The synthesis of a variety of new lanthanoid phosphine complexes has been achieved by complexing either one or two amido-diphosphine ligands to yttrium, lutetium or lanthanum. At room temperature, the seven-coordinate bis(amido- diphosphine) complexes, MCl[N(SiMe₂CH₂PR₂)₂]₂- are fluxional and display NMR spectra indicative of complexes where the phosphorus donors are rapidly exchanging, probably via a dissociation-reassociation pathway. It is possible to generate thermally unstable hydrocarbyl complexes of the type, M(R)[N(SiMe₂CH₂PMe₂)₂]₂, which undergo a clean first order elimination of R-H to generate cyclometallated complexes of the type, M[N(SiMe₂CHPMe₂)(SiMe₂CH₂PMe₂)][N(SiMe₂CH₂PMe₂)₂]; the yttrium derivative was crystallographically characterized. These thermally robust compounds will undergo a-bond metathesis with H₂ and D₂ at high temperature, but appear to be too sterically congested to react with larger molecules. The synthesis of a series of mono(amido-diphosphine) lanthanoid complexes, MCl₂ [N(SiMe₂CH₂PR₂)₂], (R = Me, Ph, Pr', Bu[symbol omitted]) has also been achieved. Complexes of the type, MCl₂[N(SiMe₂CH₂PMe₂)₂], are insoluble in hydrocarbon solvents, presumably because they are oligomeric in nature. They will however, dissolve in THF probably forming seven-coordinate bis(THF) monomers. Attempts to alkylate these compounds generally led to decomposition; the cyclometallated bis(ligand) complex, M[N(SiMe₂CHPMe₂)(SiMe₂CH₂PMe₂)] [N(SiMe2CH2PMe2)2], was identified as the major product. A route to a dimeric mono(amido-diphosphine) allyl complex, {YCl(allyl)[N(SiMe₂CH₂PMe₂)₂]}₂ (characterized by crystallography) was found via the reaction of allyl-MgCl or Mg(allyl)₂(dioxane) with YCl[N(SiMe₂CH₂PMe₂)₂]₂. The mono(ligand) complexes containing bulky phosphine donors (R = Ph, Bu[symbol omitted], Pr[symbol omitted]) are soluble in hydrocarbon solvents; YCl₂[N(SiMe₂CH₂PPr[symbol omitted]₂)₂] can be isolated as either a THF adduct or as the base-free dimer. A new reaction, mediated by a zirconium or hafnium amido-diphosphine complex, where allyl and butadiene moieties are coupled together to generate a coordinated [ɳ⁴:ɳ¹-CH₂=CHCH=CHCH₂CH₂CH₂]¹- fragment has been investigated. The process is very sensitive to the nature of the ancillary ligands at the metal. For MCl(ɳ⁴-C₄H₆)[N(SiMe₂CH₂PR₂)₂] complexes, after the addition of allylMgCl, the transformation takes about one hour when M = Hf & R = Pr[symbol omitted], two hours when M = Zr & R = Pr[symbol omitted], a week when M = Hf & R = Me, and results only in decomposition when M = Zr & R = Me. Similarly, for the zirconium mediated coupling of 1-methylallyl with butadiene, when R = Me, decomposition occurs and when R = Pr[symbol omitted], after two hours the coupling is complete. Two of the four possible coupled products are formed in unequal amounts, and the coupling occurs exclusively at the substituted end of the 1-methylallyl unit as determined by X-ray crystallography. Which diastereomer is formed in excess was not determined. The reduction of ZrCl₃[N(SiMe₂CH₂PR₂)₂] (R = Pr[symbol omitted] or Bu[symbol omitted]) with Na/Hg amalgam under nitrogen results in the formation of a binuclear zirconium dinitrogen complex, {ZrCl[N(SiMe₂CH₂PR₂)₂]}₂ (μ-ɳ²:ɳ²-N₂). X-ray crystallography (for R = Pr[symbol omitted]) reveals that the N₂ ligand is symmetrically bound in a side-on fashion to both metals. In addition, the N—N bond length of 1.548 (7) Å, the longest bond length ever reported for a dinitrogen complex, indicates that the dinitrogen has been reduced to a N₂⁴⁻ hydrazido ligand. Protonation of the complex with HCl results in a quantitative formation of hydrazine. / Science, Faculty of / Chemistry, Department of / Graduate

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Co(NO)(NO₂)₂L₂ complexes (L = PPh₃, PMePh₂, PMe₂Ph, PMe₃, PEt₃, PEt₂Ph, PEtPh₂, PPrPh₂, PBu₃ and 1/2DPPPr) were prepared from the reactions of Co(NO)X₂L₂ (X = Cl, Br) with sodium nitrite in methanol freshly distilled from magnesium methoxide. The complexes were characterized by elemental analysis, 15-N labeling, infrared and NMR spectroscopy. The crystal structure of Co(NO)(NO₂)₂(PMePh₂)₂ was determined by X-ray diffraction. The cobalt atom has tetragonal pyramidal geometry. The nitrosyl group in the axial position is strongly bent. The NO₂ ligands have two different ligating geometries: one is bound to cobalt through the nitrogen atom and the other is bidentate forming an asymmetric four membered ring. The phosphine ligands are equivalent and trans to each other. Multinuclear NMR spectroscopy (¹H, ³¹P, ¹⁵N and ¹⁴N) was used to determine the solution structure of Co(NO)(NO₂ )₂L₂ complexes, to study mono and bisnitrosyls of cobalt, to establish some correlations between NMR parameters and structural characteristics of these complexes and to follow their reactions in solution. Reactions of Co(NO)(NO₂)₂L₂ with CO, NO and RCOX were observed to produce Co(NO)₂XL complexes. Since the structure may be indicative of electronic requirements at the metal center as well as the reactivity of the compounds, The crystal structures of Co(NO)₂Cl(PPh₃) and Co(NO)₂(ONO)(PPh₃) were also determined. In these complexes the cobalt atoms have pseudotetrahedral geometry. The CoNO angles are in the range considered to be linear. They are geniculated in an "atracto" conformation. Co(NO)(NO₂)₂L₂ and Co(NO)₂(ONO)L complexes react with oxygen in the solid state or in solution to form Co(NO₃)₂(OL)₂ complexes. When the reactions with O₂ were carried out in the presence of an excess of olefins, the formation of nitrates is inhibited Co(NO₂)₂(OL)₂ and olefin oxides are formed instead. The crystal structures of Co(NO₃)₂(OPMePh₂)₂ and Co(NO₂)₂(OPMePh₂)₂ were determined by X-ray diffraction. In these complexes, the NO₃ and NO₂ groups are bidentate. They are arranged in a cis configuration around the cobalt atom.

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Die Hydrophosphinierung stellt eine wertvolle Synthesemöglichkeit zum Aufbau von primären, sekundären und tertiären Phosphanen dar. In dieser Arbeit wird die Synthese verschiedener Primär-Phosphan-Komplexes des Eisens und Ruthenium beschrieben. Untersucht wurden ihre Reaktivität bezüglich Hydrophosphinierungsreaktionen sowie den Einfluss verschiedener Liganden z.B. bidentate Phosphanliganden und hemilabilen Liganden. / The hydrophosphination reaction offers an important synthesis method for the building of primary, secondary and tertiary phosphines. In this work we report the syntheses of different primary phosphine complexes of iron and ruthenium. Also their reactivity in hydrophosphination reaction and the influence of diverse ligands, for example bidentate phosphine ligand and hemilablie ligand, were studied.