Ln₂(C₂O₄)(O₂CCH₂OH)₄ (Ln = Gd(III), Tb(III)): Unprecedented Interpenetrating 4,6-Connected Net Built on Unusual Rectangular and Distorted Hexagonal Lanthanide Nodes

Hydrothermal synthesis was used to prepare Ln₂(C₂O₄)(O₂CCH₂OH)₄ (Ln = Gd(III)/1 Tb(III)/2) from HCO₂CH₂OH and C₂O₄²⁻, the latter being formed in situ from HCO₂CH₂OH. The new compounds crystallize with the same unique 2-fold interpenetrating 4,6-connected net described by (3²·6²·7²)(3⁴·4²·6⁴·7⁵) topology, a topology that is based on a combination of highly unusual rectangular and distorted hexagonal lanthanide nodes. Gd₂(C₂O₄)(O₂CCH₂OH)₄, 1, exhibits fully paramagnetic behavior with µ_eff = 7.938(5) µ_B per Gd(III) ion; in the solid state, Tb₂(C₂O₄)(O₂CCH₂OH)₄, 2, exhibits very strong luminescence.