Mixed ligand complexes of beta-diketonates: synthesis, characterization, and FAB mass spectral analysis

摘要

Complexes of the type MLL' CENTRE DOT NB (where M = Ni(II) and Cu(II); LH and L'H = 2,4-pentanedione (acacH), 1-phenyl-1,3-butanedione (bacH), and l,3-diphenyl-l,3-propanedione (dbmH); n = 0 to 2 and B = water or pyridine) have been synthesized and characterized. IR spectra are consistent with uninegative bidentate ligands. Magnetic moments and electronic spectral studies reveal high-spin octahedral geometry for nickel(II) complexes and distorted octahedral stereochemistry for copper(II) complexes. Frozen chloroform solution ESR spectra of the copper(II) complexes display significant Jahn-Teller distortion and dimeric behavior of the complexes in solution. FAB mass spectra of the copper(II) complexes also exhibit peaks corresponding to dimers. Molecular, pseudo-molecular, dimeric pseudo-molecular, and fragment ion peaks in unit resolution mass spectra have been identified with the help of their isotope distribution pattern expected due to natural abundances of the ~(63)Cu and ~(65)Cu isotopes. All the FAB mass spectral peaks from the fragment ions containing copper have been interpreted on the basis of isotope distribution pattern.