An Investigation of Z-in Distortion in Mononuclear Cu(II) Complex with Terpyridine Ligands, [Cu(terpy)2](PF6)2

The first crystal structure of  [Cu(terpy)2](PF6 )2 , where terpy=2,2':6',2"-terpyridine is reported. Green crystals of  [Cu(terpy)2](PF6 )2 were grown by ether diffusion into an acetonitrile solution of the complex. Crystal structure of this complex is tetragonal ( space group: P21c ) with a = 8.8916(3), c = 20.0214(13) Å, and z = 2. The structure was refined by using 1828 independent reflections with I > 2σ(I) to a R  factor of 0.0809. The terpy ligands are tridentate and linked to the Cu(II) via three N atoms. The CuN6 entities have compressed octahedral geometry with the shortest Cu-N bonds that form the axial positions. This complex represents z-in distortion at 293K and has a D2d point group. The effective magnetic moment ( μeff ) of  [Cu(terpy)2](PF6 )2  was measured to be 1.95BM by Evans method. Cyclic voltammetry experiment of the complex shows that the Cu(II/I) couple is quasi-reversible.