Synthesis, Crystal Structure, Spectroscopic Property and Redox Behavior of Zinc(II) Complexes Containing Oligoaniline-functionalized Terpyridine Ligands

Two novel mono-nuclear zinc(II) complexes with oligoaniline-functionalized terpyridine ligands have been synthesized and verified by (1)H-NMR, (13)C-NMR, Elemental Analysis (EA) and X-ray Diffraction (XRD). The UV-vis spectra show the ligand-centered (LC) pi-pi* transitions and intra-ligand charge transfer ((1)ILCT) transitions, and the (1)ILCT band red-shifts with the increasing number of aromatic amine groups in the ligands. Complex [Zn(L(1))(2)](PF(6))(2) with an aromatic amine group in ligand shows a strong emission peak at 523 nm in the MeCN solution at 293 K and a blue-shifted band at 517 nm in the alcoholic glass at 77 K. However, for complex [Zn(L(2))(2)](PF(6))(2) containing aniline dimer modified ligand, no apparent emission can be observed in the MeCN solution at room temperature due to a PET non-radiative decay pathway. Both of them show multiplicate redox processes based on oligoaniline and terpyridine units. The shifts of redox potentials also reflect the D-A interactions between the oligoaniline units and [Zn(TPY)(2)](2+) core.