Synthesis and magnetic properties of binuclear complexes of unidentate ligands with acetylacetonates of bivalent manganese, cobalt, and nickel

Abstract

The magnetic properties of the binuclear complexes [M₂L(acac)₄][M = Mn, L = dimethylformamide (dmf); M = Co or Ni, L = pyridine (py); acac = acetylacetonate] and [M₂L₂(acac)₄][M = Mn, L = allylamine; M = Co, L = cyclohexylamine; M = Ni, L = piperidine (pip)] have been studied in the range 4–300 K. The complex [Ni₂(py)(acac)₄] is ferromagnetic but [Ni₂(pip)₂(acac)₄] is antiferromagnetic. The cobalt and manganese compounds have magnetic moments similar to those of monomeric octahedral complexes. The results are interpreted in terms of current theories of magnetic exchange, and related to the structures of the complexes. The preparation and characterization of the new complexes [Ni₂(3Me-py)(acac)₄](3Me-py = 3-methylpyridine), [Ni₂(4Me-py)-(acac)₄], [Ni₂{N(C₆H₁₁)H₂}₂(acac)₄], and [M₂(NPhH₂)₂(acac)₄](M = Co or Ni) are described.