Structural and Spectroscopic Evidence for Marginal Metal‐to‐Ligand Charge Transfer in Complexes Pt(abpy)Me 3 X, abpy = 2,2′‐Azobispyridine, X = Cl, Br, I

The title complexes (X = Cl, 1a ; X = Br, 1b ; X = I, 1c ) could be characterized by 1 H‐NMR spectroscopy and were partially studied by X‐ray diffraction ( 1b,c ), cyclic voltammetry and UV‐Vis spectroscopy ( 1b ). The short N=N bonds of about 1.26Å, the occurrence of only weak charge transfer absorptions in the visible, the rather small shift of the reduction potential, and the small g anisotropy in the EPR spectrum of 1b ˙ − indicate an only a marginal π interaction between the organometallic Pt IV fragments and the excellent π acceptor abpy.