181264-45-9Relevant academic research and scientific papers
Contrasting binding modes in lanthanoid pyrazolate and pseudo-pyrazolates prepared by oxidation of lanthanoid(II) complexes and lanthanoid metals with thallium(I) reagents
Deacon, Glen B.,Delbridge, Ewan E.,Fallon, Gary D.,Jones, Cameron,Hibbs, David E.,Hursthouse, Michael B.,Skelton, Brian W.,White, Allan H.
, p. 1713 - 1721 (2000)
Oxidation of Yb(C5Me5)2 with [Tl(Ph2pz)] and [Tl(azin)] (Ph2pz = 3,5-diphenylpyrazolate, azin = 7-azaindolate) yields [Yb(C5Me5)2(Ph2pz)] (1) and [Yb(C5Me5)2(azin)] (2). X-ray crystal structures of 1 and 2 reveal monomeric eight-coordinate complexes with η2-Ph2pz or azin ligands. Treatment of neodymium metal with [Tl(Ph2pz)] yields [Nd(Ph2pz)3(dme)2] (3), which is a nine-coordinate monomer with three η2-pyrazolate ligands and a chelating and a unidentate dme ligand. Oxidation of Sm(C5Me5)2 with [TI(1,4,2-P2SbC2But2)]/[TI(1,2,4-P3C2 But2)] (approximately 4:1) gave a mixture of [Sm(C5Me5)2(1,2,4-P3C2But2)] (4) and [Sm(C5Me5)2(1,4,2-P2SbC2But2)]. The former was shown to be a nine-coordinate monomer with novel pseudo-pyrazolate η2-(P2)-[1,2,4-P3C2But2] coordination of the triphosphacyclopentadienide ligand. After metathesis routes to Ln(1,4,2-P2SbC2But2)n complexes failed, redox transmetalation between ytterbium metal and [Tl(1,4,2-P2EC2But2)] (E = Sb, P) containing a substantial impurity of [Li(tmeda)2][1,4,2-P2EC2But2] yielded the first lanthanoid diphosphastibacyclopentadienide complex in a mixture with [1,2,4-P3C2But2] species. An X-ray investigation of single crystals containing an isomerically diverse mixture enabled the structure of [Li(thf)4]-[Yb(1,4,2-P2SbC2But2)3] (5) to be determined, and it was shown to contain a π-η2 and two η5-[1,4,2-P2SbC2But2] ligands. In the series 1, 4, and 5, the η2-ring varies from edge-on to side-on, reflecting a progression from σ to π coordination. [Li(tmeda)2][1,4,2-P2SbC2But2] (6) has been successfully crystallized from a [Li(tmeda)2][P2EC2But2] mixture and structurally characterized.
