Synthesis, Crystal Structure, and Chronotropic Properties of Mixed-Ligand Nickel(II) Complexes with 1,3-Diketonate and P-N Bidentate Ligands

摘要

Mixed-ligand nickel(II) complexes Ni(acac)(dmap)X, [Ni(acac)(dmap)]BPh4 (1), [Ni(acac)(dmap)]BF4 (2), and [Ni(acac)(dmap)NO3] (3) (where acac = acetylacetonate and dmap = 1-dimethylamino-2-diphenylphosphinoethane) have been obtained for the first time and their X-ray single-crystal structures have also been determined. This series of complexes show different structures, hence colors, in the solid state depending on the coordination strength of the anion X~-: the complexes with tetraphenylborate and tetrafluoroborate having no coordination ability are square-planar and orange, while on the contrary, the coordinating nitrate ligand produces an octahedral and pale blue complex. In solution, two types of solvatochromism due to solute-solvent interaction and solute-solute-solvent interaction have been observed and these spectral behaviors are attributed to the changes in their geometries due to the donor/acceptor properties of the solvents. The thermochromic behavior of complex 1 has also been studied with temperature variation UV-vis spectra in various solvents. The behavior of these solvato- and thermo-chromisms of these complexes is due to the intermediate ligand field strength created by the dmap and the acac ligands.