Complexes of the 1,3-bis(2-arylimino)benz(f) isoindoline ligand including the crystal structure of the Cu(II) acetate complex

The new BAII ligand 1,3-bis(2-pyridylimino)benz(f) isoindoline, NBAII, has been synthesized and Zn(II), Ni(II) and Cu(II) complexes with the formula (NBAII)MX (where X = OAc- for Cu(II) and Ni(II) and X = CI-for Pd(II)) have been prepared. The Ligand and complexes have been characterized by H-1-NMR spectroscopy, infrared spectroscopy and electronic absorption spectroscopy. The NBAII Ligand can accommodate both planar and distorted tetrahedral geometries in these cases. The quadruply-bonded complex (NBAII)Mo-2(OAc)(3) has also been prepared. It was found to exhibit an unusual bonding mode for the NBAII ligand. The molecular structure of the Cu(II) compound was determined by single crystal x-ray diffraction techniques: (NBAII)Cu(OAc) crystallizes in the centrosymmetric space group C2/m with a = 20.256(4) Angstrom, b = 16.166(3) Angstrom, c = 7.915(2) Angstrom, alpha = 90 degrees, beta = 94.83(2)degrees, gamma = 90 degrees, V = 2583(1) Angstrom(3) and Z = 4. The structure of this complex is compared to that of (BAII)Cu(OAc) which has been used as a model for the copper containing enzyme galactose oxidase. The addition of the benzo portion to BAII to give NBAII apparently increases electron density on the Cu(II) ion, disfavoring coordination of water and favoring a coordination number of four.