Synthesis, Structure and Characterization Of Polynuclear Rare Earth Alkoxide Clusters

Abstract

The versatile polyol/polyamine supporting ligand TDCI (1,3,5-tris(dimethylamino)- 1,3,5-trideoxy-cis-inositol was synthesized, and several lanthanide complex clusters of this ligand were produced.The coordination chemistry and characterization of these triangular lanthanide alkoxide clusters was explored. Molecular products include Ln₃(H−₃TDCI)₂(L) (Ln = Y, Eu, Gd, Tb, Dy, Ho, Er; L =MeOH, H₂O, dipivaloylmethanide, acetylacetonate, dibenzoylmethanide, tetraacetylethane, hexafluoroacetylacetonate).The dysprosium and gadolinium analogues of these clusters were used as secondary building units and were incorporated as preformed entities into coordination polymers linked by squarate (C₄O₄)²− and benzenedicarboxylate.

The dysprosium clusters Dy₃(H−₃TDCI)₂(MeOH)₆ and Dy₃(H−₃TDCI)₂(dpm)₆ (dpm = dipivaloylmethanide) as well as the coordation polymer Dy₃(H−₃TDCI)₂(C₄O₄)₃/₂ were shown to exhibit slow relaxation of magnetization characteristic of single-molecule magnet behavior. The europium and terbium analogues were characterized by spectrofluorimetry.

Hexanuclear oxo-centered Dy and Gd clusters were synthesized: the OH-face capped Gd₆(μ₆-O)(μ₃-OH)₆(μ₃-O)₂(PhB(OEt)₂)₂(dpm)₆(HOEt)₂ and Gd₆(μ₆-O)(μ₃-OH)₈(dpm)₈ as well as the edg-bridged [Dy₆(μ₆-O)(μ₂-OCH₂CF₃)₁₂(OCH₂CF₃)₆][Na(thf)₆]₂. All compounds were characterized by single-crystal X-Ray diffraction.