PREPARATION AND SPECTRAL STUDY OF MIXED-LIGAND NICKEL(II) CHELATES CONTAINING N-METHYLATED OR N,N'-METHYLATED ETHYLENEDIAMINES AND TROPOLONATE OR HINOKITIOLATE LIGANDS

Eleven mixed-ligand chelates of Ni(II) containing a molecule of N,N-di -, N,N,N'-tri-, or N,N,N',N'-tetramethylethylenediamine, and a tropolo nate (trop) or hinokitiolate (hino) ligand, were prepared, and their e lectronic spectra in solid state and in various organic solvents were studied. Most systems studied were green, containing octahedral chelat e species [Ni(trop/hino) (diamine) (H2O/Solvent)(2)](+) or [Ni(NO3) (t rop/hino)-(diamine)], but some were red, containing square planar [Ni( trop/hino) (diamine)](+), and an equilibrium between the octahedral an d square planar species was sometimes observed in solutions. Strong sp ectral resemblances with the corresponding diamine-beta-diketonate che lates of Ni(II) could be pointed out. (C) 1998 Elsevier Science Ltd. A ll rights reserved.