Synthesis, Crystal Structure And Reactivity Of Amidolanthanide Benzenethiolate Complexes

It is well know that amidolanthanide complexes possess good catalytic activity in organic synthesis while lanthanide chalcogenate complexes display interesting application advanced materials. Therefore combination of the two families of lanthanide complexes may play a great impact on their catalytic activity and other material properties. On the other hand, ligands containing donor atoms such as S, Se always show low ligating ability to hard acids lanthanide ions. Thus the chemistry of the lanthanide thiolate complexes is less explored. In this thesis, we deliberately chose and/or prepared the lanthanide amide complexes containing a bridging Cl^-and a [Li(THF)₃]⁺ unit for their protonolysis via benzenethiol. A family of novel stable amidolanthanide benzenethiolates along with a series of mono-and di-substituted bis(trimethylsily)amide lanthanide(III) chloride complexes were prepared and fully characterized by melting point determination, elemental analysis, IR spectra, and X-ray crystallography, and their catalytic activities toward ε-caprolactone were also investigated. 1 The reactions of [(TMS)₂N]₃Ln(μ-Cl)Li(THF)₃ (Ln = Pr, Nd, Sm; TMS = Me₃Si) with equimolar benzenethiol, afforded three soluble different Ln/benzenethiolate complexes [{(TMS)₂N}₂(μ-SPh)Pr(μ-SPh)Li(THF)₂]_∞(1), Li[{(TMS)₂N}₄(μ₄-Cl)Nd₄ (μ-SPh)₈]·C₆H₆ (2·C₆H₆), [{(TMS)₂N}₄(μ₄-Cl)Sm₄(μ-SPh)₄(μ₃-Cl)₄Li(THF)] (3) and two by-products [{((Me₃Si)₂N)₂Pr(μ'-Cl)Li(THF)₃}(μ-Cl)]₂ (4), [{((TMS)₂N)₂Sm (μ'-Cl)Li(THF)₂}(μ₃-Cl)]₂ (5). It is noted that the Li⁺ and/or Cl^-ions were incorporated into the polymeric backbone or cluster frameworks, which guarantee the formation of the soluble compounds 1-3. Comparative runs with their precursors and the mono-or di-substituted silylamido complexes of lanthanides, showed that 1-3 initiated faster polymerization and produced poly(ε-caprolactone) with narrower molecular weight distribution. 2 We have isolated some novel amidolanthanide benzenechalcogenate complexes [{((TMS)₂N)₂(THF)La}₂(μ-SPh)(μ-Cl)]·C₆H₅CH₃(6·C₆H₅CH₃) and [N(TMS)2]La5O(SPh)10Li(THF)2Cl2 (7) by reaction of [(TMS)2N]3La(μ-Cl)Li(THF)3 with HSPh. Reaction of [(TMS)2N]3Ln(μ-Cl)Li(THF)3 with HSePh in 1 : 1 molar ratio, produced a amidolanthanide benzeneselenolate complex [{((TMS)2N)2(THF)La}(μ-SePh)]2 (8). Complexes 6 and 7 are very stable, but compound 8 was readily turned into an insoluble material and [(TMS)2N]3La at room temperature. 3 Reactions of anhydrous lanthanide(III) trichloride (Ln = Nd, Eu, Ho, Sm, Yb) with one or two equiv. of LiN(SiMe3)2 in THF generated a family of lanthanide(III) bis(trimethylsilyl)amide chloride complexes: [{(Me3Si)2NLn(μ'-Cl)2Li(THF)2}(μ-Cl)]2 (Ln = Nd (9); Ln = Sm (10); Ln = Eu (11); Ln = Ho (12); Ln = Yb (13)), [{((Me3Si)2N)2Ln(μ'-Cl)Li(THF)3}(μ-Cl)]2 (Ln = Nd (14); Ln = Sm (15)), [{((Me3Si)2N)2Ln(μ'-Cl)Li(THF)2}(μ3-Cl)]2 (Ln = Eu (16); Ln = Ho (17)). These mono-and di-substituted silylamido lanthanide complexes exhibited catalytic activity for the ring-opening polymerization of ?-caprolactone at ambient temperature. Complexes 10, 11 and 13 showed somewhat poorer catalytic activity than the corresponding di-substituted complexes under the same condition, which might be ascribed to the fact that mono-substituted compound have a less open coordination environment around the metal (coordination number six). 4 Reactions of SmI2 in THF with ArSSAr gave rise to two dinuclear samarium benzenethiolate complexes [(THF)3I2Sm(μ-SAr)]2 (Ar = C6H5 (18); Ar = C6H4(Me2N)-4 (19)) in high yield. 5 The [PPh4]3[Bi(WS4)3] (20) was synthesized by the reaction of [PPh4]2[WS4] and BiCl3 under pure dinitrogen atmosphere using standard Schlenk-line techniques. The compound was characterized by single structure analysis, IR spectra, UV spectra.