The bidentate diimine-type ligand 2-(3,5-dimethylpyrazol-1-yl)quinoline
forms mono complexes with the bivalent chlorides of iron, cobalt, nickel and
copper. These complexes are magnetically dilute, but electronic spectral data
indicate that, except for the cobalt complex which is tetrahedral, the metal
atoms are five-coordinate and hence a chloro-bridged
structure is proposed. The cobalt(II) complex readily adds a water molecule,
and structure determination by X-ray diffraction shows that the complex aquadichloro[2-(3,5-dimethylpyrazol-1-yl)quinoline]cobalt(II)
is monomeric and five-coordinate, the coordination environment approximating
trigonal bipyramidal.
