High Nuclearity Assemblies and One-Dimensional (1D) Coordination Polymers Based on Lanthanide–Copper 15-Metallacrown‑5 Complexes (LnIII = Pr, Nd, Sm, Eu)

Complexes {[LnCu5(GlyHA)5(m-bdc)­(H2O)4–x ]2[LnCu5(GlyHA)5(SO4)­(m-bdc)­(H2O)4]2}·(30 + 2x)­H2O (where GlyHA2– = glycinehydroxamate, m-bdc2– = m-phthalate; Ln = Pr and x = 0.21 for compound 1, or Ln = Sm and x = 0.24 for 3) and one-dimensional (1D) coordination polymers {[NdCu5(GlyHA)5(H2O)5(m-bdc)] nn[NdCu5(GlyHA)5(H2O)4(μ-CO3)­(m-bdc)]}·13nH2O (2) and {[EuCu5(GlyHA)5(H2O)3]­(m-bdc)2[EuCu5(GlyHA)5(m-bdc)­(H2O)3]} n ·17nH2O (4) were obtained starting from the 15-metallacrown-5 complexes {[LnCu5(GlyHA)5(SO4)­(H2O)6.5]}2(SO4)·6H2O (Ln = Pr, Nd, Sm, Eu) by the partial or complete metathesis of sulfate anions with m-phthalate. Compounds 1 and 3 contain unprecedented quadruple-decker neutral metallacrown assemblies, where the [LnCu5(GlyHA)5]3+ cations are linked by m-phthalate dianions. In contrast, in complexes 2 and 4, these components assemble into 1D chains of coordination polymers, the adjacent {[NdCu5(GlyHA)5(H2O)5(m-bdc)]+} n 1D chains in 2 being separated by discrete [NdCu5(GlyHA)5(H2O)4(μ-CO3)­(m-bdc)]}− complex anions. The crystal lattices of 2 and 4 contain voids filled by solvent molecules. Desolvated 4 is able to absorb up to 0.12 cm3/g of methanol vapor or 0.04 cm3/g of ethanol at 293 K. The isotherm for methanol absorption by compound 4 is consistent with a possible “gate opening” mechanism upon interaction with this substrate. The χM T vs T data for complexes 1–4 and their simpler starting materials {[LnCu5(GlyHA)5(SO4)­(H2O)6.5]}2(SO4)·6H2O (Ln­(III) = Pr, Nd, Sm, Eu) were fitted using an additive model, which takes into account exchange interactions between lanthanide­(III) and copper­(II) ions in the metallamacrocycles via a molecular field model. The exchange interactions between adjacent Cu­(II) ions in metallacrown fragments were found to fall in the range of −47 < J Cu–Cu < −63 cm–1. These complexes are the first examples of a Ln­(III)-Cu­(II) 15-metallacrowns-5 (Ln­(III) = Pr, Nd, Sm, Eu), for which values of exchange parameters have now been reported.