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Ligand Design for Alkali-Metal-Templated Self-Assembly of Unique High-Nuclearity CuII Aggregates with Diverse Coordination Cage Units: Crystal Structures and Properties



The construction of two unique, high-nuclearity CuII supramolecular aggregates with tetrahedral or octahedral cage units, {(μ3-Cl)[Li⊂ Cu4(μ-L1)3]3}(ClO4)8(H2O)4.5 (1) and {[Na2⊂Cu12(μ-L2)8(μ-Cl)4](ClO4)8(H2O)10(H3O+)2} (2) by alkali-metal-templated (Li+ or Na+) self-assembly, was achieved by the use of two newly designed carboxylic-functionalized diazamesocyclic ligands, N,N′-bis(3-propionyloxy)-1,4-diazacycloheptane (H2L1) or 1,5-diazacyclooctane-N,N′-diacetate acid (H2L2). Complex 1 crystallizes in the trigonal 3c space group (a = b = 20.866(3), c = 126.26(4) Å and Z = 12), and 2 in the triclinic Pequation image space group (a = 13.632(4), b = 14.754(4), c = 19.517(6) Å, α = 99.836(6), β = 95.793(5), γ = 116.124(5)° and Z = 1). By subtle variation of the ligand structures and the alkali-metal templates, different polymeric motifs were obtained: a dodecanuclear architecture 1 consisting of three Cu4 tetrahedral cage units with a Li+ template, and a supramolecular chain 2 consisting of two crystallographically nonequivalent octahedral Cu6 polyhedra with a Na+ template. The effects of ligand functionality and alkali metal template ions on the self-assembly processes of both coordination supramolecular aggregates, and their magnetic behaviors are discussed in detail.