Light Lanthanide Metallocenium Cations Exhibiting Weak Equatorial Anion Interactions

Jingjing Liu, Daniel Reta, Jake A. Cleghorn, Yu Xuan Yeoh, Fabrizio Ortu, Conrad Goodwin, Nicholas Chilton, David Mills

Research output: Contribution to journalArticlepeer-review


As the dysprosocenium complex [Dy(Cpttt)2][B(C6F5)4] (Cpttt = C5H2tBu3‐1,2,4, 1‐Dy) exhibits magnetic hysteresis at 60 K, similar lanthanide (Ln) complexes have been targeted in order to provide insights into this remarkable property. We recently reported homologous [Ln(Cpttt)2][B(C6F5)4] (1‐Ln) for all the heavier Ln from Gd‐Lu; herein, we extend this motif to the early Ln. We find, for the largest LnIII cations, that contact ion pairs [Ln(Cpttt)2{(C6F5‐κ1F)B(C6F5)3}] (1‐Ln; La‐Nd) are isolated from reactions of parent [Ln(Cpttt)2(Cl)] (2‐Ln) with [H(SiEt3)2][B(C6F5)4], where the anion binds weakly to the equatorial sites of [Ln(Cpttt)2]+ through a single fluorine atom in the solid state. For smaller SmIII, [Sm(Cpttt)2][B(C6F5)4] (1‐Sm) is isolated, which like heavier 1‐Ln does not exhibit equatorial anion interactions, but the EuIII analogue 1‐Eu could not be synthesised due to the facile reduction of EuIII precursors to EuII products. Thus with the exception of Eu and radioactive Pm this work constitutes a structurally similar family of Ln metallocenium complexes, over 50 years after the [M(Cp)2]+ series was isolated for the 3d metals.
Original languageEnglish
Pages (from-to)7749-7758
Number of pages10
JournalChemistry: A European Journal
Issue number32
Early online date17 Apr 2019
Publication statusPublished - 7 Jun 2019


  • cyclopentadienyl ligands
  • lanthanides
  • magnetic properties
  • metallocenes
  • sandwich complexes

Research Beacons, Institutes and Platforms

  • Dalton Nuclear Institute


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