Synthesis and structure of half-sandwich Y³⁺ and Dy³⁺ carbazolyl iodide complexes

The salt metathesis reactions of equimolar amounts of potassium carbazolide Bu₄^tCarbK (Bu₄^tCarb is 1,3,6,8-tetra-tert-butylcarbazolyl) with solvent-free rare-earth metal iodides LnI₃ (Ln = Y, Dy) in toluene at 100 °C afforded the corresponding half-sandwich carbazolyl iodide complexes [(Bu₄^tCarb)Ln(μ²-I)₂]₃. The X-ray diffraction analysis showed that the yttrium compound has a cyclic trinuclear structure that is formed through μ²-bridging iodide ligands connecting Y³⁺ cations. The metal atom is coordinated by the carbazolyl ligand in a η⁵ fashion. Under similar conditions, the salt metathesis reaction of Bu₄^tCarbK with DyI₃(THF)_3.5 gave the monomeric half-sandwich carbazolyl iodide complex (Bu₄^tCarb)DyI₂(THF)₂.