A new nickel(II) coordination polymer derived from [Ni(N,N-ethylenebis(1,1,1-trifluoroacetylacetoneiminato)] and 1,4-diazabicyclo[2.2.2]octane

The presence of two electron-withdrawing CF3 groups in [Ni{N,N-ethylenebis(1,1,1-trifluoroacetylacetoneiminato)}] (NiL) has been demonstrated to promote axial coordination by pyridine (Py) ligands to form the corresponding octahedral base adduct complex in the solid state, while the corresponding solid products do not form in the absence of the CF3 groups. The change to octahedral geometry is accompanied by a spin-state change of the nickel from low- to high-spin. The structure of the octahedral product, [NiL(Py)2], has been confirmed by X-ray diffraction. In an extension of this study, [NiL] was reacted with the difunctional (stronger) base 1,4-diazabicyclo[2.2.2]octane (dabco); the X-ray structure of the product confirmed the formation of a one-dimensional coordination polymer in which dabco axially bridges [NiL] units in a highly linear fashion. This product represents an example of a new class of one-dimensional polymeric structures in which a difunctional base (in this case dabco) links square planar [NiL] units of the present type.