5)P)NiCl2, and (PP(C5H4)P)NiCl complexes.;Two new tridentate diphosphine NHP-Cl ligands have been synthesized varying the aromaticity and size of the heterocycle. A tridentate diphosphine NHP-Cl with a ring-fused aromatic phenylene backbone was synthesized (ArPPP)Cl. Additionally, a ring-expanded 6-membered NHP-Cl with pendent phosphine side arms, cyclohexyl(PPP)Cl, was synthesized along with the cationic cyclohexyl[(PPP)][PF6] ligand. Preliminary results in the coordination of (cyclohexylPPP)Cl to NaCo(CO) 4 and PdCp(allyl) suggests the formation of kappa2-cyclohexyl(PPP)Co(CO) 3, tentatively assigned as NHP-/CoI with only one bound phosphine side arm, and cyclohexyl(PPP)Pd-Cl, tentatively assigned as NHP-/PdII.;Finally, heterobimetallic complexes featuring three bidentate phosphinoamide ligands bridging a CoI center and a Nb or Ta imido fragment have been synthesized. The resulting heterobimetallic complexes, ICo(Ph 2PNiPr)3M=N tBu, are shown to have weakened dative metal-metal interactions as a result of the strongly donating imido ligand, in comparison to similar, previously reported compounds. The ICo(Ph2PNiPr) 3M=NtBu complexes can be reduced by two electrons to generate dinitrogen-bound complexes.
机译：从历史上看，掺入螯合二膦配体骨架（PPP）中的N-杂环/磷（NHP + / NHP-）配体与晚期过渡金属的配位揭示了多种可能的结合方式。在先前工作的延续中，已经合成并研究了PPP-镍配位化合物和新的二膦/ NHP +化合物。用化学计量的Ni（COD）2处理氯膦前体（PPP）Cl导致形成（PPP）NiCl，已将其描述为NHP- / NiII络合物。使用过量的Ni（COD）2和（PPP）Cl配体合成了NHP桥接的NiII / Ni0 / Ni II化合物（PPP）2Ni3Cl2和还原的NiINiI二聚体[（PPP）Ni] 2。当[PPP] [PF6]用作配体前体时，合成了一个不对称桥联的[[（PPP）Ni] 2 [PF6] 2]，其中两个Ni 0中心被两个NHP +阳离子桥接。还原的中性[（PPP）Ni] 2二聚体和离子型[（PPP）Ni] 2 [PF6] 2配合物的配比得到混合价单阳离子二聚体[（PPP）Ni] 2 [PF6]。晶体结构的检验以及密度泛函理论计算已用于评估单金属，双金属化合物中的电子结构和键合，并突出了NHP +/-配体的氧化还原非纯。通过在（PPP）Cl前体中添加LiCp将阴离子与PPP配体形成阴离子导致形成两种eta1 [PPP] Cp化合物，包括乙烯基和烯丙基NHP-Cp异构体以及去质子化化合物[PPP（C5 H4）] [Li]。主要产物是乙烯基PPP（C5H5）化合物，其中eta1 Cp发生[1,5]氢化物移位。使用过量的LiCp作为碱，可以独立合成PPP（C5H 4）。用两个当量的NiCp2处理（PPP）Cl导致形成[（micro-PPP）Ni2Cp 2] Cl，该化合物被描述为由一个NHP-配体桥接的NiIINiII系统。已显示在（PPP）Cl和NiCp2的反应中添加PPh 3可以促进Cp环从金属向配体的PNHP迁移，从而导致（PP（C5H5）P）NiCl 2的形成。 ，发现C5H5环是一种以eta1方式键合到PNHP的乙烯基异构体。 （PP（C5H5）P）NiCl2的质子化导致两性离子络合物（PP（C5H4）P）NiCl的形成。计算用于评估[（microPPP）（NiCp）2] +，（PP（C5H 5）P）NiCl2和（PP（C5H4）P）NiCl配合物的电子结构和键合。;两个新的三齿二膦NHP已经合成了-Cl配体，其改变了杂环的芳香性和大小。合成了具有环稠合芳族亚苯基骨架的三齿二膦NHP-Cl（ArPPP）Cl。此外，与阳离子环己基[（PPP）] [PF6]配体合成了具有侧链膦侧环的六环NHP-Cl环己基（PPP）Cl。 （cyclohexylPPP）Cl与NaCo（CO）4和PdCp（allyl）配位的初步结果表明形成了kappa2-cyclohexyl（PPP）Co（CO）3，暂定为NHP- / CoI，只有一个结合的膦侧最后，暂时合成了具有三个CoN中心和Nb或Ta亚氨基片段的双齿膦酰胺配体的杂双金属配合物。与以前报道的类似化合物相比，由于强力提供的亚氨基配体，所得的异双金属配合物ICo（Ph 2PNiPr）3M = N tBu具有减弱的金属间金属相互作用。 ICo（Ph2PNiPr）3M = NtBu配合物可以被两个电子还原生成二氮键结合的配合物。

著录项

  • 作者

    Evers-McGregor, Deirdra.;

  • 作者单位

    Brandeis University.;

  • 授予单位 Brandeis University.;
  • 学科 Inorganic chemistry.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 183 p.
  • 总页数 183
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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