79682-03-4Relevant academic research and scientific papers
Crystal and molecular structure of dipolar spin-coupled dimers of an irregularly pentacoordinate copper(II) complex, [Cu(5-MeIin)(DBM)]
Addison, Anthony W.,Burke, Philip J.,Henrick, Kim
, p. 60 - 63 (2008/10/08)
Ternary complexes of copper(II) with the anions of dibenzoylmethane (II) and 1,3-bis(2-pyridylimino)isoindolines were synthesized. Mononuclear pentacoordinate structures are assigned to the compound III with the 5-methylpyridyl ligand (I) as well as the 4-methylpyridyl and nonmethylated complexes V and IV. The X-ray crystal structure of the 5-methylated complex III attributes it to the space group P21/n, with a final R factor of 0.047. The coordination geometry is neither square pyramidal nor trigonal bipyramidal but an intermediate structure, in which the more distant of the dibenzoylmethanate oxygen atoms could be considered to approximate the axial donor of a square pyramid. The 5-methylated complex, III, packs uniquely in the crystal lattice as symmetry-related pairs of molecules, in which the isoindolinate ligands are cofacial, with a Cu-Cu separation of 4.453 ?. Within this noncovalent dimer, a spin-exchange process operates, so that the solid state of III exhibits the electron spin resonance spectrum of a spin-coupled triplet system, though the susceptibility obeys a Curie-Weiss law above 77 K. All of III-V are irregularly pentacoordinate in nondonor solvents.
