Abstract
Hydrothermal reactions of <TEX>$Ln(NO_3)_3{\cdot}5H_2O $</TEX> (Ln = Eu (1), Sm (2), Ho (3), Dy (4)) with 3,5-pyridinedicarboxylic acid (3,5-pdcH2) in the presence of 4,4'-bipyridine led to the formation of the 3-D Ln(III)-coordination polymers with a formula unit of <TEX>$[Ln_2(3,5-pdc)_2(C_2O_4)(H_2O)_4]{\cdot}2H_2O$</TEX>. These polymers contain a bridging oxalate ligand (<TEX>$C_2O_4\;^2$</TEX>). On the basis of GCMS study of the mother liquor remaining after the reaction, we proposed that the <TEX>$C_2O_4\;^2$</TEX> formation proceeds in three steps: (1) Ln(III)-mediated decarboxylation of <TEX>$3,5-pdcH_2$</TEX> to give <TEX>$CO_2$</TEX>, (2) the reduction of <TEX>$CO_2$</TEX> to <TEX>$CO_2\;^{\cdot}$</TEX> by the Ln(II) species, and (3) the reductive coupling of the two <TEX>$CO_2\;^{\cdot}$</TEX> radicals to the oxalate (<TEX>$C_2O_4\;^2$</TEX>) ion. All polymers were structurally characterized by X-ray diffraction.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call