Self-assembled [2 × 1 + 1 × 2] heterotetranuclear CuII3MnII/CuII3CoII and [2 × 2 + 1 × 3] heptanuclear CuII7 compounds derived from N,N′-o-phenylenebis(3-ethoxysalicylaldimine): Structures and magnetic properties

The mononuclear copper(II) compound [CuIIL1⊂(H2O)] (1) derived from the hexadentate Schiff base compartmental ligand N,N′-o-phenylenebis(3-ethoxysalicylaldimine) (H2L1) has been characterized from its IR spectrum as an inclusion product. Reaction of 1 with Cu(ClO4)2 · 6H2O leads to the formation of an interesting [2 × 2 + 1 × 3] heptanuclear copper(II) complex [{CuIIL1CuII(H2O)3}2 {CuIIL1}3](ClO4)4 · 2CH3COCH3 (2), in which two monophenoxo-bridged dinuclear [CuIIL1CuII(H2O)3]2+ cationic units are self-assembled and cocrystallized with three mononuclear [CuIIL1] complex units through the hydrogen bonded web formed between the coordinated water molecules and the phenoxo/ethoxy oxygens. Similar reactions of 1 with Co(ClO4)2 · 6H2O or Mn(ClO4)2 · 6H2O produce the [2 × 1 + 1 × 2] heterotetranuclear complexes [{CuIIL1MII(H2O)3}{CuIIL1}2](ClO4)2 · H2O · CH3COCH3 (M = Co (3), M = Mn (4)) in which one diphenoxo-bridged heterodinuclear [CuIIL1MII(H2O)3]2+ cationic unit is self-assembled and cocrystallized with two mononuclear [CuIIL1] units through hydrogen bonding. The structures of 2 and 4 have been determined. Variable-temperature (2–300 K) magnetic susceptibility measurements of 2–4 have been carried out. In all these cases, the metal centers in the bimetallic units are involved in antiferromagnetic exchange interactions with J = −22.2 cm−1, −16.7 cm−1, and −15.9 cm−1 for 2–4, respectively.

Syntheses, characterization, and magnetic properties of one mononuclear inclusion product [CuIIL1⊂(H2O)], one interesting heptanuclear copper(II) compound [{CuIIL1CuII(H2O)3}2{CuIIL1}3](ClO4)4 · 2CH3COCH3, and two heterotetranuclear CuII3MII compounds [{CuIIL1MII(H2O)3}{CuIIL1}2](ClO4)2 · H2O · CH3COCH3 (M = Co or Mn) derived from the hexadentate Schiff base compartmental ligand N,N′-o-phenylenebis(3-ethoxysalicylaldimine) (H2L1) have been described. Two monophenoxo-bridged dinuclear [CuIIL1CuII(H2O)3]2+ cationic units are self-assembled and cocrystallized with three mononuclear [CuIIL1] complex units in the CuII7 compound, while the tetrametallic complexes consist of cocrystals of one diphenoxo-bridged heterodinuclear [CuIIL1MII(H2O)3]2+ cationic unit and two mononuclear [CuIIL1] moieties. Formation of the mononuclear inclusion product and the dinuclear–mononuclear cocrystals are related to the tendency of a water molecule to be encapsulated in the O4 compartment of the [CuIIL1] moiety.Figure optionsDownload as PowerPoint slide