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

Complexes {[LnCu(GlyHA)(m-bdc)(HO)][LnCu(GlyHA)(SO)(m-bdc)(HO)]}·(30 + 2x)HO (where GlyHA = glycinehydroxamate, m-bdc = 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 {[NdCu(GlyHA)(HO)(m-bdc)]n[NdCu(GlyHA)(HO)(μ-CO)(m-bdc)]}·13nHO (2) and {EuCu(GlyHA)(HO)[EuCu(GlyHA)(m-bdc)(HO)]}·17nHO (4) were obtained starting from the 15-metallacrown-5 complexes {[LnCu(GlyHA)(SO)(HO)]}(SO)·6HO (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 [LnCu(GlyHA)] 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 {[NdCu(GlyHA)(HO)(m-bdc)]} 1D chains in 2 being separated by discrete [NdCu(GlyHA)(HO)(μ-CO)(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 cm/g of methanol vapor or 0.04 cm/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 χT vs T data for complexes 1-4 and their simpler starting materials {[LnCu(GlyHA)(SO)(HO)]}(SO)·6HO (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 < -63 cm. 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.