6533b822fe1ef96bd127cb50

RESEARCH PRODUCT

Molecular-Programmed Self-Assembly of Homo- and Heterometallic Tetranuclear Coordination Compounds: Synthesis, Crystal Structures, and Magnetic Properties of Rack-Type CuII2MII2 Complexes (M = Cu and Ni) with Tetranucleating Phenylenedioxamato Bridging Ligands

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New homo- and heterobimetallic tetranuclear complexes of formula [Cu4(mpba)(Me4en)4(H2O)4](ClO4)4·3H2O (1), [Cu4(mpba)(Me4en)4(H2O)4](PF6)4·2H2O (2), [Cu4(ppba)(Me4en)4(H2O)4](ClO4)4·2H2O (3), [Cu4(mpba)(dipn)4](ClO4)4·3H2O (4), [Cu4(ppba)(dipn)4](ClO4)4·2H2O (5), and [Cu2Ni2(ppba)(dipn)4(H2O)2](PF6)4 (6) [mpba = N,N′-1,3-phenylenebis(oxamate), ppba = N,N′-1,4-phenylenebis(oxamate), Me4en = N,N,N′,N′-tetramethylethylenediamine, and dipn = dipropylenetriamine] have been synthesized and structurally and magnetically characterized. Complexes 1−6 have been prepared following a molecular-programmed self-assembly method, where a heteropolytopic tetranucleating phenylenedioxamato bridging ligand (L = mpba or ppba) is bound to four metal ions of identical or different natures (M = CuII and/or NiII) with partially blocked coordination sites by bi- or tridentate polyamine terminal ligands (L′ = Me4en or dipn). The structures of 1−6 consist of cationic tetranuclear CuII2MII2 entities with an overall 4R rack-type arc...